Research Publications

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    Need of natural biocides in antifouling paints for prevention of marine pollution
    (International Journal of Innovation Research & Development, 2015-07) Joshi, Madhu; Mukherjee, A.; Misra, S. C.; Ramesh, U. S.
    "Antifouling paints were developed to prevent marine growth on ship hulls in the middle of the 19th century. As they were designed to continuously leach biocides at the paint/seawater interface which were the predominant means of controlling fouling for a vast majority of the vessels, over a period of years in the latter part of the last century there has been a marked improvement in the effective life of antifouling paints. Different types of antifouling paints came into being but after a particular breakthrough when self- polishing paints were developed in 1960s. Due to its controlled leaching rate, the self -polishing paints containing TBT was a huge success. However, due to serious environmental effects, these paints have been banned since 2008 and have been replaced by copper based antifouling paints with some success. It was observed that the extensive use of copper based antifouling paints has led to the accumulation of copper and its compounds in the marine environment particularly in the vicinity of ports and harbors and is beginning to pose a serious environmental problem. Foul release coatings are biocide-free –works on a foul release basis by providing a very smooth, low-friction surface which reduce the strength of adhesion of fouling. However, they are applicable only to high- speed, high-activity vessels, in addition to other issues such as high cost, difficult, application procedure and are easily prone to mechanical damage. Biocides from natural products appear to be the only viable alternative in the foreseeable future to protect ship hulls from fouling. This paper reviews the possible natural products that have the potential to be incorporated in to commercial antifouling paints and explores their range of activity"
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    Information needs and usage pattern in maritime industry - Considerations & need for setting up a national documentation centre for maritime information
    (International Journal of Innovation Research & Development, 2015-07) Padmashree, S.; Ramesh, U. S.
    In any field of study, R & D requires information and information resources and services, through which National development is directly affected. Keeping in view the maritime information needs of our country by government establishments, the industry and the corporate sector an attempt has been made in this paper to show the need for setting up of a “National Documentation Centre for Maritime Information”. The model design of NDCMI and its possible services have been sketched out for further review and suggestions from its stakeholders.
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    Analysis of antifouling paints using drum test apparatus
    (RINA, 2015-12) Joshi, Madhu; Mukherjee, A.; Misra, S. C.; Ramesh, U. S.
    Ship has been recognized as a major factor in introduction of non-native and harmful organisms which causes deleterious effects on the performance of the vessel. More than 70% of Invasive species worldwide have found to be due to hull fouling. To mitigate fouling, underwater parts of the vessels are coated with antifouling paints. Antifouling paints provide foul-free hulls up to a maximum of 95 % of the vessels underwater area. There are a number of types of these paints but “self-polishing coatings” are predominantly preferred by the shipping industry. In these types of coatings, a thin layer of biocide containing paint (typically 2 to 5 microns/month) is leached or “polished” away. This polishing action primarily depends on the hydrodynamic surface forces on the vessels hull. The higher the fluid velocity, the higher are the polishing rate. Certain areas of the vessel such as near the bow, stern, etc experience higher fluid velocity and therefore higher polishing rates thereby resulting in premature fouling. Conversely, areas where the flow rates are considerably smaller would experience lesser polishing rates which would result in insufficient amount of biocides being delivered which would again result in premature fouling. In order to study and estimate the polishing rates of Anti Fouling paint we have designed, fabricated a rotating drum test facility .Wall shear stress are to be calculated by CFD methods
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    Some statistical relationships among dredger particulars observed in the indian dredging fleet
    (International Conference on Ship and Offshore Structures, 2015-12) Arun Kishore, Eswara; Ramesh, U. S.
