Mechanics of Material Lab Manual Essay Example for Free

Mechanics of Material Lab Manual Essay To investigate how shear strain varies with shear stress. c. To determine the Modulus of Rigidity of the rubber block. 4. Hooke’s Law for Wires a. To determine the Youngs Modulus of Elasticity of the specimen wire. b. To verify Hookes Law by experiment. 5. Strain in Compound Wires a. To determine the modulus of elasticity of two wires and hence evaluate the equivalent Young’s Modulus of Elasticity of the combination b. To position the single applied load on the slotted link in order that both wires are subjected to common strain and hence to establish the load in each wire 6. Deflection of a simply supported beam To find the slope and deflection of a simply supported beam with point load at the center and to prove the results mathematically 7. Deflection of a cantilever beam To verify the slope and deflection of a cantilever beam experimentally and theoretically. 8. Deflection of a overhanging beam To find the central deflection of overhanging arm beam and confirm the results theoretically 9. Shear center for a channel Find Shear center for a channel section cantilever. 10. Unsymmetrical Deflections To determine the deflections for symmetrical bending of an angle section beam 1. Shear Forces and Bending Moment in Beams To measure the bending moment at a normal section of a loaded beam and to check its agreement with theory 12. Study and Application of experimental photoelasticty techniques on linear crack propagation analysis 13. Direction and magnitude of principal stresses To use the Photo-elasticity as an experimental technique for stress analysis and to understand construction and operation of transmission polariscope. 14. Calculation of stress intensity factor Interpretation of Fringe Data and calculation of stress intensity factor (k) at different loading conditions 5. Micro Hardness Testing 16. Thin Cylinder Experiment No. 1Compression of a spring 1. OBJECTIVES a) To obtain the relation among the force applied to an extension spring and its change in length. b) To determine the stiffness of the test spring (s). 2. PROCEDURE a) Setup the apparatus vertically to the wall at a convenient height. b) Add increasing loads to the load hanger recording to the corresponding deflection for each load. c) Continue loading until at least 30 mm of extension has been achieved. 3. RESULTS Tabulate the results obtained and draw a graph of load (y-axis) against extension (x-axis). Note the following data for each spring used:- a. Outside diameter, b. Effective length, c. Wire diameter, d. Number of turns. The stiffness to the spring is the force required to produce a nominal extension of 1 mm. [pic] If Kg masses are used: The force applied to the spring in Newtons = Mass in Kg x 9. 81. 4. POINTS TO PONDER a. What relationship exists between the applied force and compression? b. Did the spring (s) behave according to Hooke’s Law? c. State the stiffness value (s) obtained. d. If the graph drawn does not pass through the origin state why. Experiment No. 2 Extension of a spring . OBJECTIVES a. To obtain the relation among the force applied to a compression sping and its change in length. b. To determine the stiffness of the test spring (s) 2. PROCEDURE a. Setup the apparatus vertically to the wall at a convenient height. b. Add increasing weight to the load hanger recording to c. the corresponding deflection for each load. d. Continue loading until at least 30 mm of compression has e. been achieved. 3. RESULTS Tabulate the results obtained and draw a graph of load (y-axis) against compression (x-axis). Note the following data for each spring used :- e. Outside diameter, f. Effective length, g. Wire diameter, h. Number of turns. The stiffness to the spring is the force required to produce a nominal extension of 1 mm. [pic] If Kg masses are used: The force applied to the spring in Newtons = Mass in Kg x 9. 81. 4. POINTS TO PONDER a. What relationship exists between the applied force and compression? b. Did the spring (s) behave according to Hooke’s Law? c. State the stiffness value (s) obtained. d. If the graph drawn does not pass through the origin state why. Experiment No. 3 Rubber in Shear 1. OBJECTIVES 1. To determine the variation of deflection with applied load. . To investigate how shear strain varies with shear stress. 3. To determine the Modulus of Rigidity of the rubber block. 