Potential of tidal power plants with least square method on Toaya Beach

The use of energy, especially electrical power, is needed by the wider community— lots of alternative energy from nature, especially in Indonesia that can be utilized to produce electricity. One of the newest alternative examples is the energy produced by tides. Tidal energy is a type of renewable energy that is relatively more predictable in number. One method that can process the waves is the Least Square Method. Where the results of data processing using this method can be known based on tidal observations for 15 days on Toaya Beach located in Donggala Regency, Central Sulawesi, the types of tidal types that occur based on the results of Formzahl’s count is 0.357 that the tidal types that occur are varied types leaning to double daily, with a Root Mean Square Error (RMSE) of 0.028, which means that the difference between predictive results and observational data is accurate. Then also obtained the value of the design water level elevation that is the highest high water level (HHWL) is 2.7 meters, and the lowest low water level (LLWL) is -0.3 meters with a height difference is 3.0 meters. So with the high height difference, the total energy generated by two times a day with a sea area of 9 km2 which is capable of producing energy movement from seawater can be calculated the potential energy generated from the waves of Toaya Beach, which is 5,53 MW.

Evaluating the Behavior of Embankments after Widening considering Soil Consolidation and Splicing Mode

Increased traffic volume has made it necessary to increase highway capacities by widening embankments and pavements. Differential settlement of foundation consolidation and rational utilization of existing embankments are the main problems encountered in road reconstruction. In this paper, the finite difference method is used to simulate the construction process of using the existing embankments directly in the reconstruction project of expressway, and the fluid-solid coupling model of foundation settlement is established to calculate the differential settlement between foundation and subgrade. The influence of road widening mode and embankment height on differential settlement is analyzed. The mechanical response of subgrade under differential settlement is simulated and the law of uneven settlement of main reconstruction forms is investigated. The dynamic response of existing embankments soil under the action of rammer is systematically evaluated. The results show that, with the increase of consolidation time, the differential settlement is gradually obvious at the junction of the new and existing embankments, and there is a possibility of landslide along the junction of new embankments, which should be dealt with in engineering. The smaller the height difference between the existing foundation and the new foundation is, the more the position of the maximum settlement point of the foundation moves towards the new foundation. The greater the height of the new subgrade is, the greater the uneven settlement is. The criterion based on the single rammed energy and compaction stopping standard is proposed to determine the reinforcement depth of existing embankment.

Demonstrating the first postulate of relativity in a lift

The first of the two postulates of relativity states that the laws of physics are the same in all inertial reference frames. Often it is assumed that the postulates are mainly concerned with objects moving at a significant fraction of the speed of light. However, the postulates are applicable at all speeds from a snail to a photon. To practically demonstrate the first postulate, the time for a ball to drop a known distance was measured in a stationary and moving lift. An accelerometer app on an iPhone 7 was used to measure the vertical acceleration while the lift travelled between floors and verified that the lift ascended and descended at a constant speed when the ball was dropped. The slow-motion feature of the iPhone 7 (240 fps) was used to capture videos of the falling ball. The number of frames for the ball to fall in a stationary, descending, and ascending lift was respectively 102.4 ± 0.55 , 102.3 ± 1.64 , 99.8 ± 4.21. A t-test revealed no significant difference between these values, confirming the validity of the first postulate. The accelerometer signal was integrated to estimate the average speed of the lift between the bottom and top floor, which was then used to estimate the height difference. An electronic balance placed on the floor of the lift was used to demonstrate the first postulate and the equivalence principle of General Relativity that states that gravitational and inertial mass are equivalent.

Visualizing nanometric structures with sub-millimeter waves

The resolution along the propagation direction of far field imagers can be much smaller than the wavelength by exploiting coherent interference phenomena. We demonstrate a height profile precision as low as 31 nm using wavelengths between 0.375 mm and 0.5 mm (corresponding to 0.6 THz–0.8 THz) by evaluating the Fabry-Pérot oscillations within surface-structured samples. We prove the extreme precision by visualizing structures with a height of only 49 nm, corresponding to 1:7500 to 1:10000 vacuum wavelengths, a height difference usually only accessible to near field measurement techniques at this wavelength range. At the same time, the approach can determine thicknesses in the centimeter range, surpassing the dynamic range of any near field measurement system by orders of magnitude. The measurement technique combined with a Hilbert-transform approach yields the (optical) thickness extracted from the relative phase without any extraordinary wavelength stabilization.

