Two Hole Paper Punch Engineering Essay

Two Hole Paper Punch Engineering Essay The product I have chosen to manufacture is the two-hole paper punch. This product is one which is widely used in homes, schools and businesses all over the world for the purpose of punching holes in paper to allow for attaching multiple sheets together in an organised fashion. Such examples of devices used in conjunction with the two-hole punch include the ring binder folder and treasury tags. Component Parts On close inspection of existing two-hole punch products similar to the one in Fig.1 it can be observed that there exists six fundamental component parts to the piece. Some of these components are used in matching pairs and for this reason they can be considered as one single part in regards to the manufacturing of the product. Therefore the component parts can be categorised in four groups as follows: Base Plate ( To which everything is attached) Lever Handel ( The whole mechanism works from the behaviour of this part) Punchers ( Creates the holes in the paper) Springs ( Resets the mechanism for next use) Possible Materials There are countless materials which could be used to make the components of this product but the question is which ones are cost effective and also offer good quality. At this point I am considering using Perspex for the lever handle and Aluminium for the base plate. Stronger materials will be needed for the puncher heads to ensure a lasting sharpness over repeated use. Stainless steel could be a possibility in this case. And the springs will need to be strong also for the same reasons of repeated use so I would consider using some other variation of steel here too. Perspex The material we now know as Perspex began life, when the first acrylic acid was produced, in 1843. Methacrylic acid was formulated in 1865 and the reaction between methacrylic acid and methanolresults in the coumpound called metyl methacylate. In 1877 Two German chemists discovered the polymerization process that turns methyl methacrylate into polymethyl methacrylate. In 1933 another German chemist named Otto Rohmpatented and registered the name PLEXIGLAS. Then in 1936 the first commercially viable production of acrylic glass began. During World War II acrylic glass was used for submarine periscopes, and windshields, canopies, and gun turrets for airplanes. From a chemical point of view it is the polymer of methyl methacrylate that is sold under the trade names of Plexiglas or Perspex. Perspex is frequently used as a light or shatter-resistant alternative to glass. It is often favoured because of its moderate properties, easy handling and processing, and low cost. However when loaded it behaves in a brittlemanner and this is especially the case when subjected to an impact force. Also when compared to glass it is more prone to scratching. Aluminium Aluminium is a silvery-white andductilemember of theboron groupofmetals. It has the symbolAl and itsatomic numberis 13. Also it is not soluble in water. Aluminium is themost abundant metalin theEarthscrust, and the third most abundant element therein, next to oxygenand silicon. It makes up approximately 8% of the Earths solid surface by weight. Aluminium is too reactive chemically to occur as a free metal naturally. Instead, it is found combined in over 270diverseminerals.The chief resource of aluminium isbauxiteore. Aluminium is remarkable for its ability to resistcorrosiondue to the phenomenon ofpassivationand the metals low density. Aluminium is a soft, durable, lightweight,malleablemetalwith visual appearance ranging from silvery to dull grey which depends on the surface texture. Aluminium is non-magnetic and non-sparking. It is also insoluble in alcohol, though in certain forms it can be soluble in water. Theyield strengthof pure aluminium is 7-11MPa, while aluminium alloyshave yield strengths ranging from 200 MPa to 600 MPa.Aluminium has about one-third the densityandstiffnessofsteel. It isductile, and easilymachined,cast,drawnandextruded. Corrosionresistance can be excellent due to a thin surface layer ofaluminium oxidethat forms when the metal is exposed to air, effectively preventing furtheroxidation. The strongest aluminium alloys are less corrosion resistant due togalvanicreactions with alloyedcopper.This corrosion resistance is also often greatly reduced when many aqueous salts are present, particularly in the presence of dissimilar metals. Aluminium atoms are arranged in aface-centred cubic(fcc) structure. Stainless Steel Inmetallurgystainless steel, also acknowledged asinox steelorinoxfrom French inoxidable, is defined as asteelalloywith a minimum of 10.5or 11% chromiumcontent by mass.Stainless steel does not stain, corrode, or rust as easily as regular steel (itstains less, but it is not stain-proof).It is also calledcorrosion-resistant steelorCRESwhen the alloy type and grade are not detailed. There are different grades and surface finishes of stainless steel to suit the environment to which the material will be exposed to in its lifetime. Stainless steel is used where the properties of steel, and resistance to corrosion are both required. Stainless steel differs from carbon steel by the amount of chromium present. Carbon steel rusts when exposed to air and moisture. This iron oxide film (the rust) is active and accelerates corrosion by forming more iron oxide. Stainless steels contain sufficient chromium to form a passive film of chromium oxide, which prevents further surface corrosion and blocks corrosion from spreading into the metals internal structure. Carbon Steel Carbon steel, also calledplain carbon steel, issteelwhere the mainalloyingconstituent iscarbon. Carbon steel is defined as steel that has no minimum carbon content specified. The term carbon steel may also be used in reference to steel which is notstainless steel; in this use carbon steel may include alloy steels. Steel with a low carbon content has properties similar to iron. As the carbon content rises, the metal becomes harder and stronger but lessductileand more difficult toweld. In general, higher carbon content lowers the melting point and its temperature resistance. Carbon content influences the yield strength of steel because carbon atoms fit into theinterstitialcrystallinelatticesites of thebody-centered cubic(BCC) arrangement of the iron atoms. The interstitial carbon reduces the mobility ofdislocations, which in turn has a hardening effect on the iron. To get dislocations to move, a high enough stress level must be applied in order for the dislocations to break away. This is because the interstitial carbon atoms cause some of the iron BCC lattice cells to distort. Mild and low carbon steel Mild steel is the most common form of steel because its price is relatively low while it provides material properties that are acceptable for many applications. Low carbon steel contains approximately 0.05-0.15% carbonand mild steel contains 0.16-0.29%carbon, therefore it is neither brittle norductile. Mild steel has a relatively low tensile strength, but it is cheap and malleable; surface hardness can be increased throughcarburizing. It is often used when large quantities of steel are needed, for example asstructural steel. The density of mild steel is approximately 7.85g/cm3(0.284lb/in3)and theYoungs modulusis 210,000MPa (30,000,000psi). Background Research Production Process The Objective of this section is to define the materials and examine the possible production processes for each of my four component parts. There is always more than one way to carry out a