2. PROCEDURE 1. Set-up the apparatus securely to the wall at the convenient height 2. Note the initian dial gauge reading. 3. Add increasing increments of load and recird the corresponding deflections registered on the dial gauge. 4. Tabulate the results and draw a graph of deflection (x-axis) against applied load (y-axis). Describe the relationship between the deflections and the applied load. State if this follows a linear law. 3. Observations and Calculations: Load (W) |Deflection |Shear Stress |Shear Strain | | |X |= W/A |=X/L | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Modulus of rigidity of the rubber block = shear stress/ shear strain = slope of graph |Data |Dimensions (Metric) | Dimension of block |150*75*25 mm | |Dial Gauge |12 mm travel * . 01 mm | |Load Hanger |250 mm * 2 N | |Max. Load |160 N (16 kg) | Experiment No. 4 Hooke’s Law for Wires Objectives: 1. To determine the Young’s Modulus of Elasticity of the specimen wire. 2. To verify Hooke’s Law by experiment. 3. To establish a value for the ultimate stress of the wire. [pic] Procedure: 1. Note the length (L), diameter (d) and the material of the wire under test. 2. Add sufficient initial load to the hanger to remove the flexure of the specimen. 3. Let the scale measurement now showing be the zero position. 4. Add equal increments of load to the hanger and note the corresponding total extension (x) for each case. 5. Care should be taken to ensure that the elastic limit of the material is not exceeded. 6. Tabulate the results and draw a graph of load (W) against extension (X). 7. Continue to load the specimen until fracture occurs. Note the breaking load. Observations and Calculations: |S/No. Load (N) |Stress (N/m2) |Extension(mm) |Strain |Young’s Modulus (Y) | |BRASS | |1 | | | | | | |2 | | | | | | |3 | | | | | | |4 | | | | | | |5 | | | | | | |STEEL | |1 | | | | | | |2 | | | | | | |3 | | | | | | |4 | | | | | | |5 | | | | | | Young’s Modulus of elasticity E/xA = WL Ultimate Stres s = Total Load at fracture / area of wire General Questions 1. State Hooke’s Law. Did the extension of the wire under test confirm to Hooke’s Law? 2. Quote the values obtained for E and the ultimate stress and compare these with the normally accepted values for the material. Experiment No. 5 Strain in Compound Wires Objectives: 1. To determine the Module of Elasticity of the two wires and hence evaluate the equivalent Young’s Modulus of Elasticity of the combination. 2. To postion the single applied load on the slotted link in order that both wires are subjected to common strain and hence to :- 3. Establish the load in each wire. 4. To obtain an experimental value of the equivalent Young’s Modulus of elsticityof the combination. 5. To compare the experimental and theoretical results. Procedure: 1. Note the length and the diameter of each wire and the distance between their centers. 2. Remove the slotted link and suspend the hanger from the lower and of the slide attached to one of the wires. 3. Apply a range of increasing loads and note the corresponding extension of the wire. 4. Do not allow the wire to exceed its elastic limit. 5. Plot a graph of load against extension, and from the slope of the straight-line graph, determine the value of Young’s Modulus of Elasticity of the wire. a. Repeat this procedure for the other wire. b. Replace the slotted link and suspend the hanger from its edge placed at the center of the link. The length of one of the wires may require to be adjusted until the link is level. Small adjustment to the length of either one of the wires may be obtained by applying a supplementary load to its slide using another hanger. Place a load (W) on the central hanger and maintain a common extension in the wires (i. e. level condition) by adjusting the position of the knife-edge on the link. Note the new position of the load measured from the center of the left-hand wire. Note the magnitude of the applied load and the common extension of the wires. Repeat over a range of increasing loads. Tabulate the results and plot a graph of the load (W) against the extension (X) of the compound wire arrangement. Diagram and calculations: |S/No. Force (N) |fs (MPa) |fb (MPa) |fe (MPa) |ee * 10^-4 |Ee (Pa) * 10^10 | |1 | | | | | | | |2 | | | | | | | |3 | | | | | | | |4 | | | | | | | |5 | | | | | | | Experiment No. 6 Deflection of a simply supported beam OBJECTIVES To find the slope and deflection of a simply supported beam with point load at the centre and prove the results mathemati cally. APPARATUS 5. HST 6:1 with complete accessories 6. Vernier caliper, micrometer, meter rod, etc. [pic] PROCEDURE 1. Set up the two end supports at 1m span and insert the thick steel beam in the end and fixtures. 