Der Effekt von Action Observation Therapy auf die Extension nach einer vorderen Kreuzbandplastik: eine randomisierte kontrollierte Pilotstudie

ZusammenfassungEine bekannte Komplikation nach einer Plastik des vorderen Kreuzbandes (VKB) ist das Extensionsdefizit (ED). Ziel dieser Studie war, zu erforschen, ob eine zusätzlich zu den klassischen Streckübungen eingesetzte einmalige Anwendung der „Action Observation Therapy“ (AOT) die Extension des Kniegelenks nach einer VKB-Plastik deutlicher verbessert als eine Therapiesitzung ohne AOT.13 Proband(inn)en mit ED nach einer VKB-Plastik wurden in eine AOT-Gruppe (n = 8) und eine Kontrollgruppe (n = 5) randomisiert. Jede Gruppe erhielt eine Therapiesitzung. Die Therapie bestand aus dem Betrachten eines Videos, gefolgt von aktiven Extensionsübungen, wobei das Video der AOT-Gruppe Extensionsübungen und das der Kontrollgruppe Landschaftsaufnahmen zeigte. Primäres Outcome war das Bewegungsausmaß der aktiven Extension, als sekundäre Outcomes wurden das Bewegungsausmaß der passiven Extension und die Heel-Height Difference (HHD) gemessen. Die Messungen erfolgten direkt vor und nach der Behandlung.Die aktive Extension verbesserte sich sowohl in der AOT-Gruppe (von ∅ –2,0° (± 6,3) auf ∅ 0,8° (± 3,9), p = 0,036) als auch in der Kontrollgruppe (von ∅ –8,2° (± 5,5) auf ∅ –5,6° (± 4,7), p = 0,049). Die aktive Extension war in der AOT-Gruppe nach der Intervention signifikant besser als in der Kontrollgruppe (p = 0,023). Für die passive Extension und die HHD gab es keine signifikanten Unterschiede zwischen beiden Gruppen.Bei Patient(inn)en nach einer VKB-Plastik zeigte sich in der Gruppe mit AOT eine bessere aktive Knieextension als in der Kontrollgruppe ohne AOT. Weitere Arbeiten mit einer größeren Stichprobe und einer längeren Verlaufskontrolle sind notwendig, um diese Ergebnisse zu bestätigen.

Estimation of energy dissipation in step-pool reaches of mountain river - a field investigation

The bed of the step-pool rivers is adapted to the flow conditions in terms of the topographic position and the steep slope of the path in such a way to dissipate the water energy, along the river. The beds of these rivers is sinusoidal like the meander rivers. However, as the river banks are mostly rocky in mountainous areas and the erosion in these areas is less, the bed fluctuation of these reaches is mainly vertical. When the water flow streams from the step crest into the pool, most of the water energy dissipates. In addition to the height difference, other factors contribute to the energy dissipation in the step pool reaches. The present study examines the energy dissipation by determining its effective factors, including step height (H), step length (L), hydraulic radius (R), sediment material diameter (d84), velocity in the step (V), etc. by field measurements in three reaches of mountain rivers. In the same vein, an equation is provided to estimate energy dissipation in the step pool reaches, by considering measurable effective parameters.

Simultaneous extraction of profile and surface roughness of 3D SLM components using fringe projection method

Purpose The purpose of this study was expected to simultaneously monitor the surface roughness of each solidified layer, the surface roughness of the metal powder, the outline of the solidified layer, and the height difference between the solidified layer and the metal powder. Design/methodology/approach In the proposed approach, color images with red, green and blue fringes are used to measure the shape of the built object using a three-step phase-shift algorithm and phase-unwrapping method. In addition, the surface roughness is extracted from the speckle information in the captured image using a predetermined autocorrelation function. Findings The feasibility and accuracy of the proposed system were validated by comparing it with a commercial system for an identical set of samples fabricated by a selective laser melting process. The maximum and minimum errors between the two systems are approximately 24% and 0.8%, respectively. Originality/value In the additive manufacturing field, the authors are the first to use fringe detection technology to simultaneously measure the profile of the printed layer and its surface roughness.