job and yet still obtain a successful result. However some methods are more cost effective than others. I wish to present multiple solutions to manufacturing each of my parts and from there choose the best balance of quality, time and economy. Base Plate Aluminium Casting The first production process option to be examined is the idea of the multiple-use-mold casting process In the permanent-mold casting process a re usable mold is machined from grey cast-iron, steel, graphite or other such material. The mold is first pre-heated, and molten metal is poured in under the action of gravity alone. After solidification, the mold is opened and, the product is removed. The mold is then reclosed and another casting is poured. Aluminium is frequently cast by this process. There are numerous advantages for this process. The mold is reusable. A good surface finish is obtained provided the mold is in good condition. Dimensional accuracy can usually be held within 0.13-.25 mm. By selectively heating or cooling various parts of the mold, or by varing the thickness of the mold wall, directional solidification can be promoted so as to produce sound, defect-free castings with the desired mechanical properties. However there are some drawbacks to this process too. The mold life depends upon a number of factors: The allow being cast. The higher the melting point, the shorter the mold life. The mold material. Grey cast iron has about the best resistance to thermal fatigue and also machines easily. Thus it is used most frequently for permanent molds. The pouring temperature. Higher pouring temperatures reduce mold life, increase shrinkage problems, and induce longer cycle times. Mold temperature. If the temperature is too low, mis runs are produced, and high temperature differences form in the mold. If the temperature is too high, excessive cycle times result, and mold erosion is aggravated. Mold complexity is often restricted because the rigid cavity has no collapsibility to compensate for the shrinkage of the casting. As a best alternative, it is common practice to open the mold and remove the casting immediately after solidification, thereby preventing any tearing that may occur on subsequent cooling-down. Permanent molds are usually headed at the beginning of a run and are then maintained at a fairly uniform temperature as a means of controlling the cooling rate of the metal being cast. Since the mold rises in temperature as a casting is poured and sufficient time is permitted for solidification, it may be necessary to provide a cool-down delay before another casting is poured. Refractory washes are often applied to the mold walls to prevent the casting from sticking and to prolong the mold life. Mold costs are generally high so that high-volume production is necessary to justify the expense. Milling Milling is a basic machining process by which a surface is generated progressively by the removal of chips from a workpiece fed into a rotating cutter in a direction perpendicular to the axis of the cutter. Sometimes the workpiece remains stationary, and the cutter is fed to the work. In nearly all cases a multiple-tooth cutter is used so that the material removal rate is high. Often the the desired surface is obtained in a single pass of the cutter or work and, because very good surface finish can be obtained, milling is particularly well suited to and widely used for mass-production work. Several types of milling machines are used ranging from relatively simple and versatile machines that are used for general-purpose machining in job shops and tool-and-die work to highly specialized machines for mass production. Unquestionably, more flat surfaces are produced by milling than by any other machining process. The cutting tool used in milling is known as the milling cutter. Equally spaced peripheral teeth will intermittently engage and machine the workpiece. This is called interrupted cutting. Milling operations can be classified into two broad categories called peripheral milling and face milling. Each has many variations. In peripheral milling the surface is generated by teeth on the periphery of the cutter body. The surface is parallel to the axis of rotation of the cutter. Both flat and formed surfaces can be produced by this method, the cross section of the resulting surface corresponding to the axial contour of the cutter. This method is often called slab milling and is usually performed on horizontal spindle machines. In slab milling, the tool rotates at a certain rpm while work feeds past the tool. Water Jet Cutting Awater jet cutter or just waterjetis a machine capable of cutting intometaland other materials by means of a jet ofwaterat high velocity and pressure. The process is, in theory, the same aswater erosionfound in nature however it is greatly accelerated and concentrated. It is frequently used during manufacture of parts for machinery and other such devices. This is the preferred process when the materials involved are sensitive to the extreme temperatures that friction causes in other methods. Water jet cutting has found applications in a wide range of industries. Examples of these are mining and aerospacewhere it is used for operations such as shaping, cutting and carving. One important advantage of the water jet cutter its function to process material without interfering with the materials inherent structure as there is no heat-affected zone/ Haz. Minimizing the effects of heat allows metals to be processed without altering internal charachteristics. Water jet cutters also have the ability to produce rather detailed cuts in a material. When specialized computer software and 3-D machining tools are used, complex 3-D shapes can be created. The nozzle can be changed and adjusted to give the required cutting width. Typical abrasive cuts are made with a nozzle in the range of 1.016 to 1.27mm, but can be as narrow as 0.508mm. Non-abrasive cuts are normally 0.178 to 0.33mm, but can be as small as 0.076mm, which is roughly the width of a human hair. Small cutters ike these can make very small detail possible in a broad range of tasks. Waterjets are capable of accuracy of 0.13 mm, and repeatability to within a tolerance of 0.03 mm. Water jet cutting is a green technology.Nno hazardous waste is produced which reduces waste costs. Large pieces of recyclable scrap material are cut off using this method which would have been otherwise lost using traditional cutting methods. Waste water is usually clean enough to filter and disguard of down a normal drain. The abrasive is non-toxic and can be recycled for many uses. Water jets also avoid airborne fumes, and contaminates from cutting materials such as asbestos and fiberglass. This really benefits the work environment and greatly reduces any health problems arising from operator exposure. Lever Handel-Perspex Injection moulding Injection moulding is used to produce more thermoplastic products than any other process. Granules of raw material are fed from a hopper by gravity into a pressure chamber ahead of a plunger. As the plunger advances, the plastic is forced through a heated chamber, where it is preheated. From the preheating segment, it is forced through the torpedo section, where it is melted and super-heated to 200-300Â °C. It then leaves this section through a nozzle which seats up against the mold and allows the molten plastic to enter the closed-die cavities through suitable gates and runners. The die remains cool, so the plastic solidifies almost as soon as the mold is filled. To ensure proper filling of the cavity, the