2. Place a load hanger and clamp at mid span and set up a dial gauge to measure the deflection at the load point. 3. Check that the end supports are free top rotate as the beam deflects. 4. Read the support rotation gauge and central deflection gauge. 5. Add load by increments of 1N up to 10 N recording the dial gauge reading and then move the load by the same decrements to obtain a duplicate set of readings. 6. Plot the end rotations and central deflection against the load. Observations and Calculations: |S/NO. |LOAD (N) |Slope |Deflection |Theoretical |Theoretical slope | | | | | |deflection | | | | |central |central |Y = |? | | | | | |WL3/48EI |WL2/16EI | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Experiment No. 7 Deflection of a cantilever beam OBJECTIVE To verify the slope and deflection of a cantilever beam experimentally and theoretically. APPARATUS 1. HST 6:1 with complete accessories 2. Vernier Caliper, micrometer, meter rod etc. [pic] PROCEDURE 1. Clamp the thicker steel strip (2. 64 mm) in the position shown in diagram so that it forms a cantileve r. 2. Fix the hanger clamp (0. 3m) from the fixed support and setup a dial guage over it. 3. Apply a load in increments of 1 /2 N up to about 5N reading the gauge at each load. 4. Plot a graph of deflection against load Observations and Calculations: |S/NO. LOAD (N) |Slope |Deflection |Theoretical |Theoretical slope | | | | | |deflection | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | RESULTS: 1. From the graph obtained, the best fit linear relationship between displacement and load the steel strip, compares the graidient with the theoretical value. 2. Comment on the accuracy of the theoretical results. Experiment No. Deflection of an overhang beam To find the deflection of overhanging arm beam and confirm the results theoretically OBJECTIVE To verify the slope and deflection of a overhang beam experimentally and theoretically. APPARATUS 3. HST 6:1 with complete accessories 4. Vernier Caliper, micrometer, meter rod etc. PROCEDURE 5. Clamp the thicker steel strip in the position shown in diagram so that it forms a overhang. 6. Fix the hanger clampahead from the roller support and setup a dial guage over it. 7. Apply a load in increments of 1 /2 N up to about 5N reading the gauge at each load. 8. Plot a graph of deflection against load Observations and Calculations: |S/NO. LOAD (N) |Slope |Deflection |Theoretical |Theoretical slope | | | | | |deflection | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | RESULTS: 3. From the graph obtained, the best fit linear relationship between displacement and load the steel strip, compares the graidient with the theoretical value. 4. Comment on the accuracy of the theoretical results. Experiment No. 9. Shear center for a channel OBJECTIVE To determine the share centre of a channel section cantilever and to draw the graph between notch distance and gauge readings. APPARATUS 7. Unsymmetrical cantilever 8. Rigid based plate, weights 9. String, pulley 10. Calibrated ring 11. Grid, two dial gauges PROCEDURE: 7. Turn the routable head, so that the cantilever section is positioned relative to the pulley. 8. Fit the share assessory to the top of the cantilever and turn the dial gauge so that they rest against the attachment. The grooves in the notched bar have the spacing of 5 mm. 9. Turn the scales of the dial gauges until they read zero. 10. Tie the string to the left hand notch. Move the pulley to the left and hang the weight hanger on the end of the string. Put a weight of 1 Kg on the hanger so that the total weight is 1,5Kg. 11. Adjust the pulley position until the string is parallel to the lines on the pulley bracket. Record the reading of the both dial gauges. 12. Move the string to the next notch. Readjust the pulley position, Record the dial gauges readings. 13. Repeat for each notch position. Results: Experimental position of Shear Center from the outside of the web. Theoretical position Channel Shear Center is h = B-2 A-2 t / IA Experiment No. 10 Unsymmetrical Bending of a Cantilever Beam |Direction of pull|Displacement |Applied load (Kg) | |(degrees) | | | | | |. 5 |1. 0 |1. 5 |2. 0 |2. 