Keamanan Pangan: Hati-hati pilih Bahan Pengemas Makanan

Jakarta, Kompas ---  Sejumlah bahan yang digunakan serbagai kemasan tidak sepenuhnya aman. Untuk itu, pemilihan jenis kemasan makanan harus dilakukan dengan hati-hati. Hal itu dikatakan Direktur Pengawasan Produk dan Bahan Berbahaya Badan Pengawas Obat dan Makanan (BPOM) Mustofa dalam jumpa pers Rabu (3/10), di Jakarta. Menurut dia, ada sejumlah pengemas berisiko bagi kesehatan jika zat di dalamnya mencemari makanan. Bahan pengemas itu antara lain plastik jenis polimer polyvinyl chloride (PVC), polistiren (styrofoam), polikarbonat, dan melamin.
   Mustofa menilai, keamanan pangan akan terancam jika ada komponen bermingrasi (berpindah) dari kemasan ke makanan. Ancaman juga terjadi jika ada permeasi (perpindahan molekul gas dan cairan). Selain itu, ada absorpsi (penyerapan) komponen pangan ke dalam kemasan.
   BPOM menguji dan mengawasi penggunaan melamin pada tahun 2009. "Ke depan, BPOM akan memprioritaskan pengujian plastik," ujarnya.

   Ia memaparkan, PVC berupa plastik tipis jernih mengandung logam berat timbal (Pb). ester ftalat, dan vynil chloride monomer. Bahan-bahan ini merupakan karsinogen kelas 1 (ditemukan kasus pada manusia) yang dapat menyebabkan kanker, dapat mengganggu sistem endokrin, dan menyebabkan penurunan IQ. Bahan yang dapat berpindah dan harus diawasi ialah residu monomer stiren yang merupakan karsinogen kelas 2B (ditemukan kasus pada hewan uji). Melamin mengandung monomer formaldehid dan monomer melamin yang berisiko menimbulkan kerusakan ginjal dan karsinogen kelas 1.
   Mustofa menjelaskan, kemasan yang aman adalah yang terbuat dari gelas dan keramik. Jika memilih kemasan plastik, sebaiknya pilih kemasan dengan tanda tara pangan berupa simbol gelas dan garpu pada kemasan. "Kurangi penggunaan PVC, jangan gunakan kemasan berwarna mencolok, hindari plastik dalam merebus atau memanaskan makanan, dan jangan sembarangan menggunakan plastik dalam microwave, kecuali atas petunjuk produsen," katanya.

   Penggunaan plastik kresek hitam dan kertas bekas untuk kemasan langsung makanan siap santap harus dihentikan. Plastik kresek merupakan hasil daur uloang beragam plastik bekas dan tidak diketahui riwayat penggunaannya. "Bisa saja bekas wadah pestisida, limbah rumah sakit, atau limbah logam berat sehingga tidak layak sebagai kemasan makanan siap santap," ujarnya.
   Tidak semua kertas aman digunakan sebagai kemasan. Kertas koran dan majalah sering digunakan untuk pembungkus jajanan. Padahal tinta koran mengandung timbal. Kertas bekas koran mengandung pewarna Itx. (INE).

Sumber : Kompas, 5 Oktober 2012, hal 13

Concept Electric Car Uses Exotic Materials

Capable of 60 km/hour and a cruising range of 100 km, a very lightweight electric concept car from the Teijin Group's  uses proprietary materials and technologies including carbon fiber composites, polycarbonate resins and bio-derived polyester. Weighing only 437 kg, less than half that of conventional electric vehicles, the PU_PA EV (as in “pupa electric vehicle,” a reference to metamorphosis) embodies Teijin’s vision of what a vehicle will look like on the market in five to ten years. T he PU_PA EV offers the functionality and structural integrity of a practical automobile.

Weight Reduction

> Body incorporating a core structure made of carbon fiber composite material.

> Windows made of polycarbonate resin with a heat absorbing function weighing only half as much as glass.

