Yimpangakum Imsong

Hello world, just a guy who wants to learn

Student at Glocal university

Galvanic anode

A galvanic anode is the main component of a galvanic cathodic protection (CP) system used to protect buried or submerged metal structures from corrosion.They are made from a metal alloy with a more "active" voltage (more negative reduction potential / more positive electrochemical potential) than the metal of the structure. The difference in potential between the two metals means that the galvanic anode corrodes, so that the anode material is consumed in preference to the structure.The loss (or sacrifice) of the anode material gives rise to the alternative name of sacrificial anode.Theory EditIn brief, corrosion is a chemical reaction occurring by an electrochemical mechanism (a redox reaction).[1] During corrosion there are two reactions, oxidation (equation 1), where electrons leave the metal (and results in the actual loss of metal) and reduction, where the electrons are used to convert water or oxygen to hydroxides (equations 2 and 3).[2]Fe → Fe2+ + 2e−    (1)O2 + 2H2O + 4e− → 4OH−    (2)2H2O + 2e− → H2 + 2OH−    (3)In most environments, the hydroxide ions and ferrous ions combine to form ferrous hydroxide, which eventually becomes the familiar brown rust:[3]Fe2+ + 2OH− → Fe(OH)2    (4)As corrosion takes place, oxidation and reduction reactions occur and electrochemical cells are formed on the surface of the metal so that some areas will become anodic (oxidation) and some cathodic (reduction). Electrons flow from the anodic areas into the electrolyte as the metal corrodes. Conversely, as electrons flow from the electrolyte to the cathodic areas the rate of corrosion is reduced.[4] (The flow of electrons is in the opposite direction of the flow of electric current).As the metal continues to corrode, the local potentials on the surface of the metal will change and the anodic and cathodic areas will change and move. As a result, in ferrous metals, a general covering of rust is formed over the whole surface, which will eventually consume all the metal. This is rather a simplified view of the corrosion process, because it can occur in several different forms.[5]CP works by introducing another metal (the galvanic anode) with a much more anodic surface, so that all the current will flow from the introduced anode and the metal to be protected becomes cathodic in comparison to the anode. This effectively stops the oxidation reactions on the metal surface by transferring them to the galvanic anode, which will be sacrificed in favour of the structure under protection.[6]For this to work there must be an electron pathway between the anode and the metal to be protected (e.g., a wire or direct contact) and an ion pathway between both the oxidizing agent (e.g., water or moist soil) and the anode, and the oxidizing agent and the metal to be protected, thus forming a closed circuit; therefore simply bolting a piece of active metal such as zinc to a less active metal, such as mild steel, in air (a poor conductor and therefore no closed circuit) will not furnish any protection.

Transformer

A transformer is a passive electrical device that transfers electrical energy from one electrical circuit to one or more circuits. A varying current in any one coil of the transformer produces a varying magnetic flux, which, in turn, induces a varying electromotive force across any other coils wound around the same core. Electrical energy can be transferred between the (possibly many) coils, without a metallic connection between the two circuits. Faraday's law of induction discovered in 1831 described the induced voltage effect in any coil due to changing magnetic flux encircled by the coil.Transformers are used for increasing or decreasing the alternating voltages in electric power applications, and for coupling the stages of signal processing circuits.Since the invention of the first constant-potential transformer in 1885, transformers have become essential for the transmission, distribution, and utilization of alternating current electric power.[2] A wide range of transformer designs is encountered in electronic and electric power applications. Transformers range in size from RF transformers less than a cubic centimeter in volume, to units weighing hundreds of tons used to interconnect the power grid

Switched-mode power supply

A switched-mode power supply (switching-mode power supply, switch-mode power supply, switched power supply, SMPS, or switcher) is an electronic power supply that incorporates a switching regulator to convert electrical power efficiently. Like other power supplies, an SMPS transfers power from a DC or AC source (often mains power) to DC loads, such as a personal computer, while converting voltage and current characteristics. Unlike a linear power supply, the pass transistor of a switching-mode supply continually switches between low-dissipation, full-on and full-off states, and spends very little time in the high dissipation transitions, which minimizes wasted energy. A hypothetical ideal switched-mode power supply dissipates no power. Voltage regulation is achieved by varying the ratio of on-to-off time (also known as duty cycles). In contrast, a linear power supply regulates the output voltage by continually dissipating power in the pass transistor. This higher power conversion efficiency is an important advantage of a switched-mode power supply. Switched-mode power supplies may also be substantially smaller and lighter than a linear supply due to the smaller transformer size and weight.Switching regulators are used as replacements for linear regulators when higher efficiency, smaller size or lighter weight are required. They are, however, more complicated; their switching currents can cause electrical noise problems if not carefully suppressed, and simple designs may have a poor power factor.

