bluuebunny/crossref_metadata_2025 huggingface dataset:
Methods for Image Analysis of Intracellular Structures of Actin Labeled with Phalloidin
Authors: Revittser A. V. , Negulyaev Y. A.
Published: December 2024

A cell is a complex three-dimensional system, which possesses a number of highly dynamic structures with extended, rugged, and uneven morphology. The actin cytoskeleton consists of fibrillar and globular actin, as well as auxiliary proteins that regulate organization. The shape and the rearrangements of actin cytoskeleton are closely related to functioning of the cell. The ability to characterize these changes allows scientists to confirm or refute any hypotheses in the research. Obtaining a numerical equivalent of the actin cytoskeleton organization could help compare actin structures in biological experiments (example: exposure to biologically active substances). The review summarizes methods for analyzing images of intracellular actin structures labeled with phalloidin using ImageJ. The methods considered make it possible to obtain a quantitative characteristic of the organization of actin structures for further evaluation and comparison of experimental results.
The oldest island-arc granitoids of Chingiz-Tarbagatay region (Eastern Kazakhstan): age substantiation and сomposition affinities
Authors: Degtyarev К. Е. , Luchitskaya М. V. , Тret’yakov А. А. , Sal’nikova Е. B. , Plotkina Y. V.
Published: December 2024

The oldest granitoids of Kan-Сhingiz complex in Chingiz-Tarbagatay region of Eastern Kazakhstan, composed of quartz diorites, granodiorites, plagiogranites and granites, are first dated. U-Pb (ID-TIMS and SIMS) geochronological study of granites and plagiogranites is carried out and age estimates 509±2 and 512±3 Ma, approximately corresponding to the boundary of Early and Middle Cambrian, are obtained. These data allow to consider the age of volcanic-sedimentary sequences, host for granitoids, as Early Cambrian. Composition affinities of granitoids of Kan-chingiz complex indicate their formation within ensimatic island arc.
The age of the basement of Arctic Alaska – Chukotka microplate on the example of the Velitkenay granite-migmatitic dome (NE Russia)
Authors: Luchitskaya M. V. , Bushueva D. V. , Mazurkevich K. N. , Sokolov S. D.
Published: December 2024

The basement of Arctic Alaska – Chukotka microcontinent (AACHM) is exposed in Velitkenay granite-metamorphic dome of Chukotka. U-Pb (SIMS) geochronological study of the orthogneisses of the basement, paragneisses after Paleozoic rocks and leucogranites of Velitkenay pluton in the central and southwestern parts of this structure is carried out. Neoproterozoic ages of basement orthogneisses (velitkenay complex) and Albian ages of granitoids of Velitkenay pluton are confirmed. The latter concides with the age of orthogneisses migmatization. The youngest zircon clasters from paragneisses within velitkenay complex have Cambrian and Silurian ages, single zircon crystals contain inherited 1.7 and 1.9 Ma cores. The сorrelation of Neoproterozoic orthogneisses of Velitkenay granite-metamorphic dome with similar complexes of the other AACHM regions indicates unity of its basement. It is offered to enter velitkenay metamorphic complex into the legend of Chukotka series of the third-generation geological map sheets.
Isotopic U-Pb age of zircon (LA-ICP-MS method) from igneous rocks of the Chorukh-Dairon W-Mo(-Cu-Au) deposit (Tajikistan): first evidences for post-collisional ore formation in the Kurama segment of the Middle Tien Shan
Authors: Soloviev S. G. , Kryazhev S. G. , Semenova D. V. , Kalinin Y. A. , Bortnikov N. S.
Published: December 2024

The paper presents isotopic U–Pb zircon data (LA–ICP–MS method) for the main types of high-potassic intrusive rocks of the Chorukh-Dairon W–Mo(–Cu–Au) skarn deposit situated in the Kurama segment of the Middle Tien Shan near the largest porphyry Cu–Mo–Au deposits of the Almalyk mineralized cluster. Together with the other Au, W, Mo and Cu deposits, all these deposits are parts of the extended Late Paleozoic metallogenic belt of Tien Shan. The concordant isotopic U–Pb zircon data obtained for the rocks of successive intrusion phases in the Chorukh-Dairon pluton span from about 298 Ma to 290 Ma. This interval included crystallization of monzodiorite (295.1±3.3 Ma), quartz syenite (294.7±2.3 Ma), quartz monzonite (294.1±2.1 Ma), and monzogranite (293.0±3.0 Ma). These dates correspond to the pluton emplacement at the Late Carboniferous-Early Permian boundary and highlight its younger age compared to the productive high-potassic intrusions of the porphyry Cu–Mo–Au deposits in the Almalyk mineralized cluster, the latter assigned to the Late Carboniferous (about 337–313 Ma and partially to 308–297 Ma). By contrast to the latter, which were intruded in the subduction-related environment, the emplacement of the high-potassic rock of the Chorukh-Dairon pluton occurred in the transitional subduction-related to post-collisional environment or even under an actual post-collisional regime. This allows distinguishing two pulses of ore-bearing Carboniferous-Permian high-potassic calc-alkaline to shoshonitic series magmatism in the Middle Tien Shan. Consistently, there is a metallogenic evolution in the region that was expressed in the transition from porphyry Cu–Mo–Au deposits associated with subduction-related potassic magmatism, and likely evolving toward epithermal Au–Ag deposits, to essentially tungsten (W–Mo–Cu–Au) deposits associated with younger potassic magmatism occurring rather in the post-collisional environment.
Unserpentinized harzburgites of the Voikaro-Synyinsky massif of the Polar Urals as the initial source of chromium for the formation of deposits
Authors: Ivanov K. S. , Vakhrusheva N. V. , Puchkov V. N. , Shiryaev P. B. , Farrakhova N. N. , Bogomolova A. E.
Published: December 2024

