Salah satu bagian terpenting dalam membangun sebuah bangunan / rumah adalah dinding. Semakin majunya zaman, teknik membuat bangunan dan bahan-bahan yang di gunakan sebagi pembuat dinding rumah sangat bervariatif. Hal tersebut tidak terlepas seiring perkembangan ilmu pengetahuan dan teknologi serta semakin minimnya sumber bahan baku berupa tanah liat sebagai bahan batu bata merah. Namun di era modern saat ini sangat beraneka ragam, mulai dari hebel, bata ringan, batako, paving dll.

PEMBUATAN BATAKO PRES

Batako adalah bahan banguanan yang terbuat dari campuran pasir, semen yang dicetak atau di press padat, selain itu batako juga dapat dibuat dari bahan batu tras, kapur dan air. Batako pres dibuat dari campuran semen PC dan pasir atau abu batu. Ada yang dibuat secara manual (menggunakan tangan), ada juga yang menggunakan mesin press batako. Perbedaannya bisa dilihat pada kepadatan permukaan batakonya. Umumnya memiliki ukuran panjang 36-40 cm, tebal 8–10 cm, dan tinggi 18-20 cm. Untuk dinding seluas 1 m2, kira-kira membutuhkan:

    Batako pres = 15 buah
    Semen PC = 0,125 sak
    Pasir ayak (pasir pasang} = 0,015 m3

• Kelebihan dinding batako press:

    Kedap air sehingga sangat kecil kemungkinan terjadinya rembesan air.
    Pemasangan lebih cepat.
    Penggunaan rangka beton pengakunya lebih luas, antara 9 – 12 m2.

Gambar

Setelah batako jadi, baik di buat dengan press cetak manual atau mesin press batako, hasilnya  secara fisik , batako memiliki rongga kosong di bagian dalamnya. Bagian tersebut berfungsi sebagai insulasi panas, juga sebagai insulasi suara. Dengan tujuan bisa menciptakan kondisi dalam ruangan yang menggunakan materi batako terasa relatif lebih sejuk dan nyaman.

•  Kekurangan dinding batako pres:

    Mudah terjadi retak rambut pada dinding.
    Mudah dilubangi karena terdapat lubang pada bagian sisi dalamnya

Kekurangan ini yang membuat sebagian orang kurang suka menggunakan batako sebagai material dinding rumahnya. Namun , kendala tersebut dapat diatasi dengan penggunaan penggantung yang bersifat suction-cup hooks dan strong-adhesive hooks yang berdaya rekat tinggi. Penggantung multi-adhesive ini memiliki sifat pemasangan dan pelepasan yang relatif mudah. Dari harganya yang murah di bandingkan dengan bata merah, bangunan yang dibuat dengan batako akan menghemat pengeluaran uang untuk membuat banguanan. Selanjutnya jika ada anggapan bahwa batako kurang kokoh, bisa di atasi dengan menambah campuran material dasar batako dengan ampas tebu. Ampas tebu tersebut akan memberikan hasil yang lebih kuat, ringan dan tahan lama serta tentunya harganya lebih terjangkau.

MENGGUNAKAN BATAKO LEBIH HEMAT

Though Robin and Joan Rolfs owned two rare talking dolls manufactured by Thomas Edison’s phonograph company in 1890, they did not dare play the wax cylinder records tucked inside each one.

The Rolfses, longtime collectors of Edison phonographs, knew that if they turned the cranks on the dolls’ backs, the steel phonograph needle might damage or destroy the grooves of the hollow, ring-shaped cylinder. And so for years, the dolls sat side by side inside a display cabinet, bearers of a message from the dawn of sound recording that nobody could hear.

In 1890, Edison’s dolls were a flop; production lasted only six weeks. Children found them difficult to operate and more scary than cuddly. The recordings inside, which featured snippets of nursery rhymes, wore out quickly.

Yet sound historians say the cylinders were the first entertainment records ever made, and the young girls hired to recite the rhymes were the world’s first recording artists.

Year after year, the Rolfses asked experts if there might be a safe way to play the recordings. Then a government laboratory developed a method to play fragile records without touching them.

Audio

The technique relies on a microscope to create images of the grooves in exquisite detail. A computer approximates — with great accuracy — the sounds that would have been created by a needle moving through those grooves.

In 2014, the technology was made available for the first time outside the laboratory.

“The fear all along is that we don’t want to damage these records. We don’t want to put a stylus on them,” said Jerry Fabris, the curator of the Thomas Edison Historical Park in West Orange, N.J. “Now we have the technology to play them safely.”

Last month, the Historical Park posted online three never-before-heard Edison doll recordings, including the two from the Rolfses’ collection. “There are probably more out there, and we’re hoping people will now get them digitized,” Mr. Fabris said.

The technology, which is known as Irene (Image, Reconstruct, Erase Noise, Etc.), was developed by the particle physicist Carl Haber and the engineer Earl Cornell at Lawrence Berkeley. Irene extracts sound from cylinder and disk records. It can also reconstruct audio from recordings so badly damaged they were deemed unplayable.

“We are now hearing sounds from history that I did not expect to hear in my lifetime,” Mr. Fabris said.

The Rolfses said they were not sure what to expect in August when they carefully packed their two Edison doll cylinders, still attached to their motors, and drove from their home in Hortonville, Wis., to the National Document Conservation Center in Andover, Mass. The center had recently acquired Irene technology.

Audio

Cylinders carry sound in a spiral groove cut by a phonograph recording needle that vibrates up and down, creating a surface made of tiny hills and valleys. In the Irene set-up, a microscope perched above the shaft takes thousands of high-resolution images of small sections of the grooves.

Stitched together, the images provide a topographic map of the cylinder’s surface, charting changes in depth as small as one five-hundredth the thickness of a human hair. Pitch, volume and timbre are all encoded in the hills and valleys and the speed at which the record is played.

At the conservation center, the preservation specialist Mason Vander Lugt attached one of the cylinders to the end of a rotating shaft. Huddled around a computer screen, the Rolfses first saw the wiggly waveform generated by Irene. Then came the digital audio. The words were at first indistinct, but as Mr. Lugt filtered out more of the noise, the rhyme became clearer.

“That was the Eureka moment,” Mr. Rolfs said.

In 1890, a girl in Edison’s laboratory had recited:

There was a little girl,

And she had a little curl

Audio

Right in the middle of her forehead.

When she was good,

She was very, very good.

But when she was bad, she was horrid.

Recently, the conservation center turned up another surprise.

In 2010, the Woody Guthrie Foundation received 18 oversize phonograph disks from an anonymous donor. No one knew if any of the dirt-stained recordings featured Guthrie, but Tiffany Colannino, then the foundation’s archivist, had stored them unplayed until she heard about Irene.

Last fall, the center extracted audio from one of the records, labeled “Jam Session 9” and emailed the digital file to Ms. Colannino.

“I was just sitting in my dining room, and the next thing I know, I’m hearing Woody,” she said. In between solo performances of “Ladies Auxiliary,” “Jesus Christ,” and “Dead or Alive,” Guthrie tells jokes, offers some back story, and makes the audience laugh. “It is quintessential Guthrie,” Ms. Colannino said.

The Rolfses’ dolls are back in the display cabinet in Wisconsin. But with audio stored on several computers, they now have a permanent voice.

Ghostly Voices From Thomas Edisonís Dolls Can Now Be Heard

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