Lalaja, V; Nampoori, V P N; Pratap, R(Kluwer Academic Publishers, February , 1989)
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Abstract:
The theory of deterministic chaos is used to study the three rings A, B, and C of Saturn and the French and Cassini divisions in between them. The data set comprises Voyager photopolarimeter measurements. The existence of spatially distributed strange attractors is shown, implying that the system is open, dissipative, nonequilibrium, and non-Markovian in character.
Vinu, Thomas; Dr.Mathew, K T(Cochin University of Science & Technology, September , 2008)
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Abstract:
Electromagnetic tomography has been applied to problems in
nondestructive evolution, ground-penetrating radar, synthetic aperture
radar, target identification, electrical well logging, medical imaging
etc. The problem of electromagnetic tomography involves the
estimation of cross sectional distribution dielectric permittivity,
conductivity etc based on measurement of the scattered fields. The
inverse scattering problem of electromagnetic imaging is highly non
linear and ill posed, and is liable to get trapped in local minima. The
iterative solution techniques employed for computing the inverse
scattering problem of electromagnetic imaging are highly computation
intensive. Thus the solution to electromagnetic imaging problem is
beset with convergence and computational issues. The attempt of this
thesis is to develop methods suitable for improving the convergence
and reduce the total computations for tomographic imaging of two
dimensional dielectric cylinders illuminated by TM polarized waves,
where the scattering problem is defmed using scalar equations. A multi
resolution frequency hopping approach was proposed as opposed to
the conventional frequency hopping approach employed to image large
inhomogeneous scatterers. The strategy was tested on both synthetic
and experimental data and gave results that were better localized and
also accelerated the iterative procedure employed for the imaging. A
Degree of Symmetry formulation was introduced to locate the scatterer
in the investigation domain when the scatterer cross section was
circular. The investigation domain could thus be reduced which
reduced the degrees of freedom of the inverse scattering process. Thus
the entire measured scattered data was available for the optimization of
fewer numbers of pixels. This resulted in better and more robust reconstructions of the scatterer cross sectional profile. The Degree of
Symmetry formulation could also be applied to the practical problem
of limited angle tomography, as in the case of a buried pipeline, where
the ill posedness is much larger. The formulation was also tested
using experimental data generated from an experimental setup that was
designed. The experimental results confirmed the practical
applicability of the formulation.
Description:
Department of Electronics,
Cochin University of Science and Technology
Sathiyamoorthy,V; Dr.Mohan Kumar, K(Department of Atmospheric Sciences, 2001)
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Abstract:
The aim of the present study is to understand the biennial scale stratosphere-troposphere interactions over India, and synoptic to interannual timescale meridional stratosphere-troposhere exchanges caused by upper tropospheric/lower stratospheric longwaves using NCEP/NCAR reanalysis data and satellite measured total ozone data. The biennial timescale interaction between lower stratosphere and troposphere over Thumba is analysed using high-resolution radiosonde data. The results suggest that TBO and QBO are two different phenomena with nearly biennial periodicity. Interannual timescale meridional stratosphere-troposphere exchanges caused by the newly documented Asia Pacific Wave (APW) were analysed using ozone as tracer of atmospheric motion. Synoptic timescale meridional stratosphere-troposhere exchanges caused by subtropical upper tropospheric long waves over Asia were studied using global total ozone measurements from TOMS. This research work can be extended to study the influence of decadal scale epochal nature in Indian summer monsoon activity on the APW generated total ozone anomalies around the globe and the trend estimates in total ozone
Job, Thomas; Biswarup, Saikia; Phanindra, Kumar; Nanjunda Rao, K S; Ananth, Ramaswamy(Elsevier, September 20, 2006)
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Abstract:
Glass fiber reinforced polymer (GFRP) rebars have been identified as an alternate construction material for reinforcing concrete
during the last decade primarily due to its strength and durability related characteristics. These materials have strength higher than steel,
but exhibit linear stress–strain response up to failure. Furthermore, the modulus of elasticity of GFRP is significantly lower than that of
steel. This reduced stiffness often controls the design of the GFRP reinforced concrete elements. In the present investigation, GFRP reinforced
beams designed based on limit state principles have been examined to understand their strength and serviceability performance. A
block type rotation failure was observed for GFRP reinforced beams, while flexural failure was observed in geometrically similar control
beams reinforced with steel rebars. An analytical model has been proposed for strength assessment accounting for the failure pattern
observed for GFRP reinforced beams. The serviceability criteria for design of GFRP reinforced beams appear to be governed by maximum
crack width. An empirical model has been proposed for predicting the maximum width of the cracks. Deflection of these GFRP
rebar reinforced beams has been predicted using an earlier model available in the literature. The results predicted by the analytical model
compare well with the experimental data
Description:
Construction and Building Materials 21 (2007) 1709–1719
Manoj, G Tharian; Dr C.G Nandakumar(Cochin University of Science and Technology, March 16, 2015)
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Abstract:
Hat Stiffened Plates are used in composite ships and are gaining popularity in metallic ship
construction due to its high strength-to-weight ratio. Light weight structures will result in greater
payload, higher speeds, reduced fuel consumption and environmental emissions. Numerical
Investigations have been carried out using the commercial Finite Element software ANSYS 12 to
substantiate the high strength-to-weight ratio of Hat Stiffened Plates over other open section
stiffeners which are commonly used in ship building.
