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saco-indonesia.com, Petir adalah peristiwa alam yang sering terjadi di bumi, terjadinya seringkali mengikuti peristiwa hujan bai

saco-indonesia.com, Petir adalah peristiwa alam yang sering terjadi di bumi, terjadinya seringkali mengikuti peristiwa hujan baik air atau es, peristiwa ini telah dimulai dengan munculnya awan hitam dan lidah api listrik bercahaya terang yang bergerak merambat terus memanjang kearah bumi bagaikan sulur akar dan kemudian diikuti oleh suara menggelegar dan efeknya juga akan sangat fatal bila mengenai mahluk hidup.
PROSES TERJADINYA PETIR

Terdapat 2 teori yang mendasari proses terjadinya petir :

    Proses Ionisasi
    Proses Gesekan antar awan

a. Proses Ionisasi
Petir telah terjadi diakibatkan oleh terkumpulnya ion bebas bermuatan negatif dan positif di awan, ion listrik dihasilkan oleh gesekan antar awan dan kejadian Ionisasi ini telah disebabkan oleh perubahan bentuk air mulai dari cair menjadi gas atau sebaliknya, bahkan perubahan padat (es) telah menjadi cair dan pada tahap pembekuan ini mencapai suhu dibawah 0 derajat yaitu antara -10 sampai -14 derajad celcius
Ion bebas telah menempati permukaan awan dan bergerak mengikuti angin berhembus, bila awan-awan telah terkumpul di suatu tempat maka awan bermuatan akan memiliki beda potensial cukup besar untuk dapat menyambar permukaan bumi maka inilah yang disebut petir.

b. Gesekan antar awan
Pada awalnya awan akan bergerak mengikuti arah angin, selama proses bergeraknya awan ini maka akan saling bergesekan satu dengan yang lainnya , dari proses ini terlahir electron-electron bebas bermutan negatif yang telah memenuhi permukaan awan. proses ini bisa digambarkan secara sederhana pada sebuah penggaris plastik yang digosokkan pada rambut maka penggaris ini akan mampu menarik potongan kertas.
Pada suatu saat awan ini akan terkumpul di sebuah kawasan, saat inilah petir dimungkinkan telah terjadi karena electron-elektron bebas ini telah saling menguatkan satu dengan lainnya. Sehingga telah memiliki cukup beda potensial untuk dapat menyambar permukaan bumi. kedua teori ini mungkin juga masuk akal meski kejadian sebenarnya masih merupakan sebuah misteri.
PERLINDUNGAN TERHADAP BAHAYA PETIR

Manusia selalu mencoba untuk dapat menjinakkan keganasan alam,atau setidaknya menghidarinya, salah satunya adalah Sambaran Petir. dan metode yang pernah dikembangkan:
1. Penangkal Petir Kovensional / Faraday / Frangklin
Kedua ilmuan diatas Faraday dan Frangklin telah mengetengahkan system yang hampir sama , yakni system penyalur arus listrik dengan menghubungkan antara bagian atas bangunan dan grounding. Sedangkan system perlindungan yang telah dihasilkan ujung penerima / Splitzer adalah sama pada rentang 30 ~ 45 ‘ . Perbedaannya adalah system yang telah dikembangkan oleh Faraday bahwa Kabel penghantar terletak pada sisi luar bangunan dengan pertimbangan bahwa kabel penghantar juga berfungsi sebagai penerima sambaran, dan bentuknya Berupa sangkar elektris atau biasa disebut sangkar Faraday.
2. Penangkal Petir Radio Aktif
Penelitian terus terus berkembang dan dihasilkan kesimpulan bahwa petir telah terjadi karena ada muatan listrik di awan dihasilkan oleh proses ionisasi , maka penggagalan proses ionisasi di lakukan dengan cara memakai Zat beradiasi misl. Radiun 226 dan Ameresium 241 , karena 2 bahan ini juga mampu menghamburkan ion radiasinya yang bisa menetralkan muatan listrik awan.
Sedang manfaat lain adalah hamburan ion radiasi akan dapat menambah muatan pada Ujung Finial / Splitzer dan bila mana awan yang bermuatan besar tidak mampu di netralkan oleh zat radiasi kemudian menyambar, maka akan condong mengenai unit radiasi ini .
Keberadaan penangkal petir jenis ini juga sudah dilarang pemakaiannya , berdasarkan kesepakatan internasional dengan pertimbangan mengurangi pemakaian zat beradiasi dimasyarakat yang disinyalir mempunyai efek negatif pada lingkungan hidup dan kesehatan.
3. Penangkal Petir Elektrostatic
Prinsip kerja penangkal petir Elektrostatik adalah dengan mengadopsi sebagian system penangkal petir Radioaktif , yakni dengan menambah muatan pada ujung finial / splitzer agar petir selalu memilih ujung ini untuk disambar .
Perbedaan dari sisten Radioaktif dan Elektrostatik ada pada energi yang dipakai. Untuk Penangkal Petir Radioaktif muatan listrik dihasilkan dari proses hamburan zat beradiasi sedangkan pada penangkal petir elektrostatik energi listrik dihasilkan dari Listrik Awan yang menginduksi permukaan bumi.
CARA KERJA PENANGKAL PETIR NEOFLASH