The composition and age of unserpentinized harzburgites, which are found in the Voikaro-Synyinsky massif in the form of budins and relict bodies in the fields of olivine-antigorite rocks development, have been studied. The structure, compositions of rocks and minerals, as well as the distribution of rare-earth elements and Sm-Nd absolute dating (≈2330 million years) allow us to consider these unserpentinized harzburgites as fragments of the mantle and the earliest formations among the ultramafic Voikaro-Synyinsky massif. The silicates of these harzburgites are characterized by increased chromium content, which in subsequent different processes turns into chromium spinelide. Based on the data obtained, the resources of chromium mobilized during the transformation of primary ultramafics were evaluated.
Analysis of shortcomings in the strategy and practice of water supply to the population, based on the war experience
Authors: Rudenko Yu. F. , Kasteltseva N. B. , Klisko A. V. , Garanenko T. R.
Published: December 2024

The problems associated with the quantitative, qualitative, environmental, economic and other aspects of water resources, in particular the quality of drinking water, are of paramount importance today. The amount of water used is many times greater than other extractive resources. Water is the most important substance on our planet, primarily because it is necessary to sustain life. Providing the population with a sufficient amount of good quality drinking water is a strategic task for the national government.Drinking water used for centralised water supply to the population is drawn from surface water sources and groundwater aquifers. Historically, surface water has been preferred as the main source of water supply.The Dnipro River and its numerous tributaries are the main source of water supply for 75% of the Ukrainian population. However, due to significant technogenic pressures on the water quality in the Dnipro River and its catchment area the surface water is characterised as polluted and highly polluted in terms of chemical and bacterial contamination.In order to improve the quality component of the domestic drinking water supply to the population and industrial enterprises (mainly food production), particular attention should be paid to the increased use of groundwater. The experience gained during the war suggests the need to establish a local water supply system based on pumping stations (i.e., buvettes) with reserve water sources and means of delivering water to the consumption network.The article analyses the existing shortcomings and problems in the organisation of domestic drinking water supply in Ukraine and outlines some steps to improve the situation.
Мінералого-геохімічна характеристика рідкісноземельного зруденіння у Середньому Придніпров’ї (на прикладі Котлярівського рудопрояву)
Authors: Sukach V. V. , Isakov L. V. , Khomych Yu. Ye.
Published: December 2024

Надано мінералогічну, петрографічну та геохімічну характеристику рідкісноземельної мінералізації Котлярівського рудопрояву, який був виявлений св. 114 у південно-західній частині Криничанського плагіограніт-мігматитового купола під час геологічного довивчення (ГДП-50) південної частини Верхівцівської зеленокам’яної структури та її гранітоїдного облямування.Рідкісноземельні елементи (REE) відіграють важливу роль в економіках ЄС, США, Канади, Австралії та інших розвинених країн. Українсь­кий щит є однією з найбільших рідкісноземельних металогенічних провінцій Європи. Зокрема, Середньопридніпровський мегаблок залишається перспективним, але маловивченим регіоном для відкриття нових родовищ REE. Його перспективи пов’язуються із сублужними і лужними мезоархейськими гранітоїдами та метасоматитами токівського, мокромосковського і демуринського комплексів.У результаті комплексних досліджень кернових проб із корінних та гіпергенних зруденілих порід Котлярівського рудопрояву з’ясовано, що головним мінералом-концентратором REE та ітрію є монацит. Мінерал зазнав змін, які відбулися щонайменше у два основних етапи: ендогенний гідротермально-метасоматичний та гіпергенний, пов’язаний з утворенням кори вивітрювання. Інші мінерали, такі як апатит, циркон, лейкоксен, також містять певні домішки лантаноїдів та ітрій. Отримані результати роботи підкреслюють необхідність подальших досліджень рідкісноземельного зруденіння у Середньому Придніпров’ї, що має високу як практичну, так і теоретичну цінність.
Experimental evaluation of slamming pressure models used in structural design of high-speed craft
Authors: Razola Mikael , Rosén Anders , Garme Karl
Published: December 2024

