Getting Prepared for an Electromagnetic Pulse Attack or Severe Solar Storm

MELINDUNGI PERALATAN ELEKTRIK DAN ELEKTRONIK DARIPADA KESAN EMP

Sangkar Faraday atau Perisai Faraday adalah ruang bertutup yang dibentuk daripada bahan pengalir, ataupun daripada jaringan bahan sedemikian. Ruang bertutup ini menyekat medan elekrik statik luaran.

Medan elektrik statik luaran boleh menyebabkan cas elektrik di dalam bahan pengalir untuk beredar sesama sendiri untuk membatalkan kesan medan di dalam ruangan sangkar. Contohnya, untuk melindungi peralatan elektronik daripada sambaran kilat atau nyahcas elektrik yang lain.

Sangkar Faraday juga melindungi bahagian dalaman daripada radiasi elektromagnetik luaran jika bahan pengalir cukup tebal dan lubang yang terdapat juga lebih kecil daripada panjang gelombang radiasi. Contohnya, sesetengah prosedur ujian forensik komputer atau sistem yang memerlukan persekitaran bebas gangguan elektromagnetik akan dijalankan di dalam bilik layar. Bilik layar ini merupakan makmal atau ruang kerja yang ditutup sepenuhnya oleh satu atau lebih lapisan jaringan logam halus. Lapisan-lapisan ini disambungkan ke bumi bagi menyingkirkan arus elektrik yang dijana oleh medan elektromagnetik luaran, maka ia menghalang sebahagian besar gangguan elektromagnet.

BAGAIMANA SANGKAR FARADAY BERFUNGSI

Sebuah sangkar Faraday cage paling baik difahamkan sebagai pengalir berongga yang unggul. Medan elektrik luaran yang dikenakan menghasilkan daya pembawa cas (biasanya elektron) di dalam pengalir, menghasilkan arus elektrik yang menyusun semula cas. Sebaik sahaja cas sudah tersusun ia membatalkan medan yang dikenakan lalu memberhentikan pengaliran arus.

Jika cas dikenakan di dalam sangkar Faraday bawah tanah, bahagian muka dalaman sangkar akan bercas (dengan sifat yang sama seperti cas luaran) bagi mengelakkan wujudnya medan di dalam badan sangkar. Walau bagaimanapun, pengecasan muka dalaman akan mengagihkan semula cas di dalam sangkar. Ini akan mengecas muka luaran sangkar dengan cas yang sama dari segi penandaan dan magnitudnya dengan yang terdapat di dalam sangkar. Memandangkan cas dalaman dan muka dalaman saling membatal antara satu sama lain, penyebaran cas ke muka luaran tidak akanmempengaruhi kedudukan cas dalaman di dalam sangkar. Oleh itu sangkar akan menjana medan elektrik yang sama dengan medan yang dijana sekiranya ia dicas oleh cas di dalamnya.

Applications of the Faraday Cage

Let us look at some of the common applications of the Faraday cage.

• safety against lightening: Cars and aircraft act as Faraday cages / shields to protect people when the vehicle is struck by lightening. The cage protects the interior of the vehicle from the strong, electric fields of the lightening.
• microwave: the microwaves inside the oven are trapped and used for the purpose of cooking in a microwave where the metal shell of the microwave acts as a Faraday cage.
• protections for electronic goods: Electronic equipment can be shielded and protected from stray electromagnetic fields by using coaxial cables that contain a conducting shell that acts as a Faraday cage.
• protective suits for linemen: linemen often wear protective suits that act as Faraday cages to ensure their safety while working with high voltage power lines. These suits protect them from getting electrocuted.

TERUNG BELANDA

Assalamualaikum dan salam sejahtera,

Pernahkah anda meminum terung? Bagaimanakah rasanya jika terung yang berwarna ungu yang biasa kita kenali itu dijadikan jus?
Terung yang boleh dibuat jus yang mempunyai rasa yang enak ialah terung belanda. Bukan terung ungu yang biasa kita lihat itu, ya. Jangan tersilap terung. Terung belanda atau nama saintifiknya solanum betaceum juga dikenali sebagai tamarillo, tree tomato dan tergolong dalam keluarga solanaceae. Mengapa ia dipanggil terung belanda? Tidaklah diketahui mengapa, mungkin sama kisahnya dengan durian belanda. Belanda juga yang mendapat nama, hemmm....

