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Tytuł:
An Analysis of Active Regions 11036 Characteristics Leads To Solar Flare Class C7.2 Phenomena
Autorzy:
Zainol, N. H.
Hamidi, Z. S.
Husien, Nurulhazwani
Ali, M. O.
Sabri, S. N. U.
Shariff, N. N. M.
Faid, M. S.
Monstein, C.
Ramli, Nabilah
Powiązania:
https://bibliotekanauki.pl/articles/1192106.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Solar Radio Burst Type II
solar flare
Callisto network
active region
Opis:
The solar flares are generated from electromagnetic radiation which is sudden oscillation of the stored energy in the magnetic field of the sun. Flares are categorized according to their brightness as C, M and X, where X is the brightest. The X class flares caused a long-time solar storm and ionospheric radio waves sparkling. The moderate level M class flares mostly effect polar cups and cause short-time radio sparkling. However, the C class flares are weaker than the X and M flares. In this work, we present an active region from the disturbance of magnetic field on the area of the Sun and may lead to powerful event if the magnetic field become stronger. The CALLISTO system network that has been installed in Gauri, India observed data that contain Solar Radio Burst Type II (SRBT II) occurred on 22nd December 2009 at 04:57 UT to 05:02 UT. Five active regions were obtained from online data via internet from the Space Weather website and the Solar Monitor website. All data and information from these sources assist in analyze of the phenomena. The magnetic field and X-ray flux, proton density increase the possibilities that SRBT II observed by CALLISTO network to generate powerful solar flare. When X-ray flux level was at maximum, then solar flare was at peak point. However, solar activity level was low because among of five active regions present, only one C-class flare event occurred. The most active region that contributes this event is an AR11036 with C-class flare.
Źródło:
World Scientific News; 2016, 45, 2; 80-91
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Formation of Fundamental Structure of Solar Radio Burst Type II Due X6.9 Class Solar Flare
Autorzy:
Zainol, N. H.
Hamidi, Z. S.
Shariff, N. N. M.
Ali, Marhana Omar
Husien, Nurulhazwani
Sabri, S. N. U.
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/1190115.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Sun
solar burst
type II
radio region
X-ray region
solar flare
Coronal Mass Ejections (CMEs)
Opis:
A vigorous solar flare event marked on the spectrometer of the CALLISTO data, being one of the highest solar flare event that successfully detected. The formation of solar burst type II in meter region and their associated with X6. 9-class solar flares have been reported. The burst has been observed at the Blein Obsevatory, Switzerland, which detected by the Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO) system in the range of 170-870 MHz in the two polarizations of left and right circular polarization. It occurred between 08:01 UT to 08:08 UT within 7 minutes. The Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory CALLISTO spectrometer is a solar dedicated spectrometer system that has been installed all over the world to monitor the Sun activity in 24 hours. The growth of this burst is often accompanied by abundance enhancement of particles which may take the form of multiple independent drifting bands or other forms of fine structure. Due to the results, the drift rate of this burst is 85.71 MHz s-1, which is considered as a fast drift rate. The burst detected using CALLISTO also being compared to results detected by X-ray GOES data. Both different electromagnetic spectrum shows the exact time. The observations of the burst being discussed in details.
Źródło:
World Scientific News; 2016, 35; 30-43
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ethnobotanical investigation of significant seasonal medicinal weeds of Toba Tek Singh District, Punjab, Pakistan
Autorzy:
Tufail, M.
Hussain, K.
Nawaz, K.
Iqbal, I.
Arshad, N.
Shahzadi, A.
Javed, A.
Nazeer, A.
Bashir, Z.
Qurban, M.
Zeb, J.
Ali, S.S.