In this paper a methodology that enables detailed studies of the momentary slamming pressure distribution and the related structural loads is presented. The methodology involves pressure measurements, spatial and temporal pressure distribution reconstruction, and finite element analysis. Using a set of model experiments with a high-speed planing craft towed in irregular waves, the methodology is applied to evaluate different slamming pressure models regarding their ability to accurately represent the structure loads. The slamming equivalent uniform pressure model used in the prevailing semi-empirical design methods, and non-uniform time-dependent pressure models used in a method for direct calculation, are considered. It is concluded that for smaller structure members, typically found in densely spaced metal structures, the uniform pressure model performs well with respect to accurately representing the structure loads. However, for larger members found in modern sandwich structures, the underestimation of structure loads is significant, especially with respect to the shear forces. The non-uniform pressure modeling technique is concluded to be promising regarding its ability to accurately represent the structure loads, regardless of structure member size. The presented methodology is concluded to be a useful tool in further research regarding the evaluation and development of methods for high-speed craft structural design.
The Interaction of a Floating Body with Vertical Walls
Authors: Cohen S.B. , Troesch A.W.
Published: December 2024

The wave interaction of a floating sphere with two vertical walls is discussed. Graphs of the frequency domain and equivalent time domain added mass, damping, Froude-Krylov and diffraction forces, and Response Amplitude Operators (RAO) are presented. The linearized frequency domain velocity potentials are constructed by a multipole expansion used in conjunction with the method of images. The discrete Fourier Transform converts frequency data to Impulse Response Functions (IRF). Peaks in the IRF envelope curve indicate the effect of outlying images, which for practical cases are separated in time. A technique for identifying wall reflection effects from measurements in a finite basin is described.
Modelling, Design and Analysis of an Autopilot for Submarine Vehicles
Authors: Gueler G.F.
Published: December 2024

This work presents the modelling, analysis, preliminary design and build-up of a prototype of a submarine autopilot.

The autopilot is designed to perform two different missions: depth-keeping near the sea surface and depth changing control.

The vehicle dynamics are simulated by a non-linear model, whose coefficients are evaluated by the equivalent ship method.

A solution of the control problem is obtained using optimal control techniques. The system state is estimated using the Kalman filter associated with the dynamical model compensation technique. A simplified filter was also used for real time state estimation.

The prototype consists of a microcomputer with analog-digital interfaces for input-output signals.

A digital simulation of submarine manoeuvres was done and the results indicate a good performance for the autopilot, even under severe conditions. Other tests showed the accuracy of the non-linear model and the technical feasibility of the prototype.
Parametric Study of Ship-Hull Vibrations
Authors: Chen Yung-Hsiang , Bertran Ines M.
Published: December 2024

A parametric study of the vertical free vibrations of a ship hull is presented. All the effects of the rotary inertia of mass, shear distortion, thrust force, shear lag, and various damping components are taken into account in analysis. The importance of these parameters to ship-hull vibrations is discussed. The method of calculating the overall damping ratios is included and particularly emphasized.
On the Free Response of Propeller Blades
Authors: Warikoo R. , Haddara M.R.
Published: December 2024

The free vibration of a rotating ship propeller blade is studied using an iterative scheme based on Galerkin's method. The blade is idealized as a cantilever beam with variable cross section of airfoil shape. The effects of pitch angle, shear deflection, rotary inertia and speed of rotation are studied. Agreement with results available in the literature and with results obtained using a finite element method is excellent.
Linearized Inverse Method for the Design of Two-Element Ducted Propellers
Authors: Pylkkänen J.V.
Published: December 2024

The linear inverse method for ducted propellers or annular airfoils is applied to the design of the two ducts of a two-element ducted propeller. The calculated inviscid duct thrusts are corrected for viscous drag. In a parametric study, the relative lengths of the two elements were varied within a fixed total length of the installation. Also the location of the propeller in the aft duct was varied. The objective was to maximize the sum of the thrusts of the elements. As is the case with multi-element airfoils, the sum of the thrust increases compared with the single-element reference duct, provided suitable pressure distributions for both the forward and aft ducts are prescribed. The theoretically predicted increase in thrust is of about the same magnitude as the increase in the lift of two-element airfoils in comparison with the corresponding single-element airfoil. Hydrodynamically efficient short forward ducts are thin and have a sharp leading edge, which is likely to cause flow separation in the uneven wake of a ship. The minimum acceptable ratio of the forward length to the aft length may be about 1 : 3. For a forward duct of this length, a pressure distribution with a rather long roof-top is found to be advantageous, producing a well rounded leading edge.
Application Asymmetric Reaction Vanes
Authors: Gearhart W.S. , Marboe R.C.
Published: December 2024

A historical review of reaction fin development and the application of an asymmetric reaction vane system forward of a propeller on a 41 ft U.S. Coast Guard boat is presented. An analytical evaluation of the efficiency gains that can be obtained with a reaction fin system is presented and compared with experimental measurements. The use of such a system for outboard motor propulsion is proposed.
Roll and Sway-Roll Damping for Three Small Fishing Vessels
Authors: Bass D.W. , Haddara M.R.
Published: December 2024

The determination of roll damping for non-standard hull shapes continues to be an important but difficult problem. For small fishing vessels with deep skegs and hard chines the problem is particularly difficult. In order to develop and judge suitable analytical, semi-empirical, and numerical techniques for the prediction of roll damping, the authors have embarked on an extensive series of experiments to determine roll damping characteristics for a number of small fishing vessels. Amongst the attributes investigated are the dependence of damping on amplitude and roll centre. The investigations include not only the roll damping but also the roll-sway coupled damping.
Experimental Investigation into the Physics of Roll Damping of a Long Slender Hull Form
Authors: Haddara M.R. , Cumming D.
Published: December 2024

