Free Floating Research Articles

Parallel Currencies under Free Floating Exchange Rates: A Model Setting Out the Conditions for Stable Currency Competition

We use a theoretical model to set up the conditions for a country to attain monetary stability by allowing for two freely tradable currencies to circulate in parallel. For this parallel system to function properly, confidence in the good behavior of the monetary authorities in charge of the two currencies is key. Our model shows how a floating exchange rate between the two can keep the issuers of the local currency in check. The results from our model show the conditions under which a parallel currency system disciplines the issuers of the currencies and thus maintains their purchasing power. In non-volatile economies, it also discourages governments (or private issuers) from inflating one of the currencies as a means to raise seigniorage, as this policy results in the displacement of the currency from the market. When foreign payments shortfall—such as in Greece and Cyprus during the ‘euro crisis’ in the mid-2010s, or intractable hyperinflation—leave the country without a medium of exchange, our model shows how currency choice can restore monetary circulation and offer a path to achieving and maintaining monetary stability.

A Cost-Effective Open Volumetric Air Receiver Design Based on Free Floating Stackable Absorber Modules

The CAPTure Open Volumetric Air Receiver (OVAR) design is based on ceramic stackable “free floating” absorber modules that form the receiver structure and avoid a complex metallic double membrane design. The novel receiver design has been validated at small-scale (15 kWth) at a solar simulator, as well as on the top of an experimental tower at 300 kWth, up to absorber module outlet temperatures above 900ºC. The novel OVAR concept is attractive for both the concentrated solar power (CSP) sector, as well as for high-temperature process heat supply. The thermal efficiency of the receiver concept is expected to be above 80% at outlet temperatures of 900ºC.

Experimental Investigation on the Motion Characteristics of Air-Floating Tripod Bucket Foundation during Free Floating

In recent years, multi-bucket foundations have been studied and gradually adopted in engineering practices as a novel foundation for offshore wind turbines within a range of water depth of 30 to 50 m. This study investigated the motion characteristics of air-floating tripod bucket foundation (AFTBF) through a series of experiments during free air-floating. The experimental results show that the surge force appears to be the most important factor influencing pitch moment and motion, whether it is a change in water depth or a draft for AFTBF. The maximum amplitudes of surge acceleration and pitch angle show a trend of increasing with narrower spacing and decreasing with wider spacing, while the heave acceleration shows an opposite trend. The added mass and damping of heave motion for AFTBF increase with shallower water due to the increasing pressure difference between the inside and bottom of bucket foundation. The shallower the water depth and the larger the draft, the longer the resonance period of heave.

Application of Impedance Control of the Free Floating Space Manipulator for Removal of Space Debris

A broad and significant class of space debris can be mitigated by means of a satellite, capable of capturing a large non-cooperating object by using a robotized arm with a gripper. The capture operation typically comprises of an approach, a close-on manoeuvre, establishing contact between the robotic grappler arm and a suitable feature on the target satellite, and finally it is concluded when a positive mechanical connection is achieved by the gripper closed on that feature. The phase of establishing contact poses a critical challenge in this scenario, since the target typically will be tumbling with respect to the chaser satellite causing high forces on the gripper and the robotic arm. A family of control methods known collectively as impedance control is typically employed in terrestrial robots for tasks involving an interaction with an environment, especially the dynamic contact. In this work, we present the model-based impedance control applied to a robotic manipulator on a free floating base. The derivation of impedance control law for a robotic manipulator on a free floating satellite, involving Generalized Jacobian Matrix (GJM), is presented, followed by simulation results comparing the loads in the manipulator joints against a classical GJM-based Cartesian controller. The simulation results show that the impedance controlled free floating robotic manipulator completes the task of trajectory following amid contact with unknown target with lower torques in the robot joints.

