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Gravitasi
Published by Universitas Tadulako
ISSN : 14122375     EISSN : 26544318     DOI : https://doi.org/10.22487/gravitasi.v18i2
Core Subject : Science, Social,
Astronomy Computer Science & IT Earth & Planetary Sciences Energy Environmental Science Materials Science & Nanotechnology Physics
Journal Gravitasi e-ISSN: 2654-4318 contains writings raised from the results studies specialize physics sciences. Gravitasi Publishes two times a year, in June and December. For authors who are interested in submitting the manuscript in Word format, please register yourself. The manuscript must be original research, can be written in Indonesian or English, and not be simultaneously submitted for another journal or conference. Scope of published articles: Theoretical Physics and Computation, Advanced Materials , Biophysics and Medical Physics, Nuclear Physics, Oceanography, Geophysics, Astrophysics, Laser and Optoelectronics, Instrumentation Physics, and Energy and Environmental Physics.
Arjuna Subject : Ilmu Material (semua kategori) - Elektronik, Optik dan Materi Magnetik
Articles 6 Documents
 1 
Search results for , issue "Vol. 13 No. 1 (2014)" : 6 Documents clear
Determination ofCoherenceandPhaseDifferencebetween Wind versus Current60 mand Current 60 mversusCurrent 100 mUsingCrossCorrelation in OmbaiStrait, East Nusa Tenggara Sabhan, Sabhan
Gravitasi Vol. 13 No. 1 (2014)
Publisher : Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/gravitasi.v13i1.4442

Abstract

Abstract   Data analysis was performed to see coherence and phase difference between the wind versus current 60 m and current 60 m versus current 100 m using cross correlation in Ombai Strait, East Nusa Tenggara. Velocity components U and V of wind and current of wind data and the current were filtered in order to obtain new data on the initial data at any position of t from xt-n  to xt+n. Energy spectrum density of the filter result is determined to examine the fluctuations of wind energy and real currents. Cross-correlation between wind versus current 60 m and current 60 m versus current 100 m is to determine the coherence and the phase difference of the data with the same time interval. Low coherence values in the cross-correlation between the Zonal Wind and the Zonal current at a depth of 60 m indicates that the fluctuations between the Zonal Wind and the zonal current depth of 60 m does not have a strong correlation with the largest coherence value that is 0.55 with a time leg 34 days. With fluctuation current at a depth of 60 m precedes wind fluctuation with a phase difference of 34 days. Keywords: coherence, phase difference, Ombai Strait
Implosion And Ultrasonic Cavitation At Low Frequency Waves Against Carbon Pore Morphology Toana, Musfirah Cahya Fajrah
Gravitasi Vol. 13 No. 1 (2014)
Publisher : Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/gravitasi.v13i1.4443

Abstract

Abstract Havestudiedthe effect oflow-frequencyultrasonicwave technologythat producesanddistributes47kHzimplosionof cavitationon the morphology ofthe carbonpore formation. Pore formationis donebyvariationof ultrasonictimefor 10 hoursand60 hours, at a temperature of900oC, 1000oCand1200oC. The morphology ofthe poreformationfor 10hoursresulted inporemorphologywith a size of200nmto1000oCand1200oCtemperaturecoveragebutdoes notoccurin eachporeuniformity ofthe grainsize. Pore formationfor 60hoursresulted inporesbutto900oCtemperaturecoveragedoes notoccurporeuniformity, in contrast tothe temperature of1000oCand1200oCcoverageoccursuniformity ofthe porebyporesize of185nm. Keywords: ultrasonic, cavitation, implosionandcarbonpore
Groundwater investigation Geolistrik Methods In Regional District of Parigi Parigi Moutong Musa, Moh. Dahlan Th
Gravitasi Vol. 13 No. 1 (2014)
Publisher : Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/gravitasi.v13i1.4444

Abstract

The research of groundwater investigation conducted by applying the method of geoelectric in the District Parigi Parigi Moutong. Identification of the substance of the study, conducted by survey / observations and measurements in the field.Field measurements using elektrical Vertical Sounding (VES) with Schlumberger electrode configuration. The results obtained indicate that the groundwater aquifer layer in the study area are the two lithologies are lithologies alluvium and coastal sediment and rock units molasa celebes. In the alluvium and coastal sediment units are at least 3 layers of the aquifer from surface to a depth of ± 25m bmt where perlapisannya alternating with layers aquiclude. Distribution of the aquifer layer on a flat stone units tend to follow the surface topography. In lithologies molasa celebes obtained their aquifer layer that is as aquifer (+). The upper limit of this layer is at a depth ±24.6m bmt decreases eastward at a depth ±40.2m bmt. The thickness of this layer is the average ±42m. allegedly sumurbor positive groundwater measuring point 16, 17 are located in the region kampal, 23 (Maesa), 24 (Mertasari), 30 (Bambalemo) and 35 (Maesa Coast) derived from this aquifer layer. Parigi district region is an area of discharge (discharge area), while the catchment area (recharge area) is located in the west area of research. Keywords: groundwater, geoelectric method, the method vertial Eletrrial Sounding, Schlumberger configuration
Plant Watering System Design Using Soil Moisture Automatic Sensor Microcontroller Based Sen0057 ATmega328P Gani, Sitti Hardianti; Musa, Moh. Dahlan Th.; Nismayanti, Anis
Gravitasi Vol. 13 No. 1 (2014)
Publisher : Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/gravitasi.v13i1.4445

