Traditional smoking of fish in Nigeria is often carried out in open and unsanitary environment. In addition, the current process does not result in uniformly smoked fish and uses wood (an increasingly scarce material...Traditional smoking of fish in Nigeria is often carried out in open and unsanitary environment. In addition, the current process does not result in uniformly smoked fish and uses wood (an increasingly scarce material) as heat source. The fish smoking kiln designed and fabricated in this study addresses these problems. The kiln (700 × 800 × 1,500 mm) is made of stainless steel on the inside and mild steel on the outside with glass fiber insulation separating the inside and outside covers. The sample to be smoked is totally enclosed by the kiln with a latchable door provided at one of the sides for placing of samples to be smoked. In addition, the kiln was designed to use waste biomass resource as fuels (sawdust and/or maizecob). Bonga fish (Ethmalosafimbriata) and African catfish (Clarias gariepinus) were used as test samples for the kiln. The temperature of the chamber increased to about 120 ℃ to 160 ℃ when fueled with sawdust and about 150 ℃ to 200 ℃ for maizecob. The total heat transfer resistance through the kiln walls was determined to be 1.0 ℃/W. About 6-8 h was required to smoke-dry 16 kg of fish samples from initial moisture content of 75% to about 25% or 20% moisture level.展开更多
Severe solar events manifested by highly energetic X-Ray events accompanied by coronal mass ejections and proton flares caused flash floods in Makkah AI-Mukaramab, A1-Madinah AI-Munawarah and Jeddah. The responses can...Severe solar events manifested by highly energetic X-Ray events accompanied by coronal mass ejections and proton flares caused flash floods in Makkah AI-Mukaramab, A1-Madinah AI-Munawarah and Jeddah. The responses can be prompt, delayed or prompt-delayed, suggesting that the protons entered the troposphere either through the opening of a direct gate in the magnetosphere to the location concer.led due to magnetic reconnection, through the polar gates or through those two paths respectively. The authors suggest that there is a magnetic anomaly in Makkah AI-Mukaramah area which makes it liable to be subjected to flash floods. The width of the solar streams determines the width of the gate opened in the magnetosphere via magnetic reconnection and thus narrow streams affect only one location of the three cities while extended width streams can cause flash floods in all of Makkah AI-Mukaramah AI-Madinah AI Munawarah and Jeddah. In addition, the November 24-26 Jeddah flash flood could be attributed to a prompt event due to a moderately fast solar stream that arrived the earth on those days.展开更多
Coronal mass ejections(CMEs) and solar flares are the large-scale and most energetic eruptive phenomena in our solar system and able to release a large quantity of plasma and magnetic flux from the solar atmosphere in...Coronal mass ejections(CMEs) and solar flares are the large-scale and most energetic eruptive phenomena in our solar system and able to release a large quantity of plasma and magnetic flux from the solar atmosphere into the solar wind. When these high-speed magnetized plasmas along with the energetic particles arrive at the Earth, they may interact with the magnetosphere and ionosphere, and seriously affect the safety of human high-tech activities in outer space. The travel time of a CME to 1 AU is about 1–3 days, while energetic particles from the eruptions arrive even earlier. An efficient forecast of these phenomena therefore requires a clear detection of CMEs/flares at the stage as early as possible. To estimate the possibility of an eruption leading to a CME/flare, we need to elucidate some fundamental but elusive processes including in particular the origin and structures of CMEs/flares. Understanding these processes can not only improve the prediction of the occurrence of CMEs/flares and their effects on geospace and the heliosphere but also help understand the mass ejections and flares on other solar-type stars. The main purpose of this review is to address the origin and early structures of CMEs/flares, from multi-wavelength observational perspective. First of all, we start with the ongoing debate of whether the pre-eruptive configuration, i.e., a helical magnetic flux rope(MFR), of CMEs/flares exists before the eruption and then emphatically introduce observational manifestations of the MFR. Secondly, we elaborate on the possible formation mechanisms of the MFR through distinct ways. Thirdly, we discuss the initiation of the MFR and associated dynamics during its evolution toward the CME/flare. Finally, we come to some conclusions and put forward some prospects in the future.展开更多