Mekanisme Kerja
Ketika awan bermuatan listrik telah melintas diatas sebuah bangunan yang terpasang penangkal petir neoFlash, maka elektroda penerima pada bagian samping NeoFLASH ini dapat mengumpulkan dan menyimpan energi listrik awan pada unit kapasitornya . Setelah energi ini cukup besar maka dilepas dan diperbesar beda potensialnya pada bagian Ion Generator.
Pelepasan muatan listrik pada unit Ion Generator ini di picu oleh sambaran, yakni ketika lidah api menyambar permukaan bumi maka semua muatan listrik di bagian ion generator dilepaskan keudara melalui Central Pick Up agar menimbulkan lidah api penuntun keatas ( Streamer leader ) untuk dapat menyambut sambaran petir yang terjadi kemudian menuntunya masuk kedalam satu titik sambar yang terdapat unit Neoflash ini.
Kerja Simultan
Pada unit Penangkal Petir NEOFLASH secara simultan bekerja bergantian dari masing-masing unit penerima induksi , jumlahnya tergantung dari tipe dan modelnya. Bekerjanya secara bergantian dimana bila salah satu bagian unit melepaskan muatan ke udara / streamer maka ada bagian lain yang dalam proses pengisian muatan awan.
Tentu akurasi dan kemampuan Penangkal Petir NeoFlash masih tergantung dari 2 hal pendukung instalasi, yaitu:
1. Kabel Penghantar harus minimal 50 mm
2. Grounding maksimal 5 Ohm
Bila 2 syarat pendukung ini juga sudah terpenuhi maka kemampuan penangkal petir neoflash akan maksimal.
ISTILAH PENANGKAL PETIR & ANTI PETIR

Penangkal Petir dan Anti Petir mungkin itu adalah istilah yang sudah salah kaprah dalam bahasa kita, kesan yang ditimbulkan dua istilah ini adalah aman 100 % terhadap petir, akan tetapi kejadiannya tidak demikian.
Dalam penanganan bahaya petir memang ada beberapa faktor yang sangat mempengaruhi, bilamana kita ingin solusi/penyelesaian total akan bahaya petir, kita harus melihat faktor faktor tersebut.
Sambaran Tidak langsung pada bangunan yakni ketika sambaran mengenai obyek diluar areal perlindungan dari penangkal petir yang terpasang , kemudian arus petir ini akan merambat melalui instalasi listrik , kabel data atau apa saja mengarah ke bangunan. Akhirnya hentakan tegangan dan arus merusak unit peralatan listrik / elektronik kita.
Masalah ini juga semakin runyam disaat ini karena banyak peralatan elektronik dengan menggunakan tegangan kerja kecil , DC , dan sensitif, Khususnya di urusan data transfer.
Maka pada dasarnya pengaman sambaran petir langsung / Eksternal penangkal petir bukan membuat posisi kita aman 100 % terhadap petir, akan tetapi membuat posisi bangunan kita terhindar dari kerusakan fatal akibat sambaran Langsung, serta meminimalisir efek kerusakan pada peralatan elektronik bila ada sambaran menyambar bangunan kita.
mungkin Penyalur Arus Petir adalah istilah tepatnya.
Masih ada kemungkinan lain yakni sambaran petir tidak langsung , yakni sambaran yang pada dasarnya tidak mengenai lokasi bangunan tetapi mengenai jauh diluar lokasi tetapi lonjakan listriknya merambat masuk ke jaringan instalasi listrik di bangunan dan merusak peralatan elektronik, Untuk penanganan sambaran petir tidak langsung dapat digunakan Arrester yakni perangkat yang bisa memotong dan membelokkan lonjakan arus / tegangan petir ke dalam grounding .


