Fabrication, Launching and Towing of Submerged Production Unit - A Technology Development Project of Subsea7

The demand for fossil fuels drives for an advancement in the existing subsea technology. The developments evolved as the search for hydrocarbons moved from onshore to offshore, followed by a transition from shallow to deep and ultra-deep waters. Another huge milestone was achieved when production systems made a transition from topsides to subsea units for efficiency. That being said, there is an enormous drive to minimize the operational costs involved in the processing of hydrocarbons. Researches are underway towards what would be yet another significant feat in the oil and gas industry, which is by moving the processing systems to subsea. One such impressive concept which is being developed, is the Submerged Production Unit (SPU). This study is an initial attempt to investigate the challenges associated with the SPU focusing on the factors influencing fabrication, launching and towing. This thesis revolves around finding an optimized solution for the challenges associated with the integration of Glass Reinforced Plastic (GRP) and subsea buoyancy material for the assembly, which is one of the main objectives of this thesis. Industrial visits to GRP fabricator, subsea buoyancy material fabricator and the assembly yard coupled with inputs from Subsea 7 engineers, formed the base for this research work. A design concept that goes back and forth from performance and design spaces was used in solving the complexity that revolved around SPU assembly. Analytical Hierarchy Process (AHP), an effective tool dealing with complex decision making was used to decide the best possible location for assembly and launching of the SPU. Finally, OrcaFlex software was used for towing analysis. End force in global X direction on towline, obtained from static analysis was used to identify the Bollard Pull (BP) required for towing the SPU. Dynamic analysis was performed for different environment conditions to identify the maximum effective tension on the towline. The research work resulted in the development of a 3D Joint, using Autodesk Inventor software for the SPU assembly. This joint provided a one way access to connect all the SPU sub assemblies. The AHP suggested the use of syncrolift for launching the SPU by making pairwise comparisons between the yards chosen and the evaluation criteria cost, safety, fabrication facilities and commissioning facilities. BP requirement of 100T was estimated from static analysis. The maximum effective tension experienced on the lead tug towline was 837KN for waves in 180°, wave period of 20s, wave height of 7m along with current in 90°at a speed of 1m/s

Photophysical and charge transport properties of pyrazolines

Pyrazoline, an intense green emitting molecule both in solution and solid state, with extended pi-conjugation has been synthesized via simple two-step reactions in high yields. Having the electron rich pyrazoline moiety with good redox behavior, pyrazolines can be potential candidates for charge transport material in organic electronic devices. UV-Visible absorption spectra of pyrazolines exhibit peaks below 400 nm, which is a desired feature for charge transport materials because it avoids interference with donor absorption that falls in the visible to NIR region. Electrochemical and theoretical studies show that the HOMO energy level lies at around -4.8 to 5.2 eV depending on the substituents, which is in fact compatible with the PEDOT: PSS/P3HT and work function of the ITO electrode. The experimental hole transport value, measured using the hole only device and space charge limited current (SCLC) method, was found to be in the range of 10(-5) to 10(-6) cm(2) V-1 s(-1), depending on the substituents. The maximum hole mobility calculated by theoretical methods for the pyrazolines is 0.75 cm(2) V-1 s(-1)

Assessment of CI Engine Performance and Exhaust Air Quality Outfitted with Real-Time Emulsion Fuel Injection System

