THE FACT ABOUT THEORY “origin of life”

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Teori evolusi tidak bicara tentang asal penciptaan makhluk hidup, apalagi secara kebetulan. Teori yang membahas asal kehidupan adalah teori abiogenesis modern. Lucu sekali jika ingin membantah teori evolusi, tapi tak tahu beda teori evolusi (origin of species) dengan teori abiogenesis modern (origin of life). Teori evolusi juga bukan propaganda materialis. Jika karena tak membicarakan peran Tuhan di dalamnya lantas diklaim propaganda materialis, maka semua tori ilmiah juga harus dianggap propaganda materialis juga. Dan lagi, tidak ada ‘bukti ilmiah’ yang membantah teori evolusi. Sebaliknya, justru tulisan HY yang tidak ilmiah, merupakan propaganda dan penuh kebohongan serta rekayasa.

Teori evolusi bukan pandangan filosofis, tak ada kaitan dengan meterialisme atau sejenisnya. Apakah Tuhan ada atau tidak, itu bukan bahasan teori evolusi. Dan sekali lagi, tak ada bukti ilmiah yang membantah teori evolusi.

Apa yang sempurna dari Odontochelys semitestacea, kura-kura dengan tempurung yang belum terbentuk sempurna?

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METODE (ALAT) ANALISA LOGAM BERAT

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Berikut sedikit penjelasan mengenai beberapa teknik analisa untuk mineral tambang.

1. X-Ray Diffraction (XRD),
XRD merupakan salah satu teknik analisa untuk stuktur suatu mineral, garam, logam, bahkan senyawaan organik seperti DNA, vitamin dan obat. Jika ingin mengetahui mineral apa saja yang terkandung dalam suatu bahan tambang dan assosiasinya apa saja, teknik ini cukup tepat karena XRD bisa memberikan informasi mengenai bentuk molekul dan berapa sudut kristalnya. XRD bekerja berdasarkan difraksi sinar X yang dihamburkan oleh sudut kristal material yang dianalisa. Akan tetapi, kelemahannya, XRD kurang tepat jika digunakan untuk analisa quantitatif (jumlah atau kadarnya). Walaupun banyak orang meng-klaim bahwa XRD bisa memberikan informasi tentang “berapa kandungannya” namun masih kurang valid jika dibandingkan dengan teknik analisa lainnya di laboratorium. Umumnya XRD digunakan untuk analisa jumlah yang membutuhkan waktu cepat tapi tidak perlu akurat.

2. X-Ray Fluorescen (XRF),
XRF mirip dengan XRD namun perbedaannya adalah fluoresensi-nya yang digunakan untuk analisa. Suatu material tambang, cukup dibuat homogen dengan digerus dan dipadatkan atau dilebur, dicetak menjadi semacam koin (bead) atau pellet, tentunya dengan penimbangan tertentu. XRF lebih akurat dibandingkan XRD secara kuantitatif/jumlah. XRF bisa memberikan data baik dalam bentuk elemen maupun oksida. Analisanyapun relatif cepat karena simultan (beberapa elemen atau oksida bisa dianalisa sekaligus dalam sekali running). Dari segi biayanya relatif murah. Kekurangannya yaitu tidak bisa analisa untuk elemen atau oksida dalam kadar rendah < 0.01 %. Untuk analisa dengan kadar < 0.01% di sarankan menggunakan metode ICP atau AAS.

3. Inductive Coupled Plasma (ICP)
ICP merupakan teknik analisa mineral khususnya logam yang saat ini sedang naik daun karena beberapa kelebihannya, antara lain: relatif cepat untuk analisa quantitatif yang akurat, analisa secara simultan (bisa analisa banyak logam sekaligus sekali running), relatif murah jika analisa > 20 elemen sekaligus tetapi akan menjadi mahal jika elemen yg ingin dianalisa < 10 elemen. ICP mampu menganalisa logam mulai dari ppb (part per billion), ppm (part per million) sampai % (persen) tetapi umumnya lebih akurat untuk kadar kecil (ppb sampai dengan ppm). Kekurangannya dibandingkan XRD yaitu ICP hanya memberikan data analisa dalam bentuk elemen/unsur, bukan senyawaan maupun asosiasi mineral. Semua elemen yg ada dalam suatu bahan tambang akan dilarutkan dengan bahan kimia cair dan dibakar dengan suhu > 6000 K menjadi suatu plasma dan elektron yang tereksitasi di plasma itulah yang dianalisa.

