bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling and Multi-objective Optimization of Elastic Abrasive Cutting of C45 and 42Cr4 Steels
Authors: Aleksandrova Irina , Stoynova Anna , Aleksandrov Anatoliy
Published: December 2021

Elastic abrasive cutting is a new high-performance method to produce workpieces made of materials of different hardness, which ensures lower wear of cut-off wheels and higher quality machined surfaces. However, the literature referring to elastic abrasive cutting is scarce; additional studies are thus needed. This paper proposes a new approach for modelling and optimizing the elastic abrasive cutting process, reflecting the specifics of its particular implementation. A generalized utility function has been chosen as an optimization parameter. It appears as a complex indicator characterizing the response variables of the elastic abrasive cutting process. The proposed approach has been applied to determine the optimum conditions of elastic abrasive cutting of С45 and 42Cr4 steels. To solve the optimization problem, a model of the generalized utility function reflecting the complex influence of the elastic abrasive cutting conditions has been developed. It is based on the findings of the complex study and modelling of the response variables of the elastic abrasive cutting process (cut-off wheel wear, time per cut, cut piece temperature, cut off wheel temperature and workpiece temperature) depending on the conditions of its implementation (compression force F exerted by the cut-off wheel on the workpiece, workpiece rotational frequency nw, cut off wheel diameter ds). By applying a genetic algorithm, the optimal conditions of elastic abrasive cutting of С45 and 42Cr4 steels: ds = 120 mm; F = 1 daN; nw = 63.7 min–1 and nw = 49.9 min–1, respectively for С45 and 42Cr4 steels, have been determined. They provide the best match between the response variables of the elastic abrasive cutting process.
Van passend naar inclusief onderwijs?
Authors: Stolk R.J.E.
Published: December 2021

Van passend naar inclusief onderwijs? Ontwikkelingen in het Nederlandse onderwijs langs de lat van het VN-verdrag Handicap

Wat is de betekenis van het recht op onderwijs volgens het VN-verdrag Handicap? Dat komt aan bod in dit artikel. Vervolgens worden de ontwikkelingen rondom het inclusief onderwijs in Nederland besproken, met een focus op het primair en voortgezet onderwijs. Ten slotte gaat de auteur in op de vraag hoe deze ontwikkelingen zich verhouden tot het recht op onderwijs in het VN-verdrag Handicap.
Early TB case detection by community-based mobile X-ray screening and Xpert testing in Balochistan
Authors: Wali A. , Safdar N. , Manair R. , Khan M. D. , Khan A. , Kurd S. A. , Khalil L.
Published: December 2021

SETTING: This survey was conducted at 35 sites of 20 cities in 15 districts with low programmatic TB case notifications in the past years in Balochistan.OBJECTIVE: To assess the effectiveness of the systemic community-based screening and diagnosis for early detection
of TB; and 2) to describe the characteristics and understand the strengths and weaknesses of the intervention in Balochistan, and sociodemographic factors associated with it.DESIGN: This cross-sectional descriptive study was conducted using a mobile van equipped with a digital X-ray
machine with computer-aided detection for TB (CAD4TB) software for screening, followed by confirmatory high sensitivity Xpert® MTB/RIF assay testing.RESULTS: A total of 236 (3.4%) TB cases was detected out of 6,899 screened. About 1,168 (17%) presumptive TB cases were identified
and 1,065 (91%) sputum samples were tested on Xpert. Among those diagnosed, 166 (70%) were Mycobacterium tuberculosis-positive and 70 (30%) were with clinical suspicion. Of the sputum samples tested, 87% (923/1065) had a probability score of >70 on CAD4TB.CONCLUSION: Community-based
screening with innovative activities, comprising sensitive screening and diagnostic tools, effectively improves TB case detection, which might suffice to reduce the prevalence of TB and break the chain of infection transmission in the at-risk population.
Integration of TB into child health policies in Africa’s high-burden countries: a normative analysis
Authors: Ehrlich J. , Garcia-Basteiro A. L. , Brands A. , Verkuijl S. , Ndongosieme A. , Detjen A. , Lopez-Varela E.
Published: December 2021

Integration of paediatric TB care into decentralised child health services has the potential to reduce the large proportion of childhood TB that remains undiagnosed. We performed a review of national guidelines and policies for TB and child health to evaluate the normative integration
of paediatric TB into existing child health programmes in 15 high TB burden countries in Africa. While integration is addressed in 80% of the national strategic plans for TB, the child health strategies insufficiently address TB in their plans to reduce child mortality. Emphasis needs to be
put on multi-sectoral collaboration among national health programmes.
Factors associated with loss to follow-up among TB patients in rural Papua New Guinea
Authors: Umo I. , Kulai M. , Commons R. J.
Published: December 2021

