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Improvements experienced by incumbent "old" technologies when threatened by new ones, potentially supplanting them, are often addressed as the "sailing-ship effect." The latter phrase points to the eponymous case that consists of the 60-year or so technological battle between sail and steam in ships' propulsion during the 19th century, which led to unexpected large advancements in sail technology. Paradoxically, until today, the only work which addressed quantitatively that technological battle actually found a lack of evidence of the occurrence of the sailing-ship effect. In this paper, through fresh statistical analysis, we find instead confirmation of the existence of the effect in the original case. This finding contributes to the theoretical debate that explains technological persistence through mechanisms such as path dependence, cumulativeness, localized technical progress, competence and cognitive traps, the presence of complementary assets and tributary innovations, as well as institutional features. Policy dimensions are considered in Section 7 of the work. [ABSTRACT FROM AUTHOR]

This paper analyzes the design of an alpha-decay sail. While previous studies have been conducted on the feasibility of alpha-decay sails, none have investigated the effects of different backing materials and backing material thicknesses on propulsion. This paper conducts simulations using the particle simulation toolkit Geant4 to determine the thrust produced from alpha-decay sails constructed of 238Pu and a backing layer made of aluminum, beryllium, lithium, or polyethylene. The results demonstrate that alpha-decay sails can be a very useful form of in-space propulsion, having the potential to dramatically decrease travel time beyond distances of 100 AU. [ABSTRACT FROM AUTHOR]

The research deals with an interesting interdisciplinary case study for the knowledge and dissemination of masonry sail vaults in Malta between the 16th and the 17th centuries. In particular, it focuses on the sail vaults of the Magistral Palace, which have a distinctive structure. Based on a digital survey, the necessary data was extrapolated to critically analyse the geometry, through drawing and three-dimensional modelling. The paper, therefore, presents graphical and geometric investigations, which complement the study of the history of the Magistral Palace. Comparisons with the Maltese architectural context between the 16th and 17th centuries show the use of different solutions for the construction of sail vaults, according to different geometries. This implies knowledge of the international debate on the theory of stonecutting at the time. [ABSTRACT FROM AUTHOR]

In this paper, the numerical approach for the structural assessment of tall ship rigs is presented. It allows investigating complex sailing vessel structural rig layouts, composed of different types of masts (armed with both square and Lateen sails), yards, stays and spreaders. For these types of vessels, Classification Societies do not provide any direct calculation approaches, but only a mere comparison between cross sections and thicknesses with reference values as a function of the mast length. The provided approach can overcome this lack and it is based on considerations and calculations of real aerodynamic forces and the experimental evaluation of the pretension load of stays and shrouds. The herein proposed approach is very practical and can be adopted as a reference for this type of vessel, also with different mast configurations. [ABSTRACT FROM AUTHOR]

The geometric shape of the submarine sail has a significant effect on the flow uniformity amount in the submarine impeller plane. In the present study, using a Hotwire and a five-hole probe, the downstream flow field for the three sail in the SUBOFF submarine model was investigated. Two of the sails have the same NACA0018 cross-section and height, one of which has a fillet on the leading-edge. The third sail has the NACA0018 cross-section which is shaped like a dolphin's dorsal fin. In this study, the rotational field of the vortex downstream of the sail has been studied. The presence of fillets at the leading-edge of the sail significantly reduces the amount and intensity of the vortex. The sail with a dolphin's dorsal fin geometry also has a significant effect on improving the flow quality. In addition, as the distance from the sail increases downstream, the wake becomes weaker. [ABSTRACT FROM AUTHOR]

The reconstruction of the Serçe Limanı ship proposed a double-masted rig consisting of two sails with a total combined area of 100 m2. That proposal considered provenance evidence and appraised hydrodynamic and hydrostatic conditions. The current paper proposes an alternative rig consisting of a single sail. By applying computational fluid analysis and hydrostatic stability software to evaluate hull resistance, sail propulsion, and heeling moments, it has been demonstrated that a sail of no less than 150 m2 was suited to propel the Serçe Limanı. One of the two suitable alternative sails tested has been selected. [ABSTRACT FROM AUTHOR]

