Wave Energy Potential for Development of Renewable Energy in Riau Archipelago Province

Energy and electricity demand in Riau Islands is increasing rapidly due to the fast-growing population, urbanization, industrial development, and economic growth. The limitations of energy and electricity in the Riau Islands caused frequent blackouts. To support the high demand for energy and electricity in the Riau Islands, renewable energy is the most suitable alternative energy solution. Renewable energy is not only playing a key role in providing energy but also providing long-term clean and sustainable energy. We investigated the wave energy potential in the Riau Islands Sea in four different consecutive monsoons (North monsoon, East monsoon, South Monsoon and West Monsoon) using ECMWF data during January 2018 to December 2018 with 0.125o x 0.125o and 6 hourly spatial and temporal resolutions. We extracted bathymetry data from NOAA’s database ETOPO1 and forecasting wave characteristics use the SPM (Shore Protection Manual) method. The potential wave energy simulation from significant wave height (Hs) and energy period (Te) was shown in spatial distribution based on different monsoon. Our studies found that the potential wave energy was higher in north monsoon with maximum spatial of wave power density 3.240 – 3.640 kW.m-1. The east monsoon tended to be lower potential wave energy with dominance of wave power density at 0 – 0.127 kW.m-1. Keywords: wave power density, potential wave energy, ECWFM, monsoon

Multiple-Embedded-System Optimization Layout for Electromagnetic Wave Power Density in Complex Environments

Many embedded systems are implemented for healthcare, and smart homes and spaces. These devices are generally designed for elderly care, for monitoring, surveillance, and collection information. As embedded systems are ubiquitous and pervasive in a smart home, office, or space, different layout affects not only reduce the implementation cost but also the power density of electromagnetic waves. This study aimed to develop a multiple-embedded-system optimization layout to consume less electromagnetic wave power density and gain better communication strength. For smart offices, we analyzed the layout topology of n-shaped and n-shaped with door layout categories. On the basis of the location of each embedded system in a communication center via an n-shaped layout, we investigated the electromagnetic wave effect to the local, direct, and semidirect effects. Indirect and subindirect effects were also studied in the n-shaped layout with a door. In addition, we derived a set of formulas from the scope for the diverse effects to help users to quickly identify the scope of each effect. To verify the multiple-embedded-system optimization layout, 16 cooperating embedded systems with four test cases in a smart office were used to evaluate the diverse effects of electromagnetic wave power density and communication strength. Experiment results showed that the optimization layout consumed 3950 × 10−6 W/m2 electromagnetic wave power density.

Designing of a generator for wave energy conversion for outdoor activities

Wave energy is one of the renewable resources with high availability area of the wave across the world. However, the wave power density in Malaysia is smaller compared to other countries with progressive development in Wave Energy Converter (WEC), which leads to wave energy utilization to produce pico-scale power generation for the benefit of outdoor activities. Thus, this paper is presenting the modeling of a tubular longitudinal permanent magnet linear generator for wave energy conversion for outdoor activities. This research aims to design a pico-scale linear generator with 100 W output power utilizing wave energy. The design is also intended to be a portable design with a weight that less than 20 kg, which compatible with outdoor activities. The generator is proposed by designing the different shapes of permanent magnets with slotless configuration. The designs are simulated using the Finite Element Analysis (FEA) to obtain the performance of flux distribution, flux linkage, and back EMF performance.

Effectiveness of Visual vs. Acoustic Closed-Loop Stimulation on EEG Power Density during NREM Sleep in Humans

The aim of the study was to investigate whether visual stimuli have the same potency to increase electroencephalography (EEG) delta wave power density during non-rapid eye movement (NREM) sleep as do auditory stimuli that may be practical in the treatment of some sleep disturbances. Nine healthy subjects underwent two polysomnography sessions—adaptation and experimental—with EEG electrodes positioned at Fz–Cz. Individually adjusted auditory (pink noise) and visual (light-emitting diode (LED) red light) paired 50-ms signals were automatically presented via headphones/eye mask during NREM sleep, shortly (0.75–0.90 s) after the EEG wave descended below a preset amplitude threshold (closed-loop in-phase stimulation). The alternately repeated 30-s epochs with stimuli of a given modality (light, sound, or light and sound simultaneously) were preceded and followed by 30-s epochs without stimulation. The number of artifact-free 1.5-min cycles taken in the analysis was such that the cycles with stimuli of different modalities were matched by number of stimuli presented. Acoustic stimuli caused an increase (p < 0.01) of EEG power density in the frequency band 0.5–3.0 Hz (slow waves); the values reverted to baseline at post-stimuli epochs. Light stimuli did not influence EEG slow wave power density (p > 0.01) and did not add to the acoustic stimuli effects. Thus, dim red light presented in a closed-loop in-phase fashion did not influence EEG power density during nocturnal sleep.