BACKGROUND: Papua New Guinea (PNG) is a lower middle-income country that has struggled to contain TB. The loss of patients to follow-up is a major contributing factor towards the high disease burden.OBJECTIVE: To describe persons with drug-susceptible TB (DS-TB) registered
for treatment at the Gaubin Rural Hospital (GRH) on Karkar Island, Madang Province, PNG, and to investigate factors associated with patient loss to follow-up (LTFU).DESIGN: A retrospective cohort study was conducted using data from GRH DS-TB registers. Factors associated with LTFU
were investigated using univariable and multivariable logistic regression.RESULTS: A total of 722 patients were registered for DS-TB treatment and eligible for inclusion between 1 January 2014 and 30 June 2018, of whom 97 (13.4%) were lost to follow-up. Male sex was associated with
an increased odds of LTFU (adjusted OR [aOR] 1.9, 95% CI 1.2–3.0; P = 0.005), as was travel time to GRH >3 h (aOR 3.7, 95%, CI 2.2–6.3; P < 0.001).CONCLUSION: A high LTFU rate has been identified in patients with TB in PNG. This study found male sex
and increased travel time from treatment location to be associated with unsuccessful treatment adherence, highlighting the need for further interventions to improve adherence.
Isoniazid preventive therapy in child household contacts of adults with active TB in Bamako, Mali
Authors: Tolofoudie M. , Somboro A. , Diarra B. , Sarro Y. S. , Drame H. B. , Togo A. C. G. , Sanogo M. , Dembele A. , Togun T. , Nkereuwem E. , Baya B. , Konate B. , Egere U. , Traore M. , Maiga M. , Saliba-Shaw K. , Kampmann B. , Diallo S. , Doumbia S. , Sylla M.
Published: December 2021

BACKGROUND and OBJECTIVE: Isoniazid preventive therapy (IPT) is known to reduce the risk of developing active TB in about 59% in children aged 15 years. We assessed adherence, completion and adverse events among children who were household contacts of a newly diagnosed adult
with smear-positive TB in Bamako, Mali.METHODS: Children aged <15 years living in the same house with an adult smear-positive index case were enrolled in the study in the Bamako Region after consent was obtained from the parent or legal guardian. Adherence was assessed based
on the number of tablets consumed during 6 months.RESULTS: A total of 260 children aged <15 years were identified as household contacts of 207 adult patients with smear-positive TB during the study period. Among all child contacts, 130/260 (50.0%) were aged 0–4 years and
were eligible for IPT; 128/130 (98.5%) were started on IPT and 83/128 (64.8%) completed with good adherence at the end of the 6 months, and without any significant adverse events.CONCLUSION: We successfully implemented IPT with good acceptance, but low completion rate. The Mali
National TB Program and partners should expand this strategy to reach more children in Bamako and the whole country and create greater awareness in the population.
Electrodeposited palladium as efficient electrocatalyst for hydrazine and methanol electro-oxidation and detection
Authors: Lović Jelena Dušan
Published: December 2021

Electrodeposited palladium was used as an electrocatalyst for electrochemical oxidation of hydrazine and methanol and the development of a sensitive platform for their detection. The electrochemical behavior of the electrode was evaluated by cyclic voltammetry (CV) while electroanalytical properties were determined by means of differential pulse voltammetry (DPV). The electrodeposited Pd catalyst exhibited good electrocatalytic activity towards the oxidation of hydrazine in neutral solution and methanol oxidation in alkaline solution. Under optimized DPV conditions, the electrodeposited Pd electrode shows good sensing capability in hydrazine and methanol detection.
Preventing exclusion: the role of therapists and parents in the inclusion of a disabled child in the education system
Authors: Gałkowska Monika , Kruś-Kubaszewska Katarzyna
Published: December 2021

Choosing an educational system for a disabled child already at the stage of pre-school education is a difficult and stressful experience for parents, which regardless of the final decision, raises many doubts. Certain questions arise: ‘where there is a place in the education system for the child with a disability certificate?’, ‘where the child can develop best?’, but also ‘where the child simply feels happy and does not experience exclusion?’. Many things depend on the level of the child’s disability, on key choices made by parents, and on the quality of cooperation, both in the three-way parent-therapist-child relationship, but also in the two-way parent-child and therapist-child relationships. Parents more and more often make decisions about inclusive education, where a child can develop amongst non-disabled peers. This article focuses primarily on the role of parents and therapists in the process of including a disabled child in the education system, the potential of cooperation, but also the fears, difficulties and expectations accompanying both sides.
Attitudes of parents of children with normal development towards the education system of pupils with special educational needs
Authors: Iwanicki Hubert , Lacek Agnieszka
Published: December 2021

The article focuses on the issues related to the education system of students with special educational needs. At the beginning, the concept of "parental attitude" was analysed and the main typology of parental attitudes was discussed. Then the concept and the essence of special educational needs and integrate education, inclusive education were explained along with the relationship between them. The organization of integrate education was also characterized. The main part of the publication is devoted to the presentation of the results of research carried out in order to learn about and present the attitudes of parents of children with normal development towards the education system of pupils with special educational needs. The research was carried out using the diagnostic survey method and survey technique. These studies have shown that parents of children with normal development mostly have a positive attitude towards the education system of students with special educational needs. Only some of them, who are in the minority, present a strongly or rather negative attitude. Parents of children with normal development demonstrate a great knowledge about the integrate education system. There is no doubt that the entire modern education system is currently struggling with criticism not only from parents and educators, but also from the students themselves. An important activity that should take place in every educational institution is, above all, the promotion of the idea of integration. Both the integrate and inclusive education system is the future of education in Poland. That is why it is so important and necessary to undertake educational activities that increase knowledge and social awareness in this area. Thus, the creation of integrated classes becomes an opportunity for children with special educational needs because functioning in such a class enables proper social development with peers with normal development.
THE ILO AND THE SOCIAL CONSEQUENCES OF THE COVID-19
Authors: Servais Jean-Michel
Published: December 2021