Pokok terung belanda adalah tanaman asli di Andes Peru, Chile, Ecuador, Colombia dan Bolivia. Pokok ini juga banya ditanamkan di Argentina, Australia, Brazil, Indonesia, Kenya, Portugal, Amerika Syarikat dan Venezuela. Pokok terung belanda ini juga dijadikan sebagai tanaman komersil untuk eksport antarabangsa di New Zealand dan Portugal. Tanaman ini dipasarkan secara antarabangsa pada pertama kalinya di Australia iaitu sekitar tahun 1996.
Pokok terung belanda berupa perdu yang rapuh dan mempunyai ketinggiannya antara 2-3 meter. Pangkal batangnya pendek namun ia mempunyai cabang yang banyak. Daunnya tunggal, berselang-seling, bentuknya bundar telur sampai bentuk jantung, berukuran (10-35) cm x (4-20) cm, berpinggiran rata, berbulu halus, peruratannya menonjol, berujung lancip dan pendek. Kebiasaannya daun-daun itu berada hampir di hujung pucuk dan memiliki bau seperti lembu kutub(?). Daun pokok terung belanda mempunyai tangkai daun yaang agak panjang, iaitu sekitar 7-10 cm.

Bunga berada dalam rangkaian kecil di ketiak daun dan berdekatan hujung cabang. Bunganya berwarna merah jambu hingga biru muda dan berbau harum. Bunganya agak kecil, berdiameter kira-kira 1 cm sahaja. Kelopak bunga berbilangan lima, daun mahkota berbentuk genta, bercuping lima; benang sari 5 utas, berada di depan daun mahkota, kepala sari tersembunyi dalam runjung yang bertentangan dengan putik; bakal buah beruang dua, dengan banyak bakal biji, kepala putiknya kecil. [NB: Sorry, sesetengah ayat di sini tak dapat hendak diterjemah, sebab saya pun tidak berapa faham... hik hik... Walau bagaimana pun, saya akan cuba kemas kini bila cukup carian nanti, insya Allah.]

Buah terung belanda seakan buah buni bentuknya. Buahnya berbentuk bulat bujur telur dan berukuran (3-10) cm x (3-5) cm, meruncing ke dua hujungnya. Buahnya mempunyai tangkai yang panjang dan kelihatan bergantungan di pokoknya. Kulit buahnya nipis dan licin berkilat. Apabila buah terung belanda matang, ia berwarna lembayung kemerah-merahan, merah jingga sampai kekuning-kuningan.
Isi buahnya mengandung banyak sari buah. Rasanya agak masam-masam manis dan isinya berwarna kehitam-hitaman sampai kekuning-kuningan. Buah terung belanda mempunyai biji yang bulat pipih, tipis, dan keras. Isi buah terung belanda agak tajam dan manis, mungkin boleh dibandingkan dengan buah kiwi, tomato atau buah markisa. Kulit dan daging di dekat itu mempunyai rasa pahit yang tidak menyenangkan, dan biasanya tidak dimakan mentah.

Kandungan

Kulit buah terung belanda mengandung suatu zat yang rasanya pahit, tetapi zat ini dapat dibuang dengan cara mengupas kulitnya atau menyeduhnya dengan air panas selama 4 minit. Dengan menggantikan air setelah merebusnya 3-4 minit dan memanaskannya kembali dapat mengurangi rasa pahit dan kelat buah yang masih muda. Setiap 100 g bahagian buah yang dapat dimakan mengandung: air 85 g, protein 1,5 g, lemak 0,06-1,28 g, karbohidrat 10 g, serat 1,4-4,2 g, abu 0,7 g, vitamin A 150-500 SI, dan vitamin C 25 mg. Sebagian besar vitamin akan hilang jika buah direbus.