material must be forced into the mold rapidly under considerable pressure, typically 35-140 MPa. Premature solidification would cause defective products. While the mold is being opened, the part ejected, and the mold reclosed, the material for the next part is being heated in the torpedo. The complete molding process takes typically between 1 and 30 seconds and is very similar to the die-casting of molten metals. Because thermosetting plastics must be held at an elevated temperature and pressure for sufficient time to permit curing, the injection molding process must be modified for this type of polymer. In the jet molding process the polymer is preheated in the feed chamber to about 95Â °C and then is further heated to the temperature of polymerization as it passes through the nozzle. Additional time in the heated mold completes the curing process. Care must be exercised to prevent the material in the nozzle from cooling during this time and clogging the flow. Water cooling is introduced to the nozzle area as soon as the cavity is nearly filled. The water cools the material in this region and retards the hardening reaction. Because of the long cycle time, little injection molding of thermo-sets is performed. The properties can often compete with die-cast metals, provided the lower rigidity of the polymer is not objectionable. Milling The milling process is the same as before when it was discussed in relation to Aluminium. The only difference now is the material, which is Perspex. Laser cutting Laser-aided cutting has brought about a revolution in the manufacturing industries. These high-powered optical beams are used to cut through a variety of materials such as metal, wood, glass and plastic. The laser is directed at the required surface and moved around to cut the material in the desired shape. Laser cutting gives a finer finish to the end product as compared to conventional cutting methods. A typical laser beam is about 1/5th of a millimeter in width and has an intensity of 1000 to 2000 watts. Most laser cutting machines are integrated into a CAD/CAM system that helps the user design the end product on a computer before implementing it on the work piece. Laser cutting devices are proving beneficial in a wide array of industries. The plastic industry is no exception. These optic powered devices are used to cut precise shapes into plastic or acrylic sheets. The lasers can be used to cut plastics of varying thickness by simply altering the intensity of the beam. Lasers are not only used to cut through plastics but also help engrave on various surfaces. Laser plastic cutting machines bring precision and accuracy to the entire process. Since most machines are fully automated, they can perform complex cutting operations at high-speeds. The laser plastic cutting machines can also be used to cut polymers, polycarbonates and other synthetic materials such as polyesters and rubbers. The laser cutting method uses a non-contact approach when cutting the material. Due to this, the wear and tear associated with conventional methods is absent, preventing the product from any damage and deformation. The laser process also delivers a finish quality unmatched by any other process. When using laser plastic cutting machines, care should be taken to avoid the use of flammable plastics such as PVCs. These materials cannot cope with the heat generated by the laser and get damaged easily. Punches Stainless Steel Extrusion The process begins by heating the stock material. It is then loaded into the container in the press. A dummy block is placed behind it where the ram then presses on the material to push it out of the die. Afterward the extrusion is stretched in order to straighten it. If better properties are required then it may beheat treatedorcold worked. The extrusion ratio is defined as the starting cross-sectional area divided by the cross-sectional area of the final extrusion. One of the main advantages of the extrusion process is that this ratio can be very large while still producing quality parts. Hot extrusion is done at an elevated temperature to keep the material fromwork hardeningand to make it easier to push the material through the die. Most hot extrusions are done on horizontal hydraulic presses that range from 250 to 12,000 tons. Pressures range from 30 to 700MPa (4,400 to 102,000psi), therefore lubrication is required, which can be oil or graphite for lower temperature extrusions, or glass powder for higher temperature extrusions. The biggest disadvantage of this process is its cost for machinery and its upkeep. There are many different variations of extrusion equipment. They vary by four major characteristics: Movement of the extrusion with relation to the ram. If the die is held stationary and the ram moves towards it then its called direct extrusion. If the ram is held stationary and the die moves towards the ram its called indirect extrusion. The position of the press, either vertical or horizontal. The type of drive, either hydraulic or mechanical. The type of load applied, either conventional (variable) orhydrostatic. A single or twin screw auger, powered by an electric motor, or a ram, driven by hydraulic pressure (often used for steel and titanium alloys), oil pressure (for aluminum), or in other specialized processes such as rollers inside a perforated drum for the production of many simultaneous streams of material. Typical extrusion presses cost more than $100,000, whereas dies can cost up to $2000. Springs Steel The following description focuses on the manufacture of steel-alloy, coiled springs. Winding Cold winding Wire up to 0.75 in (18 mm) in diameter can be coiled at room temperature using one of two basic techniques. One consists of winding the wire around a shaft called an arbor or mandrel. This may be done on a dedicated spring-winding machine, a lathe, an electric hand drill with the mandrel secured in the chuck, or a winding machine operated by hand cranking. A guiding mechanism, such as the lead screw on a lathe, must be used to align the wire into the desired pitch (distance between successive coils) as it wraps around the mandrel. Alternatively, the wire may be coiled without a mandrel. This is generally done with a central navigation computer (CNC) machine. Examples of different types of springs. Examples of different types of springs. The wire is pushed forward over a support block toward a grooved head that deflects the wire, forcing it to bend. The head and support block can be moved relative to each other in as many as five directions to control the diameter and pitch of the spring that is being formed. For extension or torsion springs, the ends are bent into the desired loops, hooks, or straight sections after the coiling operation is completed. Hot winding Thicker wire or bar stock can be coiled into springs if the metal is heated to make it flexible. Standard industrial coiling machines can handle steel bar up to 3 in (75 mm) in diameter, and custom springs have reportedly been made from bars as much as 6 in (150 mm) thick. The steel is coiled around a mandrel while red hot. Then it is immediately removed from the coiling machine and plunged into oil to cool it quickly and harden it. At this stage, the steel is too brittle to function as a spring, and it must subsequently be tempered. Assembly Procedure Methods Quality Control Qulaity control is defined as the maintenance of standards of quality of manufactured goods. With this in mind there are a few methods i could employ in the upkeep of quality in the product choosen.