In this essay, the author gives account of how the International Labour Organization (ILO) is working to provide assistance to its members to overcome the social consequences of the pandemic in progress. The virtues of two of its tools and of their smooth interaction are successively analyzed. The Institution has first investigated the available data and published economic analyses on the disastrous consequences of the scourge on employment and therefore, on individual income. It has addressed a series of socio-economic recommendations to governments. It has secondly referred to the international legal corpus as a guide to the States in their responses to the exceptional situation. The ILO labour standards provide a threshold of minimum protection to the benefit of those who work or want to work. They constitute guarantees which appear even more important in difficult times to enable people to go through critical periods without intolerable trouble. Some could still be strengthened.
REFLECTIONS ON WORK-LIFE BALANCE FOR PARENTS AND GUARDIANS IN THE LIGHT OF DIRECTIVE (EU) 2019/1158 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL
Authors: Czerniak-Swędzioł Justyna , Kumor-Jezierska Ewelina
Published: December 2021

In this article the authors submit thorough analysis a new Directive (EU) 2019/1158 of the European Parliament and of the Council of 20 June 2019 on work-life balance for parents and carers as well as the repealing Council Directive 2010/18/EU that entered into force on August 1, 2019, paying special attention to adjusting domestic regulations to it. The solutions adopted in this Directive lay down minimum requirements designed to achieve equality between men and women regarding labour market opportunities and treatment at work, by facilitating the reconciliation of work and family life for workers who are parents, or carers. To that end, this Directive 2019/1158 provides for individual rights related to the following: paternity leave, parental leave and carers’ leave, flexible working arrangements for workers who are parents, or carers.
MODELING AND MEASUREMENT OF PARTICULATE MATTER (PM) COLLECTION FROM BOILER EXHAUST GAS IN ELECTROSTATIC WATER SPRAYING SCRUBBER
Authors: Ha T H , Nishida O , Fujita H , Harano W
Published: December 2021

Boiler exhaust gas consists of many components that cause air pollution, such as: particulate matter (PM), SOx, NOx, COx, etc. These pollutants normally are mixed. To eliminate them, an electrostatic water spraying scrubber is used, depending on a coal fuel used for combustion source in the furnace. For PM, new guidelines will be changed from the existing 10 to 2.5 microns within the next few years. The scrubber is widely used for the collection of PM from industrial exhausts because of its low equipment and maintenance costs combined with operational safety and high collection efficiency. This study presents computed and experimented results of PM collection efficiency in an electrostatic water spraying scrubber. In this scrubber electric attraction between charged PM and charged water droplet improves PM collection considerably over conventional scrubber. Computed model takes into account initial liquid momentum, hydrodynamic and electric forces. The effects of operating parameters, such as gas velocity, applied voltage, charge to-mass ratio on PM collection efficiency within the scrubber, were also investigated. Computed results are in good agreement with the experimental data obtained in the laboratory. Compared to inertial scrubbers, the electrostatic water spraying scrubbers can operate at lower flow rate, but total collection efficiency is over 98% of all PM sizes.
AERODYNAMIC LIFT FORCES ON MULTIHULLED MARINE VEHICLES
Authors: Williams A G W , Collu M , Patel M H
Published: December 2021

The need for high-speed high-payload craft has led to considerable efforts within the marine transport industry towards a vehicle capable of bridging the gap between conventional ships and aircraft. One such concept uses the forward motion of the craft to create aerodynamic lift forces on a wing-like superstructure and hence, reduce the displacement and skin friction. This paper addresses the specific aerodynamic design of multihull for optimal lift production and shows that significant efficiency can be achieved through careful shaping of a ducted hull, with lift-to-drag ratios of nearly 50 for a complete aerodynamic hull configuration. Further analysis is carried out using a hybrid vehicle stability model to determine the effect of such aerodynamic alleviation on a theoretical planing hull. It is found that the resistance can be halved for a fifty metre, three hundred tonne vehicle with aerodynamic alleviation travelling at 70 knots. Results are presented for a candidate vessel.
ENABLING TECHNOLOGY AND THE NAVAL ARCHITECT 1860-2010
Authors: Buxton I
Published: December 2021

Enabling technology permits the naval architect to do more with fewer resources, increasing output, decreasing cost and improving productivity, with the resulting benefits being widely distributed in a worldwide economy. For example a bulk carrier’s energy consumption per ton-mile today is less than 3% of what it was a century and half ago – due to more efficient machinery, larger hulls with lower resistance per ton and improved propulsive efficiency, yet with higher speed and shorter port times.
QUANTIFICATION OF UNCERTAINTY IN MANOEUVRING CHARACTERISTICS FOR DESIGN OF UNDERWATER VEHICLES
Authors: Ray Amit , Sen Debabrata , Singh SN , Seshadri V
Published: December 2021

