Analyzing the Application of Void Decks on High-rise Affordable Housing in Jakarta, Indonesia, to Achieve Optimal Urban Ventilation

Economic growth in ASEAN countries encourages significant urbanized growth. In line with the growth of urbanization, large swathes of residential buildings have been constructed in urban areas, especially, in the case of Indonesia, through the government's 1000 rusun (high-rise affordable housing) development program in Jakarta. In order to reduce energy consumption and create a sustainable rusun, a passive strategy is needed in the form of natural air conditioning through optimized natural ventilation in these buildings. In this study, testing was conducted on Rusun Rorotan in Jakarta, from two wind source directions (north and northwest) with five void decks configuration samples each, in order to determine wind flow and wind speed patterns in the Rusun area. For this purpose, the wind tunnel simulation method using the Butterfly plugin in Grasshopper was employed. T These results should provide a reference for future residential property developers, especially in the scope of other countries in ASEAN, which have similar climatic conditions to that of Indonesia.

Solar Orbiter observations of magnetic Kelvin-Helmholtz waves in the solar wind

<p>The Kelvin-Helmholtz instability (KHI) is a nonlinear shear-driven instability that develops at the interfaces between shear flows in plasmas. KHI is ubiquitous in plasmas and has been observed in situ at planetary interfaces and at the boundaries of coronal mass ejections in remote-sensing observations. KHI is also expected to develop at flow shear interfaces in the solar wind, but while it was hypothesized to play an important role in the mixing of plasmas and exciting solar wind fluctuations, its direct observation in the solar wind was still lacking. We report first in-situ observations of ongoing KHI in the solar wind using Solar Orbiter during its cruise phase. The KHI is found in a shear layer in the slow solar wind near the Heliospheric Current Sheet. We find that the observed conditions satisfy the KHI onset criterion from linear theory and the steepening of the shear boundary layer is consistent with the development of KH vortices. We further investigate the solar wind source of this event to understand the conditions that support KH growth. In addition, we set up a local MHD simulation using the empirical values to reproduce the observed KHI. This observed KHI in the solar wind provides robust evidence that shear instability develops in the solar wind, with obvious implications in the driving of solar wind fluctuations and turbulence. The reasons for the lack of previous such measurements are also discussed.</p>

Study of alpha particle properties across rarefaction regions

<p>Two large-scale interaction regions between the fast solar wind emanating from coronal holes and the slow solar wind coming from streamer belt are usually distinguished. When the fast stream pushes up against the slow solar wind ahead of it, a compressed interaction region that co-rotates with the Sun (CIR) is created. It was already shown that the relative abundance of alpha particles, which usually serve as one of solar wind source identifiers can change within this region. By symmetry, when the fast stream outruns the slow stream, a corotating rarefaction region (CRR) is formed. CRRs are characterized by a monotonic decrease of the solar wind speed, and they are associated with the regions of small longitudinal extent on the Sun. In our study, we use near-Earth measurements complemented by observations at different heliocentric distances, and focus on the behavior of alpha particles in the CRRs because we found that the large variations of the relative helium abundance (AHe) can also be observed there. Unlike in the CIRs, these variations are usually not connected with the solar wind speed and alpha-proton relative drift changes. We thus apply a superposed-epoch analysis of identified CRRs with a motivation to determine the global profile of alpha particle parameters through these regions. Next, we concentrate on the cases with largest AHe variations and investigate whether they can be associated with the changes of the solar wind source region or whether there is a relation between the AHe variations and the non-thermal features in the proton velocity distribution functions like the temperature anisotropy and/or presence of the proton beam.</p>

Pengaruh diameter dan jumlah sudu turbin angin savonius tipe L terhadap unjuk kerja yang dihasilkan