Manfaat

Buah terung belanda dimanfaatkan menurut berbagai cara, seperti masakan yang lazat dan makanan yang manis-manis. Buah mentah dapat digunakan untuk masakan ‘chutney’, kari dan sambal, sedangkan buah matang untuk sirap, sup dan rojak. Buahnya juga boleh dijadikan 'agen' pembersih daging ayam mentah (untuk nyah bau). Buah yang dibelah dapat digunakan sebagai bumbu perencah masakan. Buahnya juga boleh dibakar atau dipanggang untuk digunakan sebagai sayuran.
Buah ini boleh dimakan begitu sahaja dengan mencedok isinya dengan sudu, setelah buah dibelah dua, lebih kurang seperti kita memakan buah avokado. Jika buah ini disejukkan seketika dalam peti sejuk, rasanya manis dan menyegarkan.

Buah terung belanda akan memberikan rasa yang unik jika ditambah ke dalam masakan seperti kuah pasta, kari dan masakan lainnya. Buah ini juga sedap jika digunakan dalam salad.

Di Colombia, Ecuador dan sebahagian Indonesia seperti di Sumatera dan Sulawesi, buah terung belanda yang segar sering dicampur bersama-sama dengan air dan gula untuk membuat jus. Buah yang dibiarkan masak matang di atas pokok, boleh digunakan dalam penghasilan sirap (jus), jem, selai, pencuci mulut dan sebagai hiasan ais krim.

6.1 WAVES: INTRODUCTION

WAVES

• Waves is a periodic motion to transfer energy from the centre of vibration.
• Waves travel and transfer energy (its amplitude) and information (its frequency) from one point to another, with no permanent displacement of the particles of the medium.
• The particles of the medium are oscillate around an almost fixed positions.

EXAMPLES OF WAVES










WAVES TRANSFER ENERGY WITHOUT TRANSFERRING MATTER

• A wave transfers energy and the momentum from the source of the wave (the oscillating or vibrating system) to the surroundings

QUANTUM PHYSICS

Quantum Physics is the science of things so small that the quantum nature of reality has an effect. Quantum means 'discrete amount' or 'portion'. Max Planck discovered in 1900 that you couldn't get smaller than a certain minimum amount of anything. This minimum amount is now called the Planck unit. With this set of principles underlying the most fundamental known description of all physical systems at the subatomic level and provides accurate descriptions for many previously unexplained phenomena also given insight into the workings of many different biological systems.

Ultimately, and most importantly, I believe it describes the nature of the universe as being much different then the world we see.

Niels Bohr, the father of the orthodox 'Copenhagen Interpretation' of quantum physics once said, "Anyone who is not shocked by quantum theory has not understood it".

For beginners, I suggest you get aquainted with these experiments: Two Slits,

Two Slits

The simplest experiment to demonstrate quantum weirdness involves shining a light through two parallel slits and looking at the screen. It can be shown that a single photon (particle of light) can interfere with itself, as if it travelled through both slits at once.



Sumber: http://phoenixaquua.blogspot.com

MATAHARI MEMASUKI FASA SEPERTI ABAD KE-17

WASHINGTON - Saintis-saintis Amerika Syarikat (AS) menyatakan kitaran biasa bintik matahari kini memasuki fasa hibernasi yang tidak pernah dilihat sejak kurun ke-17 dengan suhu global dijangka turun akibat perubahan itu.
Selama bertahun-tahun, para saintis meramalkan bahawa menjelang 2012, matahari akan mengalami fasa dikenali sebagai solar maksimum dengan aktiviti ledakan api dan bintik matahari berada pada tahap paling aktif.
Keadaan tersebut dijangka menyebabkan suhu Bumi meningkat.
Namun, permukaan matahari yang agak tenang sejak kebelakangan ini menunjukkan keadaan yang sebaliknya.
Tanda-tanda perubahan tersebut termasuk ketiadaan pancutan api, sejumlah bintik yang pudar dan kelembapan aktiviti di kedua-dua kutub matahari.
Pendedahan itu dibuat menerusi tiga hasil kajian yang dibentangkan pada pertemuan tahunan Bahagian Solar Fizik Persatuan Astronomi Amerika Syarikat di Las Cruces, negeri New Mexico kelmarin.
"Keadaan ini ganjil dan di luar jangkaan," kata seorang pengarah bersama Agensi Percerapan Solar Nasional, Frank Hill.
Aktiviti matahari cenderung meningkat dan berkurangan setiap kitaran 11 tahun.
Fasa solar maksimum dan solar minimum pula berlaku setiap 22 tahun. - AFP

LETUSAN SUAR MATAHARI TERBESAR 7 JUN 2011

Solar Flare Sparks Biggest Eruption Ever Seen on Sun
Enormous ejection of particles into space shocks scientists.
Main Content
A solar flare on June 7, 2011.
A solar flare created a spectacular eruption on June 7 (pictured).