5 |3. | |0 |U | | | | | | | | |V | | | | | | | |22. 5 |U | | | | | | | | |V | | | | | | | |45 |U | | | | | | | | |V | | | | | | | |67. |U | | | | | | | | |V | | | | | | | |90 |U | | | | | | | | |V | | | | | | | |112. 5 |U | | | | | | | | |V | | | | | | | |135 |U | | | | | | | | |V | | | | | | | |157. |U | | | | | | | | |V | | | | | | | |180 |U | | | | | | | | |V | | | | | | | |Direction of pull|Displacement |Applied load (Kg) | |(degrees) | | | | | |. 5 |1. 0 |1. 5 |2. 0 |2. 5 |3. 0 | |0 |L | | | | | | | | |R | | | | | | | |22. |L | | | | | | | | |R | | | | | | | |45 |L | | | | | | | | |R | | | | | | | |67. 5 |L | | | | | | | | |R | | | | | | | |90 |L | | | | | | | | |R | | | | | | | |112. |L | | | | | | | | |R | | | | | | | |135 |L | | | | | | | | |R | | | | | | | |157. 5 |L | | | | | | | | |R | | | | | | | |180 |L | | | | | | | | |R | | | | | | | Experiment No. 11 Bending Moment in Beams |S. No. Load (N) |Balance Reading (N)/ Net Force (N) | | | |W1 |W2 |W3 | |1 | | | | | |2 | | | | | |3 | | | | | |4 | | | | | |S. No. |Load (N) |Balnce Moment (N. mm)/ Theoretical Val. |1 | | | | | |2 | | | | | |3 | | | | | |4 | | | | | Experiment No. 13 Study and Application of experimental photoelasticty techniques on linear crack propagation analysis. OBJECTIVES To familiarize the students with the Linear Elastic Fracture Mechanics in context with photoealsticity and orientation and understanding of operation off different types of polariscopes. THEORY The name photoelasticity reflects the nature of this experimental method: photo implies the use of light rays and optical techniques, while elasticity depicts the study of stresses and deformations in elastic bodies. Photoelastic analysis is widely used for problems in which stress or strain information is required for extended regions of the structure. Photo elastic stress analysis is a simple and powerful tool for design engineers that provide them with the experimental data required for validating analytical and computational designs. In using this method, a transparent plastic model of the structural part of the machine element under study is first made. Then the specimen was placed in the polariscope, and the simulating operating force was applied. When examined in the polarized light field provided by the instrument, colored fringe patterns are seen which reveal: †¢ A visible picture of the stress distribution over the whole area of the specimen. †¢ Stress distribution which is accurately readable at any point for both direction and magnitude. Two types of pattern can be obtained: isochromatics and isoclinics. These patterns are related to the principal-stress differences and to the principal-stress directions, respectively. Principles The method is based on the property of birefringence, which is exhibited by certain transparent materials. When polarized light passes through a stressed material, the light separates into two wave fronts travelling at different velocities, each oriented parallel to the direction of principal stresses(? 1,? 2) in the material but perpendicular to each other. Photoelastic materials exhibit the property of birefringence only on the application of stress and the magnitude of the refractive indices at each point in the material is directly related to the state of stress at that point. Thus, the first task is to develop a model made out of such materials. Isoclinics and isochromatics Isoclinics are the locus of the points in the specimen along which the principal stresses are in the same direction. Isochromatics are the locus of the points along which the difference in the first and second principal stress remains the same. Thus they are the lines which join the points with equal maximum shear stress magnitude. Interpretation of the Photoelastic Pattern: Once the fringes obtained by application of load on photoelasic specimen the most important step is interpretation of complete stress field. The photoelastic fringe pattern data offer suggestion to modify design to avoid from material failure. It is also helpful in reducing average stress on actual part. Complete stress field interpretation include principal stress directions as well as magnitude of stresses on different fringe order. [pic] Stimulated stress field pattern in white light for typical edge crack plate The photoelastic pattern appears as a colorful map of lines of equal color. Beginning at the lower level line of stress and progressing to