Powiązania:
https://bibliotekanauki.pl/articles/2049359.pdf
Data publikacji:
2021
Wydawca:
Instytut Włókien Naturalnych i Roślin Zielarskich
Tematy:
weeds
ethnobotany
flora
survey
chwasty
etnobotanika
badanie
Opis:
Introduction: Medicinal plants are found throughout the world but most are considered weeds. They are – directly or indirectly – the major source of medicines in pharmaceutical and herbal industries. Formulations used to prepare medicines or the method of use for these plants are mainly based on folk or traditional knowledge. This folk knowledge is not documented in many areas and needs to be explored. Objectives: This study was aimed to enlist the seasonal weed species with traditional medicinal usage in Toba Tek Singh District, Punjab, Pakistan. Methods: Field surveys were arranged in winter and summer 2019–2020 to enlist the important medicinal weeds and traditional knowledge of the local community. Data collected were as follows: local name of weed, medicinal use, method and part used. Results: Numerous wild perennial, biennial and annual plants were identified, 30 of them were ethnomedicinally important in the local community. They were grouped in 16 families. It was found that whole weed is used in many prescriptions (37%). Achyranthes aspera L. (Amaranthaceae) was the most common weed used in treating fevers, respiratory problems and asthma. Cichorium intybus L. (Asteraceae) was used in summer drinks to reduce thirst, improve digestion and liver function. Chenopodium album L. (Amaranthaceae) was used with 0.71 UV and 0.147 RFC values. Medicago polymorpha L. (Fabaceae) was used to treat kidney, intestinal and bladder infections. Its UV was 0.65 and RFC was 0.121. Tribulus terrestris L. (Zygophyllaceae) was used in impotency treatment, and in the removal of kidney stones and urinary tract infections treatment. It has 0.63 UV and 0.21 RFC values. This weed also showed the highest Fidelity Level (FL) (77%), as compared to other weeds. Conclusion: It was concluded that there are many significant medicinal weeds in the Toba Tek Singh District, Punjab, Pakistan that are used in traditional medicines in treating various disorders. These plants also showed herbal or pharmacological importance that can be used to develop medicine at commercial scale.
Źródło:
Herba Polonica; 2021, 67, 2; 29-38
0018-0599
Pojawia się w:
Herba Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CO2 laser spot welding of thin sheets AISI 321 austenitic stainless steel
Autorzy:
Shehab, A. A.
Nawi, S. A.
Al-Rubaiy, A. AAG
Hammoudi, Z.
Hafedh, S. A.
Abass, M. H.
Alali, M. S.
Ali, S. D.
Powiązania:
https://bibliotekanauki.pl/articles/1818484.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
thin sheet metal
austenitic stainless steel
CO2 CW LSW
mechanical properties
welding profile
FE analysis
blachy cienkie
stal austenityczna nierdzewna
właściwości mechaniczne
profil spawalniczy
analiza elementów skończonych
Opis:
Purpose: The present work aims to investigate the influence of CO2 laser spot welding (LSW) parameters on welding profile and mechanical properties of lap joint of AISI 321 thin sheet metals, and analyze the welding profile numerically by finite element (FE) method. Design/methodology/approach: The weld carried out using 150 W CO2 continues wave laser system. The impact of exposure time and laser power on the welding profile was investigated using an optical microscope. Microhardness and tensile strength tests were used to evaluate the mechanical properties of the joint. Ansys software was utilized to simulate the welding profile numerically. Findings: The results revealed that 2 s exposure time and 50 W power have led to uniform welding profile and highest shear force (340 N), lower hardness gradient across the heat affected zone (HAZ) and fusion zone (FZ). Finite element (FE) analysis of the welding profile showed good agreement with experimental analysis. Research limitations/implications: The selection of laser spot welding parameters for thin sheet metal was critical due to the probability of metal vaporisation with extra heat input during welding. Practical implications: Laser welding of AISI 321 steel is used in multiple industrial sectors such as power plants, petroleum refinement stations, pharmaceutical industry, and households. Thus, selecting the best welding parameters ensures high-quality joint. Originality/value: The use of CO2 laser in continuous wave (CW) mode instead of pulse mode for spot welding of thin sheet metal of AISI 321 austenitic stainless steel consider a real challenge because of the difficulty of control the heat input via proper selection of the welding parameters in order to not burn the processed target. Besides, the maintenance is easier and operation cost is lower in continuous CO2 than pulse mode.