4. Atomic Absorption Spectrophotometer (AAS)
AAS merupakan teknik analisa mineral logam yang mirip dengan ICP, tetapi dia hanya menganalisa per elemen (single). Jadi jika elemen yang akan di analisa 20 elemen, artinya AAS akan menganalisa 20x sesuai elemen yang diminta, tetapi pelarutannya cukup sekali saja. Jadi jika dibandingkan dengan ICP, kelemahannya adalah waktu analisa jadi lama. Dan beda dengan ICP yang cukup dijalankan oleh tingkat operator biasa, analisa AAS memerlukan skill dan pengalaman yang lebih tinggi. Jika elemen yang hendak dianalisa sedikit, AAS lebih menguntungkan karena hitungan biayanya per elemen.

5. Titrasi dan gravimetri
Merupakan suatu teknik analisa klasik yang sudah terbukti paling valid untuk mineral dengan kadar tinggi (dalam %). Keuntungannya yaitu selain valid untuk kadar %, tidak membutuhkan instrumen mahal, mereka juga bisa digunakan untuk analisa dengan bentuk oksida-nya. Kekurangannya, biayanya mahal karena menggunakan bahan kimia baik padatan, cair maupun gas, waktu analisanya relatif lebih lama.

STORING GAS

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WHEN YOU GET IT HOME

Storing gasoline and other highly flammable liquids at home is also dangerous if not done properly. The best way to store gasoline is in a well ventilated area separate from the house. The location should have no electrical equipment, open flames or other sources of ignition present. In addition, the location should be protected from the heat of the summer sun to keep evaporation to a minimum.

Do not store gasoline in the basement of your home or in the utility room. The furnace, water heater, clothes dryer or any of several other items could ignite fumes which may leak from the can and travel considerable distances. If you do not have a suitable storage area, consider building a cabinet outside your house for storage or purchasing a commercially available flammable liquid storage cabinet, available from safety equipment suppliers. In addition, never put gasoline or any other nonfood material in a container which resembles a food container. Keep gasoline and other dangerous materials locked up. These practices will prevent children from getting to the material and being accidentally poisoned.

Never smoke when handling gasoline and never refuel a hot or running engine. Take a break if you must smoke or let the engine cool down. If fuel is spilled, wipe it up immediately. Before starting the engine, move at least 25 feet away from the fueling area to avoid igniting fuel vapors which are heavier than air and may linger for some time.


How can I store petrol or diesel safely?

The simple answer is that the only way to do this is in the tank of your car. That’s the advice from the Fire Service in the UK.

What is wrong with storing fuel in containers?

Petrol and diesel are highly flammable liquids. This means they can easily start a fire that could destroy your property. Keeping petrol or diesel in closed containers can also create a risk of explosion. That risk is minimised by the design of vehicles, but plastic or metal containers can create problems. The biggest danger, though, is getting the fuel in and out of the containers and into your vehicle’s tank.

Decanting even a small amount of petrol or diesel in an enclosed space is a bad idea, as the fumes can fill that space very quickly. A spark or naked flame can then cause ignition – and an explosion and fireball. Just turning a light switch on in a closed garage filled with petrol fumes can be enough to cause disaster.

A cautionary tale about decanting petrol…

An attempt by a mum from York to help out her daughter, who had run out of petrol during the height of the run on the pumps at the end of March 2012, ended in a shocking tragedy. The woman decided to decant some of the petrol she had stored in a container into another container for her daughter to put in her car. Not realising the dangers, she did this in her kitchen with the cooker on, as she was cooking tea at the time. Petrol fumes filled the warm kitchen and then ignited when they reached the cooker, causing a fireball. The woman then dropped the glass jug of petrol she was holding, and this ignited, immediately setting fire to her clothes and leaving her with 40% burns. She survived but her injuries may need weeks, possibly months of treatment.

