120 research outputs found
Latitude variation of recurrent fluxes in the outer solar system
Recurrent low energy (greater than or = to 0.5 MeV) proton flux enhancements, reliable indicators of corotating plasma interaction regions, were observed on the Voyager 1 and 2 and Pioneer 11 spacecraft in the heliographic latitude range 2 deg S to 23 N and the heliocentric radial range 11 to 20 AU. After a period of rather high correlation between fluxes at different latitudes in early 1983, distinct differences developed in the fluxes during an overall flux decrease. The flux intensities returned to higher levels in early 1984 and differences in both the recurrence frequency and flux intensity persisted into 1985, as Voyager 1 traveled to 23 AU and 25 N latitude. Intercomparison of data from the three spacecraft indicates that the flux differences are most likely due to latitudinal rather than radial or temporal variations
Solar modulation and interplanetary gradients of the galactic electrons flux, 1977 - 1984
The flux of electrons with energy from approx. 10 to 180 MeV measured with the electron telescope on the Voyager 1 and 2 spacecraft in the heliocentric radial range 1 - 22 AU between 1977 and 1984 is reported. Jovian electrons were clearly observable between 1978 and 1983 (radial range 2 - 12 AU) at energies below approx. 50 MeV. Above approx. 50 MeV the electron intensity exhibited temporal variations generally related to the 11 year modulation of protons 75 MeV. The overall magnitude of the electron intensity changes between the maximum intensity observed in 1977 and the minimum intensity in 1981 was a factor approx. 2, also comparable to that observed for 75 MeV protons. By early 1985 the electron intensity had apparently recovered to the level observed in 1977 whereas the proton intensity was still about 20% lower. A detailed interpretation of these electron variations in all energy channels depends on an accurate subtraction of background induced by energetic protons of a few 100 MeV. This subtraction is facilitated by calibration results at several energies
The Energy Spectrum of Jovian Electrons in Interplanetary Space
The energy spectrum of electrons with energies approx 10 to approx 180 MeV measured with the electron telescope on the Voyager 1 and 2 spacecraft in interplanetary space from 1978 to 1983 is studied. The kinetic energy of electrons is determined by double dE/dx measurements from the first two detectors (D sub 1, D sub 2) of a stack of eight solid state detectors and by the range of particle penetration into the remaining six detectors (D sub 3 to D sub 8) which are interleaved with tungsten absorbers. From 1978 to 1983 (radial range approximately 2 to a pproximately 12 AU) electrons of Jovian origin were clearly observable for electrons stopping in D(sub 3(E approximately greater than 4 MeV)) and in D(sub 4 (E approximately greater than 8 MeV)). For electrons stopping in D(sub 5(E approximately greather than 12 MeV)), the jovian flux dominated the galactic electron flux for a period of approximately one year near the encounter with Jupiter. Jovian electrons were also observed in D(sub 6(E approximately greater than 21 MeV)) but not in D(sub 7(E approximately greater than 28 MeV)). A detailed interpretation of the electron variations in all energy channels depends on an accurate subtraction of background induced by energetic protons of a few 100 MeV. This substraction is facilitated by laboratory calibration results at several energies. Further results on the differential energy spectrum of Jovian electrons and limits on the maximum detected energies will be reported
Evidence for a Latitudinal Gradient of the Cosmic Ray Intensity Associated with a Change in the Tilt of the Heliospheric Current Sheet
Since mid-1985, the average flux of >70 MeV/nucleon cosmic rays at Voyager 2 (r_2 ∼ 17 AU, Θ_2 ∼ 0°) has been ∼3-5% greater than that at Voyager 1 (r_1 ∼ 24 AU, Θ_1 ∼ 26°N). This is the first direct observation over such a large radial range in which the galactic cosmic ray flux closer to the sun is higher than the flux farther from the sun for an extended period of time. This observation is consistent with the presence of a negative latitudinal gradient G_Θ=−0.36 ± 0.05 (or −0.60 ± 0.08) %/deg, assuming a coexistent radial gradient G_r of 1 (or 2) %/AU. We suggest that the appearance of this persistent negative latitudinal gradient may be due to the abrupt, large decrease of the heliospheric current sheet tilt to ∼20° in early 1985
Analisis Perubahan Biaya Pada Pembangunan Plengsengan Di Daerah X Yang Mengalami Kelongsoran Dinding Plengsengan Antara Hasil Pekerjaan Di Lapangan Pada Proyek Yang Dipersyaratkan