Źródło:
Archives of Materials Science and Engineering; 2020, 106, 2; 68--77
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geo-effective Disturbances from the “Beta-Gamma-Delta” Magnetic Fields on Active Region AR 2403
Autorzy:
Sabri, S. N. U.
Hamidi, Z. S.
Shariff, N. N. M.
Monstein, C.
Zainol, N. H.
Ali, M. Omar
Hussien, Nurul Hazwani
Powiązania:
https://bibliotekanauki.pl/articles/1192069.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Sun
Solar Radio Burst Type IV
X-ray region
Solar flare
active region AR 2403
Opis:
This moving solar radio burst type IV, which lies in between 980 – 1260 MHZ was observed using Compound Astronomical Low-Cost Low- Frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO) spectrometer and will discussed in detail. CALLISTO system was used and the data were recorded. From BLEN5M’s Radio Flux Density data, it shown that a brief description of the formation of a dynamic formation of solar radio burst type IV due to an active region, AR 2403. This event proved that solar radio burst type IV has a broadband continuum features and has strong pulsations in some range of time. In this event it was took about 8 minutes and it can be high in possibility solar flare and CMEs event followed due to this event. AR 2403 remained active and produced an X- class solar flares and it showed “Beta- Gamma-Delta” magnetic field that gives solar flares which can make geo-effective disturbance to our earth satellite and we have to investigate how plasma – magnetic field in the solar corona which can produce suprathermal electron pulsation about 8 minutes. In this event, it has solar wind speed in 364.8 km/sec and solar wind density in 11.0 protons/cm3.
Źródło:
World Scientific News; 2016, 37; 1-11
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Development of the X2-Class of flares with Presence of Type IV burst and Single Type III burst in Low Frequency (20-85 MHz) on 5th May 2015
Autorzy:
Sabri, S. N. U.
Hamidi, Z. S.
Shariff, N. N. M.
Zainol, N. H.
Syazwan, Nabilah Ramli
Ali, Marhana Omar
Husien, Nurulhazwani
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/1191466.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Sun
solar burst
III
IV
X-ray region
solar flare
Active Region 2335
Opis:
The plasma-magnetic field interaction in the solar corona is caused exploration of suprathermal electron population have been made to study about the phenomena solar radio burst. This burst only took about approximately 2 minutes to produce X2- class of solar flares which occurred at 22:10 UT till 22:11UT. The wave-wave interaction and wave-particle interaction influenced the characteristic structures of the emission. The CALLISTO spectrometer has been used to detect and record the Type IV and Type III occurred during 22:07UT till 22:11 UT and it only took about 3.30 minutes to occur. The range of frequency of this burst 20-85 MHz and data is from ROSWELL-NM observatory. With the presence of the data, we aim to determine the causes of the Solar Radio Burst Type IV produced Type III burst in several minutes and describe briefly about the formation and dynamics of solar radio burst type IV occurred on active region, AR2335 which also produced beta-gamma magnetic field. This event showed the strong pulsation and a broadband pattern with details about Type IV burst, then Type III burst present in fast drift. AR 2335 is the most active region and produced X2-class of solar flares which has solar wind speed about 361.6km/second and proton density about 4.3 protons/cm3 in the solar corona. AR 2335 harbor energy for X2-class from 6-H to 24-H observation on X-Ray solar flares have been recorded. The data showed that it has a strong energy electrons presence during the burst occurred in the active region and this class of solar flares are more powerful which has potential to cause radio blackout and long lasting space weather storms. As the conclusion, the sun activity showed on 5th May 2015 has quasi-periodic pulsation that has continuum and drift in lower frequency. The temperature that corona took to extend from the top of a narrow transition region still be as mysterious properties.