Fresh Frozen Plasma (FFP) Collection, Preparation and Uses

Fresh Frozen Plasma (FFP) Collection, Preparation and Uses Samuel Good Fresh Frozen Plasma Introduction Fresh Frozen Plasma (FFP) is the name for the liquid portion of human blood, which has been frozen and preserved. It is taken by blood donation and is stored until needed for blood transfusion. FFP has been available since 1941 (Hoffman, et al, 1990), it was used initially as a volume expander (Erber, et al, 2006), but is now used for the â€Å"management and prevention of bleeding in coagulopathic patients† (Ho, et al, 2005). The term FFP is confusing as the plasma cannot be frozen as well as fresh at the same time. What the term implies is that the plasma was frozen rapidly after it was taken and therefore can be considered fresh. The plasma, from a transfusion aspect, contains essential components such as fibrinogen, albumin, globulin and coagulation factors. These allow for specific individual components to be transferred to a recipient who is in need. The most efficient and effective way to make optimum use of blood which has been donated, is to separate it into its individual components. This process allows for a â€Å"wider availability of blood products† (Spence, et al, 2006) and also reduces the risk patients are exposed to â€Å"transfusion-related risks† (Erber, et al, 2006). The use of FFP and its individual products has increased tenfold since its first introduction (Hoffman, et al, 1990). One reason for this may be the declining availability of whole blood because of the trend to use component therapy (Spence, et al, 2006). Collection and Storage When a donor gives a unit of whole blood, the blood is then separated into several components parts. These include; packed red blood cells (pRBC), platelets and FFP. If required the FFP can be further divided into cryoprecipitate and something called cryo-poor plasma. Cryo-poor plasma is rarely used as a therapeutic response (Lauzier, et al, 2007). As mentioned previously, plasma is the non-cellular, liquid part of the blood. It is made up of; water, electrolytes and proteins. The proteins include the clotting factors and intrinsic coagulants (Murray, et al, 1995). The plasma is separated from the blood after donation and then frozen. For the plasma to be considered ‘fresh’ it must be frozen â€Å"within eight hours of collection† (Murray, et al, 1995) and stored at a temperature of minus 18 degrees centigrade or lower. If this fails to happen, the product is known just as ‘frozen plasma’, which like cryo-poor plasma, is rarely used for therapeutic means. However, to maintain coagulation factors to optimum levels the plasma should be stored at minus 30 degrees centigrade (Lauzier, et al, 2007). FFP can be prepared by separation from whole blood or via plasmapheresis. Plasmapheresis is the name given to a â€Å"broad range of procedures† where â€Å"extracorporeal separation of blood components† (Erber, et al, 2006) results in a plasma which is filtered. Preparation To summarise, FFP is collected in citrate-containing anticoagulant solution, frozen within 8 hours and stored at minus 30 degrees centigrade for up to a year. Although every protection is taken to ensure sterility, it is quite possible for the donor to have an asymptomatic bacteraemia at the time of donation (Stanworth, et al, 2004). The bacteria will have its proliferation down-regulated by the plasma being frozen. However, FFP can still sometimes transmit infectious diseases. Therefore, screening and pathogen inactivation may be performed to reduce the risk. FFP contains no RBC’s and also no WBC’s. As there are no WBC’s the plasma is referred to be as being leucodepleted. This is an indication as to why FFP can transmit said diseases. As mentioned pathogen inactivation can be performed and this is done by using either Methylene blue or a solvent/detergent process. The Methylene Blue Technique Methylene blue is a dye that has been shown to be very effective in the inactivation of pathogens. It binds to nucleic acids and, on illumination with white light, singlet oxygen is formed. This then destroys viral DNA and RNA, therefore viral replication cannot take place. Solvent/Detergent Technique This technique is used for the preparation of factors viii and ix as well as immunoglobulins. First, a solvent is added to the plasma which removes the lipid viral envelope. After this is complete, a detergent is added which inactivates the viral contents. The solvent and detergent are then removed by a physical separation technique, in which they are dissolved in oil. Column chromatography can then be used to isolate factors viii and ix. Once any treatment that is required is complete, the FFP is ready for use. It is an accepted practice that FFP is thawed before use (Ho, et al, 2005). The required units of FFP are placed in a water bath set at 30 – 37 degrees centigrade for approximately 20 – 30 minutes. Von Heyman, et al investigated the effects of 2 different thawing machines and running warm water of 43 degrees centigrade, on the activity of clotting factors, inhibitors and activation markers in FFP. They discovered no significant differences in the activity of coagulation markers over a 6 hour period post thawing. However, a major conclusion found was that, if FFP is immediately transfused after thawing, the product remained rich in clotting factors. Also, if the plasma is left, the activity of said clotting factors decline gradually and therefore FFP should only be maintained at room temperature for up to 4 hours. If thawed FFP is not used within 24 hours it becomes a separate product known as ‘thawed plasma’ (Murray, et al, 1995). Most clotting factors are stable in thawed plasma, however some labile factors, such as v and viii are not. Their degradation actually accelerates whilst the plasma is in a liquid state (Lauzier, et al, 2007). The only main advantage of having thawed plasma readily available, is that it can be transfused rapidly if a severely injured patient requires it. FFP Blood Type Specific It is widely accepted that O negative is the universal donor for pRBC’s, however for FFP this isn’t the case. A and B antigens of the blood are located on the red cells themselves. Type O individuals are devoid of these proteins on their red blood cells. Plasma does not contain