The results of an extensive experimental program to study the roll damping characteristics of a warship model are reported. The simple free decay curves obtained for a towed as well as a self-propelled nine metre model, fitted with and without bilge keels, rudder and propellers, were analyzed using an energy approach. A new nondimensionalization scheme is used for the representation of the results and used to derive relationships relating the damping coefficient to the value of the metacentric height of the model. The nonlinearity of the damping with forward speed is explained.
Slamming on Forced Oscillating Wedges at Forward Speed Part I – Test Results
Authors: Radev D. , Beukelman W.
Published: December 2024

As follow-up of former research forced vertical oscillation experiments have been performed to determine peak pressures and rise times for four metal wedges with different dead rise angles. These pressures have been measured as function of vertical oscillation speed, trim angle and forward speed. The results, in general, show that the peak values of the impact pressures are proportional to the squared value of the vertical speed, however, also the influence of forward speed appeared to be significant. In most of the existing mathematical models this relation has unsufficiently accounted for as shown here. Application of the prediction models in this respect is urgently required.
On Multi-Objective Fuzzy Optimization of Ship Structures
Authors: Xu Changwen , Yu Minghua
Published: December 2024

In order to solve the multi-objective fuzzy optimization problems of ship structures, two approaches, known as the Maximum Level Method and the Linear Weighted Sum Method, based on the different forms of fuzzy decision-making are presented. In these methods, the membership functions are constructed for the subsets of the fuzzy goals subject to the fuzzy constraints, and then the multi-objective fuzzy optimization problem is transformed into the single-objective ordinary optimization problem, which can be solved by using nonlinear programming techniques. The proposed approaches are illustrated by two numerical examples in the application of ship structural design.
Analysis of Diffraction-Radiation Problem of a Twin-Hull Barge System
Authors: Krishnankutty P. , Vendhan C.P.
Published: December 2024

Ocean wave is an important marine environmental phenomena which influences the performance of a marine structure. This necessitates a detailed hydrodynamic study of the wave-structure interaction problem. In the present work the finite element method has been demonstrated as an effective tool to solve the complex linearised three-dimensional hydrodynamic problem. The developed software has been validated for regular bodies and applied to a multi-body (twin-barge) system.
Developments in Surface Fairing Procedures
Authors: Tuohy S. , Latorre R. , Munchmeyer F.
Published: December 2024

This paper summarizes an investigation on the suitability of mathematical surfaces for representing an idealized curved hull surface. In contrast to hull fairing with splines, mathematical surfaces such as the Gordon or Coons surfaces can be further developed. A study for candidate mathematical surfaces is made to examine how well they represent a benchmark hull surface. The results indicate that the UNO and Gordon surfaces are more accurate. The use of geodesic traces for hull plate development and an integrated hull plate development procedure are also discussed.
A Study on Xizhang Junk Form Barge Train
Authors: Minhu Zhu
Published: December 2024

Time-honoured ancient Xizhang Junk form remains to be predominant in the barge train fleet which plays an important role in domestic transport of the Jiangnan region crisscrossed by waterways in East China.

With a view to reduce the formation coefficient of barge train, the shallow water resistance of the Xizhang Junk, both individually and in train, has been investigated both by means of towing tank model tests and full-scale trials in Grand Canal. A modified body plan is proposed. Operational results have shown good energy-saving, if the modified form barge is placed as the first one in the barge train. In the appendix, empirical formulae based on existing vessels are given to show the parametric features of Xizhang Junk form.
Experiment Investigation of a High-Lift Rudder Circulaion Control Rudder
Authors: Songlin Zhu , Xianfu Wang
Published: December 2024

The circulation control method for improving the hydrodynamic characteristics of a low aspect ratio rudder is investigated in circulating water-channel tests. Circulation control is achieved from a thin jet of water that exits through a 0.45mm spanwise slot along the upper surface of the airfoil near the trailing edge. Experimental investigations have demonstrated that the lift increases as the jet blowing increases, and the lift augmentation is obtained even at zero deg angle of attack with relatively small amounts of blowing water. Endplates installed at both ends of rudder's span are shown to increase the lift at fixed angle of attack and decrease the drag. The longitudinal V grooves engraved at Coanda surface are also shown to decreases the drag and improve the lift-to-drag ratio.
Maintenance Programme Design for Minimal Life Cycle Costs and Acceptable Safety Risks
Authors: Klein Woud J. , Smit K. , Vucinic B.
Published: December 2024

A research project has been carried out with the objective to develop a structured and systematic method for the design of a maintenance programme during the engineering phases of ship's life. With the method the life cycle costs for maintenance can be minimized with at the same time acceptable safety risks. The method consists of failure mode analysis, a quantified operational and safety risk analysis and maintenance concept design, which involves cost optimization.
Manoeuvring Coefficients for a Wing-Model in Deep and Shallow Water: Part II – Calculations
Authors: Beukelman W.
Published: December 2024