Źródło:
World Scientific News; 2016, 40; 188-198
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An alternative and indirect statistical modeling method for viscosity estimation and its experimental validation for low styrene content polyester resin
Autorzy:
Nawaz, A.
Islam, B.
Ijaz, M. Z.
Saleem, U.
Khattak, M. S.
Ahmad, S. N.
Maqsood, N.
Ali, L.
Powiązania:
https://bibliotekanauki.pl/articles/778495.pdf
Data publikacji:
2018
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
indirect method
polyester resin
statistical relation
Ford viscosity cup
Opis:
We propose an indirect method of ASTM D-1200 for measurement of viscosity from 0.1 to 30 stokes (St) using Ford cup 5 (range 2~ 12 St) by developing a statistical relation. General purpose low styrene content polyester resin (without adding initiator, hardener and accelerator) was used for viscosity measurement. In existing ASTM D 1200 standard, ford cups (1-4) are used to measure the viscosity up to 2 St, while fifth cup is used for measurement from 2 to 12 St. Viscosity above 12 St is not estimated using existing ASTM D- 1200 method. In contrast, our method and statistical relation proposed in this paper estimates viscosity in the flexible range of 0.1 to 30 St by using Ford cup 5 only. The estimated values were confirmed by existing ASTM D-1200 (0.1 to 12 St) and by using Ubbelohde viscometer (12 to 30 St). Values estimated above 12 St are from the proposed model are also in good conformance (percentage error ~ 5% or less) with experimental results. The satisfaction level of the estimated values with the experiments suggests that the model has also the potential for application to paints, polymer and oil industry.
Źródło:
Polish Journal of Chemical Technology; 2018, 20, 4; 60-65
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production of Coronal Mass Ejections in Relation With Complex Solar Radio Burst Type III Correlated With Single Solar Radio Burst Type III
Autorzy:
Hussien, Nurul Hazwani
Hamidi, Z. S.
Ali, M. O.
Sabri, S. N. U.
Zainol, N. H.
Shariff, N. N. M.
Moinstein, C
Powiązania:
https://bibliotekanauki.pl/articles/1192988.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Sun
Solar radio burst
type III
single Solar Radio Burst Type (SRBT) III
complex Solar Radio Burst Type (SRBT) III
Coronal Mass Ejection (CMEs)
magnetic reconnection
Opis:
The complex solar radio burst type III is very related to generation of Coronal Mass Ejections (CMEs). In a previous study, they deduced that the burst was produced by electron beams accelerated in blast wave shocks and injected along open magnetic field lines, similar to the herringbone bursts at metric wavelengths. Usually, if there is another solar flare recorded during complex solar radio burst type III it should be type II burst. Different for this event, the single solar radio burst recorded occur 8 minutes 30 seconds before the complex solar radio burst type III. The Coronal Mass Ejections also recorded occurred 7 hours before the single and complex solar radio burst type III. It is noted that CMEs occurred several hours before this event recorded by the SOHO websites.It is proved that the production of coronal mass ejection contributed to the production of complex solar radio burst type III.
Źródło:
World Scientific News; 2016, 36; 96-108
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Debt maturity and family related directors : evidence from a developing market
Zapadalność zadłużenia i dyrektorzy związani z rodziną : dowody z rozwijającego się rynku
Autorzy:
Hussain, H. I.
Abidin, I. S. Z.
Ali, A.
Kamarudin, F.
