bluuebunny/crossref_metadata_2025 huggingface dataset:
Force/Position Hybrid Control Technology of Heavy-duty Long Manipulator Based on IPSMC
Authors: Weicong Wu , Wenqiang Wu , Chunliang Zhang , Houyao Zhu , Chaozheng Chen
Published: November 2022

In order to solve the problems of low precision, disturbance and unsmooth movement of heavy-duty long manipulator in working conditions, an IPSMC (improved power sliding mode control) based on force impedance control is proposed. First, the robot is organized and an accurate kinematics model is established and the motion characteristics of special manipulator system are analyzed. Combined with the dynamic model, the deviation of the position and velocity feedback from the expected value is converted by the force impedance controller, which makes the manipulator more flexible under the condition of low damping. At the same time, according to the position and speed feedback, an IPSMC is proposed, which uses the sliding mode control (SMC) to reduce the disturbance and oscillation in the working condition, so as to realize the control in the position space and the control in the force space. Finally, through Adams-Simulink co-simulation, the designed control system is tested. The results show that the force/position hybrid control strategy has good anti-interference ability for the long manipulator with large working range. While improving the flexibility of the manipulator, it also weakens the end chattering problem to some extent, enhances the robustness of the control system, and meets the requirements of working conditions.
Reply to Breno Santos
Authors: Goldberg Sanford C. ,   Philosophy Documentation Center
Published: November 2022

Breno Santos (2022) criticizes my account for not having plausible things to say about the difference between cases of hearing something negative about a friend from a third party, and hearing from the friend herself. I deny the charge and respond to this criticism.
Escolarização de pescadores/as: análise das publicações acadêmicas entre 2010 até 2019
Authors: Poubel Clarissa Menezes de Souza , Pinho Leandro Garcia , Lopes Mariana Sena , Martinez Silvia Alicia
Published: November 2022

Este artigo tem por objetivo apresentar um levantamento de caráter bibliográfico a respeito das publicações acadêmicas sobre escolarização de pescadores/as. Para isso, realizou-se um mapeamento do conhecimento já elaborado na área, apontando as principais análises e suas contribuições, assim como os temas mais investigados e as abordagens metodológicas utilizadas conforme o indicativo procedimental de estudos dessa natureza (ROMANOWSKI; ENS, 2006). Para tanto, utilizaram-se nessa investigação as publicações indexadas na Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) no que tangem aos trabalhos de conclusão de curso de graduação, mestrado e doutorado e ainda no Google Acadêmico quanto aos artigos científicos, levantamentos estes com prazo de 10 (dez) anos (de 2010 a 2019). Foram encontrados um total de 30 (trinta) publicações acadêmicas que tratam especificamente da temática escolarização de pescadores, cujas abordagens reafirmam a premissa da educação como direito de todos; e, ainda, observou-se certa escassez de publicações nesse campo do conhecimento.
Análise da Implantação de Plantas Medicinais em Horta de Laje como Adjuvante no Tratamento e Prevenção da Tuberculose
Authors: Nilo Marcela Caroline Bezerra Gama
Published: November 2022

A tuberculose é uma doença infecciosa causada pelo Mycobacterium tuberculosis que ainda leva à morte cerca de 5 mil pessoas por ano no Brasil e a maior incidência é no estado do Rio de Janeiro (aproximadamente 800 pessoas por ano). O presente trabalho tem como objetivo analisar a viabilidade da implantação de uma horta-piloto na laje do Instituto Vila Rosário, em Duque de Caxias-RJ, bem como os aspectos técnicos, financeiros e produtivos dessa implantação. Visa, também, estabelecer as condições necessárias para a manutenção e a sustentabilidade do sistema em longo prazo. Foram cultivadas 7 espécies vegetais com ação cientificamente comprovada no auxílio da prevenção e no tratamento da tuberculose.        Cerca de 12kg de material vegetal foi colhido ao longo do projeto. Os resultados obtidos mostraram que é viável implantar uma horta valendo-se do modelo utilizado. No entanto, para ampliação do projeto será necessário otimizar o processo, promover a capacitação das pessoas nele envolvidas, bem como contar com incentivo político e financeiro através de organizações interessadas. Ao Instituto, caberá o acompanhamento do projeto para avaliar o efeito positivo da adesão deste projeto nos casos de tuberculose (TB) da região em que atua.
Detection of the effects of the various denture cleansing methods on overdenture retentive attachments with a scanning electron microscope
Authors: Paken Gamze , Karagözoğlu İrem
Published: November 2022