A model of a surface-piercing wing has been towed through the water at three speeds in two opposite directions for different draughts and drift angles. The experiments were carried out in both deep and shallow water. Purpose of the tests was to measure the longitudinal and transverse forces on the wing-model. From the measured forces hydrostatic manoeuvring coefficients were determined as a function of the drift angle. In addition to these static measurements forced horizontal motion tests with a Planar Motion Mechanism (PMM) were carried out to determine the hydrodynamic manoeuvring coefficients. Calculations based on the potential theory and on the variation of the added mass impulse were carried out to determine the manoeuvring coefficients for small drift angles. Comparison with the measurements showed encouraging results to determine manoeuvring coefficients also for the velocity derivatives.

Both experiments and calculations showed a strong increase of the coefficients with draught and reduction of water depth.
Hydrodynamic Forces on the Advancing Slender Body with Speed Effects, II: Wave Exciting Forces
Authors: Wang Chun-Tsung , Chiu Forng-Chen , Horng Shiann-Jorng
Published: December 2024

Based on Chapman's approach, wave exciting forces on slender ships with forward speed are solved by a two and half dimensional method. The governing equations are derived along characteristic lines. The forward speed effects are incorporated into the free surface and the body surface conditions. Relaxed radiation condition with numerical correcting term introduced by Yamasaki & Fujino is imposed on the open boundary.

Wave exciting forces on a Wigley model, and a Series 60 model with forward speed are calculated. The agreement between the wave exciting forces computed by the present method and the experimental data reported by Gerritsma is very satisfactory. Wave exciting forces computed are also compared with the numerical results from the strip theory and some three dimensional approaches.
Hot spot stress and stress concentration factors due to different fabrication imperfections in deck structures
Authors: Chakarov K. , Garbatov Y. , Guedes Soares C.
Published: December 2024

This work deals with the stress analysis of a longitudinally stiffened welded panel and evaluates the hot spot stress distributions and stress concentration factors that result from different types of imperfections. The hot spot stresses and the stress concentration factors are defined at locations adjacent to the transverse weld. Numerous calculations are performed representing realistic conditions of imperfections and various comparisons of hot spot stress distributions are presented. The stress concentration factor for the cases of pure thickness step changes and for vertical angular imperfections are fit to a quadratic polynomial function.
Benchmark study on the use of simplified structural codes to predict the ultimate strength of a damaged ship hull
Authors: Guedes Soares C. , Luís R.M. , Nikolov P. , Downes J. , Taczala M. , Modiga M. , Quesnel T. , Toderan C. , Samuelides M.
Published: December 2024

The objective of the paper is to evaluate the ability of simplified structural analysis methods, based on the Smith formulation to predict the ultimate strength of a damaged ship. Such methods are now widely accepted as a reliable and fast way to obtain the longitudinal strength of an intact ship. In order to extend these methods to damaged ships, first a benchmark study on the intact ship was performed in order for the differences between the methods to be evaluated. Afterwards the methods are applied to the same ship section but with damage, which was defined by removing the structural elements from the affected areas. These, in turn, were obtained from a previous study in which a collision was simulated using a finite element model. Results obtained for the ultimate strength were compared against each other and with the results of the finite element analysis. Aside from some exceptions, the results of the approximate methods agreed well with each other for the intact and damaged conditions. The simplified methods are more conservative than the finite element analysis in hogging while they seem to give a very good approximation to the result for sagging with some of them overestimating this value.
Corrosion wastage modeling of deteriorated bulk carrier decks
Authors: Garbatov Y. , Guedes Soares C.
Published: December 2024

Recently developed corrosion wastage models for marine structural applications are reviewed. A non-linear corrosion model is applied to measured service data of the deck of bulk carriers in order to evaluate the model parameters that adjust to the corrosion rates for those ship structures. Comparisons with corrosion wastage in tankers are given and discussed.
Roll-damping qualities of constructive stabilizers
Authors: Segal Zelik , Segal Alexander
Published: December 2024

The paper presents the description and results of a model experiment carried out for comparison of the roll-damping qualities of continuous bilge keels and of wing ledges, installed in a staggered order, during rolling of the ship at zero forward speed.

The damping qualities of constructive stabilizers were investigated also at motion of the ship ahead. The obtained data can be useful in subsequent experiments and in design of new sea vessels.
Time-based damaged ship survivability: A quasi-static equivalent method
Authors: Bulian Gabriele
Published: December 2024

This paper presents a series of ideas to make a step forward in the assessment of flooded ship survivability on a time-dependent basis. An extension of the SEM (Static Equivalent Method) to a Quasi-Static Equivalent method (QSEM) is proposed to take into account the time variable and to address the case of multiple compartments. A capsize index based, conceptually, on static calculations is defined as a function of time and sea state. Capsize is considered in terms of both a first-excursion problem concerning the wave amplitude, and as the persistence of high-runs of waves above a critical level. An example of the proposed methodology is presented for the analysis of the flooding a two decks. Using the same hydraulic model, comparisons are carried out between the presented approximate analytical methodology and direct numerical simulations of the flooding process to assess the effect of downflooding means. A discussion is given on how the time-based approach to ship survivability links with the evacuation process, in order to obtain the probability density function of the number of evacuated passengers.
Modeling of hard-chine hulls in transitional and early planing regimes by hydrodynamic point sources
Authors: Matveev Konstantin I. , Ockfen Alex E.
Published: December 2024