The main target of the current research work is effectively eliminating fossil fuel dependency and improving the exhaust air quality of conventional Compression Ignition (CI) engines. This research paper demonstrates for the first time that a nanofluid (water without surfactant) stored in separate tanks can be quantified, collected, and immediately emulsified by a high shear mixer before transfer into the combustion chamber of a diesel engine. The experiment was carried out under different load states (25%, 50%, 75% and 100%) with a constant speed of 1500 rpm. Biofuel was extracted from citronella leaves using an energy-intensive process. The 5% water share was used for preparing the biofuel emulsion and nano-biofuel emulsion. A cobalt chromate nanoadditive was used to make the nanofluid. An experimental investigation was performed with prepared test fuels, namely, ultra-low sulphur diesel (ULSD), 100% Citronella (B100), surfactant-free Diesel emulsion (SDE), surfactant-free bioemulsion (SBE), and Surfactant free nano-bioemulsion (SNBE), in a test engine. The properties of the sample test fuels was ensured according to EN and ASTM standards. The observation performance results show that the SNBE blend exhibited lower BTE (by 0.5%) and higher SFC (by 3.4%) than ULSD at peak load. The emission results show that the SNBE blend exhibited lower HC, CO, NOx, and smoke emissions by 23.86%, 31.81%, 2.94%, and 24.63%, respectively, compared to USD at peak load. The CP and HRR results for SNBE were closer to ULSD fuel. Overall, the novel concept of an RTEFI (Real-time emulsion fuel injection) system was proved to be workable and to maintain its benefits of better fuel economy and greener emissions

Self-assembly of a white-light emitting polymer with aggregation induced emission enhancement using simplified derivatives of tetraphenylethylene

White-light emitting materials and devices have gained a great deal of interest and play an important role in next generation solid-state lighting applications. The unique aggregation-induced emission (AIE) route offers a forthright solution to the bottleneck problem of aggregation caused quenching (ACQ) in the solid state. A significant fluorescence enhancement was realized by tailoring a new luminogen (2Z,2′Z)-3,3′-((9,9-dihexyl-9H-fluorene-2,7-diyl)bis(3,1-phenylene))bis(2-(4-bromophenyl)-3-phenylacrylonitrile) (FBPAN) based on the AIE strategy, which exhibits yellow fluorescence with a high quantum yield of 63.41%. Electroluminescence characteristics with a maximum luminance, current and power efficiency of 16673 cd m−2, 9.32 cd A−1 and 5.88 lm W−1, respectively, were obtained for FBPAN. The white light emitting polymers were obtained by the copolymerization of a 9,9′-dihexylfluorene host with a FBPAN moiety as a covalent dopant. Bright white light emission with a high quantum yield of 80.2% was obtained from the copolymer FBPAN 0.5, which contained 0.5% FBPAN. Importantly, the copolymers exhibit enhanced emission upon aggregation, even at low compositions of FBPAN. A careful inspection reveals that the enhanced emission in the solid state is due to the formation of “J-aggregates” with ordered supramolecular self-assembly. Interestingly, the copolymer FBPAN 0.5 exhibits a unique ordered flower shaped self-assembly and significantly reduces the charge trapping due to balanced charge transport. As a result, bright and high efficiency white light emission was achieved with Commission Internationale de l'Eclairage (CIE) coordinates of (0.32, 0.31) and a maximum luminance, current and power efficiency of 13455 cd m−2, 7.56 cd A−1 and 5.32 lm W−1, respectively. The copolymers possess very low turn-on voltage in the range of 1.5 to 3 V

Prediction of RCCI combustion fueled with CNG and algal biodiesel to sustain efficient diesel engines using machine learning techniques

This study used microalgae biodiesel as a high-reactive fuel directly injected along with various Compressed Natural Gas (CNG) energy shares (10%, 20%, 30%, and 40%) as low-reactive fuel injected into the intake system. The experiments are performed in a single-cylinder, water-cooled, 1500 rpm, 3.5 kW power Compression Ignition (CI) engine under various loading conditions to examine the effects of CNG energy share on performance and emissions in Reactivity Controlled Compression Ignition (RCCI) combustion mode. The study found that the 30%CNG share decreased Nitrogen oxides (NOx) and smoke by 25% and 31%, as well as an increase in thermal efficiency of 4.35% in comparison to traditional biodiesel combustion. Finally, two machine learning (ML) models, namely the Gradient Boosting Regressor (GBR) and LASSO (Least Absolute Shrinkage and Selection Operator) Regression, were developed for predicting the dependent variables individually from the independent variables. Both the LASSO and GBR models achieved high accuracy with R2 values of 0.98–0.99 and relatively low Root Mean Square Error (RMSE) values

