Design Considerations for Polyester Construction Stretch Removal and its Impact on Mooring System Design

Polyester based mooring systems offer unique challenges from design, analysis and installation perspective. Non-linear elongation behavior of the fiber is key to these challenges. A good understanding of the fiber elongation characteristics is critical to the design of a robust and efficient mooring system. Mooring systems are one of the primary contributors to the CAPEX of the Floating Production Units (FPU) and the drive to develop cost effective systems has led to improvements/changes to mooring systems. Off-vessel tensioning has been in use for several years, but the option has recently received more in-depth consideration. Off-vessel tensioning is becoming the standard for floating systems with the elimination of on-vessel tensioning systems. The elimination of on-vessel tensioning system brings upon new challenges in terms of mooring line installation and tensioning. A key driver for these systems is the polyester rope pre-load criteria primarily used to remove construction stretch and jump the creep curve that the system may experience. The challenges to each project are unique, however, understanding and assessing the key design impacts will be beneficial to the industry. This paper focuses on the design of a polyester based mooring system with focus on polyester fiber elongation characteristics and its impact on the design and installation. A polyester test program is established to understand the rope elongation behavior and impact of various pre-load levels. Installation assessment is also performed to understand the installation vessel requirements to achieve various pre-loads. Based on the studies, design updates are made to the mooring system and a novel two tension regime mooring system is proposed. Design impact of the two pre-tension system on various design criterions are evaluated and presented in this paper. The paper also makes recommendations on target pre-load and elongation to be considered in systems that do not plan to re-tension their system post installation. Authors appreciate that recommendations and observations reported may not be applicable for all types of floaters and mooring system.

Seismic Design of Offshore Wind Turbines: Good, Bad and Unknowns

Large scale offshore wind farms are relatively new infrastructures and are being deployed in regions prone to earthquakes. Offshore wind farms comprise of both offshore wind turbines (OWTs) and balance of plants (BOP) facilities, such as inter-array and export cables, grid connection etc. An OWT structure can be either grounded systems (rigidly anchored to the seabed) or floating systems (with tension legs or catenary cables). OWTs are dynamically-sensitive structures made of a long slender tower with a top-heavy mass, known as Nacelle, to which a heavy rotating mass (hub and blades) is attached. These structures, apart from the variable environmental wind and wave loads, may also be subjected to earthquake related hazards in seismic zones. The earthquake hazards that can affect offshore wind farm are fault displacement, seismic shaking, subsurface liquefaction, submarine landslides, tsunami effects and a combination thereof. Procedures for seismic designing OWTs are not explicitly mentioned in current codes of practice. The aim of the paper is to discuss the seismic related challenges in the analysis and design of offshore wind farms and wind turbine structures. Different types of grounded and floating systems are considered to evaluate the seismic related effects. However, emphasis is provided on Tension Leg Platform (TLP) type floating wind turbine. Future research needs are also identified.

FLOATING DRUG DELIVERY SYSTEM OF NSAIDS TO INCREASE GASTRIC RETENTION TIME IN UPPER PART OF GASTROINTESTINAL TRACT: A REVIEW

Floating drug delivery system was to organize the recent journalism with unique focus on the principal mechanism of floatation to achieve gastric retention. The recent developments of FDDS including the physiological and formulation variables affecting gastric retention, approaches to design single unit and multiple unit floating systems. In the recent decades, there have been numerous attempts to overcome the barrier like short gastric residence times and unpredictable gastric emptying times. This review also summarizes the in –vitro technique of evaluation, all the pre-formulation and post formulation evaluations criteria. These systems are useful to several problems encountered during the development of pharmaceutical dosage form. In this review, the technologies of formulation and mechanism of drug release, advantage, application in drug delivery of floating systems are discussed.