This article introduces a new method to model sailing routes before the age of steam based on real-world sailing conditions. Using a broad range of historical meteorological data, it offers monthly routing predictions for historical shipping corridors and tests them against historical evidence. In this article the model was applied to French and British ports. The output reveals the presence of historical shipping corridors and offer the first journey-time metrics to and from all European ports. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Babylon Center for Humanities Studies is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Entrepreneurship is often understood as an individualistic endeavour. This article investigates how cultural communities shape entrepreneurial activity through the process of envisioning competing imagined futures. By deploying a microhistorical approach, it explores a public debate about the transition from sail to steam in a late nineteenth-century Danish maritime community. In the debate, local actors evaluated and negotiated future entrepreneurial actions as embedded in existing norms, interpretations of the past, and socio-technical systems rather than independent, non-conformist ventures. The article demonstrates the potential role of community when we attempt to understand better how entrepreneurs construct and dispute over imagined futures. [ABSTRACT FROM AUTHOR]

Why does entrepreneurship training work? We argue that the feedback loop of the opportunity development process is a training element that can explain the effectiveness of entrepreneurship training. Building on action regulation theory, we model the feedback loop as a recursive cycle of changes in the business opportunity, goals, performance outcomes, and feedback. Furthermore, we hypothesize that error orientation and monitoring can strengthen or weaken the cycle, and that going through the feedback loop during training explains short- and long-term training outcomes. To test our hypotheses, we collected data before, during, and after an entrepreneurship training program. Results support our hypotheses, suggesting that the feedback loop of the opportunity development process is a concept that can explain why entrepreneurship training is effective. [ABSTRACT FROM AUTHOR]

Ships are a reliable means of transportation in an archipelagic country like Indonesia. The high use of fossil fuels in sea transportation is one of the contributors to emissions that needs attention apart from their dwindling availability. Efforts to use sails as an additional propulsion force on ships are one of the green technology issues in shipping for reducing the use of fossil fuels. It is about how the design affects the thrust on the ship. Tests were carried out on models M1, M2, and M3 in variations 0°, 30°, and 45° wind angles in computational fluid dynamic simulation at 12 knots constant speed. Through this article, there will be a discourse related to optimizing the design of the sail to produce energy efficiency and reduce the use of fossil fuels on ships. The shaped M3 makes greater thrust on the ships than the other two models. The tendency of a decrease in the thrust of the sails with an increase in the wind direction angle, the distribution of force in two directions, namely as normal and parallel to the sails, is suspected as the cause.

Numerous kinds of pathogens have spread around the world along with human travellers. A study of sea journeys in the age of sail and steam shows that their global distribution is not just a matter of transport availability but has to be described as a complex network of ecological factors. A better understanding of these connections sheds light on historic pandemics and might help prepare for future ones. Michael Gross reports. Pathogens have spread around the world along with human travellers. A study of historic sea journeys shows that their global distribution is not just a matter of transport availability but results from a complex network of ecological factors. Understanding these connections sheds light on historic pandemics and might help prepare for future ones. [ABSTRACT FROM AUTHOR]

The "sailing-ship effect" is the process whereby improvements to an incumbent technology (e.g. sail) are intentionally sought as a new competing technology (steam) emerges. Despite the fact that the effect has been referred to by quite a few scholars in different technological battles, the effect itself seems to have been taken for granted rather than organically defined and investigated. In this paper, within the context of evolutionary "appreciative theorizing" à la Nelson and Winter, through in-depth study of technological battles between old and new technologies, we transform what was an unfinished concept into a structured, fully-fledged, tool of analysis. [ABSTRACT FROM AUTHOR]