Type 1 diabetes

TYPE 1 DIABETESType 1 diabetes is an autoimmune disease in which the body's immune system attacks and destroys the beta cells in the pancreas that make insulin. People with this disease must inject themselves with insulin in order to stay alive. They must carefully monitor their blood sugar, and also balance their food intake and exercise. Long-term complications of type 1 diabetes include disabling or even life-threatening organ damage, including heart disease, kidney disease, blindness and nerve damage.More than one million Americans have type 1 diabetes, and the worldwide incidence of the disease is growing with the greatest increase in children under five-years-old. The disease accounts for 5 to 10 percent of all diagnosed diabetes in the United States.Type 1 diabetes, also called juvenile diabetes, usually occurs in children or young adults and is especially prevalent among people of Northern European heritage. Additionally, family members of someone who has been diagnosed with type 1 diabetes are 15 times more likely to develop the disease themselves.

Chamber of heart

The heart has four chambers: two atria and two ventricles.The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle.The right ventricle pumps the oxygen-poor blood to the lungs.The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle.The left ventricle pumps the oxygen-rich blood to the body.

Brain conditions

Headache: There are many types of headaches; some can be serious but most are not and are generally treated with analgesics/painkillers.Stroke (brain infarction): Blood flow and oxygen are suddenly interrupted to an area of brain tissue, which then dies. A blood clot, or bleeding in the brain, are the cause of most strokes.Brain aneurysm: An artery in the brain develops a weak area that swells, balloon-like. A brain aneurysm rupture can causes a stroke.Subdural hematoma: Bleeding within or under the dura, the lining inside of the skull. A subdural hematoma may exert pressure on the brain, causing neurological problems.Epidural hematoma: Bleeding between the tough tissue (dura) lining the inside of the skull and the skull itself, usually shortly after a head injury. Initial mild symptoms can progress rapidly to unconsciousness and death, if untreated.Intracerebral hemorrhage: Any bleeding inside the brain.Concussion: A brain injury that causes a temporary disturbance in brain function. Traumatic head injuries cause most concussions.Cerebral edema: Swelling of the brain tissue in response to injury or electrolyte imbalances.Brain tumor: Any abnormal tissue growth inside the brain. Whether malignant (cancer) or benign, brain tumors usually cause problems by the pressure they exert on the normal brain.Glioblastoma: An aggressive, malignant brain tumor (cancer). Brain glioblastomas progress rapidly and are very difficult to cure.Hydrocephalus: An abnormally increased amount of cerebrospinal (brain) fluid inside the skull. Usually this is because the fluid is not circulating properly.Normal pressure hydrocephalus: A form of hydrocephalus that often causes problems walking, along with dementia and urinary incontinence. Pressures inside the brain remain normal, despite the increased fluid.Meningitis: Inflammation of the lining around the brain or spinal cord, usually from infection. Stiff neck, neck pain, headache, fever, and sleepiness are common symptoms.Encephalitis: Inflammation of the brain tissue, usually from infection with a virus. Fever, headache, and confusion are common symptoms.Traumatic brain injury: Permanent brain damage from a traumatic head injury. Obvious mental impairment, or more subtle personality and mood changes can occur.Parkinson's disease: Nerves in a central area of the brain degenerate slowly, causing problems with movement and coordination. A tremor of the hands is a common early sign.Huntington's disease: An inherited nerve disorder that affects the brain. Dementia and difficulty controlling movements (chorea) are its symptoms.Epilepsy: The tendency to have seizures. Head injuries and strokes may cause epilepsy, but usually no cause is identified.Dementia: A decline in cognitive function resulting from death or malfunction of nerve cells in the brain. Conditions in which nerves in the brain degenerate, as well as alcohol abuse and strokes, can cause dementia.Alzheimer’s disease: For unclear reasons, nerves in certain brain areas degenerate, causing progressive dementia. Alzheimer’s disease is the most common form of dementia.Brain abscess: A pocket of infection in the brain, usually by bacteria. Antibiotics and surgical drainage of the area are often necessary