A linear potential-flow method based on hydrodynamic point sources is developed for modeling steady hydrodynamics of hard-chine hulls. Source singularities are distributed on the wetted hull surface and on the free water surface. The wetted hull area is not known in advance and is found iteratively. The outcome of the model is the pressure distribution on the hull and the water surface elevations. Validation studies with two- and three-dimensional hull forms demonstrate good agreement for the lift coefficient and center of pressure in transitional and early planing regimes. The near-field wake wash reasonably agree with empirical data for wave profiles behind a planing plate and for the trough position behind a submerged hydrofoil. The flexibility of the current method allows modeling of a variety of hull forms and systems with hydrodynamically interacting elements.
A time domain simulation method for nonlinear motion and wave loads of fast ships
Authors: Shan Ma , Wenyang Duan
Published: December 2024

A nonlinear time domain method is presented to calculate the vertical responses of fast ships. The extended 2.5D theory is used to evaluate nonlinear fluid radiation and diffraction forces which can take into account both the effects of the change of the underwater wet surface and the forward speed of a fast ship at free surface. A matched boundary integration equations algorithm is applied to solve the 2.5D theory in order to avoid numerical divergence observed when ships have large flare. The hydrostatic and Froude–Krylov forces are calculated below the incident wave elevation. The comparison of numerical results with model test data shows that the numerical method can capture the main nonlinear effects and is valid for the calculation of vertical motions and wave loads of high speed ships.
Effectiveness of corrosion measures to bulk carriers with Life Cycle Cost Analysis
Authors: Psarros George A. , Vassalos Dracos
Published: December 2024

This paper is aimed at providing a framework for cost-benefit assessment of proposed safety measures with the usage of Life Cycle Cost Analysis, a decision-making technique for exploiting different investment opportunities. The reasonable practicality for implementing the proposed measures is supported by cost-effectiveness indices, in terms of a risk-factored cost of the fatalities that would have been averted. Their application is demonstrated by investigating the effectiveness of corrosion measures to bulk carriers.
Model experiments of a trimaran with transom stern
Authors: Jia J.B. , Zong Z. , Shi H.Q.
Published: December 2024

This study was initiated due to the lack of published experimental data on transom stern trimaran capability. The feasibility of the model experiments was examined and a series of model tests were carried out in the towing tank of Department of Naval Architecture, Dalian University of Technology. The study concentrates on the resistance and seakeeping characteristics of transom stern trimaran. A set of configurations of the trimaran over a range of Froude numbers were tested and the results were compared. Some conclusions can be drawn as below. The wave resistance and heave response can be reduced by placing the side hulls towards the stern and the main hull at high speeds. The pitch motion response can be depressed effectively by increasing the distance between the main hull and the side hulls. Furthermore, the breadth of trimaran is a sensitive parameter to roll, and the amplitude of roll angle is reduced along with the increase of trimaran breadth.
Experimental and numerical study on trim and sinkage of a high speed catamaran vessel in shallow waterways
Authors: Krishna B. , Krishnankutty P.
Published: December 2024

Many areas of seas, harbours and channels that were considered deep and safe for vessel navigation have been changed into dangerous shallow water regions for the new generation vessels due to their drastic increase in size and speed. Hence, the understanding of the safe speed of a vessel to prevent it from grounding when it operates in restricted waterways is gaining more importance. A catamaran vessel, being one of the new generation vessel configurations, is considered here to study the effect of its under-keel clearance of water and also its demi-hull spacing in the determination of a safe vessel speed. The numerical study using RANSE based CFD solver Fluent has been complemented by results obtained from experiments carried out in the towing tank of IIT Madras using the newly commissioned floating false bottom facility.
Prediction diagrams for deterministic sea wave prediction and the introduction of the data extension prediction method
Authors: Abusedra L. , Belmont M.R.
Published: December 2024

Early in the development of the new discipline of short term deterministic sea wave prediction (DSWP) the prediction region diagram was introduced. This was intended to provide information on the region in space and time where a propagating wave system arose from waves that had been previously totally measured. This diagram is compared here with a space time plot that also incorporates the accuracy of the prediction achievable by the prediction algorithms. In this context certain issues raised in the literature about the relative roles of group and phase velocity are examined. It is shown that the stationary phase approximation, which predicts wave packets propagate at the group velocity, does not hold under the conditions applying to practical DSWP. The numerical work presented introduces a new frequency domain prediction technique termed the data extension method. This is derived from the Papoulis–Gerchberg iteration scheme and reduces prediction errors associated with periodicity artefacts. A method is described for deriving analytic guidelines that allow estimates of prediction performance to be made for standard sea types, with illustrative results being presented for the Pierson–Moskowitz power density spectrum.
Analysis of inherent course stability of a high-speed catamaran in deep and shallow water
Authors: Milanov Evgeni , Zlatev Zlatko , Chotukova Valya , Stern Frederick
Published: December 2024

The paper treats the important problem of prediction of ship's inherent course stability, based on a large amount of model experimental data for a well-known bare hull shape – the Delft catamaran 372, covering a comparatively wide range of Froude numbers and depth to draught ratios. The analysis is based on a linearized maneuvering model.

