Fusion


The origin of the energy released in fusion of light elements is due to an interplay of two opposing forces, the nuclear force which combines together protons and neutrons, and the Coulomb force which causes protons to repel each other. The protons are positively charged and repel each other but they nonetheless stick together, demonstrating the existence of another force referred to as nuclear attraction.

This force, called the strong nuclear force, overcomes electric repulsion in a very close range. The effect of this force is not observed outside the nucleus, hence the force has a strong dependence on distance, making it a short-range force. The same force also pulls the neutrons together, or neutrons and protons together.

Because the nuclear force is stronger than the Coulomb force for atomic nuclei smaller than iron and nickel, building up these nuclei from lighter nuclei by fusion releases the extra energy from the net attraction of these particles. For larger nuclei, however, no energy is released, since the nuclear force is short-range and cannot continue to act across still larger atomic nuclei. Thus, energy is no longer released when such nuclei are made by fusion; instead, energy is absorbed in such processes.


britannica.com

Fusion reactions of light elements power the stars and produce virtually all elements in a process called nucleosynthesis. The fusion of lighter elements in stars releases energy (and the mass that always accompanies it). For example, in the fusion of two hydrogen nuclei to form helium, 0.7% of the mass is carried away from the system in the form of kinetic energy or other forms of energy (such as electromagnetic radiation).

Research into controlled fusion, with the aim of producing fusion power for the production of electricity, has been conducted for over 60 years. It has been accompanied by extreme scientific and technological difficulties, but has resulted in progress. At present, controlled fusion reactions have been unable to produce break-even (self-sustaining) controlled fusion reactions.

Workable designs for a reactor that theoretically will deliver ten times more fusion energy than the amount needed to heat up plasma to required temperatures (see ITER) were originally scheduled to be operational in 2018, however this has been delayed and a new date has not been stated.

It takes considerable energy to force nuclei to fuse, even those of the lightest element, hydrogen. This is because all nuclei have a positive charge due to their protons, and as like charges repel, nuclei strongly resist being put close together. Accelerated to high speeds, they can overcome this electrostatic repulsion and be forced close enough for the attractive nuclear force to be sufficiently strong to achieve fusion.

The fusion of lighter nuclei, which creates a heavier nucleus and often a free neutron or proton, generally releases more energy than it takes to force the nuclei together; this is an exothermic process that can produce self-sustaining reactions. The US National Ignition Facility, which uses laser-driven inertial confinement fusion, is thought to be capable of break-even fusion.

The first large-scale laser target experiments were performed in June 2009 and ignition experiments began in early 2011. Energy released in most nuclear reactions is much larger than in chemical reactions, because the binding energy that holds a nucleus together is far greater than the energy that holds electrons to a nucleus.

For example, the ionization energy gained by adding an electron to a hydrogen nucleus is 13.6 eV—less than one-millionth of the 17.6 MeV released in the deuterium–tritium (D–T) reaction shown in the diagram to the right (one gram of matter would release 339 GJ of energy). Fusion reactions have an energy density many times greater than nuclear fission; the reactions produce far greater energy per unit of mass even though individual fission reactions are generally much more energetic than individual fusion ones.

 which are themselves millions of times more energetic than chemical reactions. Only Direct conversion of mass into energy, such as that caused by the annihilatory collision of matter and antimatter, is more energetic per unit of mass than nuclear fusion.(wikipedia.org)

Energy


The concept of energy and its transformations is vital in explaining and predicting most natural phenomena. One form of energy can often be readily transformed into another; for instance, a battery, from chemical energy to electric energy; a dam: gravitational potential energy to kinetic energy of moving water (and the blades of a turbine) and ultimately to electric energy through an electric generator.

There are strict limits to how efficiently energy can be converted into other forms of energy via work, and heat as described by Carnot's theorem and the second law of thermodynamics. These limits are especially evident when an engine is used to perform work. Some energy transformations can be quite efficient.

The direction of transformations in energy (what kind of energy is transformed to what other kind) is often described by entropy (equal energy spread among all available degrees of freedom) considerations, as in practice all energy transformations are permitted on a small scale, but certain larger transformations are not permitted because it is statistically unlikely that energy or matter will randomly move into more concentrated forms or smaller spaces.

Energy transformations in the universe over time are characterized by various kinds of potential energy that has been available since the Big Bang, later being "released" (transformed to more active types of energy such as kinetic or radiant energy), when a triggering mechanism is available.


eti.co.uk

Familiar examples of such processes include nuclear decay, in which energy is released that was originally "stored" in heavy isotopes (such as uranium and thorium), by nucleosynthesis, a process ultimately using the gravitational potential energy released from the gravitational collapse of supernovae, to store energy in the creation of these heavy elements before they were incorporated into the solar system and the Earth. This energy is triggered and released in nuclear fission bombs or in civil nuclear power generation.