White light emitting single polymer from aggregation enhanced emission: a strategy through supramolecular assembly

Aggregation induced emission enhancement (AIEE) is widely regarded as an efficient tool to offset the problem of aggregation caused quenching (ACQ) in luminogens. The ACQ phenomenon in small organic molecules and polymers is detrimental to the performance of OLEDs. Efficient pure white electroluminescent polymers, obtained by the copolymerization of 9,9-dihexylfluorene as a blue host with (E)-2,7-dibromo-9H-fluoren-9-yl-2-cyano-3-(4-(dimethylamino)phenyl) acrylate (FCP) as a yellow emitting covalent dopant with AIEE properties on the main chain of the copolymers, have been designed and synthesized. White light emission was achieved in copolymer FCP 2.5, which contained 2.5% of the AIEE luminogen. Interestingly the copolymers exhibited an enhanced emission upon aggregation even at low compositions of FCP. The enhanced emission in the copolymers is attributed to the supramolecular assembly of the polymeric chains. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) investigations of the monomer and copolymers of FCP revealed the presence of an intramolecular charge transfer (ICT) transition between dimethylamine and the cyanoacrylic acid unit. OLEDs were fabricated using a device with a ITO/PEDOT:PSS/EML/Al structure. White light emitting diodes were fabricated from FCP 2.5 as the emissive layer (EML) and elicited a white electroluminescence with Commission Internationale de l'Eclairage (CIE) coordinate values of (0.33, 0.34). They exhibited a maximum brightness of nearly 9332 cd m−2, a power efficiency of 4.13 lm W−1 and a luminous efficiency of 6.34 cd A−1. Interestingly, the supramolecular ordering in FCP 2.5 considerably reduces the charge trapping which results in a reproducible white light emission

Photophysical and charge transport properties of pyrazolines

Pyrazoline, an intense green emitting molecule both in solution and solid state, with extended π-conjugation has been synthesized via simple two-step reactions in high yields. Having the electron rich pyrazoline moiety with good redox behavior, pyrazolines can be potential candidates for charge transport material in organic electronic devices. UV-Visible absorption spectra of pyrazolines exhibit peaks below 400 nm, which is a desired feature for charge transport materials because it avoids interference with donor absorption that falls in the visible to NIR region. Electrochemical and theoretical studies show that the HOMO energy level lies at around −4.8 to 5.2 eV depending on the substituents, which is in fact compatible with the PEDOT:PSS/P3HT and work function of the ITO electrode. The experimental hole transport value, measured using the hole only device and space charge limited current (SCLC) method, was found to be in the range of 10<SUP>−5</SUP> to 10<SUP>−6</SUP> cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>, depending on the substituents. The maximum hole mobility calculated by theoretical methods for the pyrazolines is 0.75 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>

Challenges and opportunities of Low Viscous Biofuel- a prospective review

Under the roof of solid industrialization and accelerated intensification of multiple ranges of mobilization, a huge rise in precious fuel consumption and pollution was observed. Based on the recent hardships of fossil fuels, experts are undoubtedly eager in carrying out their research in renewable environment-friendly fuels. There have been many reviews of works considering the parameters and standards of biodiesel, which is only from various vegetable and seed oils. But very little review work was carried out on only plant-based biofuel. Plant-based fuel has a lower viscosity and higher volatility properties. The target of this review was to make a bridge to overcome these research gaps. This review extensively studies the biological background, production outcome, properties, and reliability of plant-based biofuel and also deeply investigates the feasibility of usage in a diesel engine. From deep investigation, it was identified that most of the low viscous fuel had higher brake thermal efficiency (BTE) (2% to 4%) and NOx emission (5% to 10%) than high viscous biodiesel. The formation of hydrocarbon (HC), CO, and smoke emission was similar to high viscous biodiesel. Overall, the low viscous fuel effectively improves the engine behaviors