areas of higher level, the colour sequence observed will be black, yellow, red, blue, yellow, red, green, yellow, red, green etc. The colour transmission from red to blue and from red to green is sharply marked. [pic] Polariscope: Polariscope: It is an instrument which consists of two polaroid plates mounted apart. The lower plate is generally fixed and is known as the polariser, while the upper plate can be rotated and is known as the analyser. Types: 1. Reflection Polariscope Particularly it is used to photoelastically stress-analyze opaque plastic parts. The part to be analyzed is coated with a photoelastic coating, service loads are applied to the part, and coating is illuminated by polarized light from the reflection polariscope. Molded-in or residual stresses cannot be observed with this technique. Fig. 13. 1 Typical reflection periscope on tripod stand 2. Transmission Polariscope. This type is useful for stress analysis if component is of transparent or glassy material. All transparent plastics, being birefringent, lend themselves to photoelastic stress analysis. The transparent part is placed between two polarizing mediums and viewed from the opposite side of the light source. In these experiments we will be only concerned with highlighting the dependence of stress distribution on geometric features, hence we can use the transparent materials and transmission type polariscope will be used. [pic] Fig. 13. 2 Transmission Polariscope Two arrangements of transmission polariscope are possible i. e. I. Plane polariscope Plane polariscope is used for direction measurement at a point of principal stresses for a specimen. The setup consists of two linear polarizers and a light source. The light source can either emit monochromatic light or white light depending upon the experiment. First the light is passed through the first polarizer which converts the light into plane polarized light. The apparatus is set up in such a way that this plane polarized light then passes through the stressed specimen. This light then follows, at each point of the specimen, the direction of principal stress at that point. The light is then made to pass through the analyzer and we finally get the fringe pattern. The fringe pattern in a plane polariscope setup consists of both the isochromatics and the isoclinics. The isoclinics change with the orientation of the polariscope while there is no change in the isochromatics. For this purpose, set the quarter wave plates on both the analyzer and the polarizer cells at position â€Å"D† (direction) to make the polariscope â€Å"plane† as shown below in fig13. 2 (b) Figure 13. 2 (a)Plane Polariscope Arrangement Figure 13. 2 (b)Pin postion at Plane Polariscope arrangement II. Circular polariscope When examining the model for determination of the stress distribution and magnitude, the polariscope must be transformed from a â€Å"PLANE† to a â€Å"CIRCULAR† operation. This is done by first making sure the clamp â€Å"A† is in the locked position and then withdrawing pins â€Å"B† on the ? wave plate from the hole â€Å"D† (direction) and rotating them until pins engage in hole â€Å"M† (magnitude). Now quarter wave plate is at 45 degrees to the polarizer-analyzer axis thus polariscope is in circular light operation Figure13. 3Circular Polariscope Arrangement(dark field) There are four different kinds of arrangements for the circular polariscope. Each arrangement produces either a dark field arrangement or a light field arrangement. In dark field arrangement, the fringes are shown by bright lines and the background is dark. The opposite holds true for the light field arrangement. Quarter Wave-Plates Arrangement |Polarizer’s Arrangement |Polariscope Field | |Crossed |Parallel |Light | |Crossed |Crossed |Dark | |Parallel |Parallel |Light | |Parallel |Crossed |Dark | Experiment No. 14 Calculation of direction and mag nitude of principal stresses using transmission polariscope. OBJECTIVES ) Application of photoelastic techniques to measure the direction of Principal Stresses at a point b) Calculation of magnitude of principal stresses by interpreting the fringe data. Apparatus Apparatus required to achieve the stated objectives are †¢ Transmission polariscope †¢ test specimen of different shapes †¢ Load measuring dial gauge †¢ Vernier Caliper and Meter Rod Construction of Transmission Polariscope: The basic polariscope consists of †¢ Rigid base frame ready to receive all of the modular accessory items. †¢ Two cells equipped with polarizing filters. †¢ Knob ‘H’ used to synchronously rotate the polarizer and analyzer (their common motion is indicated in degrees in the graduated dial). The quarter wave plate which can be used to convert plane polariscope into circular and vice versa. Fig 13. 