Similarly, in the case of a chemical explosion, chemical potential energy is transformed to kinetic energy and thermal energy in a very short time. Yet another example is that of a pendulum. At its highest points the kinetic energy is zero and the gravitational potential energy is at maximum. At its lowest point the kinetic energy is at maximum and is equal to the decrease of potential energy.

If one (unrealistically) assumes that there is no friction or other losses, the conversion of energy between these processes would be perfect, and the pendulum would continue swinging forever.
Energy gives rise to weight when it is trapped in a system with zero momentum, where it can be weighed. It is also equivalent to mass, and this mass is always associated with it.

Mass is also equivalent to a certain amount of energy, and likewise always appears associated with it, as described in mass-energy equivalence. The formula E = mc², derived by Albert Einstein (1905) quantifies the relationship between rest-mass and rest-energy within the concept of special relativity. In different theoretical frameworks, similar formulas were derived by J. J. Thomson (1881), Henri Poincaré (1900), Friedrich Hasenöhrl (1904) and others (see Mass-energy equivalence#History for further information).

Matter may be converted to energy (and vice versa), but mass cannot ever be destroyed; rather, mass/energy equivalence remains a constant for both the matter and the energy, during any process when they are converted into each other. However, since is extremely large relative to ordinary human scales, the conversion of ordinary amount of matter (for example, 1 kg) to other forms of energy (such as heat, light, and other radiation) can liberate tremendous amounts of energy joules = 21 megatons of TNT), as can be seen in nuclear reactors and nuclear weapons.

Conversely, the mass equivalent of a unit of energy is minuscule, which is why a loss of energy (loss of mass) from most systems is difficult to measure by weight, unless the energy loss is very large. Examples of energy transformation into matter (i.e., kinetic energy into particles with rest mass) are found in high-energy nuclear physics.(wikipedia.org)

Penyakit


Merupakan kelenjar terbesar di dalam tubuh, terletak dalam rongga perut sebelah kanan, tepatnya di bawah diafragma. Berdasarkan fungsinya, hati juga termasuk sebagai alat ekskresi.

Hal ini dikarenakan hati membantu fungsi ginjal dengan cara memecah beberapa senyawa yang bersifat racun dan menghasilkan amonia, urea, dan asam urat dengan memanfaatkan nitrogen dari asam amino. Proses pemecahan senyawa racun oleh hati disebut proses detoksifikasi.


en.wikipedia.org

Lobus hati terbentuk dari dan sel non-parenkimal. Sel parenkimal pada hati disebut hepatosit, menempati sekitar 80% volume hati dan melakukan berbagai fungsi utama hati. 40% sel hati terdapat pada lobus sinusoidal.

Hepatosit merupakan sel endodermal yang terstimulasi oleh jaringan mesenkimal secara terus-menerus pada saat embrio hingga berkembang menjadi sel parenkimal. Selama masa tersebut, terjadi peningkatan transkripsi mRNA albumin sebagai stimulan proliferasi dan diferensiasi sel endodermal menjadi hepatosit.

Lumen lobus terbentuk dari SEC dan ditempati oleh 3 jenis sel lain, seperti sel Kupffer, sel Ito, limfosit intrahepatik seperti sel pit. Sel non-parenkimal menempati sekitar 6,5% volume hati dan memproduksi berbagai substansi yang mengendalikan banyak fungsi hepatosit.

Filtrasi merupakan salah satu fungsi lumen lobus sinusoidal yang memisahkan permukaan hepatosit dari darah, SEC memiliki kapasitas endositosis yang sangat besar dengan berbagai ligan seperti glikoprotein, kompleks imun, transferin dan seruloplasmin.

SEC juga berfungsi sebagai sel presenter antigen yang menyediakan ekspresi MHC I dan MHC II bagi sel T. Sekresi yang terjadi meliputi berbagai sitokina, eikosanoid seperti prostanoid dan leukotriena, endotelin-1, nitrogen monoksida dan beberapa komponen ECM.

Sel Ito berada pada jaringan perisinusoidal, merupakan sel dengan banyak vesikel lemak di dalam sitoplasma yang mengikat SEC sangat kuat hingga memberikan lapisan ganda pada lumen lobus sinusoidal.

Saat hati berada pada kondisi normal, sel Ito menyimpan vitamin A guna mengendalikan kelenturan matriks ekstraselular yang dibentuk dengan SEC, yang juga merupakan kelenturan dari lumen sinusoid.(wikipedia.org)

Binatang


Gajah Afrika merupakan hewan darat terbesar di dunia. Sepanjang 55 juta tahun terdapat 500 spesies gajah yang dikenal dan hanya dua spesies yang masih ada yaitu gajah Asia elephas maximus dan gajah Afrika loxodonta africana.