Image courtesy SDO/NASA

Dave Mosher

for National Geographic News

Published June 8, 2011

A mushroom of cooled plasma popped like a pimple and rained onto the surface of the sun yesterday—shooting perhaps the largest amount of solar material into space ever seen, scientists say.

(Watch a video of the solar flare.)

The solar flare—an unusually bright spot on the sun—wasn't surprising as a "moderate" event. Space observatories in the past year recorded about 70 such solar flares, each roughly ten times weaker than "extreme" flares, of which only two have occurred since 2007.

(Related: "Biggest Solar Flare in Years—Auroras to Be Widespread Tonight?")

Instead, what shocked scientists was the unusual amount of material that lofted up, expanded, and fell back down over roughly half the surface area of the sun. The event's simultaneous launch of particles into space is called a coronal mass ejection (CME).

"This totally caught us by surprise. There wasn't much going on with this spot, but as it came from behind the sun, all of the sudden there was a flare and huge ejection of particles," said astrophysicist Phillip Chamberlin of NASA's Solar Dynamics Observatory (SDO), one of several spacecraft that recorded the event.

"We've never seen a CME this enormous."

(See pictures of solar eruptions.)

Solar Flares May Threaten Power Grids

Chamberlin said it will take some time to calculate the energy and mass of electrons and protons blasted into space. But he noted the volume occupied a space hundreds of times bigger than a single Earth.

The ejection of particles burst from the right limb of the sun and sprayed into space, so the blast will miss Earth—though the explosion may brighten auroras near Earth's poles, Chamberlin said.

(See pictures of auroras generated by the Valentine's Day solar flare.)

But he warned space-weather experts are concerned about future solar events.

The sun's 11-year cycle of activity, driven by tangled surface magnetic fields, will hit its maximum in late 2013 or early 2014. Magnetic messiness will peak around that time and prompt nasty solar storms.

"We'll probably see [extreme] flares every couple of months instead of years," Chamberlin said.

If one of these powerful flares—and its coronal mass ejection—faces Earth, the particles will pound satellite components with charged particles, short some out, and potentially cripple them.

On the planet's surface, extra currents of solar particles drive extra electric current through power lines and heat them up. A solar storm in 1859, for example, caused telegraph lines to burst into flames. Power companies distribute loads to avoid such a disaster, but energetic solar storms could still blow transformers and lead to power outages, especially during heat waves like the one sweeping the eastern U.S. this week.

"Despite great countermeasures, the power grid is still vulnerable. We could be in for some serious problems," Chamberlin said.

SUMBER:
http://news.nationalgeographic.com/n...rflareeruption

6.1 TRANSVERSE AND LONGITUDINAL WAVE

TRANSVERSE WAVE
Imagine a cork on a pond. Waves make the cork bob up an down but it doesn't move in the direction the wave is going. Light waves vibrate similarly, up and down and also from side to side, while the light energy moves forward. This is the characteristic of Transverse wave.











A Transverse Wave is a wave in which particles of the medium move in a direction perpendicular to the direction which the wave moves. The animation below shows a one-dimensional transverse plane wave propagating from left to right. The particles do not move along with the wave; they simply oscillate up and down about their individual equilibrium positions as the wave passes by. Pick a single particle and watch its motion.

• Transverse waves are mechanical waves. That means they need a solid, liquid, or gas medium to travel through.
• Transverse waves include all electromagnetic (radio wave, microwave, Infra Red, visible light, ultra violet., X-rays and Gamma rays)

LONGITUDINAL WAVE

• A longitudinal wave is a wave in which particles of the medium move in a direction parallel to the direction which the wave moves.
• Example: Sound waves

6.1 WAVEFRONT, AMPLITUDE, PERIOD AND FREQUENCY

WAVEFRONT
A line of surface which joins all points which have the same displacement at the same moment (they are all in phase).