Pada pelaksanaan pekerjaan bangunan terdapat berbagai kemungkinan perbedaan antara spesifikasi yang ada di lapangan dengan spesifikasi yang di persyaratakan, maka dari itu diperlukan adanya penelitian dan pengujian terhadap mutu pekerjaan di lapangan untuk mendapatkan kekuatan bangunan eksisting. Dari perbedaan spesifikasi tersebut dapat digunakan untuk mengetahui dampak yang diakibatkan dalam segi kekuatan dan selisih biaya akibat perbedaan spesifikasi yang ada di lapangan dengan spesifikasi yang telah dipersyaratkan. Penelitian ini dilakukan dengan metode pengukuran langung di lapangan. Pengukuran langsung menggunakan alat meteran roll dan meteran biasa. Selanjutnya untuk mendapatkan hasil sampel tanah dilakukan pengambilan sampel tanah lalu diuji di laboratorium mekanika tanah dari data diatas didapatkan perhitungan yang menunjukan perbedaan spesifikasi dinding penahan tanah yang telah dipersyaratkan. Biaya yang dikeluarkan dalam dokumen kontrak pada dinding penahan tanah sebesar Rp.125.826.976 sedangkan pada pekerjaan struktur eksisting dinding penahan tanah dana yang dikeluarkan sebesar Rp.33.388,367. Dari perbedaan yang diperoleh antara dokumen kontrak dengan struktur eksisting sebesar Rp.92.438.609. Perbedaan biaya diakibatkan oleh adanya perbedaan spesifikasi mutu dan bentuk bangunan yang dikerjakan. Pengaruh dari ketidaksesuaian mutu dan bentuk bangunan mengakibatkan struktur dinding penahan tanah mengalami kegagalan bangunan, karena tidak sesuai dengan spesifikasi yang ditentukan
Electronic document management system
Electronic Document Management System (EDMS) is needed by many organizations to properly managed large volumes of physical documents. One of them is Supply Chain Management (SCM) department of Oil and Gas (O&G) company in Malaysia. The objective of this research is to develop a framework of EDMS that is tailor-made to the SCM department, which is believed could help the department to manage their physical documents which are now located in their rented external storage due to the lack of space in the department itself. The requirements gathering is conducted by using interview method. The current business flow which involved the usage of the documents from one unit to another needed to be fully understood before developing the EDMS framework. This research has successfully developed an EDMS framework of SCM department and it could be used in developing the EDMS for future research
Latitude variation of recurrent Mev-energy proton flux enhancements in the heliocentric radial range 11 to 20 AU and possible correlation with solar coronal hole dynamics
Recurrent low energy ( ≳0.5 MeV) proton flux enhancements, reliable indicators of corotating plasma interaction regions in interplanetary space, have been observed on the Voyager 1 and 2 and Pioneer 11 spacecraft in the heliographic latitude range 2°S to 23°N and the heliocentric radial range 11 to 20 AU. After a period of rather high correlation between fluxes at different latitudes in early 1983, distinct differences develop. The evolution of the fluxes appears to be related to the temporal and latitudinal dynamics of solar coronal holes, suggesting that information about the latitudinal structure of solar wind stream sources propagates to these distances
Differential Measurement of Cosmic-Ray Gradient with Respect to Interplanetary Current Sheet
Simultaneous magnetic field and charged particle measurements from the Voyager
spacecraft at heliographic latitude separations from 10° to 21 a are used to
determine the latitude gradient of the galactic cosmic ray flux with respect to the
interplanetary current sheet. By comparing the ratio of cosmic ray flux at Voyager
1 to that at Voyager 2 during periods when both spacecraft are first north
and then south of the interplanetary current sheet, we find an estimate of the
latitudinal gradient with respect to the current sheet of approximately -0.15 ±
0.05 %/ deg under restricted interplanetary conditions
MeV magnetosheath ions energized at the bow shock
A causal relationship between midlatitude magnetosheath energetic ions and bow shock magnetic geometry was previously established for ion energy up to 200 keV e−1 for the May 4, 1998, storm event. This study demonstrates that magnetosheath ions with energies above 200 keV up to 1 MeV simply extend the ion spectrum to form a power law tail. Results of cross-correlation analysis suggest that these ions also come directly from the quasi-parallel bow shock, not the magnetosphere. This is confirmed by a comparison of energetic ion fluxes simultaneously measured in the magnetosheath and at the quasi-parallel bow shock when both regions are likely connected by the magnetic field lines. We suggest that ions are accelerated at the quasi-parallel bow shock to energies as high as 1 MeV and subsequently transported into the magnetosheath during this event
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