Long-term assessment of wave energy in the China Sea using 30-year hindcast data

In this study, a long-term assessment of the wave energy in the China Sea was performed for a 30-year time interval (1988–2017), using the model WAVEWATCH-III. The reliability of the wave simulation results was increased by means of longer time horizon data compared to other relevant studies in the China Sea. This analysis provided information on the regional distribution as well as on the monthly and seasonal variability. The exploitation and stability of wave energy were taken into consideration, so as to find the advantage of resource exploitation. Results indicated that values of significant wave height and wave power density had obviously differences compared with different months, especially in December with a maximum significant wave height of 2.7 m and 35 kW/m of wave power density. The minimum value of them appeared in May, was 1.0 m and 4.5 kW/m, respectively. The distribution of wave energy was abundant in winter and the poorest in summer. In winter, the significant wave height in most areas was above 1.8 m, while the maximum wave energy density in summer was only 1.2 m. As for the wave power density, in winter values in most areas were above 18 kW/m, while the maximum value in summer was only 12 kW/m. In sight of regional distribution, the highest wave energy potential was located in the Northern South China Sea, the East China Sea, the Ryukyu Islands waters, east of the Taiwan Island and the Luzon Strait, with coefficient of variation was within 2.0 and occurrence of exploitation was above 80%, whereas the Bohai Sea, the northern part of the Yellow sea, the Gulf of Thailand, and the Northern Bay were in poor contribution, with occurrence of exploitation was within 50%.

The effect of stroboscopic effect on human health indicators

The stroboscopic effect from LED light sources can become considerable in working environments. Therefore, this study aims to explore the short-term health effect of a temporal light artefact. The experiment was carried out featuring 10 university students. Three frequencies and three modulation depths were assessed. Psychological reaction was evaluated through subjective scales, while physiological parameters were also collected for mutual validation and analysis. It was found that when the conditions are in the high-risk zone defined by IEEE Standard 1789-2015, subjects considered these conditions to be unacceptable and reported discrete spatial movement and higher visual fatigue levels. Supported by psychological and physiological evidence, it is suggested that such fatigue is caused by a higher chance of flicker. Invisible flicker also significantly affected alpha and beta wave power density, suggesting that a strobe of low frequency could potentially decrease drowsiness and increase cortical arousal. Some limitations to the work performance of this study are also discussed.

BASIN-SCALE MODEL FOR PREDICTING MARSH EDGE EROSION

Recent attempts to relate marsh edge retreat rate to wave power have met varying levels of success. Schwimmer (2001) correlated wave power to marsh boundary retreat rates over a five-year period along sites within Rehoboth Bay, Delaware, USA. Marani et al. (2011) derived a linear relationship between volumetric retreat rate and mean wave power density using Buckingham’s theorem of dimensional analysis. Leonardi and Fagherazzi (2015) added an exponential function to the Schwimmer (2001) equation to account for variability in soil resistance and mean wave height. These equations factor in soil type, water elevation, vegetation, and macrofauna through field-calibrated empirical constants, i.e., they are not explicitly considered. Consequently, the existing capability of predicting marsh edge erosion rate as a function of wave power and soil and vegetation properties is rather limited for engineering applications. For instance, Allison et al. (2017) show that without taking the marsh platform, soil, and vegetation into account, the relationships between marsh edge erosion rates and wave power on a basin or coastal-wide scale are not strong enough statistically to serve as a useful predictive model. The objective of this study is to develop a more robust marsh edge erosion model by characterizing the shear strength, wave power, and retreat rates in Terrebonne Bay, Louisiana.