As a result, dependency of the stability criterion on Froude number and the water depth to draught ratio is established and clearly demonstrated for this particular ship case.
Gaussian and non-Gaussian cumulant neglect application to large amplitude rolling in random waves
Authors: Su Zhiyong , Falzarano Jeffrey M.
Published: December 2024

Large amplitude rolling in random beam seas is studied by moment equations and stochastic excitation is represented through a cascading filter driven by pure Gaussian white noise in order to apply Markov approximation. The moment equation is generated from a six state space rolling model using the Itô differential rule. The Gaussian and non-Gaussian cumulant neglect method is applied to close the infinite hierarchy of moment equations. In this paper, an automatic neglect tool is developed to handle the complex and untraceable higher-order cumulant neglect closure method to capture the non-Gaussian effect of nonlinear rolling phenomena. Both transient and stationary responses of statistical moments are obtained through the solution of the closed moment equations.
Smart control of fast ships – Part 2: A conceptual model of automated proactive thrust control
Authors: van Deyzen A.F.J. , Keuning J.A. , Huijsmans R.H.M.
Published: December 2024

A planing monohull sailing in head seas experiences large vertical accelerations, which are considered to be the main limiting factor for operability. Results of full scale trials (Part 1) showed that the operability of a small planing monohull sailing in head seas may be increased when the helmsman actively controls the thrust.

In the present paper a conceptual model of automated proactive thrust control, or smart control, is presented. The response of a small planing monohull sailing in head seas has been mimicked using an elementary model. The essential hydromechanic aspects are incorporated. A control system for the thrust has been included. The response will be predicted continuously and if necessary, an appropriate amount of thrust reduction will be applied. By temporary speed reductions the magnitude of the next occurring vertical peak acceleration is reduced.

Results generated using this conceptual model show that the operability may be increased using automated proactive thrust control if sufficient time to decelerate to a sufficiently low speed before impact is available. This is provided that the vertical peak accelerations are estimated accurately.
Theoretical and experimental investigation of propeller shaft loads in transient conditions
Authors: Amini Hamid , Steen Sverre
Published: December 2024

This paper investigates experimentally and numerically the effect on the propeller shaft loads of dynamically changing propeller speed and azimuth angle of thruster propellers. Model tests with a six-component shaft dynamometer were performed in the large towing tank at the Marine Technology Centre. A blade element momentum theory (BEMT) model is applied for numerical analysis.

It is found that the side forces and bending moments on the propeller in strongly oblique inflow are quite sensitive to dynamically changing azimuth angle; for instance are the maximum values of vertical side force and horizontal bending moments effectively doubled when the azimuth angle is changed dynamically. On the other hand, dynamically changing the azimuth angle is less important for the thrust and torque of the propeller. For ships, the effect of dynamically changing the propeller speed can be ignored and the quasi-static values used.
Effective inflow velocity for rudder calculations
Authors: Shen Young T. , Hughes Michael J.
Published: December 2024

A rudder force model is being developed at Naval Surface Warfare Center, Carderock Division (NSWCCD) for use with real time ship maneuvering and seakeeping tools. The goal of this work is to obtain reliable results with acceptable computation time. The rudder of a navy ship is typically designed with a portion of rudder area located outside the propeller slipstream and a portion in the slipstream. The inflow velocities entering the rudder plane vary significantly from the rudder tip to the rudder root due to the ship hull boundary layer. Additionally, with flow acceleration induced by the propeller loading, the portion of the rudder in the slipstream will experience much higher inflow velocities than the portion of rudder outside the slipstream. In this effort, the calculations are performed separately for several spanwise rudder segments, where the segments correspond to the portions of the rudder outside the propeller slipstream and in the upper and lower halves of the propeller slipstream. A method to compute effective inflow velocities entering the rudder plane at each segment is presented in this paper. A separate paper will describe how at each segment, the rudder forces are computed from effective inflow velocity, effective lift curve slope, and effective rudder angles encountered by the rudder. A generalized actuator disk model is applied to obtain the slipstream velocity distributions with a realistic propeller loading. An induction method is adopted to obtain the shape of the contracted slipstream. The theory is extended to calculate the tangential velocity in the slipstream. The present theory is validated against a set of velocity measurements that were conducted in The NSWCCD Large Cavitation Channel.
A ruptura da imagem-tempo: cinema e gênese do pensamento em Deleuze
Authors: Brandão Pinto Eduardo
Published: December 2024