The growing amount of space debris in geocentricorbit poses a significant threat to the future of space operations. To mitigate this problem, current international guidelines state that a satellite should be able to deorbit or insert into a graveyard orbit within 25 years from the end of its operational life. In this context, drag-enhancing devices such as drag sails are currently an active field of research and development because of their ability to make a spacecraft decay from low Earth orbit without the need for any on-board propellant. Drag sails, conceptually similar to solar sails, are thin membranes deployed by a spacecraft at the end of its operational life to increase the area-to-mass ratio and, consequently, atmospheric drag. To be effectively exploited, a drag sail should maximize the surface area exposed to atmospheric particle flow. However, this would require a fully functional three-axis stabilization system, which may either be unavailable or non-functional on an orbiting satellite after years of space operations. To simplify the deorbiting phase, in this paper we propose to use a spin-deployed and spin-stabilized drag sail, which represents a reasonable compromise between simplicity of implementation and deorbiting performance in terms of total decay time. In fact, a spinning drag sail could take advantage of centrifugal force to unfold and of gyroscopic stiffness to maintain an inertially fixed axis of rotation. Numerical simulations accounting for the main perturbation effects quantify the effectiveness of the proposed device compared with an optimal configuration (i.e., a three-axis stabilized drag sail) and a tumbling drag sail. [ABSTRACT FROM AUTHOR]

In order to help control the spread of space debris and junk, deorbit sail devices have been used for deorbiting techniques; however, this approach is still considered risky due to potential failure or malfunction as it need to be exposed to the harsh space environment for a prolonged period of time, particularly in low-Earth orbit. China has made new strides forward in managing space junk, as it has successfully unfolded a 25-square-meter deorbit sail developed by the Shanghai Academy of Spacecraft Technology in-orbit for the payload capsule of a recently launched rocket. Accordingly in this paper, a full life-cycle modelling based on Monte Carlo method is developed to reveal the damage behavior of the 25-square-meter deorbit sail surface under the combined effects of atomic oxygen erosion and deorbit sail defects. The simulation results show that as the atomic oxygen fluence increases and the material defect width widens, the interaction effect of the two factors becomes more and more pronounced, which decisively influences the erosion rate of the sail surface. Morphological characterization of aluminized film PET material, activated silanisation modified material and plasma-polymerization coating material before and after atomic oxygen erosion combined defects is carried out and the atomic oxygen erosion of the deorbit sail surfaces is quantitatively assessed. The assessment results show that compared to the PET material and activation silanisation surface modification material, the plasma polymeric coated material showed much better flexibility, folding resistance and irradiation resistance to prevent geological fold and to shield from the atomic oxygen erosion in space. The atomic oxygen erosion combined defects assessment method studied in this paper provides valuable reference data for the subsequent serialisation of deorbit sail products and other typical lightweight film materials for space applications. • Introduction of Monte Carlo method for material surface damage simulation analysis. • Compare the performance of off-orbit sail surface materials under different protection treatments. • Standardize the process of space flexible film material performance evaluation system. [ABSTRACT FROM AUTHOR]