    "Cutter suction dredgers(CSD), Trailing suction hopper dredgers (TSHD) and Grab dredgers form 88% of the total Indian fleet size, respectively in the order of individual share. Indian yards have achieved 90% indigenization in design and construction of grab hopper dredgers. However, there is a techno-economic backlog in India to manufacture some vital components for CSDs and TSHDs and companies are increasingly looking to buy foreign made dredgers at a high price. Dredging demand in India at ports and in navigable inland water ways is set to grow with the encouragement for water transport. Ministry of Shipping, Govt. of India has sponsored studies at Indian Maritime University – Visakhapatnam (formerly, NSDRC) for indigenization of dredger design and manufacture. The present paper aims to illustrate the existing dredger fleet of India and bring out some interesting correlations or conclusions that aid the design of dredgers. Dredgers are built for a specific function. Due to this design objective, they differ from other marine vessels on the aspects of principle particulars, hopper capacities, powering and other functional data such as cutter power for CSD and dredge pumps power etc. The identified correlations among a few parameters observed from the Indian dredging fleet are discussed. Certain ratios among the main dimensions for a TSHD such as length/breadth, breadth/dredge depth and breadth/draught, also known as ship ratios, are a key to dredger design and are known to vary with market conditions or time. They indicate design trends for future dredgers and require to be kept updated. "
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    Energy saving strategy on electric propulsion system integrated with doubly fed asynchronous motors
    (IEEE, 2016-11) Singh, Raja R.; Chelliah, Thanga Raj; Khare, Deepak; Ramesh, U. S.
    Electric propulsion system integrated with doubly-fed asynchronous motor contributes efficient characteristics and flexibility in operation. However, in perception of energy saving and full-scale speed variation, the conventional doubly fed asynchronous motor is limited by the ratings of power converters. Generally, the electrical machines are designed to attain maximum efficiency around the full load. To increase energy saving and operating speed range under lightly loaded condition, the proposed strategy injects a low voltage DC supply to the stator winding instead of full rated AC supply. Wherein the DC supply is obtained from the converter's DC-link instead of external source. The proposed system is mathematically modelled using Matlab/Simulink tool and implemented experimentally with a 2.2 kW doubly fed asynchronous motor. In addition to this, the comparative energy conservation analysis of an electric propulsion system (2 MW) with the proposed strategy is carried out as a case study.
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    Control strategy for fuel saving in asynchronous generator driven electric tugboats
    (IEEE, 2016-12) Anil Kumar, B.; Anil Kumar, K.; Radha, T.; Chelliah, Thanga Raj; Khare, Deepak; Ramesh, U. S.
    Usually electric tugboats are equipped with diesel engine based electric generator for power production, battery for supplying power to auxiliary loads and electric motors for propulsion. This paper proposes control strategies for diesel engine and electric generators used in electric tugboat to improve energy efficiency of the system. Doubly fed induction machine (DFIM), asynchronous in nature, is considered in this research which serves as generator (power production). The speed of diesel engine is controlled in accordance with the power demanded by the tug. Output voltage and frequency of generator during sub-synchronous operation are regulated by controlling its rotor current with the help of power electronic convertors. Comparison of fuel consumption at fixed and variable speeds of operation is performed. From the test results, it is observed that the variable speed operation of diesel generator offers significant reduction in fuel consumption.
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    The prostects of dredging and indigenization of dredger design
    (Dredge Yard, 2015-06) Arun Kishore, Eswara; Ramesh, U. S.
    The scope for dredging in India is potentially vast, looking at the prospects of development and maintenance of existing major ports, building new ports, o_shore resources exploration, demand from navy and more interestingly the projects envisaged for national waterways. The capital dredging demand during 2012-2017 is about 639 million m3 and that of maintenance dredging during the same period is about 521 million m3. This requires the employment of substantial number of dredgers of varying capacities. The minor sector dredging demand of about 100 million m3, during the said period, oers additional opportunity for dredging. The modal shift of cargo to inland and coastal waterways o_ers bright prospects for a sustainable economic prosperity. The government encouragement for \Make in India" has brought in a lot of economic interest as well. This is an excellent period to target for indigenization of dredger manufacture. Locally manufactured dredgers not only reduce costs of dredging but also encourage business climate. Further, it will enable India to produce globally competitive world class dredgers. The present paper is written in this context of presenting our study encompassing the scope for dredging activity, identifying suitable types and capacities of dredgers for employment in India. The paper also touches upon the present shipbuilding infrastructure, dredger equipment manufacturers and a road map for indigenization. The paper concludes with forecasting future dredging demands, scope for native dredgers manufacture, identifying a particular target range for indigenization.
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    Failure analysis of antifouling paints on ships hull
    (NISCAIR-CSIR, India, 2014-11) Joshi, Madhu; Mukherjee, A.; Misra, S. C.; Ramesh, U. S.