RBC’s, but it contains antibodies to the corresponding absent protein. An example of this is: Type A individual has Anti-B antibodies in their blood. Type O plasma has both Anti-A and Anti-B antibodies and is incompatible with about 55 percent of the population. An individual with type AB blood has neither Anti-A nor Anti-B antibodies. This makes the AB plasma ideal for universal use when the blood type of the patient is unknown. The Rh status is irrelevant because any plasma with Anti-D is destroyed at the manufacturing stage. Recipient blood Acceptable blood groups of donor plasma O O,A,B,AB A A,AB B B,AB AB AB The major problem with blood type AB is that the percentage of the population which has it is only 4 percent. Therefore it is better to use FFP which is blood type compatible, which will be determined at the blood bank. Usage There are very few actual specific needs for the use of FFP (Spence, et al, 2006). Usually FFP is used to treat â€Å"deficiencies of coagulation proteins where specific factor concentrates are unavailable† (Hoffman, et al, 1990). Coagulation deficiencies can occur in a variety of different clinical situations. These include massive blood loss, surgery, and infection or acquired multiple coagulation factor deficiencies. Examples of FFP usage: Replacement of isolated factor deficiencies Reversal of Warfarin effects Massive blood transfusion Antithrombin III deficiency Treatment of immunodeficiency Treatment of thrombotic thrombocytopenic purpura Treatment of Disseminated intravascular coagulation Replacement of isolated factor deficiency FFP can be used to heat deficiencies of factors II, V, VII, IX, X and XI. It is only chosen as a treatment when no specific component therapy is available. Certain factors require a different haemostatic level, for example; severe factor X deficiency only requires a factor level of about 10 percent. Therefore FFP has a range of success when treating factor deficiencies. Reversal of Warfarin effect If a patient is being treated with Warfarin, they have been shown to be deficient in â€Å"functional vitamin K dependent coagulation factors II, VII, IX and X† (Spence, et al, 2006). Usually vitamin K will be administered, however anticoagulated patients will be actively bleeding, and therefore FFP can be used. Massive blood transfusion The use of FFP as a treatment on massive blood transfusion has increased over the decades. Massive bleeding is defined as â€Å"the loss of one blood volume within 24 hours† or as â€Å"50 percent blood loss within 3 hours† or a â€Å"bleeding rate of 150 ml/minute† (Lauzier, et al, 2007). It is indicated for use in patients who have documented blood clotting abnormalities after large blood loss and who are in need of urgent treatment. This is due to the fact that in most emergency situations it is unacceptable to wait hours for lab results to be returned. Antithrombin III deficiency FFP is sometimes used as a source of Antithrombin III in people who are deficient of this inhibitor. Especially if the patients are undergoing surgery or who use Heparin to treat thrombosis. Treatment of Immunodeficiency FFP has been used in children and adults with a humoral immunodeficiency as a source of immunoglobulin. It is also sometimes used for infants when parental nutrition is lacking, and they are suffering with severe protein losing enteropathy (Erber, et al, 2006). Treatment of thrombotic thrombocytopenic purpura The treatment recommended for this condition is a daily plasma exchange (Murray, et al, 1995). Prompt intervention is indicated if development of neurological abnormalities start to appear. This plasma exchange usually continues for at least 2 days after remission (Ho, et al, 2005). Treatment of Disseminated intravascular coagulation Disseminated intravascular coagulation (DIC) is a syndrome where the control of the coagulation system becomes disturbed and out of control. This is usually due to pro-coagulants being dispersed into circulation (Stanworth, et al, 2004). Most of the time this happens secondary to a disease or disorder, such as cancer. In the presence of DIC, fibrinogen, platelets and coagulation factors V and VIII become rapidly depleted. FFP is given as treatment to prevent further problems or progression. Treatment usually involves a patient being infused with a single line of FFP and then coagulation tests performed to assess the clinical benefit (Stanworth, et al, 2004). There are also some conditional uses where FFP can be used but is not the first choice treatment, such as liver disease and Paediatric use. If patients have an abnormal coagulation profile and are suffering from liver disease, they can be treated with FFP. There is varying success and treatment must be monitored by regular transfusion coagulation tests. Clotting times of infants have been shown to be longer than that of adults (Murray, et al, 1995), and even longer in premature babies (OShaughnessy, et al, 2004). Vitamin K deficiency is the most common cause of neonatal bleeding (Murray, et al, 1995). FFP can be used to counter the effects if required. In the case of babies suffering from haemorrhagic disease of the newborn, FFP can be used as treatment. But only if the â€Å"chance of bleeding is greater than the risk of harmful reactions† to the treatment with FFP (Lauzier, et al, 2007). Risks As with any transfusion there is a risk of infection, the main risks identified include: Disease transmission Excessive intravascular volume Anaphylactoid reactions Alloimmunisation Transfusion related acute lung injury The risks associated with viral infectivity of FFP are similar to that of whole blood and RBC’s. As mentioned earlier this risk can be countered by photochemically treating the plasma. Allergic reactions that occur in response to FFP transfusion vary in severity from â€Å"hives to fatal non-cardiac pulmonary oedema† (Stanworth, et al, 2004). Transfusion relate acute lung injury (TRALI) is defined as a â€Å"new episode of acute lung injury within 6 hours of complicated therapy† (OShaughnessy, et al, 2004). It manifests as severe respiratory problems, including hypoxia and other symptoms linked to pulmonary oedema. Symptoms will usually subside 2 days after ceasing FFP treatment (Stanworth, et al, 2004). Alloimmunisation can occur if Anti-Rh antibodies are formed after treatment