The science of mountainous hydrology spans the atmosphere through the bedrock and inherently crosses physical and disciplinary boundaries: land-atmosphere interactions in complex terrain enhance clouds and precipitation, while watersheds retain and release water over a large range of spatial and temporal scales. Limited observations in complex terrain challenge efforts to improve predictive models of the hydrology in the face of rapid changes. The Upper Colorado River exemplifies these challenges, especially with ongoing mismatches between precipitation, snowpack, and discharge. Consequently, the U.S. Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) user facility has deployed an observatory to the East River Watershed near Crested Butte, Colorado, between September 2021 and June 2023 to measure the main atmospheric drivers of water resources, including precipitation, clouds, winds, aerosols, radiation, temperature, and humidity. This effort, called the Surface Atmosphere Integrated Field Laboratory (SAIL), is also working in tandem with DOE-sponsored surface and subsurface hydrologists and other federal, state, and local partners. SAIL data can be benchmarks for model development by producing a wide range of observational information on precipitation and its associated processes, including those processes that impact snowpack sublimation and redistribution, aerosol direct radiative effects in the atmosphere and in the snowpack, aerosol impacts on clouds and precipitation, and processes controlling surface fluxes of energy and mass. Preliminary data from SAIL's first year showcase the rich information content in SAIL's many datastreams and support testing hypotheses that will ultimately improve scientific understanding and predictability of Upper Colorado River hydrology in 2023 and beyond. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bodrum Gulets are worldwide known sailing yachts, for their unique designs and cultural background that they have. In this paper, sail and rigging parameters of Bodrum Gulets with schooner and ketch type riggings are examined and parametric models are developed by using the data collected from 20 Bodrum Gulets with schooner and 27 Bodrum Gulets with ketch rigging configurations. Parametric models are used to compare sailing performances of two different sail and rigging types on Bodrum Gulets. The results show that, for the parametric model that obtained by using the hull form, sail and rigging parameters, the difference between sail area of ketch and schooner configuration is 14%. However, the polar graph shows that the difference between the hull speeds of two rigging configurations is in the range of 1.5–10%. Finally, a design framework for the hull, sail and rigging parameters of Bodrum Gulets is developed. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the influence of a morpholinium-based ionic liquid, N-pentadecyl-N-methylmorpholinium bromide [Mor1,15]Br on the aggregation behavior of a conventional cationic surfactant, tetradecyltrimethylammonium bromide, and imidazolium-based surface-active ionic liquid, 1-tetradecyl-3-methylimidazolium bromide [C14mim]Br in the aqueous medium. The aggregation behavior has been investigated in (0.00, 0.03, 0.06, and 0.10) wt% of [Mor1,15]Br by employing conductometry, refractive index and surface-tension measurements. The obtained data leads to the determination of the critical micelle concentration values, which have been further used to find various thermodynamic and surface-active parameters of micellization for the investigated system. The modulations observed in the aggregation behavior and the values of obtained parameters are indicative of various interactions prevailing among different constituents of the solution. The knowledge of these interactions is important for the utilization of such systems in various industrial applications such as foams, froths, emulsions, suspensions, and surface coatings to enhance their quality and performance. [ABSTRACT FROM AUTHOR]

Wits, Sweers and Maetsuijker Eÿlanden were the first three groups of islands named by Abel Tasman on the west and south coasts of Van Diemen’s Land in November 1642. The first theories about where to place Wits Eÿlanden go back to French and British expeditions in the late 1700s. Others have later suggested where to place the second group, Sweers Eÿlanden. This article presents a study of the charts, sketches and descriptions in Tasman’s journals, comparing them with the landscape they passed, and shows that the combined information hidden in the old sources may be more precise than previously believed. This understanding can be used to sail in Tasman’s wake and suggest where these “islands” should be placed on the modern map. As an entry to the analyses, it is necessary also to look at some questions connected to the placing and naming of Wits Eÿlanden on the old charts and to modern-day De Witt Island. [ABSTRACT FROM AUTHOR]

ALE-1, a micro-satellite created for the demonstration of artificial shooting stars, required orbital descent before mission execution due to safety aspects in orbit. ALE-1 utilized a drag sail called SDOM (Separable De-Orbit Mechanism) for a passive de-orbit maneuver, which was successfully completed, lowering the orbit from about 500 km down to about 400 km. This paper summarizes the detailed history of satellite operation and the results of the de-orbit maneuver demonstration during the past three years. Although the SDOM sail faced difficulty in keeping the desired deployed shape of the drag sail due to mechanical troubles, by letting the sail be a drag flag instead, it could still deliver a meaningful de-orbit performance to allow the satellite to successfully lower the orbit as planned. The de-orbit effect of the drag flag was evaluated using comparisons between orbit propagation simulations and the actual orbit transition flight data provided in the form of TLE (Two-Line Element) sets. Through this study, it is demonstrated that the SDOM can provide orbit transfer capabilities for satellites. Furthermore, the de-orbit performance of the drag flag can be evaluated, which could be an important reference for the future implementation of de-orbit devices to solve space debris problems. [ABSTRACT FROM AUTHOR]