Editor : Dian Sukmawati

Saco-Indonesia.com - Penyakit Influenza adalah infeksi pada sistem pernapasan atas yang bisa menyebabkan berbagai gejala mulai dari batuk kering, sakit tenggorokan, mual, muntah, dan kehilangan nafsu makan.

Saco-Indonesia.com - Penyakit Influenza adalah infeksi pada sistem pernapasan atas yang bisa menyebabkan berbagai gejala mulai dari batuk kering, sakit tenggorokan, mual, muntah, dan kehilangan nafsu makan.

Penyakit influenza sangat mudah menular karena sel virusnya ada di udara. Meski istirahat dan cukup cairan adalah terapi terbaik untuk penyakit ini, pencegahan tetap yang terbaik. Melatih kekebalan tubuh akan membantu tubuh melawan virus influenza.

Langkah 1: Tambahkan potongan bawang putih segar ke dalam sup. Penelitian mengungkapkan bawang putih akan meningkatkan sistem imun, selain itu kandungan allicin dalam bawang putih mengandung komponen antivirus.

Langkah 2: Konsumsi makanan yang kaya vitamin C, seperti kiwi, stroberi, orange, nenas, atau grapefruit. Vitamin C akan meningkatkan fungsi sistem imun dan melindungi tubuh dalam melawan infeksi. Vitamin ini juga memberi perlindungan dari kerusakan radikal bebas.

Langkah 3: Bila Anda rutin mengonsumsi suplemen, cobalah pilih yang mengandung ginkgo biloba. Herbal yang berasal dari Cina ini diketahui meningkatkan sirkulasi tubuh. Sirkulasi yang lancar akan membantu pengantaran vitamin dan mineral yang diperlukan.

Langkah 4: Lindungi tubuh dari serangan virus dengan mengonsumsi tiram. Kandungan mineral zinc dalam makanan laut yang identik dengan afrodisiak ini juga memiliki efek antivirus.

Langkah 5: Selalu ingat nasihat ibu untuk rajin makan sayuran. Salah satu sayuran yang direkomendasikan untuk meningkatkan kekebalan tubuh adalah bayam. Kandungan folatnya akan memicu produksi sel-sel baru dan memperbaiki DNA. Sayuran hijau ini juga kaya vitamin C, serat, dan antioksidan. Jangan masak bayam terlalu matang untuk mendapatkan manfaat optimal.

Editor : Maulana Lee

Sumber :LiveStrong/kompas.com

Imagine an elite professional services firm with a high-performing, workaholic culture. Everyone is expected to turn on a dime to serve a client, travel at a moment’s notice, and be available pretty much every evening and weekend. It can make for a grueling work life, but at the highest levels of accounting, law, investment banking and consulting firms, it is just the way things are.

Except for one dirty little secret: Some of the people ostensibly turning in those 80- or 90-hour workweeks, particularly men, may just be faking it.

Many of them were, at least, at one elite consulting firm studied by Erin Reid, a professor at Boston University’s Questrom School of Business. It’s impossible to know if what she learned at that unidentified consulting firm applies across the world of work more broadly. But her research, published in the academic journal Organization Science, offers a way to understand how the professional world differs between men and women, and some of the ways a hard-charging culture that emphasizes long hours above all can make some companies worse off.

Photo
 
Credit Peter Arkle

Ms. Reid interviewed more than 100 people in the American offices of a global consulting firm and had access to performance reviews and internal human resources documents. At the firm there was a strong culture around long hours and responding to clients promptly.

“When the client needs me to be somewhere, I just have to be there,” said one of the consultants Ms. Reid interviewed. “And if you can’t be there, it’s probably because you’ve got another client meeting at the same time. You know it’s tough to say I can’t be there because my son had a Cub Scout meeting.”

Some people fully embraced this culture and put in the long hours, and they tended to be top performers. Others openly pushed back against it, insisting upon lighter and more flexible work hours, or less travel; they were punished in their performance reviews.