The prediction of manoeuvring characteristics of underwater vehicles during design involves approximations at various stages. This paper attempts to quantify some of the uncertainties involved in the manoeuvring characteristics of underwater vehicles. The first source of uncertainty is in idealization of mathematical model selected for trajectory simulation. This is illustrated for alternative mathematical models in trajectory simulation programs. Next, the values of the hydrodynamic coefficients (HDCs) in the equations of motion have their own levels of uncertainty, depending upon the methods used to determine them. The sensitivity of trajectory simulation results to uncertainty levels in various HDCs is examined. Finally, the level of uncertainty in full-scale measurements of manoeuvres of underwater vehicles is discussed and estimated. It emerges that the cumulative errors in the prediction process during design need to be reduced further, in order to maintain their levels of uncertainty below those of the validation process.
COLLATING EVIDENCE FOR A UNIVERSAL METHOD OF STABILITY ASSESSMENT OR GUIDANCE
Authors: Deakin B
Published: December 2021

This paper reviews two related projects conducted for the Maritime and Coastguard Agency, and collates their findings with additional casualty data, in an attempt to promote a simple method of safety assessment. The method was developed by the author during research conducted for the Maritime and Coastguard Agency. It was evaluated in a subsequent research project, where the recommendations were that it was not worthy of adoption or further development for regulatory purposes.

Contrary to that evaluation, the method has received supportive comments from a number of naval architects, and this paper is offered as a means of presenting it more widely to the industry. Individuals may wish to use the method to assess their own designs, or to provide some simple safety guidance to operators.
LIFE-CYCLE CO2 EMISSIONS OF BULK CARRIERS: A COMPARATIVE STUDY
Authors: Gratsos G A , Psaraftis H N , Zachariadis P
Published: December 2021

In order to maintain shipping capacity to serve seaborne trade, new ships have to be built to replace those scrapped. The cost of building, manning, operating, maintaining and repairing a ship throughout its life is borne by society at large through market mechanisms. Gratsos and Zachariadis (2005) had investigated through a cost/benefit analysis how the average annual cost of ship transport varies with the corrosion additions elected at the design stage. The results of that paper clearly indicated that ships built with sufficient corrosion allowances, truly adequate for the ship’s design life, have a lower life cycle cost per annum despite the fact that such ships would carry a slightly smaller quantity of cargo. Furthermore the safety and environmental benefits due to the reduced repairs and extended lifetime of such ships were briefly discussed. The debate of how “robust” a ship should be was also transferred to IMO in the context of Goal Based Standards following a submission by Japan which stated that the increased steel weight of a more robust ship will result in increased CO2 emissions due to a reduced cargo carrying capacity. Greece replied by submitting a summary of the aforementioned paper and preliminary estimations on Life cycle CO2 emissions disputing the Japanese contentions. However, taking onboard the challenge, an update is provided in the present paper, using the final Common Structural Rules (CSR) of the International Association of Classification Societies (IACS) bulk carrier corrosion margins and taking into account the major environmental implications of the heavier ship scantlings for two bulk carrier size brackets, Panamax and Handymax. The results show that the more robust ships would produce less CO2 emissions over their lifetime.
DESIGN OF COMPLETELY AUTOMATIC ODMCS
Authors: Dave D
Published: December 2021

This paper presents a novel approach for designing a completely automatic Oil Discharge Monitoring and Control System (ODMCS) for the discharge of oily mixtures/effluents from cargo area and slop tank of oil tankers. The Global Positioning System (GPS) and modified World Vector Shorelines (WVS) data are used for the development of a system, which completely automates the working of ODMCS to comply with Marine Pollution (MARPOL) regulations. The system level hardware and software design for the same is discussed. An animated simulator for the completely automatic ODMCS is developed. The developed system may also be used as ODMCS emulator when main ODMCS fails. The results obtained by applying the test inputs to such a system have been presented and verified against the requirements of MARPOL regulations.
PROBABILISTIC SAFETY OF ESTUARY VESSELS BASED ON NONLINEAR ROLLING IN WIND AND WAVES
Authors: Bačkalov I
Published: December 2021

In the first place the discusser would like to congratulate Dr. Bačkalov with his paper, in which he assesses the new Belgian safety regulations for estuary vessels by means of a non-linear approach taking account the effect of a combination of beam waves and unsteady beam wind. The results presented are based on a solid, scientific background, and the author’s approach as published in former papers can be considered as the base of a promising methodology for evaluating the stability and safety of a vessel in waves and wind. As the discusser has supported the Belgian federal authorities in defining the methodology and formulating the present regulations, it is a pleasure to learn that the implementation of the latter is considered as a significant step in the general improvement of ship safety regulations.
150 YEARS OF SHIP DESIGN
Authors: Andrews D
Published: December 2021

My comments are aimed in three directions: Where is the role of the naval architect heading? Are the students of today sufficiently aware of the achievements of their predecessors to learn from them? Is it appropriate that the public at large takes the capability of modern shipping for granted, if not how do we educate?
FROUDE’S LAW OF SIMILITUDE – CONTEMPORARY AND FUTURE SEAKEEPING TESTING
Authors: Dallinga R P , Huijsmans R H M
Published: December 2021