Background/Aim: The purpose of this in vitro study was to evaluate the effect of mechanical and chemical denture cleansing methods on dental attachments of varying retention with a scanning electron microscope. Material and Methods: An implant analog and a male part of a dental attachment were embedded into an acrylic block, and an abutment was screwed onto the analog. Different locator attachments with varying retention were tested using different denture cleansing methods and tap water for a time simulating 12 months of clinical use. A pull-out test was performed for each attachment, followed by analysis of the samples with a scanning electron microscope. Results: For the blue attachment group, there was no statistically significant difference between the retention values of control and chemical and mechanical denture cleansing groups (p>0.05). The clear and pink attachments were affected by chemical and mechanical denture cleansing, and had significantly decreased retention values compared to the control group (p<0.05). For both types of attachments, the mechanical cleansing group exhibited the lowest retention loss value. Scanning electron microscopy results showed that surface irregularities, scratch lines, and deformations were detected in chemical and mechanical denture cleansing groups for all types of retentive attachments. Conclusions: Both attachment systems with different retentions were influenced by the denture cleansing method. Considering the results, clinicians could recommend the most appropriate method to patients, one that does not adversely affect the properties of the retainer parts. Clinicians should not advise using mechanical and chemical denture cleansing methods to protect the long-term retention of pink and clear attachments.
Is there any differences in magnetic resonance imaging findings of painful temporomandibular joint between patients with and without vertigo?
Authors: Fatih Çiçek , Kirarslan Özge , Iğneci Mehmet , Tuncay Ezgi , Koca Cansu
Published: November 2022

Background/Aim: Temporomandibular disorder (TMD) is an umbrella term and consists of pathological situations about temporomandibular joint (TMJ) internal structure, masticatory muscle and associated structures. Otalgic complaints are included in the group of complaints within TMJ associated structures and are frequently seen with TMD. The aim of this study is to evaluate the magnetic resonance imaging findings (MRI) of patients who had unilateral pain in the preauricular region, diagnosed with vertigo. Material and Methods: The present retrospective and cross-sectional clinical study was carried out on patients presenting with preauricular pain referred to XXX University Faculty of Dentistry Department of Oral and Maxillofacial Surgery between 2018 and 2020. There were 2 groups as vertigo and health groups. MRI findings were the primary predictor variables, while pain was the primary outcome variable, recorded on a visual analog scale (VAS). Results: 120 patients were included in the study. The patients included in both groups are between 19 and 65 years of age and there is no significant statistical difference between mean ages of the groups (p>0.05). The VAS values varies between 6 and 9 in both groups. There is no significant statistical difference between mean VAS values of the groups (p>0.05). On the painful side there is no significant difference between the groups in terms of disc/condyle relation (p>0.05). On the other hand moderate effusion (61.4%) was significantly higher in the healthy group while severe effusion (54%) was significantly higher in the vertigo group (p<0.01). Conclusions: Although both groups had the same pain scale, it was observed that the vertigo group had more dramatic MRI findings in terms of disc/condyle relation and presence of effusion. This study is the first to evaluate the disc/condyle relation and the presence of effusion through MRI in vertigo patients diagnosed with TMD.
Antidepressants and COVID-19: A case report and review of the literature
Authors: Dabetić Marija , Nešić Milica , Dabetić Uroš , Latas Milan
Published: November 2022

Introduction. Anti-inflammatory potential of antidepressants was observed before the COVID-19 pandemic. However, it recently regained spotlight when studies with large number of patients showed that antidepressants reduced the risk of intubation and death in COVID-19 symptomatic infection. Also, the response to antidepressants seems to be more rapid in post-COVID depression that in non-COVID19 related depression. The aim of this paper to review the literature regarding the effects and mechanisms of action of antidepressants in COVID-19 infection and post-COVID sequalae, and to present a case repot of a typical outpatient with post-COVID depression. Conclusion. Post-COVID depression is a common sequela of COVID-19 infection. Selective serotonin reuptake inhibitors elicit a rapid and efficient response in patients with post-COVID depression, which may be explained by their anti-inflammatory properties. Timely screening and treatment of post-COVID psychiatric disorders can significantly decrease the burden of COVID-19 pandemic both at the individual and societal level. Also, it is discussed how the pandemic studies of antidepressant mechanisms of actions provided new insights on the aetiology of depression.
Melodic models and modelling: The fundamental system of knowledge acquisition in music
Authors: Karan Gordana
Published: November 2022

In the pursuit of developing a fundamental understanding of terms, phenomena, rules and meanings in music, vital to the performance and interpretation of a musical work, it is necessary to apply a methodologically grounded system to the reading of a score that efficiently establishes a basis for understanding the musical content and contributes to the development of musical abilities and musicality more broadly. In the musical-pedagogical process, as part of the wider set of music disciplines (harmony, counterpoint, music forms, knowledge of music styles), the most crucial are the methods and systems of work which allow the reading of musical notation and the understanding of a musical piece to be generated and profiled. The system of models and modelling is a form of work about the perception and reception of a musical work composed on a musical model and the process of working with that model, i.e. modelling. The complexity of the system is reflected in the two sub-elements of modelling: the development of associative abilities by recalling the sound of the model, and gaining an automatic response to sound. Until now, work on models and modelling has been treated using a musical-pedagogical approach. In this study it is defined as a system which is applicable to the process of reading and interpreting a musical text, without being predicated on musical style or the tonal bases of music.
Ideas of globalism in Hollywood sitcoms
Authors: Simović Vlade
Published: November 2022