with FFP. To counter this, plasma containing Anti-D antibodies should not be given to an RhD-positive recipient. There has also been reported incidences of post-transfusion Hepatitis, and depends on a number factors, including donor selection. Also with any intravenously transfused fluid, there is a chance of hypervolemia which could lead to cardiac failure, therefore administration of FFP should not be given in excessive doses. Below is a suggested dosage breakdown: Volume of 1 Unit Plasma: 200-250 mL 1 mL plasma contains 1 u coagulation factors 1 Unit contains 220 u coagulation factors Factor recovery with transfusion = 40% 1 Unit provides ~80 u coagulation factors 70 kg X .05 = plasma volume of 35 dL (3.5 L) 80 u = 2.3 u/dL = 2.3% (of normal 100 u/dL) 35 dL In a 70 kg Patient: 1 Unit Plasma increases most factors ~2.5% 4 Units Plasma increase most factors ~10% Figures taken from (http://reference.medscape.com/drug/ffp-octaplas-fresh-frozen-plasma-999499) Conclusion In conclusion, FFP can be used as an effective treatment for a number of different clinical issues. It also does not come without risk and therefore FFP should be collected, stored, prepared and used in an efficient and safe manner. Below I have summarised the administration of FFP. FFP (Fresh Frozen Plasma) Volume: 240-300ml (mean 273ml) Storage: designated temperature controlled freezer. Core temperature -30 o C Shelf life: 24 months (frozen) Must be ABO compatible, but Rh is not necessary to be considered for transfusion and no anti D prophylaxis is required if Rh-D negative patients receive Rh-D positive FFP. Prior to the transfusion FFP must be thawed under controlled conditions using specifically designed equipment. Thawing usually takes approximately 15-30 minutes Once thawed, FFP must not be re-frozen and should be transfused as quickly as possible. Post-thaw storage results in a decline in the quality of coagulation factors. If stored at 4 degrees centigrade post thawing (in a designated temperature controlled refrigerator), the transfusion must be completed within 24 hours of thawing. Pooled solvent-detergent treated plasma is also commercially available Dose: typically 10-15ml/kg. This dose may need to be exceeded in massive haemorrhage depending on the clinical situation and its monitoring (BCSH 2004) Typical infusion rate 10-20ml/kg/hr (approximately 30 minutes per unit) Rapid infusion may be appropriate when given to replace coagulation factors during major haemorrhage. There is anecdotal evidence that acute reactions may be more common with faster administration rates. (http://reference.medscape.com/drug/ffp-octaplas-fresh-frozen-plasma-999499) REFERENCES Erber WN, Perry DJ: Plasma and plasma products in the treatment of massive hemorrhage. Best Pract Res Clin Haematol 2006, 19:97-112 Hewson JR, Neame PB, Kumar N, Ayrton A, Gregor P, Davis C, Shragge BW. Coagulopathy related to dilution and hypotension during massive transfusion. Crit Care Med. 1985;13(5):387-391. Ho AM, Karmakar MK, Dion PW. Are we giving enough coagulation factors during major trauma resuscitation? Am J Surg. 2005;190(3):479-484. Hoffman M, Jenner P. Variability in fibrinogen and Von Willebrand factor content of cryoprecipitate.  Brief Sci Rep. 1990;93(5):694-697. Lauzier F, Cook D, Griffith L, Upton J, Crowther M: Fresh frozen plasma transfusion in critically ill patients. Crit Care Med 2007, 35:1655-1659. Leslie SD, Toy PT. Laboratory hemostatic abnormalities in massively transfused patients given red blood cells and crystalloid. Am J Clin Pathol. 1991;96(6):770-773. Murray DJ, Olson J, Strauss R, Tinker JH. Coagulation changes during packed red cell replacement of major blood loss. Anesthesiology. 1988;69(6):839-845 Murray DJ, Pennell BJ, Weinstein SL, Olson JD.Packed red cells in acute blood loss: dilutional coagulopathy as a cause of surgical bleeding. Anesth Analg. 1995;80(2):336-342. OShaughnessy DF, Atterbury C, Bolton Maggs P, Murphy M, Thomas D, Yates S, Williamson LM, British Committee for Standards in Haematology, Blood Transfusion Task Force: Guidelines for the use of fresh-frozen plasma, cryoprecipitate and cryosupernatant. Br J Haematol 2004, 126:11-28. Spence RK: Clinical use of plasma and plasma fractions. Best Pract Res Clin Haematol 2006, 19:83-96. Stanworth SJ, Brunskill SJ, Hyde CJ, McClelland DB, Murphy MF: Is fresh frozen plasma clinically effective? A systematic review of randomized controlled trials. Br J Haematol 2004, 126:139-152 Tieu BH, Holcomb JB, Schreiber MA. Coagulopathy:its pathophysiology and treatment in the injured patient. World J Surg. 2007;31(5):1055-1065 http://en.wikipedia.org/wiki/Fresh_frozen_plasma http://www.psbc.org/therapy/ffp.htm http://reference.medscape.com/drug/ffp-octaplas-fresh-frozen-plasma-999499 http://ccforum.com/content/14/1/202

Essay --

In 1916, Susan Glaspell wrote Trifles, when the egotistical male-dominated social order was ruthlessly manipulating women’s right to vote and cruelly restricting their functions in social, business, and government positions. In the home, the husband was dictator and the wife merely a domestic servant. The domestic sphere of women is minimized to the activities of the farmhouse which are considered trifles or insignificant in the world of men. Trifles explores the classical male stereotype of women during this period by expressing that women habitually worry about matters of little, or unimportance. This label creates the perception males are the only people concerned with essential issues, issues that a female would never discuss or confront during this era. Trifles is based on an actual murder case Susan Glaspell wrote about as a reporter for a newspaper in Iowa at the turn of the century. To completely comprehend and give an accurate analysis of Trifles, it is critical to acknowledge the condition of the women’s movement at the time the play was written and first produced. The significance of the position of women in this early 20th century community and the title of the play Trifles, is condescending. Susan Glaspell manipulatively uses her extensive knowledge about the murder case, to expose and express the way women actually felt during this period. As a reporter she was controlled and restricted to what she could actually publish. She constantly uses subtle but deep ways to associate the play