Historically “scale effects” in the interpretation of tests with scale models in waves using Froude’s Law of Similitude are mostly associated with viscous effects. Nowadays, with a much more complete modelling of reality and a focus on higher order non-linear phenomena, scaling of model test results implies a wider range of assumptions than the validity of Froude’s Law. Our contribution to the conference is a visionary review of contemporary and future problems in the interpretation of these tests. In this context we will discuss the developments in test techniques, including the development of a new Two-Phase Laboratory facilitating seakeeping and sloshing tests at reduced air pressure.
NON LINEAR ANALYSIS OF SHIP MOTIONS AND LOADS IN LARGE AMPLITUDE WAVES
Authors: Mortola G , Incecik A , Turan O , Hirdaris S.E.
Published: December 2021

A non linear time domain formulation for ship motions and wave loads is presented and applied to the S175 containership. The paper describes the mathematical formulations and assumptions, with particular attention to the calculation of the hydrodynamic force in the time domain. In this formulation all the forces involved are non linear and time dependent. Hydrodynamic forces are calculated in the frequency domain and related to the time domain solution for each time step. Restoring and exciting forces are evaluated directly in time domain in a way of the hull wetted surface. The results are compared with linear strip theory and linear three dimensional Green function frequency domain seakeeping methodologies with the intent of validation. The comparison shows a satisfactory agreement in the range of small amplitude motions. A first approach to large amplitude motion analysis displays the importance of incorporating the non linear behaviour of motions and loads in the solution of the seakeeping problem.
NUMERICAL MODELLING AND ASSESSMENT OF THE UGEN FLOATING WAVE ENERGY CONVERTER
Authors: Fonseca N , Silva S R , Pessoa J
Published: December 2021

The paper presents a linear hydrodynamic model for the UGEN wave energy converter, an analysis of the dynamics of the system and the predicted ability to extract energy from the waves. The UGEN (floating device with a U tank for GENeration of electricity from waves) consists of an asymmetric floater with a large internal U tank filled with water, where the energy is extracted from the relative motion between the water inside the tank and the rolling of the floater. The floater rolling mode of motion is the main stimulator of the motion of the water in the tank, however the sway and heave motions are also coupled therefore the system has motion.
ON THE ROLL DAMPING OF AN FPSO WITH RISER BALCONY AND BILGE KEELS
Authors: Veer R van ’t , Fathi F
Published: December 2021

Although the topic of roll damping of vessels at sea is already brought to the attention of naval architects by Froude more than 100 years ago, the physics of it remain intriguing, even today. An accurate prediction of the motions of offshore structures in harsh environments, designed for 25 years continuous operation, is the topic of this paper. Model test experiments for two FPSO’s developed by SBM for Petrobras are discussed. It is shown that the FPSO submerged riser balcony on one side of the vessel contributes to the roll damping through similar physics as the bilge keel does. Flow memory effects are discussed in detail since these are shown to have a noticeable effect on the roll damping coefficients. The paper further employs 3D CFD simulations to enhance the understanding of the fluid behaviour around the FPSO appendages, necessary to construct a rational and accurate roll damping model in the future.
THE INFLUENCE OF FORWARD SPEED AND NONLINEARITIES ON THE DYNAMIC BEHAVIOUR OF A CONTAINER SHIP IN REGULAR WAVES
Authors: Chapchap A , Hudson D A , Temarel P , Ahmed T M , Hirdaris S E
Published: December 2021

The aim of this paper is to compare the heave and pitch motions for the S175 containership, travelling in head regular waves, obtained from frequency domain linear and time domain partly nonlinear potential flow analyses. The frequency domain methods comprise the pulsating and the translating, pulsating Green’s function methods, with the relevant source distribution over the mean wetted surface of the hull. The time domain method uses the radiation and diffraction potentials related to the mean wetted surface, implemented using Impulse Response Functions (IRF), whilst the incident wave and restoring actions are evaluated on the instantaneous wetted surface. The calculations are carried out for a range of Froude numbers, and in the case of the partly nonlinear method for different wave steepness values. Comparisons are made with available experimental measurements. The discussion focuses on the necessity for a nonlinear approach for predicting the radiation potential and the possible numerical methods for its formulation.
SHIP OPERABILITY PREDICTED FROM LONG TERM DIRECTIONAL WAVE RECORDS
Authors: Wing D A , Johnson M C
Published: December 2021

Ship operability assessments have traditionally been made using wind and wave data derived from wave atlases, however there are several drawbacks, including the fact that they are usually based on observation rather than measurement, and that spreading or directional effects are lost – such as the separation of sea and swell directions. An alternative approach is demonstrated here, instead of the data summarised in the wave atlas scatter diagram, long term hourly historical wave buoy data may be used. Detailed data sets, including directional wave spectra, are available for a number of specific locations. Direct use of many years’ hourly wave data involves significant computational effort, but results may be achieved within a reasonable time. The technique is demonstrated with the examples of four naval ships and two sites. Analysis considered two main themes, the differences in the ship performance calculated when (a) using wave buoy data rather than wave atlas data for the same sea area and (b) using the most complex available model of the ocean waves compared with the simplified wave descriptions in common use. For (a) the wave buoy data both looked rather different than the wave buoy data for the same nominal area, and produced rather different ship performance results. For (b) it was shown that there were also significant differences between the operability calculated for the four different ships at one of the sites. The implications for operability assessment in the ship procurement process are briefly discussed.
DETERMINATION OF WAVE SLAMMING LOADS ON HIGH-SPEED CATAMARANS BY HYDROELASTIC SEGMENTED MODEL EXPERIMENTS
Authors: Lavroff J , Davis M R , Holloway D S , Thomas G
Published: December 2021