Globalization is a process that has lasted for centuries. People naturally tend to cross state borders. Some from cultural motives of getting to know the world, others from economic ones, and others from political ones. Over time, the idea of globalism emerged. It implied a directed activity of global importation of the world with the aim of strengthening large corporations and their countries. These are primarily corporations and political elites of the United States. Those ideas of globalism are promoted and imported into the modern world through the creation of greater economic interdependence and de-sovereignization of states, through military and political domination, through new technologies, but also through culture and the media. In that context, Hollywood series also play an important role. By analyzing the content of the most watched Hollywood sitcoms, such as The House of Cards, The Americans, The Big Bang Theory and Two and a Half Men, this research determines which ideas of globalism these series promote and in what way. This raises the question of the importance of Western media and culture in the process of globalization of the world.
Enforcement of the EU law in member states: Case of the rule of law in Poland
Authors: Tučić Boris
Published: November 2022

The subject of the paper is a six-year dispute between Poland and the European Union (EU) related to a systemic crisis in the field of the rule of law in this member state and the instruments the EU and some other relevant international political and legal authorities such as the Council of Europe used in order to overcome this challenging situation, as well as the results achieved to date. Considering their nature, the instruments used in this matter are generally divided into two categories. On the one hand, there are political instruments, such as the Rule of Law Framework, established in 2014 by the European Commission, or the procedure of the implementation of political sanctions against a member state defined in Article 7 of the EU Treaty. On the other hand, there are judicial instruments managed primarily by the European Commission and the Court of Justice of the European Union, among which the infringement procedure from Article 258 of the Treaty of Functioning of the European Union holds the central position. The analysis shows that none or very little progress has been achieved until now, and that the effects of the EU's bureaucratic manner of managing the crisis have been counter-productive, only provoking a more explicit involvement of the Constitutional Court of Poland, as a "heavy player", into this dispute. At this moment, it seems that both sides faced the wall and that everyone is staring into the Constitutional Court expecting the magic formula out of it, according to which the fundamental EU criteria in the field of the rule of law would be met with zero or minimum political damage made to the Polish ruling political subjects. In our opinion, the aforementioned implies that a possible way out of the conflict must be sought in the sphere of political negotiations and diplomacy and not in rigid but ineffective legal or judicial procedures.
Sociocultural aspects of political activism: A new model proposal
Authors: Nešić-Tomašević Ana , Žolt Lazar
Published: November 2022

This paper analyses the correlation between political activism, political participation, and certain value orientations, as crucial parts of modern governance in society today. A sample of the survey were members of the ruling and opposition parties, who were structured by age, place of residence, political affiliation, and role in local parliaments in six cities in Serbia. Results show a mixture of pre-modern (traditional), modern, and postmodern values, with traditional values still being viable, which could be one of the factors that significantly reduces the process of social transition. Socio-demographic variables and value orientations (autocratic-democratic, traditional-modern), along with the aspects of political culture, determine political behaviour to a large extent. The model of political activism, on which the study is based, is the model of socio-economic status. The results of the research suggest that a new, enhanced model should be proposed, entitled socio-cultural model of political activism.
The Structure of Tip Vortices Over a Range of Cavitation Number
Authors: Higuchi H. , Arndt R.E.A. , Arakeri V. , Killen J.
Published: November 2022

The tip vortex roll-up process from an elliptic wing was experimentally investigated. Cavitation provided an excellent method for visualizing the mechanism of vortex roll-up. The velocity profiles of the non-cavitating vortex were first obtained with a laser Doppler velocimeter. The measured asymmetry of the velocity profile and the computed pressure distribution in the vortex core are discussed. In the case of fully developed cavitation, the vortex trajectory was analyzed and compared with theory. The cavity core radius increased with reduced pressure until the developed cavity forms a twisted ribbon structure. The core thickness and the wave length of these structures are also discussed.
Scaling of Tip Vortex Cavitation Inception
Authors: Hsu C. C. , Renmers K.
Published: November 2022

A practical method for predicting tip vortex cavitation inception of marine propellers is described. Cavitation of tip vortex first occurs when the local pressure inside the vortex reduces to the vapor pressure of the fluid. The minimum pressure in the vortex is reached at the radius of the viscous core. An expression for tip vortex cavitation inception number is derived based on a study of Hsu (1989). with the assumption of power-law circulation distribution.

The radius of the viscous core in this approximation depends on the circulation distribution and diffusive action of the fluid viscosity.