Nos livros Cinema 1 (1983) e Cinema 2 (1985), Gilles Deleuze não descreveu uma, mas duas rupturas do sistema sensório-motor. No capítulo 7, do segundo livro, o autor empreende um recuo em direção à gênese do pensamento na filosofia e no cinema: o que, na imagem, força o cinema a pensar? A primeira ruptura, que diz respeito à imagem-movimento, já fora concebida em Diferença e Repetição (1968), como o choque que interrompe o prolongamento das recognições para dar lugar a um pensamento não-representativo. A segunda ruptura, à qual este artigo prioritariamente se dedica, diz respeito à quebra de ligação entre homem e mundo, algo que forçará Deleuze a produzir uma filosofia do impensável e da impotência.
Inteligência artificial e regressão mimética: algumas palavras sobre um comercial da Volkswagen
Authors: Hussak van Velthen Ramos Pedro
Published: December 2024

Trata-se de uma análise do comercial da montadora Volkswagen em que a cantora Maria Rita faz um dueto com sua mãe, Elis Regina, ressuscitada graças à ação da inteligência artificial (IA). A hipótese central é que toda a polêmica em torno da peça publicitária, travada em grande medida nas redes sociais, está ancorada no fato de que há uma escolha estética nomeada aqui de regressão mimética de modo que todas as críticas à utilização da IA nesse caso ressoam as críticas que Platão faz à mímesis no livro X d’A República. O desenvolvimento do artigo faz uma discussão com autores contemporâneos, em particular Jean Baudrillard e Bernard Stiegler, que mobilizam, cada um a seu modo, o arcabouço conceitual platônico para pensar a situação da imagem na contemporaneidade para defender que o antídoto para a regressão mimética não seria um “retorno ao real”, mas o estímulo a que artistas aprendam a programar para propor uma utilização criativa das imagens produzidas por IA.
A natureza política das ações humanas nas primeiras history plays de Shakespeare
Authors: Dias José , Cunha Junior
Published: December 2024

Versa-se, primeiro, sobre o pensamento ético-político do período elisabetano e sobre o contraste entre os preceitos Tudors e o pensamento político de Nicolau Maquiavel. Na sequência, é feito um exame sintético das primeiras history plays de Shakespeare, buscando compreender como o autor aborda a esfera política no início de sua carreira. Conclui-se que os personagens de Shakespeare transitam sobre um território fronteiriço — os quadros sociopolíticos que denotam a luta pelo poder e revelam pressões sociais, privilégios, preconceitos e interesses de classe, é uma amostra do conflito entre as ideias medievais e de um emergente impulso a um novo conjunto de ideias que possam fundamentar a nova forma de ver o mundo; que os personagens de Shakespeare não ocupam posições fixas no encadeamento dos seres e, em alguns casos, agem contra esse ordenamento; e que Shakespeare parece sempre guardar certa distância de um preceito hierárquico taxativo e de uma obediência incondicional a quem quer que seja.
Hermenêutica, Fenomenologia e Pragmatismo na filosofia da tecnologia de Don Ihde: Uma visada interrelacional de humanos e artefatos tecnológicos
Authors: Buenos Aires de Carvalho Helder , Wellysson Sousa Brito Gustavo
Published: December 2024

O artigo visa mostrar como a filosofia da tecnologia de Don Ihde, que ele denominou de pós-fenomenologia das relações humanos-tecnologias, articula hermenêutica, fenomenologia e pragmatismo para a compreensão da tecnologia e o sentido de suas inserções no mundo da vida, de modo a construir uma visão não-instrumentalista dos artefatos tecnológicos. Essa convergência triplamente teórica da pós-fenomenologia de Ihde, na perspectiva de uma filosofia da práxis, enriquece criticamente nossa compreensão do fenômeno tecnológico e nos convida a uma reflexão mais profunda de suas implicações para os nossos modos de ser e viver, em que humanos e artefatos tecnológicos estão intrinsecamente interrelacionados.
SiReRAG: Indexing Similar and Related Information for Multihop Reasoning
Authors: Zhang Nan , Choubey Prafulla Kumar , Fabbri Alexander , Bernadett-Shapiro Gabriel , Zhang Rui , Mitra Prasenjit , Xiong Caiming , Wu Chien-Sheng
Published: December 2024

Indexing is an important step towards strong performance in retrieval-augmented generation (RAG) systems. However, existing methods organize data based on either semantic similarity (similarity) or related information (relatedness), but do not cover both perspectives comprehensively. Our analysis reveals that modeling only one perspective results in insufficient knowledge synthesis, leading to suboptimal performance on complex tasks requiring multihop reasoning. In this paper, we propose SiReRAG, a novel RAG indexing approach that explicitly considers both similar and related information. On the similarity side, we follow existing work and explore some variances to construct a similarity tree based on recursive summarization. On the relatedness side, SiReRAG extracts propositions and entities from texts, groups propositions via shared entities, and generates recursive summaries to construct a relatedness tree. We index and flatten both similarity and relatedness trees into a unified retrieval pool. Our experiments demonstrate that SiReRAG consistently outperforms state-of-the-art indexing methods on three multihop datasets (MuSiQue, 2WikiMultiHopQA, and HotpotQA), with an average 1.9% improvement in F1 scores. As a reasonably efficient solution, SiReRAG enhances existing reranking methods significantly, with up to 7.8% improvement in average F1 scores.