Different Chondrus crispus Aquaculture Methods and Carrageenan Extraction

With the notable scarcity of Chondrus crispus on the Portuguese coast, and interest in exploiting compounds such as carrageenan, this study focuses on investigating different aquaculture methods and recording the yield of carrageenan from specimens grown by different methods. We compare the growth of Chondrus crispus in aquaculture using Free Floating, Cages, Attempted Fixation on Rock, and Fixed Line similar to Long Line. The best method was Free Floating where Nursery 0 had a 24-day Specific Growth Rate (SGR) of 2.08 ± 0.47%/day. The worst method in terms of growth was Nursery 2 (Attempted Fixation on Rock) where the SGR at 28 days was 0.33 ± 0.69%/day, and no fixation was observed. In terms of carrageenan extraction, all culture methods gave rise to biomass that had a lower extraction yield than wild specimens, at 50.95 ± 4.10%. However, the Free-Floating method from Nursery 1 showed an acceptable carrageenan content (31.43 ± 7.00%). Therefore, we demonstrate that the concept of C. crispus cultivation may be key to promoting the sustainability and stability of this species.

Disorder to order transition in cell-ECM systems mediated by cell-cell collective interactions

Cells in functional tissues execute various collective activities to achieve diverse ordered processes including wound healing, organogenesis, and tumor formation. How a group of individually operating cells initiate such complex collective processes is still not clear. Here, we report that cells in 3D extracellular matrix (ECM) initiate collective behavior by forming cell-ECM network when the cells are within a critical distance from each other. We employed compaction of free-floating (FF) 3D collagen gels with embedded fibroblasts as a model system to study collective behavior and found a sharp transition in the amount of compaction as a function of cell-cell distance, reminiscent of phase transition in materials. Within the critical distance, cells remodel the ECM irreversibly, and form dense collagen bridges between each other resulting in the formation of a network. Beyond the critical distance, cells exhibit Brownian dynamics and only deform the matrix reversibly in a transient manner with no memory of history, thus maintaining the disorder. Network formation seems to be a necessary and sufficient condition to trigger collective behavior and a disorder-to order transition. Statement of significanceMacroscopic compaction of in vitro collagen gels is mediated by collective mechanical interaction of cells. Previous studies on cell-induced ECM compaction suggest the existence of a critical cell density and phase transition associated with this phenomenon. Cell-mediated mechanical remodeling and global compaction of ECM has mostly been studied at steady state. Our study reveals a link between a transition in cell dynamics and material microstructure as cells collectively compact collagen gels. It underscores the significance of temporal evolution of these cell-ECM systems in understanding the mechanism of such collective action and provides insights on the process from a mechanistic viewpoint. These insights can be valuable in understanding dynamic pathological processes such as, cancer progression and wound healing, as well as engineering biomaterials and regenerative tissue mimics.

Supply and Demand Analysis of a Free Floating Bike Sharing System

This article presents an analysis of the supply and demand of a FFBSS recently implemented in the city of Bologna, Italy. The main aspects treated in this paper are: analysis of bike availability; temporal analysis of FFBSS demand; calibration and validation of a novel model that predicts the number of daily trips per available bike. This model is based on a linear combination of several day attributes, including meteorological and day-type attributes. Moreover, an origin to destination analysis is generated showing the spatial distribution of FFBSS trips. The methods are applied to a scenario with almost a million GPS traces recorded between July and October 2018 by the FFBSS in Bologna. Findings could support FFBSS companies to better understand the fluctuation of both the transport demand and supply of this relatively recent transport mode, as to make more efficient decisions when distributing or relocating bicycles.

Large Vessel Occlusions By Free Floating Thrombi in Strokes During the COVID-19 pandemic- A Single Center Observational Study.

An increased incidence of systemic macrothrombotic phenomena such as strokes has been observed in moderate and severe COVID. However, strokes have also been increasingly observed in mild COVID, post COVID, or without obvious COVID illness. To share our experience with a specific stroke type noted during the COVID pandemic period. A single-center observational study was conducted in Western India from January to December 2020, and data regarding stroke patients admitted under Neurology services were noted. Clinical, laboratory, and radiological characteristics of strokes and subtypes were documented. A total of 238 stroke patients were admitted in 2020, 76.5% during the COVID pandemic period. Among 153 ischemic strokes, 16.3% and 56.2% had large vessel occlusion (LVO) in pre-COVID and COVID pandemic period, respectively. Of all ischemic strokes, 20.9% (18 patients) and 12% (3 patients) had free floating thrombus (FFT) in the COVID versus pre-COVID period, respectively. Only 44.4% of all FFT patients could be proven SARS-CoV-2 RT-PCR positive while 50% were COVID suspect with surrogate markers of heightened inflammation at time of stroke. All patients were given anticoagulation and average mRS at discharge was 3.1 (range: 1-6) and 1.84 (range: 0-4) at 3-month follow-up in survivors. This study highlights the presence of FFT causing LVO as a new stroke subtype during the COVID-19 pandemic. With renewed and steeper spike in COVID-19 cases, especially new variants, the resurgence of this stroke subtype needs to be actively explored early in the course of illness to reduce morbidity and mortality.