Rectifier

A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction.The process is known as rectification, since it "straightens" the direction of current. Physically, rectifiers take a number of forms, including vacuum tube diodes, mercury-arc valves, stacks of copper and selenium oxide plates, semiconductor diodes, silicon-controlled rectifiers and other silicon-based semiconductor switches. Historically, even synchronous electromechanical switches and motors have been used. Early radio receivers, called crystal radios, used a "cat's whisker" of fine wire pressing on a crystal of galena (lead sulfide) to serve as a point-contact rectifier or "crystal detector".Rectifiers have many uses, but are often found serving as components of DC power supplies and high-voltage direct current power transmission systems. Rectification may serve in roles other than to generate direct current for use as a source of power. As noted, detectors of radio signals serve as rectifiers. In gas heating systems flame rectification is used to detect presence of a flame.Depending on the type of alternating current supply and the arrangement of the rectifier circuit, the output voltage may require additional smoothing to produce a uniform steady voltage. Many applications of rectifiers, such as power supplies for radio, television and computer equipment, require a steady constant DC voltage (as would be produced by a battery). In these applications the output of the rectifier is smoothed by an electronic filter, which may be a capacitor, choke, or set of capacitors, chokes and resistors, possibly followed by a voltage regulator to produce a steady voltage.More complex circuitry that performs the opposite function, that is converting DC to AC, is called an inverter.

Brain treatment

Brain TreatmentsThrombolytics: Clot-busting medicines injected into the veins can improve or cure some strokes if given within a few hours after symptoms start.Antiplatelet agents: Medicines like aspirin and clopidogrel (Plavix) help prevent blood clots. This can reduce the chance of a stroke.Cholinesterase inhibitors: These medicines can improve brain function slightly in mild or moderate Alzheimer’s disease. They do not slow or prevent Alzheimer’s disease.Antibiotics: When a brain infection is caused by bacteria, antibiotics can kill the organisms and make a cure more likely.Levodopa: A medicine that increases brain levels of dopamine, which is helpful in controlling symptoms of Parkinson’s disease.Brain surgery: An operation on the brain can cure some brain tumors. Brain surgery may be performed any time increased pressure in the brain threatens brain tissue.Ventriculostomy: A drain is placed into the natural spaces inside the brain (ventricles). Ventriculostomy is usually performed to relieve high brain pressures.Craniotomy: A surgeon drills a hole into the side of the skull to relieve high pressures.Lumbar drain: A drain is placed into the fluid around the spinal cord. This can relieve pressure on the brain and spinal cord.Radiation therapy: If cancer affects the brain, radiation can reduce symptoms and slow the cancer's growth.

RHEUMATOID ARTHRITIS

RHEUMATOID ARTHRITISRheumatoid arthritis (RA) is an autoimmune disease in which the body’s immune system mistakenly begins to attack its own tissues, primarily the synovium, the membrane that lines the joints. As a result of this autoimmune response, fluid builds up in the joints, causing joint pain and systemic inflammation.RA is a chronic disease in which most people experience intermittent periods of intense disease activity punctuated by periods of reduced symptoms or even remission. In the long term, RA can cause damage to cartilage, tendons, ligaments and bones which can lead to substantial loss of mobility.An estimated 1.5 million people in the United States have RA—almost 1 percent of the nation’s adult population. There are nearly three times as many women as men with the disease. In women, RA most commonly begins between the ages of 30 and 60. In addition, as many as 300,000 children are diagnosed with a distinct but related form of inflammatory arthritis called juvenile arthritis.

Lupus

LUPUSSystemic Lupus Erythematosus (SLE) is a chronic, systemic autoimmune disease which can affect the joints, skin, kidney and other organs of the body. It may affect as many as 1 in 1,000 people, and typically affects women of child-bearing age, although men as well as children and older persons may be affected.Lupus flares can range from mild to severe, often resulting in periods in which the disease is relatively quiescent. However, in intense and complex forms, it may cause significant disability or even death.Currently, no cures or remission-inducing therapies truly exist for lupus, and treatment often involves corticosteroids or other immunosuppressants. At BRI, research programs study the cells which regulate lupus in an effort to further understanding of disease pathogenesis, translating these findings into therapeutic targets. In addition, clinical trials are ongoing to evaluate novel therapies in this disease. 