to hash treatment of women and the way they are viewed by males in society. Lewis Hale casually states that "women are used to worrying over trifles"(Glaspell 663). He is enforcing how the men actually perceive the women in society ... ...ce to society and viewed as a servant to their husband and family. The female was looked down upon and was considered a second class citizen compared to their male counterpart. The significance of the female contribution to society was evolving and was a painful transition women had to endure so women can have what they have today. Women endured mental, emotional, physical, and political abuse that was comparable to that of slaves. The suffering women endured paved the way for future generations of females to be looked at as equals not peasants compared to men. The women decided not to tell the men about the things they found, which undoubtedly stressed the women enduring Minnie’s pain together for the greater good of women. If they had exposed the trifles that they had uncovered, the women would have presented the motive that the men could not find to convict her.

How Magnets Affect Computer Disks :: essays research papers

How Magnets Affect Computer Disks BackGround One of the most commonly used Computer data storaged mediums is a Computer Disk or a Floppy. These are used in everyday life, in either our workplace or at home. These disks have many purposes, such as: Storing data: Floppies can be used to store software/data for short preiods of time, Transferring data: Floppies are used to transfer/copy data from one computer to another. Hiding data: Floppies are also sometimes used to hide sensitive or confidential data, because of the disk's small size it can be hidden very easily. Advertising: Because floppies are cheap to buy, they are used to advertise different types of software, such as: Software for the internet advertised on America Online Floppies. Floppies are also considered to be very sensitve data storage mediums. These Disks have numerous advantages and disadvanteges. Even though floppies are used so commonly they are also not very dependable. They have numerous conditions under which they should normally be kept. For example: the actuall magnetic disk inside the hard cover of the disk must NEVER be touched, the magnetic disk inside, must be protected by the metallic sliding shield, the disk must always be within the temperature of 50Â ° to 140Â ° Fahrenheit and the disk must never be bought near a magnet! (3M Diskettes) There are many such hazards to computer disks. Problems caused by magnets are very common. A floppy can be damaged unknowingly if it is kept near a magnet, that may be in the open or inside any device, such as a speaker phone in computer speakers or stereo or a telephone. And becuase of the common use of magnets in everyday life, more and more floppies are damaged everyday. Even though protective coverings against magnets and other electrical hazards, are available for floppies, they are not used very commonly. Therefore, floppies are not a very safe media for storage, even though they are convienient. Some of the most commonly used diskettes are by 3M and Sony and other such companies. The floppies are sold in boxes with instructions on them to not to bring floppies near magnets and other instructions of DOs and DONTs. These instructions must always be followed. Floppies have different capacities such as 720 KB (kilobytes) and 1.44 MB (megabytes). Floppies also have different sizes, 3.5" and 5.25". The most commonly used floppy is usually 3.5". It is not soft and cannot be bent, where as a 5.25" disk is soft and can be bent! A floppy is a round, flat piece of Mylar coated with ferric oxide, a rustlike substance containing tiny particles capable of holding a magnetic field, and

Nanotechnology Essay examples -- Science Technology Essays

Nanotechnology Nanotechnology is the development of atoms in a certain object. Nanotechnology has become very popular in the past few years. It is a way to rebuild the systems of life. To make systems move faster than ever before. Nanometer is about 10 times the size of an atom. Each of these has a huge effect on a system. Still there are questions out there that keep people wondering how important nanotechnology is to us. Many wonder how will it affect them and if we should continue this research. I myself wondered about nanotechnology. After researching this topic I have learned new and interesting facts to help me understand the entire concept. Nanotechnology is defined as â€Å"the development and use of devices that have a size of only a few nanometers. Research has been carried out into very small components many of which depend on quantum effect and many involve movement of very small number of electrons in their action. Such devices would act faster than larger components. Considerable interest has been shown in the production of structures on a molecular level by suitable sequences of chemical reactions or lithographic techniques. It is also possible to manipulate individual atoms to surfaces using a variant of the atomic force microscope to make, for example, high density storage devices.† (Joseph Andersen’s Guide to Physics). In this definition we find that nanotechnology is very complex but as we continue to pursue this extraordinary idea, we find that it is very important to us in many ways. Nanotechnology is the development of devices that build our computer systems and aid in our everyday lives. T ake your families computer for example, the entire system of your computer is made up of millions upon millions of tin... ...ducts to make our lives that much easier and that much safer. Look around you and see if you can guess all that has been helped or bettered by nanotechnology. From your computer to your cell phone, all of these things are available to you because of nanotechnology. Tell me this, could you live without them? Bibliography Andersen, Joseph â€Å"Nanotechnology definition† 23 July, 2004 http://physics.about.com/cs/glossary/g/nanotechnology.htm Schmergel, Greg â€Å"Nanotechnology Now† 23 July, 2004 http://nanotech-now.com/ U.S. Department Of Health and Human Services â€Å"Cancer Nanotechnology† 23 July, 2004 http://otir.nci.nih.gov/brochure.pdf â€Å"What is Nanotechnology?† 23 July, 2004 http://www.nano.gov/html/facts/whatIsNano.html â€Å"What is Nanotechnology?† 23 July, 2004 http://www.lanl.gov/mst/nano/definition.html