Motivation to Use Free Floating Car Rental Service in Riga: The CARGURU Case

Digital transformation and digitalization in general have made a significant impact on the service industry, including banking, commerce and renting. Technology, including mobile applications, has converted traditional and formerly inseparable services into ones that can be used from any place and at any time.

Coordinated Control of Underwater Biomimetic Vehicle–Manipulator System for Free Floating Autonomous Manipulation

This article presents a coordinated vehicle-manipulator control method for an underwater biomimetic vehicle-manipulator system (UBVMS) to implement floating autonomous manipulation in practice. An algorithm framework composed of adaptive tracking differentiator (ATD), extended state observer (ESO), improved nonsingular terminal sliding-mode control (I-NTSMC), fuzzy-logic controller (FLC), and estimator of manipulator disturbances, is proposed. The ATD is designed to generate desired motion state and alleviate noise. The ESO is developed to estimate the motion state, systematic uncertainties, and external disturbances. The proposed I-NTSMC method assures the finite-time convergence of the system states and alleviate chattering. The estimation of the manipulator disturbances is incorporated into the control strategy to enhance the station keeping of the vehicle. Finally, underwater autonomous free floating manipulation experiments about opening a door and grasping objects are conducted to validate the theoretical results and confirm the feasibility of the proposed control strategy.

Design of A Free Floating Ultrasonic Inner Spherical Detector for Pressure Pipeline

Ultrasonic inspection of the corrosion and scaling in industrial pressure pipelines is necessary due to the adverse effects of defects on medium flow and heat transfer. In this paper, a free floating ultrasonic inner spherical detector has been designed to detect and locate defects in pipelines. The flange mechanical structure of ultrasonic inner detection intelligent ball meets the internal space requirements and external environmental requirements. They are connected of two parts flange type. A complete set of spherical shell structure design covering the functions of sealing and external pressure resistance is proposed and completed. One part is the inner sphere, and the other is the outer shell. Pipeline experiments show that the spherical detector can reach the exit smoothly through curved pipes, inclined pipes and vertical pipes without jamming and stable motion attitude, collects all kinds of information along the way, determines the existence of defects and achieves accurate positioning.

Integration of Free Floating Car Sharing Systems in Rail Stations: A Web Based Data Analysis

In the last decades, car sharing has been a tool for city planners to reduce private car traffic and pollution in big urban areas. The emergence of the ICTs (Information and Communication Technologies), together with the development of the collaborative economy, has allowed for the birth of the new Free-Floating Carsharing (FFCS): A more flexible type of carsharing, in which electric cars can be used. Little research has been devoted using real FFCS flows data, to the FFCS impacts on user behavior and even on the public transport system thus far. Furthermore, in big metropolitan areas, central rail stations should promote modal interchanges, including new modes of electric FFCS systems. The aim of this paper is to design a web-based platform to collect and analyze FFCS demand on the surrounding areas of rail stations and makes a proposal to provide these systems with electrical recharging energy obtained from the regenerative braking of high-speed trains. This case study includes Atocha and Chamartín Central Stations in Madrid (Spain). Scientific evidence shows a high demand of FFCS cars at central rail stations and a trip profile with a short time duration linked to the closest districts of rail stations.

