scholarly journals Probabilistic and Fuzzy Arithmetic Approaches for the Treatment of Uncertainties in the Installation of Torpedo Piles

2008 ◽  
Vol 2008 ◽  
pp. 1-26 ◽  
Author(s):  
Denise Margareth Kazue Nishimura Kunitaki ◽  
Beatriz Souza Leite Pires de Lima ◽  
Alexandre Gonçalves Evsukoff ◽  
Breno Pinheiro Jacob

The “torpedo” pile is a foundation system that has been recently considered to anchor mooring lines and risers of floating production systems for offshore oil exploitation. The pile is installed in a free fall operation from a vessel. However, the soil parameters involved in the penetration model of the torpedo pile contain uncertainties that can affect the precision of analysis methods to evaluate its final penetration depth. Therefore, this paper deals with methodologies for the assessment of the sensitivity of the response to the variation of the uncertain parameters and mainly to incorporate into the analysis method techniques for the formal treatment of the uncertainties. Probabilistic and “possibilistic” approaches are considered, involving, respectively, the Monte Carlo method (MC) and concepts of fuzzy arithmetic (FA). The results and performance of both approaches are compared, stressing the ability of the latter approach to efficiently deal with the uncertainties of the model, with outstanding computational efficiency, and therefore, to comprise an effective design tool.

Author(s):  
S. Chandrasekaran ◽  
Arvind Kumar Jain ◽  
Syed Azeem Uddin

Abstract Offshore complaint structures dominate the deepwater oil exploration and production due to their adaptive geometric form and well-established construction practices. Semi-submersible is one of the widely preferred, floating production systems due to its form-dominant ability, better stability characteristics, and best constructional features. It is usually position-restrained using a dynamic-positioning system (active-restraining) or mooring system (passive-restraining); being less-sensitive to freak ocean environment is an added advantage. The Semi-submersible, chosen for the present study is based on a similar configuration of a 6th generation deep-water Hai Yang Shi You (HYSY) – 981 platforms, commissioned by the China National Offshore Oil Corporation (CNOOC) in 2012. A sixteen-point, spread catenary-mooring without submerged buoy (case-1) in the form of chain-wire-chain type configuration is used for position-restraining. Response behavior of the semi-submersible with a conventional spread catenary-mooring system with a submerged buoy (case-2) is compared. API spectrum is used for computing wind loads, while the JONSWAP spectrum is used to represent irregular waves for various directions of wave heading. The effect of non-linearly varying current is considered up to 10% of water depth. Numerical analyses of the semi-submersible are carried out under 10-years, and 100-years return period events using Ansys Aqwa. Under wind, wave, and current loads, motion responses of the Semi-submersible at 1500 m and 2000 m water depths are investigated for both the cases in time-domain. Dynamic mooring tension variations arise from the environmental loads are further investigated for a fatigue failure using the S-N curve approach. It is found that the fatigue life of the mooring lines after the inclusion of the buoy is enhanced. It was also observed that, during failure of mooring lines there is an increase in tension of the mooring lines which are adjacent to the failed mooring lines and this is due to the transfer of mooring load and hence reducing their fatigue life.


2016 ◽  
Vol 10 (1) ◽  
pp. 70-77
Author(s):  
Jantri Sirait ◽  
Sulharman Sulharman