HYDRO-PHYSICAL CHARACTERISTICS OF SUBSTRATES FOR LETTUCE PRODUCTION IN FLOATING GROWTH SYSTEM

HYDRO-PHYSICAL CHARACTERISTICS OF SUBSTRATES FOR LETTUCE PRODUCTION IN FLOATING GROWTH SYSTEM ALEX BECKER MONTEIRO1; IVAN DOS SANTOS PEREIRA2; ADILSON LUÍS BAMBERG3; CRISTIANE MARILIZ STÖCKER4; PABLO LACERDA RIBEIRO5 E LUÍS CARLOS TIMM6 1Departamento de Solos, Universidade Federal de Pelotas, Campus Universitário, s/n, CEP 96160-000, Pelotas, Rio Grande do Sul, Brasil, [email protected]. 2Departamento de Solos, Universidade Federal de Pelotas, Campus Universitário, s/n, CEP 96160-000, Pelotas, Rio Grande do Sul, Brasil, [email protected]. 3Embrapa Clima Temperado, Rodovia BR 392, km 78, 9º Distrito, CEP 96010-971, Pelotas, Rio Grande do Sul, Brasil, [email protected]. 4Departamento de Fitotecnia, Universidade Federal de Pelotas, Campus Universitário, s/n, CEP 96160-000, Pelotas, Rio Grande do Sul, Brasil, [email protected]. 5Departamento de Solos, Universidade Federal de Pelotas, Campus Universitário, s/n, CEP 96160-000, Pelotas, Rio Grande do Sul, Brasil, [email protected]. 6Departamento de Engenharia Rural, Universidade Federal de Pelotas, Campus Universitário, s/n, CEP 96160-000, Pelotas, Rio Grande do Sul, Brasil, [email protected]. 1 ABSTRACT The objective was to evaluate the hydro-physical properties of different substrates and their effects on the development of lettuce seedlings in a floating system. The study was carried out in a greenhouse during the months of January and February of 2017. The design was randomized blocks with 16 treatments, represented by 13 proportions of substrates based on organic fertilizer, carbonized rice husk and vermiculite, and three other commercial substrates. The hydro-physical characteristics (granulometric fraction, dry bulk density, total porosity, aeration space, easily available water, available water, remaining water and water retention capacity), pH, and electrical conductivity of the substrates were evaluated. Number of leaves, plant height, root system length, fresh mass of root and shoot and dry mass of root and shoot were evaluated at 25 days after emergence. Aeration space and remaining water are the priority hydro-physical variables that should be evaluated in substrates that will be used in floating systems. The formulations with 33.33% organic fertilizer, 43.33 to 53.33% of carbonized rice husk, and 23.33 to 13.33% vermiculite presented the best performance among the substrates studied for the production of seedlings lettuce in floating systems. Keywords: Lactuca sativa L., carbonized rice husk, organic compost. MONTEIRO, A. B.; PEREIRA, I. S.; BAMBERG, A. L.; STÖCKER, C. M.; RIBEIRO, P. L.; TIMM, L. C. CARACTERÍSTICAS FÍSICO-HÍDRICAS DE SUBSTRATOS PARA A PRODUÇÃO DE MUDAS DE ALFACE EM SISTEMA FLOATING 2 RESUMO O objetivo foi avaliar as propriedades físico-hídricas de diferentes substratos e seus efeitos no desenvolvimento de mudas de alface em sistema floating. O estudo foi realizado em casa de vegetação durante os meses de janeiro e fevereiro de 2017. O delineamento foi de blocos casualizados, com 16 tratamentos, representandos por 13 proporções de substratos à base de composto orgânico, casca de arroz carbonizada e vermiculita e três substratos comerciais. Foram avaliadas as características físico-hídricas (fração granulométrica, densidade seca, porosidade total, espaço de aeração, água facilmente disponível, água disponível, água remanescente e capacidade de retenção de água), pH e condutividade elétrica dos substratos. O número de folhas, altura das plantas, comprimento do sistema radicular, massa fresca de raiz e parte aérea e massa seca de raiz e parte aérea foram avaliados aos 25 dias após a emergência. O espaço de aeração e a água remanescente são as variáveis físico-hídricas aprioritárias que devem ser avaliadas em substratos que serão utilizados em sistema floating. As formulações com 33,33% de composto orgânico, 43,33 a 53,33% de casca de arroz carbonizada, e 23,33 a 13,33% de vermiculita apresentaram os melhores desempenhos entre os substratos estudados para a produção de mudas de alface em sistema floating. Palavras-chave: Lactuca sativa L., casca de arroz carbonizada, composto orgânico.

The Influence of the Cuboid Float’s Parameters on the Stability of a Floating Building

Usually, the concept of sufficient stability of a floating structure is connected with the capacity to keep a small heel angle despite the moment of heeling. The variable responsible for these characteristics is the initial metacentric height, which is the relation between the hydrostatic features of the pontoon and the mass properties of the entire object. This article answers the questions of how heavy the floating system should be, what the minimum acceptable draft is, and whether it is beneficial to use internal fixed ballast. To cover various technologies, a theoretical model of a cuboid float with average density representing different construction materials was analysed. The results indicate that the common practice of using heavy and deep floating systems is not always reasonable. In the case of floating buildings, which, unlike ships, can be exploited only under small heel angles, the shape and width of the submerged part of the object may influence the stability more than the weight or draft.