> Modularized parts made with single-piece molding, etc., reducing total parts to about 20.

Biotechnology

> Interior items (seats, floor mats, etc.) made with bio-derived polyester.

Reduced Environmental Burden

> Metal-toned Teflex PET film, used as an alternative to chrome plating.

> Low-noise tire cord made with Teonex polyethylene naphthalate (PEN) fiber.

Electronics

> Multi-device communication using Cell Form two-dimensional communication sheet.

Going forward, Teijin will use its innovative concept car as a marketing tool to showcase the group’s environmentally responsive technologies and customer-oriented solutions.

The Mobility Business Project, a department overseen directly by the CEO, was established in April 2009 to support business expansion in the automobiles and aircraft sectors, focusing on the development of materials and technologies for lightweight, hybrid and electric vehicle designs. 

For more information, please visit www.teijin.co.jp/english
Sumber: http://www.ecnmag.com/news/2010/04/concept-electric-car-uses-exotic-materials

Understanding Bike Frame Materials

Not all bike frames are created equal. Since the backbone of any bike is its frame, it can be enlightening to understand how it's made and what that means for you, the cyclist. The goal of any frame is to offer extraordinary strength with minimum weight. However, frame strength is determined by many factors. Whether the frame is aluminum or chromoly is only part of the equation. The way those materials are used is equally important.

Which Material Is Right for You?

It depends. Many factors—your style of riding, your weight, your sense of adventure—all play a role in your choice of material. The following paragraphs explain the different types of material commonly used on bikes. A few bikes out there are made of exotic metals, but that's another discussion entirely.

Carbon (High-Tensile) Steel

Steel is the most commonly used material in bike frames. Carbon or high-tensile steel is a good, strong, long-lasting steel, but it isn't as light as its more high-tech brother, the steel known as chromoly.

Chromoly (Chrome Molybdenum) Steel

A workhorse of the industry, chromoly is a light, strong steel. When it is butted and shaped to take off excess weight, it can deliver a fairly light frame that will last through years of hard use. Chromoly is responsive and offers good flex while maintaining its form.

Aluminum

Having come a long way from the oversized tubes of old, aluminum is now less expensive and very widely used on today's bikes. It's light, strong and stiff. With proper design it can give a solid ride for climbing, or lively handling in tight situations.

Titanium

Lighter than steel but just as strong, this more-expensive metal is found on high-end road or cross-country mountain bikes. It flexes so well while maintaining its shape that some very high-end bikes use the metal itself as a shock absorber.

Carbon Fiber

Take a bundle of parallel continuous fibers and bind them together with glue. This creates a ply. Several plies are made up to form a laminate (just like plywood). And the laminate, if designed right, can be very tough. It's also light. So why aren't all bikes made out of carbon fiber? It tends to be brittle. The fact that metal can bend and regain its shape is what makes it last. Because of this, carbon fiber bikes are built even stronger than needed.

What to Look For in a Frame

Manufacturing processes and market trends continue to literally shape the bicycle frame. While not as common as it used to be, the process of butting is still used in the manufacture of bicycle frames. Meanwhile, steel, the long-running workhorse, is being replaced more and more by aluminum—its hardy cousin that grows less expensive every year. So what do you look for in a frame? Is next year's frame necessarily better than this year's?

Weight

Striving to shave precious grams from frame designs, manufacturers have employed all sorts of exotic metals and methods. Essentially, though, what you pay for is inversely proportional to the weight of your bike. The more you pay, the less it weighs.

Geometry

In theory, aggressive angles lead to aggressive ride characteristics. Relaxed angles lead to more casual ride characteristics. Which is best for you? The answer really depends on how much time you spend in the saddle. If you ride a lot and aren't interested in attacking the road or trail, go for a relaxed geometry of about 70 or 71 degrees on the head tube. More aggressive bikes have a head-tube angle of 72 or 73 degrees.