A 2.5m hydroelastic segmented catamaran model has been developed based on the 112m INCAT wave-piercer catamaran to simulate the vibration response during the measurement of dynamic slam loads in head seas. Towing tank tests were performed in regular seas to measure the dynamic slam loads acting on the centre bow and vertical bending moments acting in the demihulls of the catamaran model as a function of wave frequency and wave height to establish the operational loads acting on the full-scale 112m INCAT catamaran vessel. Peak slam forces measured on the bow of the model are found to approach the weight of the model, this being similar to the findings of full-scale vessel trials. A review of the motions of the hydroelastic segmented catamaran model found that the heave and pitch motions give a good indication of slamming severity in terms of the dimensionless heave and pitch accelerations. The dynamic wave slam forces are closely related to the relative motion between the bow and the incident wave profile.
FATIGUE RELIABILITY ASSESSMENT OF WELDED JOINTS OF VERY FAST FERRY ACCOUNTING FOR VEHICLE LOADS
Authors: Garbatov Y , Guedes Soares C
Published: December 2021

This work deals with the fatigue reliability assessment of a welded joint in a longitudinal stiffener of trapezoidal shape in a very fast ferry. Based on the analysis of wave and cargo induced loads the ship hull structure is evaluated. The local structure is represented by a longitudinal stiffener with a trapezoidal transverse section. The critical hot-spots and the stress distributions are defined by FEM. The fatigue damage assessment of considered hot spots is analysed accounting for the combination of wave induced and car-breaking transient loadings. The formulation for the assessment of the welded steel joint is based on the S-N approach and FORM/SORM techniques are applied to evaluate the reliability against fatigue failure accounting for corrosion deterioration. The structural system composed by several hot spots is evaluated as a series system based on second order reliability bounds.
COATINGS AND PERMANENT MEANS OF ACCESS – THE ANTI-CORROSION CHALLENGES
Authors: Lomas J P , Contraros P D , Papadakis G
Published: December 2021

The introduction of new regulations for Means of Access (MA) has led to an increase in the number and complexity of access openings, an increase in the size of the access openings in the ship’s structure, and a stricter maintenance regime which presents new challenges throughout the life of modern vessels. Several of the major issues at the design stage of Permanent Means of Access (PMA); the construction of ships; the application of protective coatings during new building, together with coating maintenance during the service lifetime; problems related to cleaning holds after cargoes have been removed; action by the Butterworth crude oil washing action and the challenges of maintenance in ballast tanks, are discussed in this paper.
PROBABILISTIC RISK ASSESSMENT FOR INTEGRATING SURVIVABILITY AND SAFETY MEASURES ON NAVAL SHIPS
Authors: Liwång H , Ringsberg J W , Norsell M
Published: December 2021

Conflicts of today are characterized by both traditional and irregular tactics and by non-state actors making innovative use of modern technologies. These conditions set new demands on naval ships. The aim of this investigation is to describe how, based on probabilistic risk assessment, the concept of operation for a naval ship can be turned into safety scenarios to be used in the evaluation of risk. In this investigation, civilian state-of-the-art methods for probabilistic risk assessment are merged with the specific demands of naval ships. Relevant aspects of safety culture, codes, regulations and rules are analysed with respect to requirements on safety scenarios, and military operational research with respect to modelling military systems. The results show that the scenarios must have calculable probability and must be adapted to the vessel in question. Results from simulations show that modelling operational tasks is one way to support experts in the definition of safety scenarios.
AN EXPERIMENTAL STUDY ON THE RELATIVE MOTIONS BETWEEN A FLOATING HARBOUR TRANSHIPPER AND A FEEDER VESSEL IN REGULAR WAVES
Authors: Macfarlane G J , Lilienthal T , Ballantyne R J , Ballantyne S
Published: December 2021

The Floating Harbour Transhipper (FHT) is a pioneering logistics solution that was designed to meet the growing demands for coastal transhipment in the mining sector as well as commercial port operations. The primary advantage of the FHT system is that it can reduce transhipment delays caused by inclement weather, by reducing relative motions between the FHT and feeder vessel. The feeder is sheltered when inside the FHT well dock when compared to the more exposed location when a feeder is in a traditional side-by-side mooring arrangement.