Accurate determinations of circulation distributions for propellers operating behind ships by purely theoretical means can be quite difficult. In the present paper a calculation procedure for estimating tip vortex cavitation inception number is outlined with the aid of model experimental data. Cavitation experiments of various model propeller in simulated full scale wake were carried out in the David Taylor Research Center 36-inch Variable Pressure Water Tunnel. Experimental data have been extensively analyzed and used for tip vortex cavitation inception predictions. Some comparisons between the present prediction method and ship trial data are made. with results in good agreement.
Unsteady Gaseous Diffusion Associated with a Fully Cavitating Oscillating Flat-Plate Hydrofoil
Authors: Ravindra Krishnaswamy , Parkin Blaine R.
Published: November 2022

Although the emphasis of this paper is on gaseous diffusion into a full cavity behind an oscillating flat-plate hydrofoil, the unsteady diffusion theory given below applies also to the limiting case of "steady" supercavitating flow. The entire unbounded flow is assumed to be turbulent and a turbulent diffusivity is employed which enables one to make engineering estimates of the total diffusion rate into or out of the cavity. The theory accounts for fluctuations in cavity gas pressures and in cavity lengths.
A Numerical Model for Three-Dimensional Bubble Dynamics in Complex Flow Configurations
Authors: Chahine Georges
Published: November 2022

In most practical configurations where cavitation occurs, bubbles are not in a uniform or axisymmetric flow field and existing bubble dynamics models, either spherical or axisymmetric, are only more or less appropriate approximations. In this paper we will describe on-going studies which consider the fully three-dimensional bubble dynamics problem. The interaction between a growing, deforming and collapsing bubble near a boundary and/or in a non-uniform flow field is simulated numerically using a Boundary Integral Method. The collapse of a large bubble near a solid flat plate in a gravity field is considered as a first example. The plate orientation relative to the gravity field significantly influences the three-dimensional bubble shape and behavior. Another not previously solved case considered here is the growth and collapse of a bubble in a vortex line flow. The paper presents the method and shows on examples the influence of the various geometric or flow parameters on the bubble dynamics.
Cavitation Inception on Rotating Rods
Authors: Latorre R.
Published: November 2022

In order to investigate the character of cavitation inception from rotating rods, a series of experiments were performed in the 5000x450x450 mm test section of the University of Tokyo Propeller Cavitation Tunnel. This paper presents a summary of the experimental design, a comparison of the cavitation patterns for stationary and rotating rods, and the measured noise spectrum. The test results showed that for the smaller Rod I the pattern and noise spectra of the cavitation are similar. In the case of the larger Rods 11 and III, there is some difference in the patterns and corresponding noise levels.
Scaling Problem of Dynamic Motions in Waves From Model Tests of Surface Effect Ships and Air Cushion Vehicles
Authors: Kaplan Paul
Published: November 2022

A description of the reasons for the unconservative lack of motion response scaling from model tests in waves of surface effect ships (and other air cushion vehicles) is given. The dominant influence of ambient atmospheric pressure is shown, with results considered in terms of both steady state and transient response characteristics. Special model test procedures that attempt to overcome this problem are discussed, together with a final recommended procedures for use in predicting full scale behavior.
1800 AD High Speed Marine Vehicles - 1800 AD
Authors: Gillmer Thomas
Published: November 2022

The political situation in the U.S. in these first years of the 19th century was, on a smaller scale, much like subsequent situations, even today. The administration of Thomas Jefferson had trouble with Mediterranean mid-East terrorists working out of Libyia, pirating and taking American hostages. A naval squadron was sent to stabilize the matter. Otherwise, there was much pressure to cut down the defense budget and decommission all but ten active warships… which was done.
Ridge Modelling: Model Scale Simulation of Ridge Ramming Event with the USCG Polar Star
Authors: Comfort G. , Keinonen A. , Spencer D. , Peirce T.
Published: November 2022

Ridges are important features of the ice environment which can greatly effect the performance of ice breaking vessels. The performance of ships the ridges is an area that is not well understood at present as the vork to date has generally been focused on the performance of ships in level ice.
Effect of Normal Pressure on Kinetic Friction Coefficient: Myth or Reality?
Authors: Tatinclaux J.
Published: November 2022

Analysis of a number of friction experiments, mostly between ice and various materials, has shown that in all cases the frictional force is a linear function of the normal load rather than proportional to some fractional power of it as predicted by Oksanen's theoretical equation. This could indicate that Oksanen's basic assumption that "the only cause of friction is the water layer formed by frictional heating between the ice and any given surface on which it is sliding” may be invalid, in particular when the roughness height of the surfaces is greater that the water layer thickness. Other processes, gouging or mechanical abrasion, may then become predominant.
A Preliminary Investigation of Model Ice Failure Pattern and Piece Size Generated by IceBreaker Bow Form
Authors: Newbury S.
Published: November 2022

The icebreaking pattern and piece size is studied by photographing the breaking pattern in EG/AD model ice after the icebreaker model has been stopped and backed up. The ice pieces broken by the bow float to the surface and the breaking pattern is evident.