Plain-Gauge Tubing

Even with advances in materials, manufacturing processes and design, the best frame tubing for the buck is plain-gauge. These are tubes that don't rely on butting (see below) or oversizing or exotic blends, but are straight and strong and easy to manufacture. As a consequence they are cheaper. Those who are "serious" about cycling may point out that plain-gauge tubes weigh more than butted tubes. This is true, but the difference is sometimes only a matter of three or four pounds. If you're just out enjoying the town or trail and not attacking mountains, then this weight difference is of no consequence.

Butting

The goal of any good bike manufacturer is to put the material where you need it. And you need the material where the bike frame undergoes the most stress—at each end of the various tubes. This process is known as butting.

Internal Butting—Looking at the tube, you won't notice butting because it's hidden within the tube. So how do you know if the bike is butted? Bike manufacturers will certainly tell you, as it's a big selling point.

External Butting—The older, more expensive way is to add material onto the outside of the tube. This is rarely done anymore. However, you sometimes will see an extended weld. (See below.)

There are two methods used to butt a frame tube.

Double Butting—As the tube is shaped, extra material is allowed internally at each end of the tube. By increasing these areas of the tube, the overall tube wall thickness can be reduced, thus saving weight.

Triple Butting—To save even more weight, the double butting process is refined by stepping down the material at the ends of the tube. This means the butting starts out in the standard, double-butted manner but then is thinned before stepping down again to the normal tube wall thickness. In a cutaway, the inside of the tube looks like three terraced rice paddies on a hillside.

Welding

There are essentially 3 ways to join frame tubes:

• Weld them using the same material as the tube (TIG welding).
• Braze the tubes together using silver or brass.
• Use lugs to join the tubes.

Each method has its proponents, yet nearly all but the very high-end bikes use the TIG welding method. This approach is relatively inexpensive and creates a good, solid weld. However, look closely at a bike's welds. You'll see that quality bikes offer a thick, even weld that goes around the entire tube. On department store bikes the welds are thin and spotty, dabbed down generally on the top, bottom and sides, but leaving open areas in between.

Extended Welds—One inexpensive way of adding material to the end of a tube is to simply add welding material. Generally, this is an elliptical circle or a double line extending from the joint to about an inch or so down the tube where it fades out. What's the problem with this method? The heat used in this process can actually weaken the tube. After welding, manufacturers will again heat-treat the entire tube—baking it, essentially—to bring the metal back up to par. While effective, this is a less substantial method than actually building the butting while the tube is being drawn out.

What Other Factors Should I Consider?

How Long Are You Going to Keep Your Bike?

Steel will oxidize (rust) faster than aluminum. However, steel can take more stress over the long run than aluminum. Which is better? If you live in a wet climate, aluminum may be the better choice. Dry climate? You can do well with steel.

How Much Do You Weigh?

If you go much above the 170-pound mark, you'll want a bike with a higher strength. This may take an added pound of frame weight to achieve, but it's worth it in the long run. Also, steel and titanium are generally better for bigger riders due to something called elongation. They can flex more without breaking.

Is Money a Factor?

Though aluminum and titanium have come down in price, steel is still the least expensive metal. But since most cyclists like the lighter weight of aluminum or carbon fiber, manufacturers are creating bikes that are aluminum or carbon fiber and more affordable. Titanium? Still expensive.

Sumber: http://www.rei.com/learn/expert-advice/bike-frame-materials.html

Badminton Set

GBAD_S5 (aluminum pole) 
Net : 21'x2.5'x9ply 0.75"mesh, nylon net 
Tube : 38mm x 1.0mm(T) 
Aluminum pole 
Stake : 8"x 4pcs steel stake 
Racket : 4pcs aluminum rackets 
w/2 shuttlecocks Carry-all bag

Materials Used to Make a Badminton Racket

Aluminum and Graphite

• 
  

  

  The badminton racket frame is normally made from lightweight, man-made metals such as graphite or aluminum. This is because most players believe that the lighter the racket, the more manageable and maneuverable it is. Lightweight rackets are also thought to move more quickly through the air and with more freedom, helping trace and hit fast-moving shuttlecocks. Other players, however, prefer a heavier racket because it provides more power and reduces shock. These rackets of differing weights are not made from different materials; the heavier racket is simply made with more graphite fiber. The standard weight of a badminton racket should be between 2.8oz (80g) and 3.5oz (100g).