The third group is most interesting. Some 31 percent of the men and 11 percent of the women whose records Ms. Reid examined managed to achieve the benefits of a more moderate work schedule without explicitly asking for it.

They made an effort to line up clients who were local, reducing the need for travel. When they skipped work to spend time with their children or spouse, they didn’t call attention to it. One team on which several members had small children agreed among themselves to cover for one another so that everyone could have more flexible hours.

A male junior manager described working to have repeat consulting engagements with a company near enough to his home that he could take care of it with day trips. “I try to head out by 5, get home at 5:30, have dinner, play with my daughter,” he said, adding that he generally kept weekend work down to two hours of catching up on email.

Despite the limited hours, he said: “I know what clients are expecting. So I deliver above that.” He received a high performance review and a promotion.

What is fascinating about the firm Ms. Reid studied is that these people, who in her terminology were “passing” as workaholics, received performance reviews that were as strong as their hyper-ambitious colleagues. For people who were good at faking it, there was no real damage done by their lighter workloads.

It calls to mind the episode of “Seinfeld” in which George Costanza leaves his car in the parking lot at Yankee Stadium, where he works, and gets a promotion because his boss sees the car and thinks he is getting to work earlier and staying later than anyone else. (The strategy goes awry for him, and is not recommended for any aspiring partners in a consulting firm.)

A second finding is that women, particularly those with young children, were much more likely to request greater flexibility through more formal means, such as returning from maternity leave with an explicitly reduced schedule. Men who requested a paternity leave seemed to be punished come review time, and so may have felt more need to take time to spend with their families through those unofficial methods.

The result of this is easy to see: Those specifically requesting a lighter workload, who were disproportionately women, suffered in their performance reviews; those who took a lighter workload more discreetly didn’t suffer. The maxim of “ask forgiveness, not permission” seemed to apply.

It would be dangerous to extrapolate too much from a study at one firm, but Ms. Reid said in an interview that since publishing a summary of her research in Harvard Business Review she has heard from people in a variety of industries describing the same dynamic.

High-octane professional service firms are that way for a reason, and no one would doubt that insane hours and lots of travel can be necessary if you’re a lawyer on the verge of a big trial, an accountant right before tax day or an investment banker advising on a huge merger.

But the fact that the consultants who quietly lightened their workload did just as well in their performance reviews as those who were truly working 80 or more hours a week suggests that in normal times, heavy workloads may be more about signaling devotion to a firm than really being more productive. The person working 80 hours isn’t necessarily serving clients any better than the person working 50.

In other words, maybe the real problem isn’t men faking greater devotion to their jobs. Maybe it’s that too many companies reward the wrong things, favoring the illusion of extraordinary effort over actual productivity.

Late in April, after Native American actors walked off in disgust from the set of Adam Sandler’s latest film, a western sendup that its distributor, Netflix, has defended as being equally offensive to all, a glow of pride spread through several Native American communities.

Tantoo Cardinal, a Canadian indigenous actress who played Black Shawl in “Dances With Wolves,” recalled thinking to herself, “It’s come.” Larry Sellers, who starred as Cloud Dancing in the 1990s television show “Dr. Quinn, Medicine Woman,” thought, “It’s about time.” Jesse Wente, who is Ojibwe and directs film programming at the TIFF Bell Lightbox in Toronto, found himself encouraged and surprised. There are so few film roles for indigenous actors, he said, that walking off the set of a major production showed real mettle.

But what didn’t surprise Mr. Wente was the content of the script. According to the actors who walked off the set, the film, titled “The Ridiculous Six,” included a Native American woman who passes out and is revived after white men douse her with alcohol, and another woman squatting to urinate while lighting a peace pipe. “There’s enough history at this point to have set some expectations around these sort of Hollywood depictions,” Mr. Wente said.

The walkout prompted a rhetorical “What do you expect from an Adam Sandler film?,” and a Netflix spokesman said that in the movie, blacks, Mexicans and whites were lampooned as well. But Native American actors and critics said a broader issue was at stake. While mainstream portrayals of native peoples have, Mr. Wente said, become “incrementally better” over the decades, he and others say, they remain far from accurate and reflect a lack of opportunities for Native American performers. What’s more, as Native Americans hunger for representation on screen, critics say the absence of three-dimensional portrayals has very real off-screen consequences.