    Fouling on ships hull occurs due to the attachment of barnacles, mollusks and other aquatic organisms on the underwater area of the hull. This leads to increased drag, fuel consumption, resulting in unscheduled dry-docking. Recent advances in antifouling (AF) paints, in general, offer protection against fouling in about 95 % of the vessels immersed surface. However, the remaining area which amounts to 5% or less of the total area does get fouled. Although this level of fouling has marginal impact on the routine performance of the vessel, it is a predominant vector for the transmigration of invasive species which is a serious environmental concern. Virtually all ocean going vessels are coated with antifouling paints, predominant among them are “Self polishing coatings”. These coatings depend on the shear forces on the hull surface caused by the motion of the vessel for the paint to “polish” away and release a biocide at a predetermined rate that results in the hull to be essentially fouling free. Currently hulls are coated with a uniform layer of antifouling paints. However, computational fluid dynamics (CFD) analysis conducted on various types of vessels have indicated that there are certain “hotspots” where shear stresses and therefore the polishing rates are exceedingly high which would polish the AF paints at a much faster rate and ultimately result in the failure of the AF coating. The analysis also indicates that these hotspots primarily depend on the profile of the vessels, its speed and its draft. The current practice of a uniform coat of AF paint does not take into account the fact that there are certain areas of the vessel where the polishing rates are excessive. A possible solution to this issue is to first identify these hotspots and suitable paint schemes/formulations are to be applied in these areas. Such painting schemes would prevent the premature failure of the AF coating in general and significantly reduce the risk of transmigration of invasive species.
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    Natural biocides in antifouling paints
    (International Conference on Ship and Offshore Technology : Technological Innovations in Ship Building, 2013-12) Joshi, Madhu; Mukherjee, A.; Misra, S. C.; Ramesh, U. S.
    Since the 1970’s Tributy tin based antifouling (AF) paints were widely used to control fouling on ships hulls. These coatings offered up to 5 years of foul-free hulls and were the most effective antifouling paints ever produced. However, due to serious environmental effects, these paints have been banned since 2008 and have been replaced by copper based antifouling paints with some success. However, the extensive use of copper based antifouling paints has led to the accumulation of copper and its compounds in the marine environment particularly in the vicinity of ports and harbors and is beginning to pose a serious environmental problem. Restrictions on the use of copper based AF paints have been initiated by many western countries and it is expected that these restrictions would only grow in the years to come. In addition, these coatings are usually incorporated with “booster biocides” such as Diuron, Irgarol, Seanine, etc to improve their efficacy. The booster biocides also significantly contribute to the existing environmental concerns. The search is therefore on for a “benign AF product” that affects target organisms only and exhibits low persistence in the aquatic environment. A few natural produces fill in to these requirements. In the Indian context, Neem and Karanjin exhibit biocidal properties which could be tapped as effective AF agents. This paper reviews the various natural products that show promise as AF agents and explores the possibility of incorporating these products in AF paint formulation.
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    Introduction to natural gas : A comparative study of storage, fuel costs and emissions for a harbor tug
    (SNAME Maritime Convention, 2013-11-08) Arun Kishore, Eswara; Misra, S. C.; Ramesh, U. S.
    This paper discusses the science of natural gas, its composition and ways to determine and coherently express its physical and chemical properties. Pricing of natural gas is shown with regard to weight and energy. A 60 Ton harbor tug employing either a set of constant rpm engines for CPP operation, or a set of variable rpm engines for FPP operation, with a standard load profile is made the basis for discussion. Advantage of evaluating thermal efficiency of gas engines relative to the higher heating value of natural gas, as against its lower heating value is explained. A compendium of storage options and the resulting endurance with the use of natural gas forms such as liquified gas (LNG), compressed gas (CNG) and adsorbed gas (ANG) is presented. Steps to ascertain fuel consumption of the gas engines operated according to the load profile and an approach to evaluate and relate the quantities of LNG, CNG and ANG is shown. Fuel costs and emissions from the tug operation using natural gas as fuel are evaluated per month and compared with diesel and residual fuels. Green House Gas emissions as a summation of emission constituents from the natural gas fuelled tug operation is detailed, and its need emphasized. The concepts of useful work done, emission efficiency parameter and energy efficiency parameter, which may be helpful in the design of harbor tugs and similar service vessels are proposed. The emission efficiency parameter is evaluated and analyzed for the 60 ton harbor tug.