Experimental and Numerical Study on Roll Damping Structure of Floating Crane Catamaran in Free Floating and Moored Conditions

This research discusses the experimental study of free decay test This research discusses related to the experimental study of free decay test motion roll on the catamaran floating crane structure which is reviewed from free-floating and moored conditions. Experiments were conducted on the facilities of Maneuvering and Ocean Engineering Basin owned by the BTH – BPPT. The structure used as an experiment was a model of the catamaran floating crane with a scale of 1:36. The test is carried out with a horizontal mooring link system Taken from mooring system modelling, spring stiffness is used as a reference for mooring rope stiffness in numerical analysis. The analysis carried out in this final project is to compare the experimental results of the decay test with the results of the analysis using Moses software. From the results of the experiments obtained a comparison of free-floating conditions to tethered to decay tests of 38%, 8%, and 9% for linear damping values, then 93%, 12%, and 13% for quadratic damping values. Comparison of experiment results to numerical results found a difference of 128.39% for decay test 1 for quadratic damping value, then in decay test 2 and decay test 3 against the numerical got difference of 60.80% and 66.83% in linear damping value.

Kerapatan dan Persebaran Tumbuhan Air di Danau Buyan Kabupaten Buleleng, Provinsi Bali

The Bali province has four lakes, one of them is Buyan lake. One of communities that has important roles in lake waters ecosystem as an primary production is a community of aquatic plants. The existence of aquatic plants as weed will suffer losses more than the beneficial. So that research on density and distribution of aquatic plants in Buyan lake is very important to do. The research aims to find out the density, distribution, domination, percent of closure and other types of aquatic plants in Buyan lake. This research was conducted for 1 month during the month of March until April 2017. The value of the density of the population (KP) aquatic plants has ranged from 2-357 individuals/m2. The value of the frequency of attendance (FK) aquatic plants ranging between 0,1-1. Morisita Index (Id) has ranged from 4,9-1,39 which shows a pattern of clumped. The value of Dominance (D) aquatic plants has ranged between 0,0001-0,9823 that showed with its low variation and high abundance. The value of aquantic plant cover has percent range from 1-72% that showed of the vegetation very rare, rare and dense. The aquatic plants found during research had 4 types of living that were type of free float (Free Floating) Salvinia molesta, Eichhornia crassipes (Submerged) Myriophyllum aquaticum, (Floating) Alternanthera philoxeroides, sticking (Emergent) Schoenoplectus paludicola, Phragmites australis, Typha capensis.

Predicting Car Availability in Free Floating Car Sharing Systems: Leveraging Machine Learning in Challenging Contexts

Free-Floating Car Sharing (FFCS) services are currently available in tens of cities and countries spread all over the worlds. Depending on citizens’ habits, service policies, and road conditions, car usage profiles are rather variable and often hardly predictable. Even within the same city, different usage trends emerge in different districts and in various time slots and weekdays. Therefore, modeling car availability in FFCS systems is particularly challenging. For these reasons, the research community has started to investigate the applicability of Machine Learning models to analyze FFCS usage data. This paper addresses the problem of predicting the short-term level of availability of the FFCS service in the short term. Specifically, it investigates the applicability of Machine Learning models to forecast the number of available car within a restricted urban area. It seeks the spatial and temporal contexts in which nonlinear ML models, trained on past usage data, are necessary to accurately predict car availability. Leveraging ML has shown to be particularly effective while considering highly dynamic urban contexts, where FFCS service usage is likely to suddenly and unexpectedly change. To tailor predictive models to the real FFCS data, we study also the influence of ML algorithm, prediction horizon, and characteristics of the neighborhood of the target area. The empirical outcomes allow us to provide system managers with practical guidelines to setup and tune ML models.

Free Floating Electric Car Sharing: A Data Driven Approach for System Design

In this paper, we study the design of a free floating car sharing system based on electric vehicles. We rely on data about millions of rentals of a free floating car sharing operator based on internal combustion engine cars that we recorded in four cities. We characterize the nature of rentals, highlighting the non-stationary, and highly dynamic nature of usage patterns. Building on this data, we develop a discrete-event trace-driven simulator to study the usage of a hypothetical electric car sharing system. We use it to study the charging station placement problem, modeling different return policies, car battery charge and discharge due to trips, and the stochastic behavior of customers for plugging a car to a pole. Our data-driven approach helps car sharing providers to gauge the impact of different design solutions. Our simulations show that it is preferred to place charging stations within popular parking areas where cars are parked for short time (e.g., downtown). By smartly placing charging stations in just 8% of city zones, no trip ends with a discharged battery, i.e., all trips are feasible. Customers shall collaborate by bringing the car to a charging station when the battery level goes below a minimum threshold. This may reroute the customer to a different destination zone than the desired one; however, this happens in less than 10% of all trips.