Advice from the Fire Service in the UK

The official advice about storing petrol or diesel in containers is DON’T. Instead keep your car topped up more frequently so that it is almost full most of the time.

If you choose to keep some petrol or diesel in storage, whether it’s a backup for your vehicle, or fuel for something like a petrol lawnmower or strimmer, remember the legal limits:

In addition, the Fire Service recommends that you treat the fuel with great care:

Storing fuel:

Handling fuel

You may think it would be a nightmare to not be able to use your car if a strike, or other crisis, lead to a fuel shortage, and be tempted to store petrol over the legal limits. But the cost may be your home, or even your life – is storing petrol or diesel really worth it?



This document is apart of a series from the Agricultural Engineering Department, Agricultural Extension Service, University of Tennessee, Knoxville, Tennessee. Publication date: April 1986.

Timothy G. Prather, Extension Assistant, Agricultural Engineering Department, Agricultural Extension Service, University of Tennessee, Knoxville, Tennessee.

 

MOBILE PHONE/HANDPHONE AND GASTATION/FUEL/GASOLINE : Can Using A Cellphone At A Gas Station (Petrol Pump) Cause An Explosion?

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If you own an automobile and happen to frequent gas stations (petrol pumps) quite often, you have almost certainly come across warning signs in those particular spots. Aside from prohibiting smoking, these bills often advise you to keep your cellphones switched off, and some may even suggest that the use of cellphones can cause an explosion at the gas station.

Is there any truth in that? Can using a cellphone at a gas station cause an explosion?


Why are we told to switch off cellphones at a gas station?

In order to figure out if using cellphones at a gas station is dangerous or not, it’s important that we first understand the reason behind this omnipresent warning.


Cellphones: Wireless devices that communicate with network towers

Although this may seem like a silly question to start with, it’s important, so… what is a cellphone exactly?

A cellphones is a wireless tool that keeps you connected to the entire world, but how does it do that, you may ask? It’s such a cute little device, but as they say, appearances can be deceiving. Under their thin external skin, cellphones contain a myriad of tiny electronic components that help them communicate with network towers wirelessly.

Even though there are no wires involved, there is still an exchange of information between your cellphone and the network tower? How does that happen?


Electromagnetic Radiation

The two-way communication between your phone and the network tower takes place through electromagnetic waves – invisible waves that race to the network tower and return to your phone in seconds! These waves have energy values in the range of 1.24 Megaelectron-Volts to 12.4 Peta-electronvolts. It is assumed that this electromagnetic radiation is a cause of concern; because they carry so much energy, they may cause sparks and consequently ignite gas, which could cause monumental damage in a place like a gas station!


Can cellphones really cause explosions at a gas station?

Credit: luckytonyom/Shutterstock

As far as science is concerned, there is no documented connection between explosions at gas stations and the use of cellphones. In fact, according to a study carried out at gas stations all over the world between 1994 and 2005, in all the cases of gas station fires, none were related to cellphones. Mobile phones have low-voltage batteries that are not ‘potent’ enough to ignite a spark at a gas station.

A probable cause of fire (related to a cellphone) may be a defective battery in a phone. However, that is very unlikely, as there is a much smaller chance of you using your phone if it has a defective battery! Also, if we’re talking about defective batteries, then not only your phone, but even your vehicle’s battery, could be defective and potentially cause a fire.


A Word of Caution

Using a cellphone at a gas station, even if it doesn’t cause a fire, is still not a healthy practice. You may not realize it, but using your phone (talking, texting, or merely skimming through notifications) may distract you and potentially cause accidents, such as being hit by another vehicle or running over pedestrians etc.

It may not seem like it, but putting gas in your vehicle is an important task that requires your undivided attention. Therefore, it’s in your own best interest that you put your phone away for a few moments and keep yourself safe from any nasty accidents.

References

  1. HowStuffWorks
  2. ABC News

HEXAGON IN NATURE

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Is nature a mathematician?

Patterns and geometry are everywhere. But nature seems to have a particular thing for the number 6. Beehives. Rocks. Marine skeletons. Insect eyes.