Three different scale models or the R-Class icebreaker have been tested (1:40, 1:20, 1:8), as well as a 1:22.5 scale model or the "Kigoriak". The data from these tests are compared to the available full scale data. Comparisons show a realistic breaking pattern in the model ice, but non-dimensionalized piece sizes are larger than those in full scale. Cracks in the model ice pieces indicate a smaller piece size, but this is prevented by what ls believed to be a high residual strength in the model ice.
Ship Model Testing in Simulated Ice Flow Covered Waters
Authors: Aboulazm A. , Muggeridge D.
Published: November 2022

The problem of ship resistance in ice floe infested waters has been investigated experimentally in the Towing Tank of Memorial University of Newfoundland. Ships and ice have been modelled to simulate the natural condition of ships sailing in waters covered with ice fragments.

Ships advancing in waters coveted with ice floes of moderate size, with less than 100% concentration and with no lateral pressure seldom break any ice. The ship and the ice floes have therefore, been treated in this investigation as freely floating rigid bodies. Both the ice floes and the ship have, therefore been modelled in accordance with Froude principles.

The ice cover was modelled using blocks of paraffin wax spread over the water surface. Slabs of wax were cut into small blocks having thickness and size in accordance with the required geometrical modelling scale. Wax blocks were spread over the water surface according to the required ice cover concentration. Ship models were towed in the tank at different speeds. The model resistance for each run was measured and recorded.

Results obtained from model testing experiments are presented in this paper. The results cover a number of ship model runs at different ship speeds, and for a variety of ice cover conditions. The results have been compared with ice floe resistance data available in the literature.
A Six Degree-of-Freedom Dynamic Test Facility: Concept and Feasibility
Authors: Mackay M. , Walker R.
Published: November 2022

This paper outlines the requirements, concept and feasibility of a six degree-of-freedom test rig for dynamic experiments with captive models. The specifications are driven by the requirements of submarine testing, although the rig must also be fully capable of testing surface ship models. Large amplitude motions and rates are required in order to obtain the nonlinear stability derivatives.

The test rig was designed for operation on the carriage of the 200 meter towing tank at the Institute of Marine Dynamics, St. John's. It will accept submarine models up to 6 meters long, using a sting mount at the tail of the model to alleviate support interference, but modelling the propulsion system will generally require an alternative mounting arrangement. The principal actuators are hydraulically-driven ballscrew jacks, Under the control of a microcomputer. In addition to testing with harmonic motions, there is a capability for measuring forces and momenta for an arbitrary trajectory of the model, subject only to kinematic limitations.
Video Systems For Propeller Viewing Trials
Authors: Kennedy J. , Sponagle N. , Wheaton D. , MacDonald P. , Creaser R.
Published: November 2022

Propeller viewing trials are a necessary adjunct to towing tank and cavitation tunnel tests, if a full assessment of propeller performance is to be made. Unfortunately, viewing trials are rare because of the expense and disruption caused by the installation of propeller viewing ports. Additionally, assessment of cavitation inception and other performance parameters is difficult because of the poor performance of the human eye under stroboscopic lighting.

The Defence Research Establishment Atlantic, in conjunction with its contractors, Networx Technologies and Eyretechnics Limited, has developed video systems to overcome many of the deficiencies of conventional viewing trials. The development of this system is described, from a concept demonstrator employing conventional viewing ports, to systems which are external to the hull. The external systems eliminate the need for viewing ports and can be installed by divers with the ship afloat. The current system, cperating with shaft synchronized stroboscopic lights, allows storage of selected propeller cavitation images for simultaneous or later display on conventional video equipment. Examples of installation and trial results are given.
Recent Developments at UNO (1986-89)
Authors: Latorre R.
Published: November 2022

On July 23, 1987 the University of New Orleans (UNO) dedicated Its new engineering building which houses the 125ft 8 in x 15ft x 0-7ft deep Ship Offshore University Laboratory Towing Tank. This paper describes the developments from 1987-1989 as well as some of the future plans for the tank in the areas of

Teaching

Research

Technical Support.
Model and Full Scale Monitoring of a Jacket Docking over a Template
Authors: da Silva Sergio , Hirata Kazuo
Published: November 2022

This work presents results of model tests and full scale monitoring of a jacket docking over a template.

In model tests the system composed by the jacket and the crane ship were expose to regular, transient and irregular waves. Jacket accelerations crane ship motions and guide loads were recorded at tests. Similar variables were monitored at full scale.

Differences in environmental conditions precluded a comparison between model tests and full scale monitoring. But some few conclusions were obtained as follows:

Crane ship rolling motions occurs in following seas. As a consequence, loads at guides perpendicular to wave direction become the same order of loads parallel to wave direction.

Loads at guides are changed significantly due to waves direction.