Powiązania:
https://bibliotekanauki.pl/articles/404736.pdf
Data publikacji:
2018
Wydawca:
Politechnika Częstochowska
Tematy:
debt maturity
capital structure
family related directors
board composition
corporate governance
family firms
zapadalność zadłużenia
struktura kapitałowa
dyrektorzy rodzinni
skład zarządu
ład korporacyjny
firmy rodzinne
Opis:
This paper examines the debt maturity structures of Malaysian firms based on the presence of family-related directors (FRDs) on boards. The motivation is derived from the board composition literature, which highlights reforms taken place over the years in order to ensure proper governance mechanisms. Conversantly, debt maturities are also linked to reductions in agency costs whereby firms with short-term borrowings will be subject to greater levels of monitoring by markets. Furthermore, this reduces information asymmetry. Thus, the paper evaluates the effectiveness of FRDs in alleviating the agency problem by studying the trade-off of such presence on debt maturity structures. The study finds that firms with the presence of FRDs tend to opt for longer maturity structures. These points towards a substitution effect where firms with FRDs will not rely on short-term borrowing as a mechanism for reducing agency problems. The findings of the study are further validated given that the presence of FRDs is not motivated by firms matching strategy of assets versus liabilities. However, these firms also opt for long-term borrowing in order to mitigate potential liquidity problems. The study further documents that these firms face lower bankruptcy costs. Interestingly, the authors also document that FRD opt to lengthen maturity structures during periods of increase in share prices indicating that control by family members tend to take into consideration shareholders’ wealth maximization. The finding is valid given that most firms with FRD also tend to have significant ownership by families.
W niniejszym artykule przeanalizowano strukturę zapadalności długu malezyjskich firm w oparciu o obecność dyrektorów rodzinnych (FRD) w zarządach. Motywacja pochodzi z literatury poświęconej składom zarządów, która podkreśla reformy, które miały miejsce od lat w celu zapewnienia odpowiednich mechanizmów zarządzania. Konsekwentnie, zapadalność długu jest również powiązana z obniżeniem kosztów pośrednictwa, w wyniku czego firmy o pożyczkach krótkoterminowych będą podlegać większemu monitorowaniu na rynkach. Ponadto zmniejsza to asymetrię informacji. W związku z tym, w artykule dokonano oceny skuteczności FRD w łagodzeniu problemu agencji poprzez zbadanie zysku takiej obecności w strukturach dojrzałości długu. Badanie wykazało, że firmy z obecnością FRD wybierają dłuższe struktury dojrzałości. Wskazuje to na efekt substytucyjny, w którym firmy z FRD nie będą polegać na pożyczkach krótkoterminowych jako mechanizmie zmniejszającym problemy agencji. Wyniki badania są dalej potwierdzane, ponieważ obecność FRD nie jest uzasadniona przez firmy, które dopasowują strategię aktywów do zobowiązań. Firmy te również wybierają długoterminowe pożyczki, aby złagodzić potencjalne problemy z płynnością. Badanie to dokumentuje również, że firmy te ponoszą niższe koszty bankructwa. Co ciekawe, autorzy dokumentują również, że FRD opowiadają się za przedłużeniem struktur zapadalności w okresach wzrostu cen akcji, wskazując, że kontrola członków rodziny ma tendencję do uwzględniania maksymalizacji zamożności akcjonariuszy. Stwierdzenie jest słuszne, biorąc pod uwagę, że większość firm z FRD ma również znaczny udział rodzinny w strukturze własności.
Źródło:
Polish Journal of Management Studies; 2018, 18, 2; 118-134
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Enlargement of Type II Burst After Type III at AR 12522 on 16th March 2016 In Conjunction With Flare-Related Coronal Mass Ejections Event
Autorzy:
Husien, Nurulhazwani
Hamidi, Z. S.
Shariff, N. N. M.
Ali, M. O.
Zainol, N. H.
Sabri, S. N. U.
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/1178545.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Coronal Mass Ejections
Sun
X-ray emission
Opis:
On 16th March 2016 the solar radio burst type II is recorded to appear on spectrograph after the type III formation. These two bursts related to the Coronal Mass Ejections (CMEs) event that recorded by the SOHO spacecraft several minutes before the formation of Type III on the spectrograph. It has been reported that the Type III burst a fast drift compared to the Type II burst. In this paper, the calculation has been proved that the type III burst has a higher drift rate compared to Type II. These two events of Type II and III burst also has been contributing to the formation of C class flare with magnitude of C2.2 It is also proven that the type III burst has a fast drift rate compared to type II burst. In this case, the type III has a fast drift rate of 81% compared to the type II burst. During this event, the active region AR 12522 erupted the C-class X-ray emission with magnitude of C2.2 contribute to these type III and II burst
Źródło:
World Scientific News; 2017, 70, 2; 230-240
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Solar Radio Burst Type II Correlated With Minor CME Contributes to The Production of Geomagnetic Disturbance
Autorzy:
Husien, Nurulhazwani
Hamidi, Z. S.