2 show these components.. Specimen prepration: In this experi ment we are using photoelastic sheets (Polyurethane material) The photoelastic sheet was made into different specimens as stated below: a) specimen with holes drilled. b) specimen with cracks, which is manually cut c) specimens with notches Typical single edge crack specimen 2-D model is shown in fig. 14. Fig. 14. 1 PROCEDURE Measurement of Direction of Principal Stresses at a Point: To measure the direction of the principal stresses at a point in the specimen we follow the following steps: Place the specimen in the polariscope making sure that the specimen is aligned correctly within the clamps, hence avoiding any twisting of the specimen. †¢ Apply load (compressive or tensile) by turning the loading screw. †¢ Set the quarter wave plates on both the analyzer and the polarizer cells at position â€Å"D† to make the polariscope â€Å"plane† (Fig 13. 2 b). †¢ By means of knob ‘C’ rotate the analyzer until pointer â€Å"P† is positioned at 0 and 100 on the scale. †¢ Release the clamp ‘A’ if it was locked previously and by means of knob â€Å"H† rotate the whole assembly during this rotation some black and all the colored fringes will be observed to move. These black fringes which move are the isoclinics. †¢ Identify the point of measurement using a grease pencil or scriber. By means of knob â€Å"H† rotate the polarizer-analyzer assembly until a black isoclinic crosses over the marked point. At this point the axes of the polarizer and analyzer are parallel and perpendicular to the directions of the principal stresses and their directions can be seen from the scale by a pointer â€Å"V†. The rotation of the assembly may be clockwise or anti-clockwise; in order to accommodate this, sign is used with the value of this direction angle. The positive sign is used for clockwise rotation and negative is used for counter clockwise. Magnitude calculations ? The polariscope, and the digital camera are turned on ? Specimen undergoes tensile force/compressive load in Transmission Polariscope with one end fixed as in fig 13. 2 Fringes formed and photographed by digital camera ? A gradual tension was then added onto specimen and record the load reading by using dial-guage ? Print and interpret fringe pattern obtained in photographs according to the proce dure explained. Formulation for Stress Distribution: When examining the specimen for determination of the stress distribution and magnitude, the polariscope must be transformed from a â€Å"PLANE† to a â€Å"CIRCULAR† operation. This is done by first making sure the clamp â€Å"A† is in the locked position and then withdrawing pins â€Å"B† on the ? wave plate from the hole â€Å"D† (direction) and rotating them until pins engage in hole â€Å"M† (magnitude). Now quarter wave plate is at 45 degrees to the polarizer-analyzer axis thus polariscope is in circular light operation. Difference of principal stresses is given by (1 (2 = (N * C)/t Where N=fringe order at point of measurement C= stress constant of specimen material T = specimen thickness C is usually given by manufacturer. Thus the remaining number to be found is N which can be found according to color pattern as mention in the topic of interpretation of fringe pattern. CALCULATIONS AND RESULTS |S/No. |Applied load |Thickness of |Fringe Order |Direction of |Direction of |Magnitude of |Magnitude of | | |lbs/. 01 inch |specimen |‘N’ |principal stress |principal stress |principal stress |principal stress | | | |‘t’ | | |(threotcal value) | |(threotcal value) | |1 | | | | | | | | |2 | | | | | | | | |3 | | | | | | | | |4 | | | | | | | | |5 | | | | | | | | POINTS TO PONDER: 1. What will be the magnitude of shear stress at a plane of principle stress? 2. Describ e the functions of plane polriscope vs circular polriscope. 3. Describe the importance of calculation of stresses with reference to safety factor in engineering design. 4. Discuss the region of maximum stress for specimen used in experiments and explain with reasoning. 5. In case of residual stresses as a result of specimen machining which recovery method is preferable and why?