The study of windward sailing in antiquity is subject to discord, misunderstandings and misinterpretations. This paper attempts to broaden the understanding of windward sailing by revisiting the theoretical basis of windward sailing, performing a critical review of previous works, reconstructing historic passages with new methods to re-evaluate them being considered as unfavourable wind passages, and considering the ancient mariner's limits of windward sailing. It is suggested that ancient ships had less windward capability than commonly perceived, and that the limits of the ancient mariners were more restrictive than ships' technological windward capabilities, highlighting the necessity to consider practical windward capabilities. [ABSTRACT FROM AUTHOR]

A comprehensive mapping of potential sailing mobility was performed for the eastern and central Mediterranean basins. The mapping is based on newly developed methods for measuring potential sailing mobility of merchant ships with a loose-footed square sail in antiquity, both for direct passages and for coastal sailing. The metrics of the measured direct and coastal sailing passages generate new measures of potential sailing mobility that provide new insights into the functioning of maritime links. The study also applies the measurements to several case studies in historical context including mapping of potential sailing mobility for the grain shipments from Egypt to Rome and the potential sailing mobility of Phoenician maritime links between the Levant and colonies to the west. The mappings reveal the bottlenecks for westward sailing from the Levant in the summer months. The mappings also highlight the bi-directional sailing links that could be maintained throughout the summer season despite the prevailing Etesian winds. The mappings contribute to deeper understanding of seafaring options and challenges during Antiquity. [ABSTRACT FROM AUTHOR]

Matondoni village in the Lamu archipelago is known for its jahazi (dhow) building tradition. The Swahili used to build dhows without using nails. Such dhows were known as mtepe (pl. mitepe). This article traces why mtepe became extinct and discusses jahazi building traditions, beliefs, dances and sacrifices in Matondoni village. These include jahazi launch feast, sewing and trying the sail and the role of the women's vugo4 dance. In addition, it investigates Swahili navigation and astronomy, from the Lamu archipelago to Arabia. The article establishes that jahazi became more popular than mtepe due to the need for a stronger vessel to promote the emerging maritime economy. The article finds that jahazi did not immediately replace mtepe, but the two coexisted until jahazi became the vessel of choice, which stopped the production of mtepe. [ABSTRACT FROM AUTHOR]

This research concerns the introduction and dissemination of masonry sail vaults in Malta between the sixteenth and the eighteenth centuries. A digital survey is produced to capture a reality-based 3D model, undertake analysis, and compare case studies with the aim of interpreting the sail vaults' construction systems. [ABSTRACT FROM AUTHOR]

The most dramatic changes in modern shipping occurred with the application of new industrial-age technologies to oceanic transportation. In metal-hulled and engine-powered trading platforms, industrial-age steamers (especially tramps and liners) lead to marked increases in the average tonnage of a typical vessel crossing the seas of an expanding global economy. Some of the most important developments had to do with the substitution of traditional wind-driven ships by successive cohorts of vessels exploiting the comparative advantages of mechanization. In this paper, we deploy a set of both established and less-orthodox quantitative approaches to historical commercial shipping time-series so as to model the (complex) relationship between steam and sail performance. We find that, indeed, there is evidence of leader-follower dynamics during the later part of 19th century. This process of 'creative destruction' was non-linear. [ABSTRACT FROM AUTHOR]