The perpendicular distance between two wavefronts represents one wavelength.






Plane wavefront & Circular wavefront
Amplitudes

• The distance from the maximum displacement to the equillibrium position is called the Amplitudes, a.
• SI unit : meter, m
• Loud sounds have a large amplitude.
• Brightness in light have a large amplitude.

Wavelength
The distance between two adjacent point of the same phase of waves.

• The times taken for the system make a complete oscillation is known as Period, T.
• The number of complete oscillations made by a system in one second is called frequency, f.

The relationship between wavelength, frequency and speed of wave is:















Displacement-time graph










Displacement-distance graph

6.1 DAMPING & RESONANCE

DAMPING

• Damping is the decrease in the amplitude of an oscillating system when its energy is drained out as heat energy.
• The amplitude of an oscillating system will gradually decrease and become zero when the oscillation stops.
• Damping causes a decrease in amplitude and energy but the frequency of the oscillation remain unchanged.

In the diagram on the right the blue spring is experiencing damping but not the black spring. take note of the decrease in amplitude but the frequency is the same. The initial amplitude was 2 unit and it was decreasing. But the frequency remains as 4 complete oscillations in 25 s (0.16 Hz).

There are two types of damping: External Damping and Internal Damping.

1. External Damping

• Is lost of energy to overcome frictional force or air resistance.

2. Internal Damping

• Is due to compression and extension of atoms and molecules of the system.

To enable an oscillating system to go on continuously, an external force must be applied to the system.

• The external force supplies energy to the system.
• Such a motion is called a forced oscillation.

The frequency of a system which oscillates freely without the action of an external force is called the natural frequency.

Application of damping in our daily lives
Vehicle suspension system. A vehicle spring and shock absorber system provides damping to prevent the vehicle from bouncing up and down continuously.







How car suspension work.








RESONANCE

• Occurs when a system/matter oscillate at a frequency equivalent to its natural frequency by an external force.
• Due to resonance, particle/matter oscillate at a higher amplitude.

In the Barton's pendulum on the right when pendulum X was oscillated it supplied energy to the other pendulums making them oscillate. It was observed that pendulum C oscillates with the largest amplitude. This is because pendulum X and pendulum C have the same pendulum length. The natural frequency of an oscillating system depends on its pendulum length. Therefore pendulum X and pendulum C are of the same natural frequency. Hence pendulum C is at resonance.

Video clip for Resonance


Good effects of Resonance in our daily lives

1. A tuner in the radio or television enables you to select the channel we want. Te circuit in the tuner is adjusted until resonance is achieved, at the frequency transmitted by a particular station selected. Hence a strong electrical signal is produced.
2. The loudness of a wind musical instrument like trumpet and flute is the result of resonance of the air.

Bad effects of Resonance in our daily lives

1. A bridge may collapse when the amplitude of its vibration increases because of resonance. The action of the wind can cause the bridge to vibrate with a large amplitude as a result of resonance
2. The loud explosion can cause a glass window to break
3. The high pitch note of an opera singer can cause a thin glass to shatter

6.2 REFLECTION OF WAVES

REFLECTION OF WAVES

• Occurs when a waves strikes an obstacle.
• The wave will change its direction of propagation when it is reflected.

Characteristics of Reflection of waves:

• The value of frequency (f), wavelength ( λ) and speed (v) remain the same after reflection.
• The phenomenon of reflection of waves obeys the Laws of reflection.

Law of Reflection
The incident wave, the reflected wave and the Normal lie in the same plane which is perpendicular to the reflecting surface at the point of incident.
The angle of incident, i is equal to the angle of reflection, r.

Reflection of plane water waves in a ripple tank

• The phenomenon of reflection of water waves can be investigated using a ripple tank.
• The water waves are produced by a vibrating source on the water surface.

A horizontal bar will produced a plane wave.












While a round source will produce circular wave













See video wave reflections from ripple tank.


Diagram shows reflection of waves