Wind is a renewable mechanical energy source that can be used as an energy source because the energy from the wind can be used to drive wind turbines. Savonius wind turbine type L is a tool to convert wind energy into electricity with a simple construction and can work with low wind speeds. The purpose of this study was to determine the effect of differences in diameter and number of blades on the power produced. The method used is a simulation method with an artificial wind source. With a wind speed of 8 m/s. The data analysis technique used is 2-way ANOVA using the SPSS application. Variations used are 20 cm and 40 cm in diameter and the number of blades 2 and 4 . The result is a wind turbine with a variation of 40 cm and 4 blades capable of producing the best output which produces 350.98 RPM voltage of 11.64 volts current of 0.144 amperes and power of 1,676 watts. As for BHP, torque, and turbine efficiency with a variation of 40 cm and 4 blades capable of producing the best output where the generated BHP is 3.352 watts, torque 0.091 N / m efficiency 2.17. For the results of calculations with SPSS wind turbines with a diameter variation of 40 cm and 4 blades, the biggest power is 1,744 watts and for BHP produces 3.3520 watts and the efficiency reaches 2.17%. Keyword : Diameter, number of blade, Performance Abstrak Angin adalah sumber energi mekanik yang bisa diperbaharui sehingga dapat dimanfaatkan sebagai sumber energi karena dapat digunakan untuk menggerakkan turbin angin. Turbin angin savonius tipe L merupakan alat untuk mengubah energi angin menjadi listrik dengan konstruksi yang sederhana dan dapat bekerja dengan kecepatan angin yang rendah. Tujuan penelitian ini untuk mengetahui pengaruh perbedaan diameter dan jumlah sudu terhadap unjuk kerja yang dihasilkan. Metode yang digunakan adalah metode simulasi dengan sumber angin buatan. Dengan kecepatan angin 8 m/s. Teknik analisis data yang digunakan adalah ANOVA 2 arah dengan menggunakan aplikasi SPSS. Variasi yang digunakan adalah diameter 20 cm dan 40 cm serta jumlah sudu 2 dan 4. Hasilnya turbin angin dengan variasi 40 cm dan 4 sudu mampu menghasilkan output terbaik yang dimana menghasilkan RPM 350,98 tegangan 11,64 volt arus 0,144 ampere dan daya 1,676 watt. Sedangkan untuk BHP, torsi, dan efisensi turbin dengan variasi 40 cm dan 4 sudu mampu menghasilkan output yang terbaik dimana BHP yang dihasilkan adalah 3,352 watt, torsi 0,091 N/m efisisensi 2,17. Untuk hasil perhitungan dengan SPSS turbin angin dengan variasi diameter 40 cm dan 4 sudu menghasilkan daya terbesar yakni 1,744 watt dan untuk BHP menghasilkan 3,3520 watt dan efisiensinya mencapai 2,17 % untuk torsi tertinggi dicapai turbin variasi 40 cm 2 sudu dengan torsi 0,116. Kata kunci : diameter, jumlah sudu, unjuk kerja

Directly comparing coronal and solar wind elemental fractionation

Context. As the solar wind propagates through the heliosphere, dynamical processes irreversibly erase the signatures of the near–Sun heating and acceleration processes. The elemental fractionation of the solar wind should not change during transit, however, making it an ideal tracer of these processes. Aims. We aim to verify directly if the solar wind elemental fractionation is reflective of the coronal source region fractionation, both within and across different solar wind source regions. Methods. A backmapping scheme was used to predict where solar wind measured by the Advanced Composition Explorer (ACE) originated in the corona. The coronal composition measured by the Hinode Extreme ultraviolet Imaging Spectrometer (EIS) at the source regions was then compared with the in situ solar wind composition. Results. On hourly timescales, there is no apparent correlation between coronal and solar wind composition. In contrast, the distribution of fractionation values within individual source regions is similar in both the corona and solar wind, but distributions between different sources have a significant overlap. Conclusions. The matching distributions directly verify that elemental composition is conserved as the plasma travels from the corona to the solar wind, further validating it as a tracer of heating and acceleration processes. The overlap of fractionation values between sources means it is not possible to identify solar wind source regions solely by comparing solar wind and coronal composition measurements, but a comparison can be used to verify consistency with predicted spacecraft-corona connections.

Wind power and competitiveness: a Bibliometric Analysis

In the last few decades, the relationship between energy production through fossil fuels and climate change has been widely discussed, which has led to a significant increase in studies on new forms of energy generation, using clean and renewable sources. Among these sources, wind power is considered as one of the most promising, since it has exponential growth, economicity and guarantee of continuous supply. Despite this, given that fossil sources are already consolidated, both in economic terms and in technical knowledge terms, it is necessary to know the competitiveness factors that can be characterized as potentialities or restrictions for the full development of the wind source. In order to know these aspects, the central objective of this research was to analyze the evolution path of the studies related to the competitiveness factors pertinent to wind energy, using bibliometric analysis so that future research directions can be identified. The results showed that studies on wind power and competitiveness have gained prominence since 2006, remaining constant until the current period. It was also found, through analysis by keywords and qualitative assessment of publications, that these surveys were classified into nine aspects related to competitiveness: Economic Analysis, Competition, Technology, Operational Costs, Regulation/Government, Environmental Impacts, Competitiveness, Market and Hybrid Generation, thereby providing guidance for future investigations. Keywords: Wind Energy. Competitiveness. Renewable Energy. Bibliometric Analysis.

Comparison of properties of the solar wind helium component close to the Sun and at 1 AU

<p>The relative helium abundance (AHe) and alpha-proton relative drift often serve as one of the solar wind source identifiers. However, observations at 1 AU suggest that these relative properties may be affected by the interaction of different solar wind streams. Since the influence of stream interaction is reduced near the Sun, a comparison of observations at 1 AU and close to the Sun could help to reveal the processes which lead to AHe variations. In-situ measurements near the Sun are provided by the SWEAP instrument onboard Parker Solar Probe. It consists of electrostatic analyzers (SPANs) and the Faraday cup (SPC). SPAN-Ai measures the 3-D ion distribution from the shadowed region behind the spacecraft thermal shield and is equipped with a mass-to-charge detection. SPC is directed to the Sun and provides fast measurements of the ion reduced distribution function (RDF) as a function of energy/charge. We develop a new data analysis technique for computations of the proton and helium parameters from the RDFs measured by SPC and compare it with SPAN observations. Then, we combine the PSP measurements with observations at 1 AU and focus on variations of the helium properties. Finally, we discuss the connection between AHe variations and changes of the solar wind source region.</p>