REVIEW DAN ANALISIS PERKEMBANGAN PLTS PADA SARANA TRANSPORTASI LAUT

This paper aims to review the current development of vessels with solar power to reference the research and development of solar power vessels in Indonesia. The research method is a systematic literature review on the development of solar-powered vessels and includes an online survey of vessels using solar PV. This study found 86 solar-powered vessels consisting of boats, utility boats, ferries, houseboats, research, vehicle carriers, dive boats, and yachts developed from 1988 to 2020. These solar-powered vessels were built for various functions such as competitions, cleaning the environment, passenger transportation, and water tourism. Production of solar-powered vessels is increasing in terms of production volume, PV capacity, and battery capacity. In terms of PV configuration, the solar array is dominated by a fixed array structure. However, there have been innovations using sun-tracking, wind tracking airfoils, and expandable channels to increase PV capacity.

Infrasound measurement system for real-time in-situ tornado measurements

Previous work suggests that acoustic waves at frequencies below human hearing (infrasound) are produced during tornadogenesis and continue through the life of a tornado, which have potential to locate and profile tornadic events and provide a range improvement relative to current radar capabilities, which are the current primary measurement tool. Confirming and identifying the fluid mechanism responsible for infrasonic production has been impeded by limited availability and quality (propagation-related uncertainty) of tornadic infrasound data. This paper describes an effort to increase the number of measurements and reduce the uncertainty in subsequent analysis by equipping storm chasers and first responders in regular proximity to tornadoes with mobile infrasound measurement capabilities. The study focus is the design, calibration, deployment, and analysis of data collected by a Ground-based Local INfrasound Data Acquisition (GLINDA) system that collects and relays data from an infrasound microphone, GPS receiver, and an IMU. GLINDA has been deployed with storm chasers beginning in May 2020 and has provided continuing real-time automated monitoring of spectrum and peak detection. In analysis of sampled severe weather phenomena, the signal measured from an EFU tornado (Lakin, KS) show an elevated broadband signal between 10 and 15 Hz. A significant hail event produced no significant increase infrasound signal despite rotation in the storm. The consistency of these observations with existing fixed array measurements and real-time tools to reduce measurement uncertainty demonstrates the value of acquiring tornado infrasound observations from mobile on-location systems and introduces a capability for real-time processing and display of mobile infrasonic measurements.

MagIK: a Hand Tracking Magnetic Positioning System based on a Kinematic Model of the Hand

In this paper we present a hand tracking system based on magnetic positioning. A single magnetic node is mounted on each fingertip, and two magnetic nodes on the back side of the hand. A fixed array of receiving coils is used to detect the magnetic field, from which it is possible to infer position and orientation of each magnetic node. A kinematic model of the whole hand has been developed. Starting from the positioning data of each magnetic node, the kinematic model can be used to calculate position and flexion angle of each finger joint, plus the position and orientation of the hand in space. Relying on magnetic fields, the hand tracking system can work also in nonline-of-sight conditions. The gesture reconstruction is validated by comparing it with a commercial hand tracking system based on a depth camera. The system requires a small amount of electronics to be mounted on the hand. This would allow building a light and comfortable data glove that could be used for several purposes: human-machine interface, sign language recognition, diagnostics, and rehabilitation.

MagIK: a Hand Tracking Magnetic Positioning System based on a Kinematic Model of the Hand

In this paper we present a hand tracking system based on magnetic positioning. A single magnetic node is mounted on each fingertip, and two magnetic nodes on the back side of the hand. A fixed array of receiving coils is used to detect the magnetic field, from which it is possible to infer position and orientation of each magnetic node. A kinematic model of the whole hand has been developed. Starting from the positioning data of each magnetic node, the kinematic model can be used to calculate position and flexion angle of each finger joint, plus the position and orientation of the hand in space. Relying on magnetic fields, the hand tracking system can work also in nonline-of-sight conditions. The gesture reconstruction is validated by comparing it with a commercial hand tracking system based on a depth camera. The system requires a small amount of electronics to be mounted on the hand. This would allow building a light and comfortable data glove that could be used for several purposes: human-machine interface, sign language recognition, diagnostics, and rehabilitation.

Simulations on Simple Models of Connexin Hemichannels Indicate That Ca2+ Blocking Is Not a Pure Electrostatic Effect

Connexin hemichannels allow the unspecific but regulated interchange of molecules from ions to second messenger and ATP, between the eukariotic cell and its extracellular space. The transport of ions and water through hemichannels is important for physiological functions and also in the progression of several pathological conditions. Extracellular Ca2+ concentration is one of the regulators that drives the channel to a closed state. However the relation between their functional and structural states is far for being totally understood. In this work, we modelled connexin hemichannels using simple systems based on a fixed array of carbon atoms and assess the Ca2+ regulation using molecular dynamics simulations. The two proposed mechanism described so far for calcium action were studied combined, e.g., an electrostatic effect and a pore stretching. Our results show that the addition of positive charge density inside the channel cannot stop the flow of potassium, chloride nor water. Only a pore stretching at the center of the pore can explain the channel blocking.

Experimental studies of a single flexibly-mounted rod in a triangular rod bundle in cross-flow

Experiments on flow-induced vibrations using a closely-packed triangular rod array with a pitch-todiameter ratio of 1.1 in water cross-flow was carried out at Paul Scherrer Institute. The bundle consists of 21 row of five rods in each one. Single flexibly-mounted test rod (TR) is in the fourth row in an otherwise fixed array. The test rod can freely move in the transverse and in-line direction. Two accelerometer sensors were attached at both ends of the TR to measure the rod response on the fluid flow. The effect of flow rate on the stability of the flexibly-mounted TR has been analysed. During experiments, it reveals a set of conditions and tendencies for the flow-induced vibration in the closely-packed multi-rod system.

Maneuvering and Seakeeping Basin Wave Characterization Study

A series of experiments aimed at characterizing the wavefield generated by the new multi-directional wave making system in the Maneuvering and Seakeeping (MASK) Basin at the Naval Surface Warfare Center Carderock Division in West Bethesda, MD are described. These experiments were focused on the repeatability of phase resolved seaways, the spatial variability of wave parameters throughout the basin, and the stationarity of the wavefield over the span of 2 hours. Two different wave spectra were run repeatedly over a two week test window covering 21 discrete locations with one fixed array of sensors as a control. The results from the test show that when sampling at the same location and running the same wave condition, the phase resolved seaway exhibits a coherence of over 95% between 0.25 and 0.75 Hz. The spatial variability of the wave statistics proved to be within 5% of the average values throughout the tank, with a larger deviation over the 35ft deep trench section.

Whirlwinds and Hairpins in the Atmospheric Surface Layer

Vortices in the atmospheric surface layer are characterized using observations at unprecedented resolution from a fixed array of 31 turbulence sensors. During the day, these vortices likely are dust devils, though no visual observations are available for confirmation. At night, hairpin vortices appear to have been observed. The structure and dynamics of several types of vortices are described and related to other vortex investigations, including tornadoes and hurricanes.