Ali, M. O.
Zainol, N. H.
Sabri, S. N. U.
Shariff, N. N. M.
Faid, M. S.
Ramli, Nabilah
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/1192691.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Solar radio burst
solar radio burst type II
Coronal Mass Ejections
geomagnetic disturbance
Opis:
The solar radio burst type II on 4th November 2015 was associated with minor CME that not lead towards the Earth. This clear type II burst recorded on spectrographs detected by the antenna in several locations (Gauri, Almaty, Kasi and Ooty) were obtained from CALLISTO website. The average time of the burst occurred are around 03:24 UT until 03:28 UT with the clear minor CME emerged recorded by SOHO at 03:12 UT. Although it just a minor CME but it is still giving the effect on Earth as it contributes to geomagnetic disturbance on the Earth during that day. The affected region reported by The Local news is Sweden, where the radar system for aviation was not clear, but it is back to normal after a few hours later. This geomagnetic disturbance is powerful enough that may cause the satellite damage, endanger astronauts and produce destructive surges on power grids.
Źródło:
World Scientific News; 2016, 46; 165-175
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Current Situation of Radio Frequency Interference (RFI) Profile at Outdoor and Indoor Sites of Faculty of Applied Sciences, UITM, Malaysia
Autorzy:
Hamidi, Z. S.
Nizamudin, Nur Izzani
Shariff, N. N. M.
Syazwan, M.
Husien, Nurulhazwani
Ali, M. O.
Zainol, N. H.
Ramli, Nabilah
Sabri, S. N. U.
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/1191429.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Radio Frequency Interference (RFI)
radio astronomy
RFI sources
Opis:
This Radio Frequency Interference (RFI) study is currently one of a main sub-research in radio astronomy in Malaysia. The main objective of this monitoring is to test and qualify the potential of radio astronomical sources that can be observed in Malaysia generally. Analysis process focuses at indoor and outdoor of Faculty of Applied Sciences, UITM Shah ALAM, Malaysia (latitude: 03°06.534’N, longitude: 101°50.396’E). There are three mobile network communications that operate at the upper band frequency of 1800MHz, which are Maxis (1805-1830 MHz), Celcom (1830-1855 MHz) and Digi (1855-1880 MHz) for GSM/LTE network. We observed that both sites having the highest and second highest peak at the same frequency of 420 MHz and 1835 MHz with the same source, which were due to mobile application followed by the lowest peak due to radio navigation satellite. We verified that the source of RFI of 1835 MHz at the Faculty of Applied Sciences may come from Celcom mobile telecommunication network signal because there is transmitter on top of two Celcom towers. This observation must be continuously done to ensure that RFI level does not increase drastically and to ensure that allocation spectrum band that was reserved for radio astronomy activities was always protected.
Źródło:
World Scientific News; 2016, 40; 23-33
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heart-shape Active Region 2529 Producing Strong M6.7 class Solar Flare and Gradual Coronal Mass Ejections
Autorzy:
Hamidi, Z. S.
Omar Ali, M.
Nurul, Hazwani Husien
Sabri, S. N. U.
Zainol, N. H.
Shariff, N. N. M.