The Female Reproductive System :: essays research papers

The reproductive system is one of the most vital systems because it determines whether a species will survive. The reproductive system produces human offspring. One of the most prevalent diseases of the reproductive system is prostate cancer. Prostate cancer occurs when the cells of the prostate begin to grow and divide uncontrollably. One out of six men will be diagnosed with prostate cancer in the United States. Some of the key parts of the reproductive system are to learn how a female egg is fertilized by a male sperm cell, about the parts of the male and female reproductive system and learn about prostate cancer. The male reproductive system works to create sperm and then release it into the female during sexual intercourse. The organs in the system are the testes, the epididymides, hanging in a skin bag called the scrotum, the sperm ducts, the prostate gland, and the penis containing the urethra. The testes are also known as sperm glands. They make tiny sperm cells called spermatozoa. They also produce hormones especially testosterone (this activates the production of sperm cells). Epididymides are tightly coiled tubes on each side of the testes. They help sperm become mature. The sperm ducts carry fresh sperm towards the outside. The ducts join with the urethra inside of the prostate. The urethra carries the sperm through the penis to the outside. This pathway is also known as the male reproductive tract. The parts of the female reproductive system work together to produce pin- head size eggs that join with a male's sperm to fertilize one of the eggs. The system nourishes the egg until it forms a full-grown baby. Then, once the baby is born, it produces milk for the baby. The main parts of a female reproductive system are the ovaries, the oviducts (also called the fallopian tubes), uterus (womb), vagina, vulva and the breasts (where the milk for the baby is released). The ovaries are called "egg glands". They store tiny eggs called ova. These will develop into a baby, if a man's sperm fertilizes them. The ovaries also produce hormones. The two oviducts each link the two ovaries with the uterus. They carry the ripe eggs to the uterus. When a male fertilizes a female's egg, it usually occurs in the oviduct. The uterus is where the fertilized egg grows and is nourished until it is ready to come out. At first, the uterus is about the size of a baseball or a tennis ball.

Does Khaled Hosseini’s Writing Matter?