Spesies gajah Asia dan gajah Afrika mulai terpecah kira-kira dua juta tahun dahulu. Gajah Asia berbeda dengan gajah Afrika.


Gajah Asia memiliki telinga lebih kecil sedikit daripada gajah Afrika, mempunyai dahi yang rata, dan dua bonggol di kepalanya merupakan puncak tertinggi gajah, dibandingkan dengan gajah Afrika yang mempunyai hanya satu bonggol di atas kepala.

Selain itu, ujung belalai gajah Asia hanya mempunyai 1 bibir, sementara gajah Afrika mempunyai 2 bibir di ujung belalai. Kedua jenis kelamin gajah Afrika mempunyai gading sementara hanya gajah Asia jantan yang mempunyai gading yang jelas terlihat.


terengganutoday.com

Ada pula spesies gajah kerdil atau pygmy elephants dengan nama latin elephas maximus borneensis adalah spesies terkecil gajah, bahkan lebih kecil dari gajah Sumatra. Ukuran tubuhnya hanya sekitar 2,5 meter, seperti pada ukuran bayi gajah lainnya, gajah ini berkerabat dekat dengan Gajah Kalimantan.

Data menunjukkan bahwa DNA pada gajah kerdil adalah sama sekali berbeda dari gajah Asia dan gajah Afrika, hal ini berarti bahwa gajah kerdil merupakan subspesies baru dari gajah. Habitat tempat hidup mereka ada di kedalaman hutan Borneo, perbatasan antara Kalimantan Timur - Indonesia dengan Malaysia.

Penyebaran gajah di Asia meliputi India, Asia Tenggara termasuk Indonesia bagian barat dan Sabah (Malaysia Timur). Sedangkan gajah di Afrika pernyebarannya meliputi sebagian besar daratan Afrika yang berupa padang rumput.

Di Indonesia, gajah terdapat di Sumatera (gajah Sumatera) dan di Kabupaten Nunukan, Kalimantan Timur (gajah Borneo).(wikipedia.org)

Teknologi


Jika saat ini smartphone berkamera di atas 10 megapiksel masih jarang ditemui atau hanya digunakan untuk perangkat unggulan, tidak demikian tampaknya di tahun yang akan datang.

Seperti dikatakan oleh CEO Largan Precision sebuah perusahaan pembuat modul lensa di Taiwan, Lin En-ping, modul kamera di atas 10 megapiksel disebut bakal menjadi resolusi yang umum digunakan pada smartphone dan tablet di tahun 2014.


techday.com

Bukan tanpa alasan, Lin mengklaim bahwa hampir semua klien perusahaannya disebut bakal mengadopsi model lensa di atas 10 MP.

"Hampir semua klien telah mengadopsi atau akan mengadopsi modul lensa di atas 10 MP untuk smartphone dan tablet yang akan diluncurkan pada tahun 2014," kata Lin seperti dilansir DigiTimes.

Mengacu pada pengiriman modul lensa di kuartal ketiga tahun ini, Lin mencatat bahwa pengiriman model 13 MP dan di atasnya mencapai 10 – 20%, 8 MP mencapai 30 – 40%, 5 MP mencapai 20 - 30%, serta model 1.3 MP dan di bawahnya sekitar 20 – 30%.

Jadi, apakah perkiraan Lin En-ping ini bakal terjadi di tahun 2014, kita buktikan saja nanti.(beritateknologi.com)

Ikan


Arwana Asia (Scleropages formosus), atau Siluk Merah adalah salah satu spesies ikan air tawar dari Asia Tenggara. Ikan ini memiliki badan yang panjang; sirip dubur terletak jauh di belakang badan.


www.citraarowana.com

Arwana Asia umumnya memiliki warna keperak-perakan. Arwana Asia juga disebut "Ikan Naga" karena sering dihubung-hubungkan dengan naga dari Mitologi Tionghoa.

Arwana Asia adalah spesies asli sungai-sungai di Asia Tenggara khususnya Indonesia. Ada empat varietas warna yang terdapat di lokasi:
  • Hijau, ditemukan di Indonesia, Vietnam, Birma, Thailand, dan Malaysia
  • Emas dengan ekor merah, ditemukan di Indonesia
  • Emas, ditemukan di Malaysia
  • Merah, ditemukan di Indonesia
Arwana Asia terdaftar dalam daftar spesies langka yang berstatus "terancam punah" oleh IUCN tahun 2004. Jumlah spesies ini yang menurun dikarenakan seringnya diperdagangkan karena nilainya yang tinggi sebagai ikan akuarium, terutama oleh masyarakat Asia.

Pengikut Feng Shui dapat membayar harga yang mahal untuk seekor ikan ini.(wikipedia.org)