This paper discusses previously published studies into the relative motions of vessels engaged in side-by-side mooring arrangements and also presents details and results from a series of physical scale model experiments. In these experiments, both side-by-side and aft well dock mooring arrangements are investigated. The results provide strong evidence that the FHT well dock concept can significantly reduce the heave, pitch and roll motions of feeder vessels when transhipping in open seas – this being the cornerstone of any successful open water transhipment operation.
HANDLING TEMPORAL COMPLEXITY IN THE DESIGN OF NON-TRANSPORT SHIPS USING EPOCH-ERA ANALYSIS
Authors: Gaspar H M , Erikstad S O , Ross A M
Published: December 2021

A core aspect of temporal complexity in the design of non-transport vessels is the uncertainty related to the future market and contract opportunities, and the corresponding changeability that should be incorporated into the ship design to meet this uncertainty. The development of an appropriate design specification for a new ship represents a core strategic decision for ship owners as part of a fleet renewal or expansion programme, with a high financial risk and a long time horizon of typically 20-30 years. This type of temporal complexity is one out of several complexity aspects to be handled as part of a ship design process.

In this paper we model possible realizations of an uncertain future for a vessel using the Epoch-Era Analysis (EEA) method. Here, we use the epochs as the primary instrument for capturing major market developments, such as the opening of new offshore areas, new emission regulatory regimes, or the availability of new, disruptive technologies. From these, more specific epoch variables are derived, for which specific contract opportunities can be generated. The epoch-specific performance of the vessels is found by solving a Ship Design and Deployment Problem (SDDP) of concurrently identifying both a preferable ship design and the corresponding path of consecutive contracts that maximizes total revenue.

We present a case study related to the design of an Anchor Handling Tug Supply (AHTS) vessel. The study illustrates the complexity in striking the correct balance between optimizing the vessel for an initial scenario, while at the same time providing addition performance capabilities to be competitive in the context of future market requirements.
EXPERIMENTAL STUDY OF THE INTERACTION OF CORROSION DAMAGE AND OUT-OF-CIRCULARITY IN THE COLLAPSE OF SUBMARINE PRESSURE HULLS
Authors: MacKay J R , Smith M J , Van Keulen F , Bosman T N
Published: December 2021

The effect of corrosion damage on overall collapse strength of submarine pressure hulls was studied experimentally. Ring-stiffened cylinders were machined from aluminium tubing and loaded to collapse under external pressure. In selected specimens, some of the outer shell material was machined away in large single patches, representing general corrosion. Other specimens had many smaller patches, representing corrosion pitting from the outside of the hull, followed by grinding. Large-amplitude out-of-circularity (OOC) was introduced by mechanically deforming selected cylinders. Clusters of artificial corrosion pits were found to have approximately the same effect on collapse pressure as equal-depth general corrosion covering the same region of plating. General corrosion was found to be most severe when it was “in-phase” with OOC, since, during pressure loading, high compressive stresses resulting from corrosion were compounded by compressive bending stresses associated with OOC, and furthermore, the corrosion tended to increase the geometric imperfection itself. On the other hand, out-of-phase corrosion reduced the effect of OOC, while at the same time the thinning-associated compressive stresses were counteracted by local tensile bending stresses associated with OOC, so that strength reductions were correspondingly smaller. Overall collapse pressures for corroded specimens were reduced by, on average, 0.85% for each 1% of shell thinning. That result is based on a linear approximation of the nonlinear relationship between thinning and collapse pressure. The linear trend-line, which was used to account for the experimental scatter, is based on specimens with 13 to 27% shell thinning, and with a variety of corrosion areas and OOC amplitudes.
THE USE OF A FUZZY LOGIC SET-BASED DESIGN TOOL TO EVALUATE VARYING COMPLEXITIES OF LATE-STAGE DESIGN CHANGES
Authors: McKenney T A , Gray A W , Madrid C , Singer D J
Published: December 2021

Advanced design methods, such as set-based design (SBD), can provide a structured approach to evaluating the design space in order to make accurate and informed decisions towards reaching a globally optimal design. The set-based communications required to appropriately implement SBD are counter-intuitive to the point-based communications of a typical design process. The use of a hybrid agent fuzzy logic design tool can help to facilitate the SBD process by ensuring the use of set-based communication of design variables. The design tool uses automation of certain aspects such as data collection and analysis while still allowing for input from human designers. One important advantage of using SBD is the ability to delay decisions until later in the design process when more information is known. This paper focuses on the robustness of the SBD process and its ability to handle late-stage design changes of varying complexity. Multiple SBD experiments instituting design changes of varying magnitude late in the design process were conducted using a hybrid agent fuzzy logic SBD tool. A simplified planing craft design was utilized for the experiments. Conclusions regarding the robustness of the SBD process under late-stage design changes were determined and outlined using information gathered by the SBD tool.
FAULT TREE ANALYSIS (FTA) - FORMAL SAFETY ASSESSMENT (FSA) IN SHIP REPAIR INDUSTRY A MADE EASY APPROACH
Authors: Njumo D A
Published: December 2021