Current forces acting on jacket, simulated by a counterweight, increases the dynamic loads on guides.
Model Testing of Deep Water Mooring Systems
Authors: Leonard J. , Tulin M.
Published: November 2022

A technique is developed which allows, for the first time, many deep water mooring systems to be experimentally modelled In tanks previously considered too shallow. Special use is made of pertinent non-dimensional parameters which describe how to artificially adjust the models masses, stiffnesses and damping. We call this new technique "Bi-Scaling. Essentially the scale factor for the vessel Is allowed to be different than the scale factor for the mooring lines (and depth). A complete set of Bi-Scaling relations for the artificial adjustments is presented and experimental verification of the Bi-Scaling technique is carried out.
Self-Propulsion Experiment for Icebreakers in Ice and Open Water
Authors: Molyneux W.
Published: November 2022

An icebreaker propulsion system has to be versatile in order to perform at optimum efficiency in all operating conditions. It must be economical when steaming in open water, and yet deliver large thrusts in the bollard condition. It must also withstand the loads imposed by the fee, which can be in the form of a steady load during tee milling, or a transient load due to tee impact. All these factors combine in a complicated manner, and physical model experiments are currently the best method available for studying the problem. An experiment program to predict the propulsive performance of an icebreaker must therefore address both the open water and icebreaking aspects, in an accurate and efficient manner.

This paper discusses some techniques developed to predict the propulsive performance of large ice­breakers, using models in a refrigerated tee basin and a towing tank. It is based on some experiments recently carried out at the Institute for Marine Dynamics (IMO). in St. John's, Newfoundland and the results are used for illustration purposes throughout this paper.
Mean-Flow Measurements in the Boundary Layer and Wake of a Series 60 CB = .6 Model Ship With and Without Propeller
Authors: Toda Y. , Stern F. , Tanaka I. , Patel V.
Published: November 2022

Results are presented from a towing-tank experiment of propeller-hull interaction conducted in order to provide detailed documentation of the complete flow field appropriate both for explicating the flow physics and validating computational methods. Mean-velocity and pressure field measurements were made for the with and without propeller conditions for the Series 60 CB = .6 hull form, Surface-pressure distributions and wave profiles were measured for both conditions. Resistance and self-propulsion teats were also conducted, An overview of the experiments is given, and some example results are discussed to point out the essential differences between the flows with and without propeller. The results are analyzed to assess the nature of the interaction between the propeller and the hull boundary layer and wake. To this end, use is made of a propeller performance program with both nominal and effective inflows. It is shown that most features of the interaction can be explained as a direct consequence of the propeller loading resulting from its operation with a three-dimensional nonuniform inflow.
An Examination of Axisymmetric Propeller-Hull Interaction Effects and Their Impact on the Design of Propeller-Vehicle Systems
Authors: Uhlman James
Published: November 2022

It has been recognized for some time that the interaction between the flow past a vehicle hull with that through the vehicle's propulsor is significant in the sense that the loads experienced by the propulsor and the hull can be drastically alterred by the interaction. Traditionally these interactions have been taken into account empirically. More recently simple interaction models have begun to be used 10 obtain more accurate theoretical predictions of these effects. Herein is contained a program which advances the state-of-the-art by integrating currently available models to calculate these interaction effects directly.

Separate numerical models presently exist for the calculation of the flow about an axisymmetric body and for the flow through a propeller. The present program, APHIPS (Axisymmetric Propeller-Hull Interaction Program System), employs a boundary-integral model for the axisymmetric potential flow about the vehicle hull, a finite-difference model for the axisymmetric boundary-layer flow along the hull and a full three-dimensional boundary-integral model for the calculation of the potential flow through the propeller. These three flow models interact and the solution of each modifies the solution of the other two. The final equilibrium achieved represents the flow solution about the hull-propeller system with all the interactions taken into account.

The APHIPS program has been employed to predict the interaction of the hull and propeller flows about bodies of Navy interest for which experimental measurements exist. The results of the numerical calculation have been compared with the experimental findings for validation and the agreement has been found to be good. Preliminary investigations into the nature and magnitude of the flow interactions have also been performed. Examination of these results indicates that the interactions can be quite significant and can therefore have a large impact on the design of propeller-vehicle systems.
Computation of Total Forces and Moments of Bodies of Revolution Moving Beneath the free Surface
Authors: Hong Young
Published: November 2022