Analysis of stiffened plate has always been a matter of concern for the structural engineers
since it has been rather difficult to quantify the actual load sharing between stiffeners and
plating. Finite Element Method has been accepted as an efficient tool for the analysis of stiffened
plated structure. Best results using the Finite Element Method for the analysis of thin plated
structures are obtained when both the stiffeners and the plate are modeled using thin plate
elements having six degrees of freedom per node. However, one serious problem encountered
with this design and analysis process is that the generation of the finite element models for a
complex configuration is time consuming and laborious. In order to overcome these difficulties
two different methods viz., Orthotropic Plate Model and Superelement for Hat Stiffened Plate
have been suggested in the present work.
In the Orthotropic Plate Model geometric orthotropy is converted to material orthotropy
i.e., the stiffeners are smeared and they vanish from the field of analysis and the structure can be
analysed using any commercial Finite Element software which has orthotropic elements in its
element library. The Orthotropic Plate Model developed has predicted deflection, stress and
linear buckling load with sufficiently good accuracy in the case of all four edges simply
supported boundary condition. Whereas, in the case of two edges fixed and other two edges
simply supported boundary condition even though the stress has been predicted with good
accuracy there has been large variation in the deflection predicted. This variation in the
deflection predicted is because, for the Orthotropic Plate Model the rigidity is uniform throughout the plate whereas in the actual Hat Stiffened Plate the rigidity along the line of
attachment of the stiffeners to the plate is large as compared to the unsupported portion of the
plate.
The Superelement technique is a method of treating a portion of the structure as if it were a
single element even though it is made up of many individual elements. The Superelement has
predicted the deflection and in-plane stress of Hat Stiffened Plate with sufficiently good accuracy
for different boundary conditions. Formulation of Superelement for composite Hat Stiffened
Plate has also been presented in the thesis. The capability of Orthotropic Plate Model and
Superelement to handle typical boundary conditions and characteristic loads in a ship structure
has been demonstrated through numerical investigations.
Sarada,S; Sankaranarayanan,K C(School of Management studies, Faculty of Social sciences, 2004)
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Abstract:
The focus of this study is the stress of women entrepreneurs.As stress is associated with constraints and demands, and as a set of emerging conditions seem to affect the quality of life of women, it is more than just an occasional need to enquire in to the possibilities of promoting entrepreneurship by empowering women.As women entrepreneurs are increasingly involved in inherently complicated activities of improving their enterprise functioning ,it would be appropriate for women entrepreneurs to focus on transformational coping interventions.The study is limited to women entrepreneurs in the tiny sector.Women entrepreneurs registered in the Distric Industries ( DIC) and in the Kerala State Women’s Industries Association (KSWIA) are only selected for the study.It gaves a detailed description about empowerment of women.The social , economic ,political,ecological,and psychological importance of the study are detailed.It explains the family related stress, and the contextual system.This study is suggested on beliefs and values of women about their self-perception influencing gender bias, which contribute to stress and coping.This study is also needed about women’s believes and expectations about the probable effectiveness of various course of action and their ability to perform those actions.It is also neede for appraising coping potential of women and enhancing their stress base.It is important to research on stress and self-concept
Sunil,K Narayanankutty(Technomic Publishing Co., Inc., April , 1998)
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Abstract:
The stress relaxation behavior of polyurethane elastomer and
short polyester fiber filled elastomer composites with and without bonding
agents at different strain levels and strain rates was studied. It was found that
these compounds exhibit a multistage relaxation mechanism and that the rate
of relaxation and cross-over time depend on the strain level and strain rate.
The incorporation of fibers reduced the stage-I relaxation rate and increased
the cross-over time of the gum vulcanisate. A higher rate of relaxation (first
stage) was shown by the composites with longitudinal fiber orientation and
composites with bonding agents.