Has done design tool is a tool of refined coconut oil coconut grater, squeezer coconut milk and coconut oil heating, with the aim to streamline the time of making coconut oil and coconut oil increase production capacity. The research method consists of several stages, among others; image creation tool, procurement of materials research, cutting the material - the material framework of tools and performance test tools. The parameters observed during the performance test tools is time grated coconut, coconut milk bleeder capacity, the capacity of the boiler and the heating time of coconut oil. The design tool consists of three parts, namely a tool shaved coconut, coconut milk wringer and coconut milk heating devices. Materials used for the framework of such tools include iron UNP 6 meters long, 7.5 cm wide, 4 mm thick, while the motor uses an electric motor 0.25 HP 1430 rpm and to dampen the rotation electric motor rotation used gearbox with a ratio of round 1 : 60. the results of the design ie the time required for coconut menyerut average of 297 seconds, coconut milk wringer capacity of 5 kg of processes and using gauze pads to filter coconut pulp, as well as the heating process takes ± 2 hours with a capacity of 80 kg , The benefits of coconut oil refined tools are stripping time or split brief coconut average - average 7 seconds and coconut shell can be used as craft materials, processes extortion coconut milk quickly so the production capacity increased and the stirring process coconut oil mechanically.ABSTRAKTelah dilakukan rancang bangun alat olahan minyak kelapa yaitu alat pemarut kelapa, pemeras santan kelapa dan pemanas minyak kelapa, dengan tujuan untuk mengefisiensikan waktu pembuatan minyak kelapa serta meningkatkan kapasitas produksi minyak kelapa. Metode penelitian terdiri dari beberapa tahapan antara lain; pembuatan gambar alat, pengadaan bahan-bahan penelitian, pemotongan bahan - bahan rangka alat dan uji unjuk kerja alat. Parameter yang diamati pada saat uji unjuk kerja alat adalah waktu parut kelapa, kapasitas pemeras santan kelapa, kapasitas tungku pemanas serta waktu pemanasan minyak kelapa. Rancangan alat terdiri dari tiga bagian yaitu alat penyerut kelapa, alat pemeras santan kelapa dan alat pemanas santan kelapa. Bahan yang dipergunakan untuk rangka alat tersebut  yaitu besi UNP panjang 6 meter, lebar 7,5 cm, tebal 4 mm, sedangkan untuk motor penggerak menggunakan motor listrik 0,25 HP 1430 rpm dan untuk meredam putaran putaran motor listrik dipergunakan gearbox  dengan perbandingan putaran 1 : 60. Hasil dari rancangan tersebut yaitu waktu yang dibutuhkan untuk menyerut kelapa rata-rata 297 detik, kapasitas alat pemeras santan kelapa 5 kg sekali proses dan menggunakan kain kassa untuk menyaring ampas kelapa, serta Proses pemanasan membutuhkan waktu ± 2 jam dengan kapasitas 80 kg. Adapun keunggulan alat olahan minyak kelapa ini adalah waktu pengupasan atau belah kelapa singkat rata – rata 7 detik dan tempurung kelapa dapat digunakan sebagai bahan kerajinan, proses pemerasan santan kelapa cepat sehingga kapasitas produksi meningkat dan proses pengadukan minyak kelapa secara mekanis. Kata kunci : penyerut, pemeras, pemanas,minyak kelapa,olahan minyak kelapa.


Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2032
Author(s):  
Pâmela A. Melo ◽  
Lívia A. Alvarenga ◽  
Javier Tomasella ◽  
Carlos R. Mello ◽  
Minella A. Martins ◽  
...  

Landform classification is important for representing soil physical properties varying continuously across the landscape and for understanding many hydrological processes in watersheds. Considering it, this study aims to use a geomorphology map (Geomorphons) as an input to a physically based hydrological model (Distributed Hydrology Soil Vegetation Model (DHSVM)) in a mountainous headwater watershed. A sensitivity analysis of five soil parameters was evaluated for streamflow simulation in each Geomorphons feature. As infiltration and saturation excess overland flow are important mechanisms for streamflow generation in complex terrain watersheds, the model’s input soil parameters were most sensitive in the “slope”, “hollow”, and “valley” features. Thus, the simulated streamflow was compared with observed data for calibration and validation. The model performance was satisfactory and equivalent to previous simulations in the same watershed using pedological survey and moisture zone maps. Therefore, the results from this study indicate that a geomorphologically based map is applicable and representative for spatially distributing hydrological parameters in the DHSVM.


2019 ◽  
Vol 9 (1) ◽  
pp. 600-605 ◽  
Author(s):  
Gabriel Fedorko ◽  
Martin Vasil ◽  
Michaela Bartosova

AbstractIntra-plant transport systems within their operation directly impact on the performance of production systems. For their effective operation, it is, therefore, necessary to realize evaluation of operational performance and effectivity. For the realization of this type of evaluation, in addition to a wide range of sensors that can be difficult for installation and operation, we can also use indirect methods that are equally able to provide reliable operational characteristics. Indirect analytical methods are presented above all by the approach which is based on the use of simulation methods. The method of computer simulation provides a wide range of options for the evaluation of efficiency and performance. The paper describes the use of a simulation model created in the program Tecnomatix Plant Simulation for analyzing the supply of production workplaces within the MilkRun system.