The accurate prediction of the total forces and moments of a body of revolution which is moving beneath the free surface with and without an angle of attack is one of the important areas in ship hydrodynamics. The experiments to measure these forces and moments were undertaken in the past by several researchers. The experimental results of forces and moments for a body of revolution near the free surface were reported in Reference 1 for various angles of attack and depths. Those of deep submergence were given in References 2, 3, and 4 for different angles of attack. Although there are many other published papers on the measurement of forces and moments, only the results of References 1-4 are used in this paper to compare with the predicted results. The total forces and moments consist of two parts in the present method; namely the inviscid part and the viscous part. The inviscid part of the forces and moments is computed using three-dimensional potential theory. The body boundary condition is exact and the free-surface condition is linearized. The body surface is discretized with many surface elements and the unknown strengths of the source and sink at each surface element are assumed to be constant. The velocities at surface elements are computed and saved for later computation of the viscous forces and moments. The viscous part of the forces and moments is computed with the application of the boundary layer theory for laminar and turbulent flows. The method developed by Young (Reference 5) is used to compute the total drag of bodies of revolution. It is assumed in this method that there is no flow separation. The axial force is computed with this method. The lateral force and pitching moment are computed under the assumption that there is separation in the two-dimensional cross flow. The boundary layer equation is solved to the separation point and the friction force is integrated to compute frictional drag. Furthermore, it is assumed that a constant pressure is acting on the two-dimensional section beyond the separation point.
Uncertainty in Measurement of Ship Model Wave Profiles and Wave Pattern Resistance
Authors: Ratcliffe Toby , Wilson Michael
Published: November 2022

Two sets of longitudinal wave cut data serve as the basis for estimating the measurement uncertainty associated with the ship model waves profiles and wave pattern resistance. The data was obtained from two similar frigate type hull forms tested over a speed range from Fn=0.25 to 0.5. Five wave probes were used simultaneously to measure wave elevations and from these measurements five parallel estimates of wave pattern resistance were obtained. The elemental bias and precision error sources which are encountered are grouped and discussed according to three categories; calibration, data acquisition and analysis.
An Investigation into Effect of Hull Form on the Wake Wave Generated by Low Speed Vessels
Authors: Renilson M. , Lenz S.
Published: November 2022

The erosion caused by vessel wake has for many years caused problems in restricted waterways (See for example Camfield et al. [1980]). It has generally been assumed that the errosive qualities of a wake wave pattern is related to the maximum wave height of that pattern. (Nanson et al, [1987]).

In order to investigate the effect of hull shape on the size of the wave, model and full scale experiments were carried out by the Ship Hydrodynamics Centre at the Australian Maritime College.
Roll Damping For Small Fishing Vessels
Authors: Bass D. , Haddara K.
Published: November 2022

The successes of Naval Architects in predicting ship motions in waves, have been mainly confined to motions other than roll. For roll motions it has long been recognized that roll damping for wave encounter frequencies near the natural roll frequency is not only an extremely significant parameter but also very difficult to predict accurately. Because of the need to consider viscous flow (or even 'slightly viscous flow') to correctly model roll damping phenomena, there is still some way to go before an adequate numerical model of the hydrodynamics of roll is forthcoming. For this reason empirical and semi-empirical methods have played and will continue to play an important role in the prediction of roll motions. For small fishing vessels with deep skegs, hard chines and nonstandard hull shapes, the prediction of roll damping is particularly difficult due to lack of available data bases, semi- empirical formulae, and of course adequate theoretical models. It was for this reason that the present study was undertaken. In all, six small fishing vessels will be studied, each of which lies in the 'less-than 25 meter' class. They are all of similar dimensions but have varying hull forms ranging from the angular (e.g. model '363') to the rounded hull form of '366' (see figure 1).

Apart from providing a data base for the estimation of damping for different hull forms, the study will be used in the analysis of mathematical and/or numerical methods for the prediction of roll damping that the authors hope to develop (or hope will be developed) in the future. The present paper describes preliminary investigations of roll damping characteristics for just 3 of the boats. The methodology employed was that of the classical roll decay test with an innovative feature-namely the use of a newly developed method of analysis which enabled the authors to obtain the non- dimensional damping coefficient from the complete roll decay curve taken over just one full cycle. This method of analysis is based on an energy approach and is explained in [l]. Using this approach, the roll damping moment dependence on the initial roll angle is easy to obtain. The emphasis in this paper is a 'frequency domain' analysis of the results with equivalent linear damping as the primary target. The advantage of the simple decay test is that it allows for analysis in both the frequency and time domains. A study of the results in the time domain will be presented in a later paper. The simplicity of the roll decay experiment also means that many experiments can be perfomed and regression analysis carried out on the results. Over one thousand such tests were performed for the three models in this study. The body plans for the three models are shown in figures 1 (a), (b), (c), and their particulars are given in Table l.

In the experiments the models were attached to a dynamometer with just 2 degrees of freedom; the model was free to roll and heave, but restrained in all other modes.
Swath Resistance in Waves with Associated Steady and Dynamic Responses
Authors: Chun H. , Djattniko E. , McGregor R. , Ferguson A.
Published: November 2022

A series of tank tests were conducted to compare the hydrodynamic performances of single and twin strut SWATH models with forward speeds. The measurements were the added resistance in regular head waves of frequency of 0.3 to 1.6 Hz together with associated dynamic responses (heaving, pitching and surging) and steady responses (sinkage and trim).