Nylon

• Nylon is used to make the strings of a badminton racket. The synthetic material is cheap to produce but strong and long lasting. Nylon string sizes are designated by gauge number. The lower the gauge value, the thicker the string. Thicker nylon strings give control and durability but sacrifice power. Thinner synthetic strings provide power to a player's shots but are prone to wear, tear and breaking.

Natural Animal Gut

• Interestingly, some badminton players still prefer animal gut strings because they give rackets more feel, control and power. They also absorb shock and reduce vibration on the user's playing arm. Natural animal gut is costly, however, and doesn't last as long as other synthetic strings.

Cotton and Elastic

• Badminton towel grips are made from cotton and elastic. They can be bought to slip over the more common rubber racket grips and are used by professional players due to their perspiration-absorbing qualities. The cotton compounds in the grip absorb excess body moisture ensuring that a strong hand grip remains constant and gives the user more control and confidence in his stroke. Because grips are made from cotton compounds, the material can be dyed in various colors, allowing players to customize their rackets.

Sumber : http://www.ehow.com/list_7156569_materials-used-make-badminton-racket.html

Cermat Memilih Material Kamar Mandi

Walaupun sering diabaikan, kamar mandi adalah salah satu ruang terpenting di rumah. Fungsinya tidak tergantikan oleh ruang manapun. Saat ini tersedia banyak sekali material yang dapat digunakan untuk membuat atau merenovasi kamar mandi. Namun, material-material itu harus diperhatikan agar kamar mandi bisa berfungsi secara optimal.

Lantai
   Kriteria untuk memilih material lantai adalah yang permukaannya tidak licin, kuat, mudah dibersihkan, serta tahan terhadap bahan kimia. Pilihlah bahannya bisa cat lantai keramik, batu alam (marmer, granit, dan sejenisnya), atau bahan vinil. Selain bahan, pemasangan lantai perlu diperhatikan. Kemiringan lantai yang disarankan adalah 1 persen dari panjang dan lebar lantai.

Dinding
   Pelapis dinding dipilih dari bahan yang mudah dicuci dan tahan air sehingga mudah dibersihkan. Bahan yang dapat digunakan antara lain cat jenis water proofing, keramik, batu alam, atau partisi pembatas yang dilaminasi dan tahan air. Sebagai alternatif, bahan dinding yang lebih murah bisa digunakan dinding batako yang dilapisi cat tahan air. Pilihan warna terang pada dinding akan sangat memudahkan dalam mengontrol kebersihannya.

Pintu
   Mengingat kegiatan di toilet akan intensif menggunakan air, pilihan bahan pintu dan kusen pun sebaiknya terbuat dari bahan yang tahan air, ringan dan mudah dibersihkan. Bahan yang disarankanantara lain pintu dan kusen PVC, kusen alumunium, daun pintu dari lembaran alumunium/seng/lembaran fiber, atau pintu yang dilaminasi. Ketinggian pintu dari lantai harus mempunyai ambang yang lebih tinggi dari biasanya (jenis pintu-pintu lainnya). Jika tak ada kendala terkait dengan luasan ruang, sebaiknya daun pintu dipasang di sebelah kanan dan membuka ke dalam (untuk menghindari benturan dengan aktivitas di luar).


Sumber: Kompas, 13 September 2012, hal 44

unDER CoSTRuctiON

Ini adalah blog baru saya, sebagai ganti dari blog lama dengan judul yang sama (milik saya juga). Isi blog lama akan saya pindahkan kesini, karena blog lama sering mengalami gangguan.