It could just be a mathematical coincidence. Or could there be some pattern beneath the pattern, why nature arrives at this geometry? We’re going to figure that out…

A bubble is just some volume of gas, surrounded by liquid. It can be surrounded by a LOT of liquid, like in champagne, or just a thin layer, like in soap bubbles. So why do these bubbles have any shape at all?

Liquid molecules are happier wrapped up on the inside, where attraction is balanced, than they are at the edge. This pushes liquids to adopt shapes with the least surface. In zero g, this attraction pulls water into round blobs.

Same with droplets on leaves or a spider’s web. Inside thin soap films, attraction between soap molecules shrinks the bubble until the pull of surface tension is balanced by the air pressure pushing out.

It’s physics! Physics is great, but mathematics is truly the universal language.

Bubbles are round because if you want to enclose the maximum volume with the least surface area, a sphere is the most efficient shape. Yeah. That’s another way of putting it.

What’s cool is if we deform that bubble, the pull of surface tension always evens back out, to the minimal surface shape. This even works when soap films are stretched between complex boundaries, they always cover an area using the least amount of material. That’s why German architect Frei Otto used soap films to model ideal roof shapes for his exotic constructions.

Now let’s see what happens when we start to pack bubbles together. A sphere is a three-dimensional shape, but when when we pack bubbles in a single layer, we really only have to look at the cross-section: a circle. Rigid circles of equal diameter can cover, at most, 90% of the area on a plane, but luckily bubbles aren’t rigid.

Let’s pretend for a moment these bubbles were free to choose any shape they wanted. If we want to Bubbles are round because if you want to enclose the maximum volume with the least surface area, a sphere is the most efficient shape. A plane with cells of equal size and *no* wasted area, we only have three regular polygons to choose from: triangles, squares, or hexagons.

So which is best? We can test this with actual bubbles. Two equal-sized bubbles? A flat intersection. Three, and we get walls meeting at 120˚. But when we add a fourth… instead of a square intersection, the bubbles will always rearrange themselves so their intersections are 120˚, the same angle that defines a hexagon. If the goal is to minimize the perimeter for a given area, it turns out that hexagonal packing beats triangles and squares.

In other words, more filling with fewer edges. In the late 19th century, Belgian physicist Joseph Plateau calculated that junctions of 120˚ are also the most mechanically stable arrangement, where the forces on the films are all in balance. That’s why bubble rafts form hexagon patterns.

Not only does it minimize the perimeter, the pull of surface tension in each direction is most mechanically stable. So let’s review: The air inside a bubble wants to fill the most area possible. But there’s a force, surface tension, that wants to minimize the perimeter.

And when bubbles join up, the best balance of fewer edges and mechanical stability is hexagonal packing. Is this enough to explain some of the six-sided patterns we see in nature?

Basalt columns like Giant’s Causeway, Devil’s Postpile, and the Plains of Catan form from slowly cooling lava. Cooling pulls the rock to fill less space, just like surface tension pulls on a soap film. Cracks form to release tension, to reach mechanical stability, and more energy is released per crack if they meet at 120˚. Sounds pretty close to the bubbles.

The forces are different, but it’s using similar math to solve a similar problem. What about the facets of insect’s eye? Here, instead of a physical force, like in the bubble or the rock, evolution is the driver. Maximum light-sensing area? That’s good for the insect, but so is minimizing the amount of cell material around the edges. Just like the bubbles, the best shapes are hexagons. What’s even cooler, if you look down at the bottom of each facet?? There’s a cluster of four cone cells, packed just like bubbles are. Bubbles can even help explain honeycomb.

It would be nice to imagine number-crunching bees, experimenting with triangles and squares and realizing hexagons are most efficient balance of wax to area… but with a brain the size of a poppy seed? They’re no mathematicians. It turns out honeybees make round wax cells at first. And as the wax is softened by heat from busy bees, it’s pulled by surface tension into stable hexagonal shapes. Just like our bubbles. You can even recreate this with a bundle of plastic straws and a little heat.

So is nature a mathematician? Some scientists might say nature loves efficiency. Or maybe that nature seeks out the lowest energy. And some people might say nature follows the rules of mathematics. However you look at it, nature definitely has a way of using simple rules to create elegant solutions.

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