“Our people are still healing from historical trauma,” said Loren Anthony, one of the actors who walked out. “Our youth are still trying to figure out who they are, where they fit in this society. Kids are killing themselves. They’re not proud of who they are.” They also don’t, he added, see themselves on prime time television or the big screen. Netflix noted while about five people walked off the “The Ridiculous Six” set, 100 or so Native American actors and extras stayed.

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But in interviews, nearly a dozen Native American actors and film industry experts said that Mr. Sandler’s humor perpetuated decades-old negative stereotypes. Mr. Anthony said such depictions helped feed the despondency many Native Americans feel, with deadly results: Native Americans have the highest suicide rate out of all the country’s ethnicities.

The on-screen problem is twofold, Mr. Anthony and others said: There’s a paucity of roles for Native Americans — according to the Screen Actors Guild in 2008 they accounted for 0.3 percent of all on-screen parts (those figures have yet to be updated), compared to about 2 percent of the general population — and Native American actors are often perceived in a narrow way.

In his Peabody Award-winning documentary “Reel Injun,” the Cree filmmaker Neil Diamond explored Hollywood depictions of Native Americans over the years, and found they fell into a few stereotypical categories: the Noble Savage, the Drunk Indian, the Mystic, the Indian Princess, the backward tribal people futilely fighting John Wayne and manifest destiny. While the 1990 film “Dances With Wolves” won praise for depicting Native Americans as fully fleshed out human beings, not all indigenous people embraced it. It was still told, critics said, from the colonialists’ point of view. In an interview, John Trudell, a Santee Sioux writer, actor (“Thunderheart”) and the former chairman of the American Indian Movement, described the film as “a story of two white people.”

“God bless ‘Dances with Wolves,’ ” Michael Horse, who played Deputy Hawk in “Twin Peaks,” said sarcastically. “Even ‘Avatar.’ Someone’s got to come save the tribal people.”

Dan Spilo, a partner at Industry Entertainment who represents Adam Beach, one of today’s most prominent Native American actors, said while typecasting dogs many minorities, it is especially intractable when it comes to Native Americans. Casting directors, he said, rarely cast them as police officers, doctors or lawyers. “There’s the belief that the Native American character should be on reservations or riding a horse,” he said.

“We don’t see ourselves,” Mr. Horse said. “We’re still an antiquated culture to them, and to the rest of the world.”

Ms. Cardinal said she was once turned down for the role of the wife of a child-abusing cop because the filmmakers felt that casting her would somehow be “too political.”

Another sore point is the long run of white actors playing American Indians, among them Burt Lancaster, Rock Hudson, Audrey Hepburn and, more recently, Johnny Depp, whose depiction of Tonto in the 2013 film “Lone Ranger,” was viewed as racist by detractors. There are, of course, exceptions. The former A&E series “Longmire,” which, as it happens, will now be on Netflix, was roundly praised for its depiction of life on a Northern Cheyenne reservation, with Lou Diamond Phillips, who is of Cherokee descent, playing a Northern Cheyenne man.

Others also point to the success of Mr. Beach, who played a Mohawk detective in “Law & Order: Special Victims Unit” and landed a starring role in the forthcoming D C Comics picture “Suicide Squad.” Mr. Beach said he had come across insulting scripts backed by people who don’t see anything wrong with them.

“I’d rather starve than do something that is offensive to my ancestral roots,” Mr. Beach said. “But I think there will always be attempts to drawn on the weakness of native people’s struggles. The savage Indian will always be the savage Indian. The white man will always be smarter and more cunning. The cavalry will always win.”

The solution, Mr. Wente, Mr. Trudell and others said, lies in getting more stories written by and starring Native Americans. But Mr. Wente noted that while independent indigenous film has blossomed in the last two decades, mainstream depictions have yet to catch up. “You have to stop expecting for Hollywood to correct it, because there seems to be no ability or desire to correct it,” Mr. Wente said.

There have been calls to boycott Netflix but, writing for Indian Country Today Media Network, which first broke news of the walk off, the filmmaker Brian Young noted that the distributor also offered a number of films by or about Native Americans.

The furor around “The Ridiculous Six” may drive more people to see it. Then one of the questions that Mr. Trudell, echoing others, had about the film will be answered: “Who the hell laughs at this stuff?”

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