Assessing water quality in the Ceyhan River basin (Turkey) with the use of aquatic macrophytes

ABSTRACTAs a major biotic component of many lotic ecosystems, macrophytes consist a major component of running waters are often used as indicators within the European Water Framework Directive (WFD) to establish ecological quality. In this study, we investigated macrophyte community structure (e.g. composition, abundance and diversity) in Ceyhan River Basin located in the Southeastern Anatolian Region in Turkey. Data was collected during 2014–2015 from river sites located throughout the basin to evaluate the relationship between aquatic vegetation and river physico-chemical factors. The ecological status of the river basin was also calculated based on Macrophyte Biological Index for River (IBMR). In total, 33 macrophyta taxa were observed. According to their biological classification (life form), filamentous algae (FA), free floating (FF), floating leaved (FL) and submersed (S) macrophytes reached their maximum abundance value in summer, while emergent (E) macrophytes were at their maximum abundance in both summer and autumn. The ecological status of the Ceyhan River basin ranged from moderate to bad. The values found are reasonably comparable to IBMR scores recorded in rivers of other Mediterranean countries. IBMR index may be suitable to some extent to establish a basis for ecological quality assessment in Turkish River systems.

Fully Nonlinear Analysis of the Interaction between Water and Free Floating Ship

Based on the theory of velocity potential function, the fully nonlinear interaction between water and free floating simplified ship is studied through numerical model of fluid-solid coupling of ship-lift. The nonlinear numerical analysis of the coupling model of the water and the simplified ship body with different sizes, in which the boundary conditions included the free water surface boundary condition, the non-moving boundary condition and the water-solid coupling boundary condition. The numerical results show that the size change of the floating body affected the dynamic mechanical characteristics of the fluid-solid interaction of ship lift system, and affected the stress response of the floating simplified ship body.

Free floating electric car sharing design: Data driven optimisation

In this work we consider the design of a Free Floating Car Sharing (FFCS) system based on Electric Vehicles. We face the problems of finding the optimal placement of charging stations, and the design of smart car return policies, i.e, how many and where to place charging stations, and whether to ask or not customers to return the car to a charging pole.We leverage actual data containing rentals performed by Car2Go customers. We obtain information for several months worth of actual trips in the city of Turin, our use case. Via trace driven simulations, we replay the exact same trips while simulating electric car based FFCS, to accurately gauge battery discharging and recharging. With this, we compare different charging station placements, also driven by optimisation algorithms. Moreover, we observe the impact of collaborative or selfish car return policies.Results are surprisingly: just as few as 13 charging stations (52 poles) guarantee a fleet of 377 vehicles running in a 1 million inhabitant city to work flawlessly, with limited customer’s discomfort. We believe our data driven methodology helps researchers and car sharing providers discerning different design solutions. For this, we make available all data and tools to foster further studies in these directions.

A Tunneling Dielectric Layer Free Floating Gate Nonvolatile Memory Employing Type-I Core-Shell Quantum Dots as Discrete Charge-Trapping/Tunneling Centers.

A nonvolatile memory with a floating gate structure is fabricated using ZnSe@ZnS core-shell quantum dots as discrete charge-trapping/tunneling centers. Systematical investigation reveals that the spontaneous recovery of the trapped charges in the ZnSe core can be effectively avoided by the type-I energy band structure of the quantum dots. The surface oleic acid ligand surrounding the quantum dots can also play a role of energy barrier to prevent unintentional charge recovery. The device based on the quantum dots demonstrates a large memory window, stable retention, and good endurance. What is more, integrating charge-trapping and tunneling components into one quantum dot, which is solution synthesizable and processible, can largely simplify the processing of the floating gate nonvolatile memory. This research reveals the promising application potential of type-I core-shell nanoparticles as the discrete charge-trapping/tunneling centers in nonvolatile memory in terms of performance, cost, and flexibility.