Anupama Nair, P R; Dr.Mohammed Salih,K Y; Dr.Sujatha, C H(Cochin University Of Science And Technology, May , 2008)
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Abstract:
Poisoning by pesticides from agricultural fields is a serious water
pollution problem and its environmental long-term effect may result in the
incidence of poisoning of fish and other aquatic life forms (jyothi and
Narayan, 1999). Fishes like Heteropneustesfbssilis and C/arius batrac/nus are
especially prone to serious pesticide pollution as their habitat is mostly the
agriculture area. Though only few studies are conducted in this area, it can
be assessed from the local information that, population of such fish is on
the verge of vulnerability due to extensive use of pesticides. The knowledge
of sublethal effects of xenobiotic compounds on hematological parameters,
enzyme activities and metabolite concentrations is very important to
delineate the fish health status and provide a future understanding of
ecological impacts. These pesticides act by causing inhibition of
cholinesterase enzymes (ChE) by formation of enzyme inhibitor complex
(O'Brien, 1976) and damaging the nervous system. These effects may result
in metabolic disorders. Associated to cholinesterase activities, a study of
other enzymes such as phosphatases and aminotransferases close to
intermediary metabolite determination provides a wider view of
metabolism. Interest in toxicological aspects has grown in recent years and
research is now increasingly focused on mechanistic aspects of oxidative damage and cellular responses in biological system. The term ‘biomarker’ is
generally used in a broad sense to include almost any measurement
reflecting an interaction between a biological system and a potential hazard,
which may be chemical, physical or biological (WHO, 1993). As biomarker
stands for immediate responses, they are used as early warning signals of
biological effects caused by environmental pollutants.
The present work attempts to assess the toxicity of organophosphorus
insecticide monocrotophos on the experimental organism selected for this
study namely stinging catfish (Heteropneustesfossi/is) (Bloch), and to probe
into the stress responses of the organism
Description:
Department of Marine Biology, Microbiology and
Biochemistry, Cochin University of Science and Technology
Bright Singh, I S; Rosamma, Philip; Rejish Kumar, V J; Cini, Achuthan; Manju, N J(Springer, September 21, 2008)
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Abstract:
For establishing nitrification in prawn (non-penaeid, salinity 10–15 ppt) and
shrimp (penaeid, salinity 30–35 ppt) larval production systems, a stringed bed suspended
bioreactor (SBSBR) was designed, fabricated, and validated. It was fabricated with 5 mm
polystyrene and low density polyethylene beads as the substrata for ammonia and nitrite
oxidizing bacterial consortia, respectively, with an overall surface area of 684 cm2. The
reactors were activated in a prototype activator and were transported in polythene bags to
the site of testing. Performance of the reactors activated with the nitrifying bacterial
consortia AMONPCU-1 (ammonia oxidizers for non-penaeid culture) and NIONPCU-1
(nitrite oxidizers for non-penaeid culture) was evaluated in a Macrobrachium rosenbergii
larval rearing system and those activated with AMOPCU-1 (ammonia oxidizers for penaeid
culture) and NIOPCU-1 (nitrite oxidizers for penaeid culture) in a Penaeus monodon
seed production system. Rapid setting up of nitrification could be observed in both the
static systems which resulted in a higher relative per cent survival of larvae
Description:
Aquacult Int (2009) 17:479–489
DOI 10.1007/s10499-008-9218-2
K G Nair; Mohanan, P; Stephen, Rodrigues(Department of Electronics, 1991)
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Abstract:
Design and development of a new feed -horn antenna
with low sidelobe levels is reported . The E-walls of this
antenna are fabricated with low -loss dielectric substrate , periodically
loaded with thin conducting strips . The antenna is found
to be simulating the radiation characteristics of metallic corrugated
horns . This can be an ideal substitute for metallic corrugated
horns with added advantages like light -weight and low
production cost.
Mohanan, P; K G Nair; Stephen, Rodrigues(Department of Electronics, November , 1991)
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Abstract:
Design and development of a new feed -horn antenna
with low sidelobe levels is reported . The E-walls of this
antenna are fabricated with low -loss dielectric substrate , periodically
loaded with thin conducting strips . The antenna is found
to be simulating the radiation characteristics of metallic corrugated
horns . This can be an ideal substitute for metallic corrugated
horns with added advantages like light -weight and low
production cost.
Design and development of a new feed -horn antenna
with low sidelobe levels is reported . The E-walls of this
antenna are fabricated with low -loss dielectric substrate ,
periodicallyloaded with thin conducting strips . The antenna
is found to be simulating the radiation characteristics of metallic
Corrugated horns . This can be an ideal substitute for metallic
Corrugated horns with added advantages like light -weight and low
production cost
Joseph, V P; Biju Kumar, S; Mathew, K T(John Wiley & Sons, April 5, 2001)
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Abstract:
The radiation characteristics of a new type of hollow dielectric H-plane sectoral horn antenna are presented. Metallic strips of optimum length are loaded on the H-walls of the sectoral horns. The effects of strip loading for producing square patterns in the H plane are discussed.