How does radiation damage DNA Essay

Mobile phones harm body cells and damage DNA Radio waves from mobile phones harm body cells and damage DNA in laboratory conditions, The research project, which took four years and which was coordinated by the German research group Verum, studied the effect of radiation on human and animal cells in a laboratory. After being exposed to electromagnetic fields that are typical for mobile phones, the cells showed a significant increase in single and double-strand DNA breaks. The damage could not always be repaired by the cell. DNA carries the genetic material of an organism and its different cells. This means the change had procreated. Mutated cells are seen as a possible cause of cancer. The radiation used in the study was at levels between a Specific Absorption Rate (SAR) of between 0.3 and 2 watts per kilogram. Most phones emit radio signals at SAR levels of between 0.5 and 1 W/kg. SAR is a measure of the rate of radio energy absorption in body tissue, and the SAR limit recommended by the International Commission of Non-Ionizing Radiation Protection is 2 W/kg. The study also measured other harmful effects on cells. Because of the lab set-up, the researchers said the study did not prove any health risks. But they added that â€Å"the genotoxic and phenotypic effects clearly require further studies †¦ on animals and human volunteers.† Adlkofer advised against the use of a mobile phone when an alternative fixed line phone was available, and recommended the use of a headset connected to a cellphone whenever possible. Previous independent studies into the health effects of mobile phone radiation have found it may have some effect on the human body, such as heating up body tissue and causing headaches and nausea, but no study that could be independently repeated has proved that radiation had permanent harmful effects. In a separate announcement in Hong Kong, where consumers tend to spend more time talking on a mobile phone than in Europe, a German company called G-Hanz introduced a new type of mobile phone which it claimed had no harmful radiation, as a result of shorter bursts of the rad io signal. How does radiation damage DNA? Radiation can damage anyone’s DNA. Radiation is really just high-powered particles or energy. When something like that smashes into your DNA , it is  definitely going to do some damage. Luckily, our cells are very good at repairing the damage so it takes a lot of radiation to do permanent harm. Damaged DNA matters because your DNA has the instructions for making and running you. If these instructions get damaged, it can sometimes affect how well you run. Like any good instructions, the ones in DNA are written up with letters. The high energy of radiation can mess up the instructions by changing a letter. It can also tear the DNA removing one, some, or even millions of these letters. This would be like ripping out anything from part of a page to a whole chapter of your personal instruction manual.

Haemon’s Speech Analysis

Haemon’s Speech Analysis Pride and stubbornness can be harmful things, and Haemon touches upon this within his speech to Creon as he attempts to dissuade his father from taking Antigone’s life. Using rhetorical devices such as tone, ethical, emotional, logical appeal, and metaphor, Haemon manages to make an impact on Creon’s eventual decision as he speaks in Antigone’s defense.Starting at the beginning of his speech, Haemon ventures to convince Creon to change his mind about his harsh ruling against Antigone, not by raising his voice or attempting to beat his â€Å"earnest† views into his father, but by using great tact and endeavoring to find a common ground with Creon, possibly trying to understanding his father’s position on the matter at hand. First, Haemon alleges that reason is â€Å"God’s crowning gift to man†, and that his father is â€Å"right† to â€Å"warn [him]† against losing that reason.He even keenly asserts that he never wants to say that â€Å"[Creon] has reasoned badly†, continuing on to make other mindful concessions. However, when this thoughtful mode of speaking doesn’t take any immediate effect, Haemon starts to become more candid with his words, implying (although not directly) that Creon’s actions are unjust and stubborn, taking care to adopt a point of view that is constructively criticizing as opposed to being completely insulting. He rationally cautions his father against the mindset of him having all of â€Å"the power†, noting that if Creon continues upon that path he will eventually â€Å"turn out† an â€Å"empty† man.He states that even people like his father must be able to stop, listen, and learn from others—not be completely fixed and â€Å"unchangeable†, because no man in the world is completely infallible. A few lines later in the speech, in addition to his amiable tone, Haemon also begins to use some emotional appeal, acknowledging his love and respect for his father, affirming that â€Å"nothing [is] closer to [him] than [his father’s] happiness†, and that he â€Å"values his father’s fortune† as much as his own.Haemon also logically recognizes his youthfulness and lack of wisdom as well, although he astutely uses what the people of Thebes have been â€Å"muttering and whispering† to support his argument, using aspects of ethical appeal to attest that Antigone’s innocence is what the people of his father’s city would want, realizing that while Creon would like first and foremost to be a good ruler, e also wishes to be well-liked by his people. Then coming to closing lines of his speech, Haemon begins to weave in clever metaphors here and there, first comparing a â€Å"stubborn tree† being â€Å"torn up† and then a â€Å"fast† and â€Å"never-slackened sail† going â€Å"head over heels and under† the water to his father, indicating that this is the type of thing what will happen if Creon thinks that he alone â€Å"can be right†.And in the very end, Haemon leaves his father with some loaded words, advising that Creon listen to him, because while â€Å"men should be right by instinct†, â€Å"[they] are all too likely to† be led astray, and that the smartest thing would be to learn from those who can are willing to teach them how to stay, or even make their own paths, in life.