Multiple sclerosis

MULTIPLE SCLEROSISMultiple sclerosis (MS) is an autoimmune disease in which the body’s immune system mistakenly attacks myelin, the fatty substance that surrounds and protects the nerve fibers in the central nervous system. When the myelin is damaged, the nerve impulses are not transmitted as quickly or efficiently, resulting in symptoms such as numbness in the limbs, fatigue, dizziness, paralysis and/or loss of vision.Symptoms of MS will often improve and relapse with time and vary from one person to another. In progressive forms of multiple sclerosis, they gradually worsen.    MS affects approximately 400,000 Americans (1 in 1,000) but is much more common in the Northwest where approximately 12,000 (2 in 1,000) people have MS. Some likely factors that contribute to this may be vitamin D deficiency, genetic predisposition and environmental triggers. Other factors are still unknown. Additionally, women are twice as likely as men to be affected by MS. 

Drought and its Types in Agriculture

Droughts and Drought ManagementDrought is a climatic anomaly, characterized by deficient supply of moisture resulting either from sub-normal rainfall, its erratic distribution, higher water requirement or a combination of all these factors. Understanding mechanisms of plant adaptation under severe water stress is very essential. Adaptation of rainfed crops to the changing environment is assessed on the basis of stability in yield over years. The factors contributing to the yield stability of any crop are root system, morphological characteristics, stomatal mechanisms, metabolic adaptation, canopy architecture and drymatter partitioning (Gangadhar Rao et al., 1999). The National Commission on Agriculture (Anon., 1976) categorized droughts into three types, viz., 1.meteorological, 2.hydrological and3.agricultural drought. Meteorological drought is the negative departures of kharif rainfall in different parts of the country. Hydrological drought is the extended dry period leading to marked depletion of surface water and consequent drying up of reservoirs, lakes, streams, rivers, cessation of spring flows, and depletion of ground water levels. Agricultural drought refers to extended dry period in which the lack of rainfall results in insufficient moisture in the root zone, causing adverse effects on arable crops. The spatial and temporal variations in such droughts are of paramount importance particularly when it occurs at any critical phenological stage of a crop.Agricultural drought is said to occur when the actual evaporation (AE)/ potential evaporation (PE) is <0.25 at the critical phenological stage of the crop. The critical stages in case of pearlmillet are tillering, flowering and grain formation stages.The studies on probabilities of meteorological droughts in different regions of the country were reviewed by Singh and Ramana Rao (1988) based on their occurrence from 1875 to 1987. They observed that about 70% of the geographical area was affected during the disastrous drought years, 1918 and 1899. Though the worst drought of 1987 had affected over 83% of area till the end of July, the good rainfall received in the following month (August) had saved the crops. Thus the impact of droughts on our food production could be minimized through later rains together with improved kharif and rabi crop management strategies.Drought managementThe risk involved in successful cultivation of crops depends on the nature of drought (chronic and contingent), its probable duration, and periodicity of occurrence within the season. In the arid region where mean annual rainfall is less than 500 mm, drought is almost an inevitable phenomenon in most of the years (Ramakrishna, 1997). In semi-arid region (mean annual rainfall 500-750 mm), droughts occur in 40 to 60% of the years due to deficit seasonal rainfall or inadequate soil moisture availability between two successive rainfall events. Even in dry sub-humid regions (annual rainfall 750-1200 mm), contingent drought situations occur due to break in monsoon conditions. Therefore, drought management strategies need to be identified separately for each climatic region and for each major crop. Types of agricultural droughtsCrop production in rainfed areas is generally affected by five distinct categories of drought, viz., early season, mid-season, late season, chronic and apparent drought (Rao, et al., 1999).• Early season drought generally occurs either due to delayed onset of monsoon or due to prolonged dry spell soon after the onset, resulting in seedling mortality, need for re- sowing or poor crop stand and seedling growth. The early withdrawal of monsoon results in reduced water availability period for crop growth. Thus, the crops suffer from acute shortage of water during reproductive stage.• Mid-season drought occurs due to inadequate soil moisture availability between two successive rainfall events during crop growth. Its impact depends on crop growth stage, duration and intensity of the drought spell.• Late season or terminal drought occurs as a result of early cessation of monsoon, mainly during the years with late commencement or weak monsoon activity. Terminal droughts are more critical as the crop yield is strongly related to water availability during the reproductive stage. Rainfed rice in dry sub-humid regions is often subjected to terminal droughts due to failure of September rains with 40 to 50% of dry spells of over 5 days during that month.• Chronic drought is common in arid areas where rainfall and stored soil moisture are inadequate to meet crop water requirement during most of the years. Here, the assured growing period is hardly 6 to 7 weeks. These are characterized as chronic drought or highly drought prone areas.• Apparent drought conditions are observed in low to medium rainfall regions due to mis-matching of the cropping pattern in relation to rainfall / moisture availability.