Variation in the Polarization Loss Factor in an Unmanned Aerial Vehicle Jamming Link Due to the Attitude Change

A method to analyze the variation of the jamming power received by an unmanned aerial vehicle (UAV) receiver according to the change in the attitude of the small UAV is presented. The main interest of the study is in the variation of the polarization loss factor (PLF) in the UAV jamming link due to attitude change, which may be caused by the wind or intended movement. The attitude change is modeled by a combination of three successive rotations using roll, pitch, and yaw, which are defined as UAV rotations. The proposed method is applied to a jamming link, where a small UAV with an omnidirectional antenna is jammed by a jammer antenna on the ground. The method is applied to a plane ground and over a simulated terrain. The variation of the PLF according to the change of UAV attitude may be higher than the generally expected PLF at locations where the height difference between the UAV and the jammer is large, and near the locations where the jammer is located close to the vertical plane containing the rotation axis when the attitude change is represented by one rotation.

Research On Dynamic Stability Of Vibrating Disk Worktable

This paper studies the influence of the material quality in the vibrating plate and the relative height difference of the leaf springs on the stability of the worktable, i n order to obtain the disturbance law; firstly, the control variable method is adopted an d the Ansys workbench software is used to determine the quality of different materials on the worktable under static force. Secondly, the deformation of the beam and the cr ossbeam was compared by a simulation test. The results showed that the heavier the m aterial, the greater the deformation of the upper beam and the smaller the deformation of the crossbeam. Finally, the harmonic response method was used to study the effect of the height difference of the leaf spring on the deformation of the beam and the cro ssbeam of the worktable. The results show that the greater the height difference, the s maller the impact on the stability of the workbench.

STUDI PERBANDINGAN ANALISA KETELITIAN TINGGI MENGGUNAKAN TOTAL STATION DAN SIPAT DATAR

This research was conducted to analyze and determine the height difference accuracy using the method of measuring the different heights of a closed loop using Waterpass B2 and Total Station Kolida 420SR. The location of research in the Ciloto area, Puncak, West Java with coordinates 107˚ east longitude and 06˚ south latitude, on 14-15 December 2014 using a local high point reference. Measurements were made three times with different looped but the starting and ending points were the same points. Accuracy of calculation is done by calculating the average of the least squares to determine the standard deviation of the measurement results with each equipment. The result is the standard deviation of the height difference with the waterpass is 0.01mm, while with the Total Station it is 0.02 mm. Based on the results of the standard deviation of the height difference, the Total Station can be used for height measurements in civil engineering project that does not require very high accuracy and height difference measurements with the Total Station are more economical because the time required for measurement is a quarter of the time required height difference measurement with Waterpass. Keywords: height measurement; Waterpass; Total station. AbstrakPenelitian ini dilakukan untuk menganalisis dan mengetahui ketelitian beda tinggi menggunakan metode pengukuran beda tinggi suatu ring tertutup menggunakan Waterpass B2 dan Total Station Kolida 420SR. Lokasi penelitian terletak di daerah Ciloto, Puncak Jawa Barat dengan koordinat 107o bujur timur dan 06o lintang selatan, pada tanggal 14 dan 15 Desember 2014 dengan menggunakan referensi titik tinggi lokal. Pengukuran dilakukan tiga kali dengan ring yang berbeda namun titik pangkal dan ujung adalah titik yang sama. Hitungan ketelitian dilakukan dengan hitung perataan kuadrat terkecil untuk mengetahui standar deviasi hasil pengukuran dengan masing-masing alat. Hasilnya adalah standar deviasi beda tinggi dengan waterpass sebesar 0.01mm, sedangkan dengan Total Station sebesar 0.02 mm. Berdasarkan hasil perhitungan nilai standar deviasi pengukuran beda tinggi, maka Total Station dapat digunakan untuk pengukuran beda tinggi pada pekerjaan teknik sipil yang tidak memerlukan ketelitian yang sangat tinggi, dan pengukuran beda tinggi dengan Total Station lebih ekonomis karena waktu yang diperlukan untuk pengukuran adalah seperempat dari waktu yang diperlukan pengukuran beda tinggi dengan Waterpass.