Abstract

It has been designed and created a plant watering system that is expected to help watering plants from a manual system to an automated system. The watering system is designed for watering plants at the right time and humidity. This tool utilizes SEN0057 soil moisture sensors to detect the level of soil moisture and ATmega328P microcontroller as the main controller. This tool is also used as a stop relay contact or disconnect from the current to flow to the pump, the LCD to display the time and the level of soil moisture and pump to drain the water. The working principle of this device when the sensor detects kelambaban ground level is less than the pre-defined limit, the microcontroller will command the process of watering until the soil moisture value equal to or greater than the pre-defined. Pepper plants as objects of research have suitable soil moisture ranging from 50% - 60%. Thus limits for soil moisture for plant watering is 3:38 volts. Watering the plant is operated at 5:45 pm and 17:45 pm.Keywords: Soil Moisture Sensor SEN0057, ATmega328P, Relays
A Study of the Effect of Thermal Annealing on the Morphology of Copper Foils as Catalyst for Graphene Growth Kasman, Kasman
Gravitasi Vol. 13 No. 1 (2014)
Publisher : Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/gravitasi.v13i1.4446

Abstract

Telah dilakukan penelitian tentang pengaruh “thermal annealing” terhadap morphology pada tembaga (Cu) sebagai katalis penumbuh graphene.Penelitian ini bertujuan untuk menemukan suatu kondisi optimal untuk mempersiapkan katalis tersebut pada penumbuhan graphene.Dalam penelitian ini, foil tembaga telah diteliti dengan memvariasikan suhu annealing, waktu annealing dan laju gas hydrogen. Dari hasil penelitian didapatkan bahwa kondisi optimal adalah annealing pada suhu 900 oC selama 10 menit dengan laju aliran hydrogen sebesar 100 sccm. Selain itu, penelitian “pre-thermal annealing” telah juga dilakukan untuk menguji perubahan sifat-sifat struktur dan morphology tembaga tersebut.Dari hasil penelitian ditemukan bahwa tembaga tersebut memiliki “nanocrystalline cubic structure” yang baik, di mana didominasi oleh (100) dengan ukuran crystal ~200 nm.Penelitian ini juga menunjukkan bahwa gas hydrogen efektif dalam mereduksi impurity dari oksidasi tembaga.Dan juga, annealing pada suhu 900 oC ke atas, sampel tersebut memiliki morphology yang halus pada seluruh permukaannya dan grain-grain berukuran ~ 88 µm. Kata kunci : Foil tembaga, Thermal annealing, Ukuran crystal,  and Ukuran grain.
Accuracy and Automatic Computation of Seismic Refraction: a case of Forward Modeling and Inversion Hiden, Hiden; B, Kirbani S; S, wiwit; S, Hadmoko D; Setiawan, Ari
Gravitasi Vol. 13 No. 1 (2014)
Publisher : Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/gravitasi.v13i1.4447

Abstract

It has been built a data processing program to perform the first arrival waktu tempuh inversion of seismic refraction profiles zero distance. Analysis of the first wave arrival time is obtained by 1) using two-way analysis of time-taking to control the accuracy of the passage and identify the mistakes geometry,, 2) parameterization slowness and intercept-time of travel-time, in which the velocity model and multi-layer thickness obtained by inversion LSQ method (unconstrained, constrained and Marquardt) on seismic refraction. For automatic calculation and accurate, we make a data processing program for the third inversion LSQ method. Analysis of the model resolution and measurement data to determine the optimal parameters of the model, the algorithm used Menke (1989). Resolution inversion results, we tested with: forward modeling, the level of misfit (error) and the convergence between the observed data and the model. Once the program is successfully tested on a number of data, then we apply to the real seismic. The results of field data inversion interpreted that the subsurface strata bedding row from the top (first layer) in the form of: soil, sand (loose), sand (saturated, loose) and sandstone, limestone. Resolution velocity and thickness in the forward modeling program: a) the error between: 10-17 - 10-5 and b) the residue of convergence is: 10-11-10-4, while the resolution of the results of the third inversion LSQ method on the field data, obtained misfit between: 10-17 - 10-4 and residual convergence between measurement data and the model are: 10-11 -10-4.Keywords —seismic refraction, forward modeling, LSQ inversion, parameter models, resolution.

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