2017 ◽  
Vol 57 (2) ◽  
pp. 338 ◽  
Author(s):  
Z. C. Nziku ◽  
G. C. Kifaro ◽  
L. O. Eik ◽  
T. Steine ◽  
T. Ådnøy

This research aimed at describing reasons for keeping dairy goats in Tanzania, and possible goals for a sustainable breeding program. Three districts, each representing a unique dairy goat breed population, were selected for the study. The Saanen, Toggenburg and Norwegian were the main dairy goat breeds in Arumeru, Babati, and Mvomero districts, respectively. A total of 125 dairy goat farmers were interviewed. A holistic approach of both quantitative and qualitative research methods was used to study the perceptions of farmers. More milk yield, sale of breeding stock and manure were the highest ranked reasons for keeping dairy goats. The reasons were coherent to the production systems. The three most preferred traits for improvement were milk yield, adaptability and twinning ability. These preferences were absolutely important in the context of the referred production system. Selection of replacement stock, animal identification and performance recording were the main challenges emphasised by farmers. The present study views these challenges as a result of knowledge gaps in animal breeding that require solutions. Based on result findings it is suggested that the milk yield and survival traits should be the primary dairy goat breeding goals. Generally, there are possibilities for developing sustainable dairy goat breeding programs in the surveyed areas given relevant breeding goals are incorporated. The design of simple and manageable dairy goat breeding schemes is necessary.


1975 ◽  
Vol 12 (02) ◽  
pp. 146-162
Author(s):  
J. A. Beverley ◽  
R. L. Koch ◽  
E. C. Stewart ◽  
J. Weiks

This paper describes the ac-rectified dc propulsion system designed for the two ferry vessels, MV Spokane and MV Walla Walla, and reports the results of an analog study conducted as a design tool. Similar data are presented showing the results obtained by recording electrical system performance during builder's trials.


Author(s):  
Sudhakar Y. Reddy

Abstract This paper describes HIDER, a methodology that enables detailed simulation models to be used during the early stages of system design. HIDER uses a machine learning approach to form abstract models from the detailed models. The abstract models are used for multiple-objective optimization to obtain sets of non-dominated designs. The tradeoffs between design and performance attributes in the non-dominated sets are used to interactively refine the design space. A prototype design tool has been developed to assist the designer in easily forming abstract models, flexibly defining optimization problems, and interactively exploring and refining the design space. To demonstrate the practical applicability of this approach, the paper presents results from the application of HIDER to the system-level design of a wheel loader. In this demonstration, complex simulation models for cycle time evaluation and stability analysis are used together for early-stage exploration of design space.


Author(s):  
Emmanuel E. Anyanwu ◽  
Nnamdi V. Ogueke

The transient analysis and performance prediction of a solid adsorption solar refrigerator, using activated carbon/methanol adsorbent/adsorbate pair are presented. The mathematical model is based on the thermodynamics of the adsorption process, heat transfer in the collector plate/tube arrangement, and heat and mass transfers within the adsorbent/adsorbate pair. Its numerical model developed from finite element transformation of the resulting equations computes the collector plate and tube temperatures to within 5°C. The condensate yield and coefficient of performance, COP were predicted to within 5% and 9%, respectively. The resulting evaporator water temperature was also predicted to within 4%. Thus the model is considered a useful design tool for the refrigerator to avoid costly experimentation.


2014 ◽  
Vol 1018 ◽  
pp. 571-579
Author(s):  
Günther Schuh ◽  
Thomas Gartzen ◽  
Felix Basse

Reliable and accurate predictions on future states of production systems are the objective of production theories. In this paper, the authors determined shortcomings of current deterministic models and traced them back to the poor theoretical basis of scientific research in the area. The observations resulted in the development of the conceptScientific Management 2.0as an appropriate research methodology for production management. This new empirical approach takes into account three requirements to scientifically precise investigations: It expands existing theory by socio-technical aspects, uses embedded experiments as a profound basis for investigation and provides a design that warrants the methodical exactness required. RWTH Aachen’sDemonstration Factoryrepresents an adequate infrastructure to prove feasibility and performance of the new approach.


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