Also, stationary tests were performed to measure the motion responses for the two models in head, quartering and beam seas. The measurements of the bending moment at the cross deck mid section of both models in beam seas were included. Some of these hydrodynamic properties for both models are compared with the computational results based on a 3-D diffraction theory. The main purpose of this paper is to compare the single and twin strut SWATH ship from the hydrodynamic performance point of view.
Seakeeping Tests of a Swath Model in a small Towing Tank
Authors: Ninh P. , Li J. , Hsiung C.
Published: November 2022

The Technical University of Nova Scotia, Halifax, Nova Scotia has a small ship-model towing tank located in the Civil Engineering Hydraulic Laboratory, currently being used by the Ship Hydrodynamics Research Group.The dimension of the tank is lm x lm x 30m. A carriage is driven by a 1/4 horsepower constant torque DC motor. It can reach a maximum velocity of 2.44 m/s (8 ft/s) and sustain a maximum model resistance of 9.1 kgs (20 lbs). The motor control unit permits the carriage to be run in both forward and reverse directions at the same speed with a maximum acceleration or deceleration of 1.22 m/s^2 (4 ft/s^2) as shown in Fig. 1.

A precisely computer-controlled wave-making system has been purchased from Edinburgh Design Ltd., U.K. and recently installed in the tank. It has two wave-makers, one at each end. Either one can act as a wave-maker or a wave-absorber (Figs. 2 and 3). The system can make progressive waves or standing waves, as well as regular waves or irregular waves. The maximum wave height is about 0.3 m (1 ft) and the frequency range for sinusoidal wave generation is from 0.2 hz to 2 hz.

A motion measurement device was developed in-house for the two-degree of freedom of motions. In particular, heave and pitch displacements could be measured simultaneously. It consisted of a LVDT (linear variable differential transformer) and a RVDT (rotational variable differential transformer) of 10% linearity. The LVDT was mounted on the carriage just above the model and the RVDT was attached directly at the base of the heave staff. The model was attached to one end of the heave staff by a connecting device. This device was designed in a way such that only one rotational motion, pitch was permitted. The heave staff was made of a square aluminum rod and guided by eight high-precision roller bearings housed in a PVC block. This rod, in tum, allowed the model to move in heave only. Except heave assembly is shown in the schematic arrangement (Fig. 4) and Fig. 5.

The hull form chosen for this seakeeping test was a SWATH 4A hull with the sectional area curve and the waterplane curve shown in Fig. 6 [l). The model used in the present study was constructed of balsa wood to a scale factor of 1:153 (Fig. 7). A list of principal particulars is given in Table 1. The model was ballasted to the design waterline. Longitudinal CG was measured by weighing the model on a weighing scale, vertical CG was measured through an inclining experiment, and the radius of gyration was determined by swinging the model in pitch with the pivotal method.
LA PERCEPCIÓN MUSICAL: UN ESTUDIO CON ESTUDIANTES UNIVERSITARIOS DE ESPAÑA Y PORTUGAL
Authors: Olcina-Sempere Gustau , Reis-Jorge José , Ferreira Marco
Published: November 2022

El presente artículo se ha realizado con estudiantes universitarios que estaban realizando el Grado de Maestro de Educación Primaria en España y Portugal durante el curso 2018-2019. El objetivo prin- cipal es conocer hasta qué punto la visualización de la interpretación musical transmite emociones diferentes de las transmitidas solo al escucharla. Diversos estudios han demostrado que la percepción de las emociones provocadas por la escucha de la música está en gran medida influenciada por la interpretación de los músicos. En este estudio, se utilizó un cuestionario compuesto por preguntas cerradas para recopilar los datos. Participaron 125 estudiantes de sus respectivas instituciones de edu- cación superior tanto en Portugal como en España. Los resultados obtenidos corroboran, en general, las representaciones teóricas y los resultados empíricos presentados en la literatura previa. Los parti- cipantes muestran que la visualización de una obra musical genera diferentes emociones generadas por la interpretación del músico, es decir, que los rasgos interpretativos de cada intérprete son de vital importancia para la transmisión de las distintas emociones.
ENTREVISTA A ARTURO MÁRQUEZ
Authors: López Prado José María , Salcedo Moncada Beania
Published: November 2022

1El compositor mexicano Arturo Márquez es uno de los compositores más célebres a nivel inter- nacional del panorama musical mexicano de la música de concierto. El maestro ha sido acreedor a diversos galardones en México y el extranjero, entre ellos las medallas Bellas Artes, Mozart, Dr. Alfonso Ortiz Tirado y Orgullo Sonorense 2009, así como el California Institute of the Arts Distin- guished Alumnus Award y el Premio Nacional de Ciencias y Artes 2009, por mencionar algunos. Asimismo, ha recibido numerosos homenajes en festivales de música de Latinoamérica, donde sus obras han sido interpretadas y han conseguido popularidad. Sus danzones son utilizados con mayor frecuencia en producciones balletistas alrededor del mundo, gracias a lo cual en 2004 el Festival Internacional de Música realizado en Caracas, Venezuela, fue denominado con su nombre