Wing-sailed autonomous sailing monohulls are promising platforms used in various scenarios to provide data for marine science research. These platforms need to operate long-term in changing seas; their general configurations (size matching between sail, hull, and keel) necessitate careful trade-offs to balance safety and efficiency. Since autonomous sailboats are often designed for different observation missions, scientific pay-loads and target areas, their design space is considerably large. It is also challenging to obtain prior performance estimation from historical designs. Therefore, traditional offline surrogate-based simulation-driven design frameworks suffer from a large amount of sampling required, the computational cost of which remains too expensive for such ad hoc design tasks. This paper proposes an innovative, generalised simulation-driven framework combining Bayesian optimisation and knowledge transfer. It allows for high-quality, low-cost optimisation of autonomous sailing monohulls' general configuration without initial design and prior performance estimation. The proposed optimisation framework has been used to optimise the 'Seagull' prototype within the design constraints. The optimised design exhibits significant performance improvements. At the same time, the results show that the present method is significantly superior to traditional offline methods. The authors believe that the proposed framework promises to provide the autonomous sailing community with a solution for a general design methodology. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of magnetic sail-based spacecraft formation control around the artificial equilibrium points (AEPs), which can eliminate the requirement of the propellant. The thrusts are achieved by utilizing the interaction between the solar wind and the artificial magnetosphere generated by superconducting current coil onboard. The circular restricted three-body problem (CRTBP) of magnetic sail is discussed including the allowed regions and linear stability of AEPs, the locations of collinear AEPs and the possibility of existence of periodic orbits around the collinear AEPs. Next, the dynamical models of magnetic sail formation around the collinear AEPs are established. A novel fast fixed-time nonsingular terminal sliding mode controller (FFNTSM) based on fixed-time disturbance observer (FTDO) is developed to account for external disturbances. Several numerical simulations are conducted to substantiate that spacecraft formation can be precisely controlled by the proposed propellantless propulsion method in the presence of external disturbances. [ABSTRACT FROM AUTHOR]

In the traditional motion control method of an unmanned sailboat, the sail and rudder are divided into two independent controllers. The sail is used to obtain the thrust and the rudder is used to adjust the yaw angle. The traditional control method does not consider the synergy between the two controllers and ignores the influence of the roll angle on sailing. It is easy for these methods to cause an excessive roll angle and large yaw angle error, which will weaken the safe navigation and accurate path tracking of an unmanned sailboat. This paper presents a collaborative control method of sail and rudder based on model predictive control. A four-degree-of-freedom kinematics and dynamics model of the unmanned sailboat considering roll angle was established, with the yaw angle and roll angle as the control objectives at the same time. The collaborative control method outputs sail angle and rudder angle simultaneously. By comparing the motion of this method and the separation control of sail and rudder under the same wind field conditions, it is verified that the collaborative control has better effects of yaw angle control and roll angle limitation and can obtain a more accurate path tracking effect. [ABSTRACT FROM AUTHOR]

Aerodynamic coefficients from wind-tunnel tests are presented for the ILCA 7 in all six degrees of freedom. Two apparent wind speeds are considered: a light wind case corresponding to 4 m s-1 at full scale and a strong wind case corresponding to 7 m s-1. The light wind tests comprise five apparent wind angles, seven sheet angles, three kicker trims and three heel angles. For the strong wind case the dinghy is assumed sailing upright and only dead downwind, but with four sheet angles and three kicker trims. The scale is 1/7, which gives a reasonable blockage in the wind-tunnel. Blockage corrections are obtained using CFD. Correct scaling of the sail stretch, and mast bend is achieved with the full-scale sail cloth and a solid stainless-steel mast exposed to a wind speed √7 times larger than at full-scale. However, the Reynolds number is √7 times smaller. The main result of the investigation is the comprehensive data set, which is available on a public server. This data can be used in a VPP to optimise downwind sailing in smooth water. Several interesting conclusions can also be drawn directly from the data. Thus, for the light wind case the best sheet angle is 90◦ regardless of the course sailed. However, for the strong wind case (dead downwind), the best angle is 80◦. In all cases the tight kicker trim produces the largest drive force and in the light wind case also the smallest side force. [ABSTRACT FROM AUTHOR]

Copyright of Antiguo Oriente is the property of Pontificia Universidad Catolica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)