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/1179601.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Gradual Coronal Mass Ejections
Heart-shape active region
Sun
X-ray region
solar flare
Opis:
The Centre of the Sun is very important to be study because this layer is where the nuclear reaction will be occurred. During large event pre-flare usually continues a few minutes and followed by impulsive phase about 3 to 10 minutes. Solar storms such as solar flare and Coronal Mass Ejections are frequently occurred on the area of the Sun that have strong magnetic field or known as active region The release of the stored free magnetic energy that probably drives a CME can take many forms including (predominantly) mechanical in the form of an expanding CME and erupting filament, electromagnetic emission in the form of a flare, and also in the acceleration of energetic particles, magnetic field reconfiguration and bulk plasma motion. In this study, the data of active region of the Sun was taken from official website of the Langkawi National Observatory. The image of the active region was observed by using 11-inch Celestron telescope with solar filter. This data confirms that there was a strong M class of solar flare during the day due to eruption of AR 2529 was occurred on 18th of April. From the x-ray flux data also, it can be observed that few days before M6.7 class solar flare occurred, there were several C classes of flare. The evolution of small AR 2529 to a big heart-shape forms an eruption that producing strong M6.7 class of flare and three gradual CMEs. This strong flare caused significant impact around the high technologies of Pacific Ocean by fading the signal at frequencies below 15 MHz.
Źródło:
World Scientific News; 2017, 74; 181-193
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solar Radio Burst Type III due to M 2.9 Class Flare with a Geomagnetic Disturbance
Autorzy:
Hamidi, Z. S.
Ali, M. O.
Shariff, N. N. M.
Monstein, C.
Zainol, N. H.
Hussien, Nurul Hazwani
Ramli, Nabilah
Farid, M. S.
Powiązania:
https://bibliotekanauki.pl/articles/1190207.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
solar radio burst
solar storm
flare
geomagnetic disturbance
Opis:
Varying forms of solar radio burst were classified by their frequent changes in time, which are known as drift rate. There are 5 types of radio emission were named type I, II, III, IV and V. This paper is highlighted on the type III event which occurred on 27th August 2015. In the IP medium, type III solar radio burst can be classified in three different groups which representing three different situations of electron beam production and propagation which are isolated, complex and storm type III burst. The most powerful manifestation of solar activity is solar flare together with coronal mass ejections, eruptive prominences and the solar wind are the solar events which affect the earth's atmosphere and can cause geomagnetic disturbance. In this study, the effect of M class flare with solar radio burst type III was investigated. During the day, the solar wind proton density seems to be high which is 8.4 protons/cm3 and accompanied by normal solar wind speed of 348.7 km/Sec. Spaceweather.com reported that there is one sunspot was detected (AR2403) and M class of the flare was detected during the day at 0544 UT. The data geomagnetic signal shows that during the day only geomagnetic disturbance that occur no such geomagnetic storm since the sunspot not facing the earth directly.
Źródło:
World Scientific News; 2016, 44; 155-167
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Correlation between Solar Flare Phenomena in an X-ray Region and Radio Flux Measurement from January to September 2010
Autorzy:
Hamidi, Z. S.
Shariff, N. N. M.
Ali, M. F.
Monstein, C.
Zulkifli, W. N. A. W.
Ibrahim, M. B.
Arifin, N. S.
Amran, N. A.
Powiązania:
https://bibliotekanauki.pl/articles/411743.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
sun
chromospheres
flares
radio flux
solar activity
Opis:
A short term variation of solar flare in nine months (January 2010 to September 2010) is presented. This paper review and analyze the correlation between radio flux strength measurement and solar flare in the X-ray region. The radio flux measurement data were taken from the National Research Council; Ottawa while hard X-ray emission observed by Royal Observatory of Belgium. The overall range of solar radio flux recorded in this study ranging from 68 x 10-22 Wm-2Hz-1 to 96 x 10-22 Wm-2Hz-1. As there was no class of an X of solar flare reported at all in this study, we can confirm that there are no major effects that happened on Earth and outer space such as Coronal Mass Ejections (CMEs) and solar storms. We concluded that the Sun shows a very minimum activity towards 24th solar cycle.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 9; 84-92
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
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