文摘Traditional smoking of fish in Nigeria is often carried out in open and unsanitary environment. In addition, the current process does not result in uniformly smoked fish and uses wood (an increasingly scarce material) as heat source. The fish smoking kiln designed and fabricated in this study addresses these problems. The kiln (700 × 800 × 1,500 mm) is made of stainless steel on the inside and mild steel on the outside with glass fiber insulation separating the inside and outside covers. The sample to be smoked is totally enclosed by the kiln with a latchable door provided at one of the sides for placing of samples to be smoked. In addition, the kiln was designed to use waste biomass resource as fuels (sawdust and/or maizecob). Bonga fish (Ethmalosafimbriata) and African catfish (Clarias gariepinus) were used as test samples for the kiln. The temperature of the chamber increased to about 120 ℃ to 160 ℃ when fueled with sawdust and about 150 ℃ to 200 ℃ for maizecob. The total heat transfer resistance through the kiln walls was determined to be 1.0 ℃/W. About 6-8 h was required to smoke-dry 16 kg of fish samples from initial moisture content of 75% to about 25% or 20% moisture level.
文摘Severe solar events manifested by highly energetic X-Ray events accompanied by coronal mass ejections and proton flares caused flash floods in Makkah AI-Mukaramab, A1-Madinah AI-Munawarah and Jeddah. The responses can be prompt, delayed or prompt-delayed, suggesting that the protons entered the troposphere either through the opening of a direct gate in the magnetosphere to the location concer.led due to magnetic reconnection, through the polar gates or through those two paths respectively. The authors suggest that there is a magnetic anomaly in Makkah AI-Mukaramah area which makes it liable to be subjected to flash floods. The width of the solar streams determines the width of the gate opened in the magnetosphere via magnetic reconnection and thus narrow streams affect only one location of the three cities while extended width streams can cause flash floods in all of Makkah AI-Mukaramah AI-Madinah AI Munawarah and Jeddah. In addition, the November 24-26 Jeddah flash flood could be attributed to a prompt event due to a moderately fast solar stream that arrived the earth on those days.
基金supported by the Fundamental Research Funds for the Central Universitiesthe National Natural Science Foundation of China (Grant Nos. 11303016, 11373023, 11533005, 11203014)National Key Basic Research Special Foundation (Grant No. 2014CB744203)
文摘Coronal mass ejections(CMEs) and solar flares are the large-scale and most energetic eruptive phenomena in our solar system and able to release a large quantity of plasma and magnetic flux from the solar atmosphere into the solar wind. When these high-speed magnetized plasmas along with the energetic particles arrive at the Earth, they may interact with the magnetosphere and ionosphere, and seriously affect the safety of human high-tech activities in outer space. The travel time of a CME to 1 AU is about 1–3 days, while energetic particles from the eruptions arrive even earlier. An efficient forecast of these phenomena therefore requires a clear detection of CMEs/flares at the stage as early as possible. To estimate the possibility of an eruption leading to a CME/flare, we need to elucidate some fundamental but elusive processes including in particular the origin and structures of CMEs/flares. Understanding these processes can not only improve the prediction of the occurrence of CMEs/flares and their effects on geospace and the heliosphere but also help understand the mass ejections and flares on other solar-type stars. The main purpose of this review is to address the origin and early structures of CMEs/flares, from multi-wavelength observational perspective. First of all, we start with the ongoing debate of whether the pre-eruptive configuration, i.e., a helical magnetic flux rope(MFR), of CMEs/flares exists before the eruption and then emphatically introduce observational manifestations of the MFR. Secondly, we elaborate on the possible formation mechanisms of the MFR through distinct ways. Thirdly, we discuss the initiation of the MFR and associated dynamics during its evolution toward the CME/flare. Finally, we come to some conclusions and put forward some prospects in the future.