Fault tree-Formal Safety Assessment (FT-FSA) is the premier scientific method that is currently being used for the analysis of maritime safety and for formulation of related regulatory policy. To apply FSA in this paper, all five steps are considered and critical information highlighted in each step as reviewed in the literature. A novel 15 steps approach of FT-FSA is introduced in the systematic accident scenario considered in this study as emergent phenomena from variability and interactions in shipyard (considered as a complex system).The results of this paper will be useful for guidelines and regulatory reforms in ship repair industry as demonstrated by identifying ‘fall from height in ship repair occupational hazards’ for recommendation in decision making.
PASSENGER RESPONSE TIME DATA-SETS FOR LARGE PASSENGER FERRIES AND CRUISE SHIPS DERIVED FROM SEA TRIALS
Authors: Brown R , Galea E R , Deere S , Filippidis L
Published: December 2021

This paper describes research that was carried-out under the EU FP7 research project SAFEGUARD and presents passenger response time data generated from five full-scale semi-unannounced assembly trials at sea. The data-sets were generated from three different types of passenger ships, a RO-PAX ferry without cabins (RP1), a cruise ship (CS) and a RO-PAX ferry with cabins (RP2). In total, response times from 2366 people were collected making it the largest response time data-set ever collected – on land or sea. The analysis methodology used to extract the response time data and the resultant response time distributions (RTD) is presented. A number of key findings from the data analysis are presented along with three recommendations to modify the IMO guidelines governing ship evacuation analysis, namely; (a) it is inappropriate to use the same RTD for cruise ships and RO-PAX vessels; (b) a new Day Case RTD is suggested for RO-PAX vessels and (c) new Day and Night RTDs are suggested for cruise ships.
VIRTUAL ARRIVAL: A REAL OPTION FOR ENERGY SAVING?
Authors: Capurso V , Ferrando M , Gualeni P , Viviani M
Published: December 2021

The maritime traffic is the real backbone of the international transport of goods in the world and it is driven by a severe observance of time scheduling. Nevertheless, mainly in relation with the most traveled routes, frequently it might happen that port facilities are congested, and the time schedule for ship load/unload operations is accordingly delayed. In this circumstance the choice is between meeting the original ETA (estimated time of arrival) and then let the ship riding at anchor or slowing down the ship in order to adjust the arrival to the actually needed time window.

The latter option is called "Virtual Arrival"[1] because it consists of applying a speed reduction that fits the new time for port operations instead of arriving at the original ETA. The purpose of this paper is to investigate to what extent the Virtual Arrival policy could be a valuable option providing a reasonable energy saving for ships. The potential benefits are considerable and they result in direct saving in fuel consumption, reduction of CO2 emissions and less congested port areas.
PASSENGER RESPONSE TIME DATA- SETS FOR LARGE PASSENGER FERRIES AND CRUISE SHIPS DERIVED FROM SEA TRIALS
Authors: Brown R , Galea E R , Deere S , Filippidis L
Published: December 2021

The paper consists of 27 figures; numerous equations and 12 notes/ references, many of which are written by the authors of this paper. Whilst this may indicate a lack of “reading around the subject” it also indicates the unique nature of the topic and that little exists at present in the public domain about this topic. Indeed the authors and the research group they represent are the main contributors to the IMOs discussions and circulars on this subject. Given that background the paper is very detailed and consists of comparisons between the evacuation times of 3 passenger ships, 2 being Ro-Pax vessels and 1 a cruise liner. On board evacuation time statistics have been gathered from significant populations enabling the authors to draw significant conclusions relating to evacuation times in the presented scenarios. The paper is therefore a useful addition to the debates on this subject which is of major relevance to the understanding of evacuation times in passenger vessels. Data and research in this area is difficult to obtain thus the authors should be congratulated for their work.
SUPPORT FOR OFFSHORE MONOPILE INSTALLATION THROUGH THE TRENCH CUTTER TECHNOLOGY
Authors: Spagnoli G , Weixler L
Published: December 2021

Europe is currently facing an energetic revolution. Several offshore wind farm projects are currently under construction or under planning in North and Baltic Sea. Typical foundation structures for offshore wind farms are steel open-ended monopiles with large diameters up to 6 m. Currently, the monopiles are installed by driving with large impact hammers. However, there are many situations where pile refusal is reached, due to hard soil layers or erratic blocks. Driving and drilling technique is therefore applied. This manuscript briefly describes the trench cutter technology normally used for foundation works on land. Three case histories onshore and one offshore project are discussed and the evolution of the trench cutter technology for supporting the installation of offshore monopile is described.
FATIGUE ASSESSMENT OF SHIP SUPERSTRUCTURE AT EXPANSION JOINT
Authors: Petinov S V , Guchinsky R V
Published: December 2021

Despite the long history of application of subdivided superstructures and deckhouses, and efforts of ship designers and researchers a sensible solution in design of reliable details at the cut endings was not found yet. It may be explained as consequence of controversial requirements in design of the cut endings.

Fatigue design of the superstructure details is addressed to solution of the problem. Presented is an example of fatigue design of the cut ending in a fast ship superstructure based on application of modified «Strain-Life» criterion for fatigue and subsequent approach which utilizes Neuber’s formula and material cyclic properties. To realize the approach a procedure of the long-term stress distribution transformation to the block-type format is developed. Efficiency of the developed technique is illustrated by comparing the results with those of application standard S-N criteria based techniques. The results of analysis allowed selection of the expansion joint detail of the superstructure geometry and construction procedure providing necessary reliability.