Kevin Ortiz Ms. Meredith AP Literature and Composition 11/18/11 Does Khaled Hosseini's Writing Matter? Salman Rushdie is perhaps the most prolific foreign writer of modern times. As such, one can consider him a major voice in the criteria for what makes for a good expatriated writer. In his 1992 collection of essays, Imaginary Homelands, Rushdie sets forth multiple essential qualities the expatriated writer must possess. The most important three of these qualities are the ability to create universal subjects, must be daring, and encourage people to be open-minded. Khaled Hosseini's The Kite Runner mostly accomplishes these tasks, though coming short in one of Rushdie's major qualities. This is shown from the novel's subject matter, in conjunction with an article from online magazine Slate, which highlights the major flaw. Rushdie's first point is that an exiled writer should be able to â€Å"speak properly on a subject of universal significance and appeal. † Hosseini, in his many subjects pertaining to human nature that is present everywhere, accomplishes this task. One such topic in Kite Runner is loss. At some point or another, every human being has experienced loss. Whether it be the loss of a parent, like Amir losing Baba, the loss of a close friend, such as Amir's loss of Hassan, or loss early in life such as Sohrab's loss of Sanuabar, the reader can relate, regardless of race, place, or creed. The losses do not necessarily have to be physical, as the loss of innocence that occurs in the father-son tandem of Hassan and Sohrab is transferable to the everyday struggles one may face with beliefs, experience, or emotions. The easily acceptable nature of these topics as realities of the â€Å"normal† world, as well as being a clear burden on the characters in the universe set forth by Hosseini show that he is definitively able to accomplish the task of relating loss. Another such subject is that of redemption. Throughout the novel, Amir's conquest for the reconciliation of his deeds knows no bounds. This is very much the situation many people are in after a terrible mistake leaves them begging not only for forgiveness, but redemption. The people who are in these situations will often go to great lengths, risking their mental or physical well-beings in order to rest their conscience at the end of their journeys. For Amir, it meant the rescue of Sohrab, but for the common man, it can be as small as apologizing or as large as turning to an enemy in order for help. The ability of the themes, though being masterfully complex and unique, to be related to and associated with on a deep, connective level are clear indications that Hosseini has fulfilled the first task set out by Rushdie, to create universal subject matter. While performing extremely well in the area of creating a universally relatable subject matter, Hosseini falls short in one of the major tasks of Rushdie, being daring. While some may argue that Hosseini's depictions of rape and violence are edgy or daring, his presentation of them, is not. In fact, Slate argues that â€Å"the Hollywood elements of his story conduce to a view of Afghanistan and its dilemmas that is in the end more riddled with facile moralizing than even the author may realize. † The argument set forth by Slate's Meghan O'Rourke is that though Hosseini's novel does depict these brutal scenes, they are moralized. They are painted in a light where they are seemingly not allegorical or necessary, but simple tools for shock value or fear induction. It is because of this shortcoming, that he is firstly failing the task set forth by Rushdie, in being daring. He once more fails this task in the choice of writing style. Because Hosseini chose to write a book deeply engraved with Afghan culture, which is already a fine line for an English novel, one would hope that he would take the risk of writing with a style that mirrors the roots of the storyline. Instead, Hosseini chooses a cinematic approach, which mirrors that of American film, and American culture, which is a safe approach to the subject matter. He is not reflecting the risk that comes with changing between cultures for expatriates, therefore is not fulfilling the task set forth by Rushdie. Though Hosseini is able to mostly fill the requirements for what Rushdie defines as a great expatriated writer, the biggest flaw comes in his inability to take risks in his prose that reflect the risks taken by the exiles who preceded him. Though he does have flaws, the final task set forth by Rushdie, making the reader open-minded, is easily fulfilled by Hosseini and his subject matter. Hosseini’s use of the Hazara-Pashtun conflict is effective in that it creates a more in-depth look at how a place many generalize as having one ethnicity is actually diverse, but not without conflict. The conflict also humanizes both parties in showing that although societal standards separate them, Hazaras and Pashtuns are not always treated as less than equals. This concept works to make the reader aware that every Muslim that they may see, be it in America, France, or England, is more than simply a â€Å"potential terrorist,† but as many individuals with complex emotions and conflict, trying to create a new life. In addition, Assef’s introduction into the story further humanizes the Afghans. This is because, the concept of the Middle-Eastern groups bullying the world, the Afghan people are having their country destroyed by Assef, who is a neo-Nazi. His socially and morally despicable actions lead the reader to feel a sense of sympathy for the Afghan people. It is due to this feeling of sympathy that the standard Afghan is looked at as not only a human being, but an equal, with fears and oppression as great as that of a man from America to Japan. These two forms of humanization lead the reader to not only become more accepting of Afghan people, but all new people in general, showing that they could be as troubled and frightened as the person judging them. When judging an expatriated writer’s work, one often needs a guideline, or â€Å"measuring stick,† in order to truly gauge the significance of the writing. Salman Rushdie’s qualifications of the expatriated writer are extremely important in that they set that guideline for what an exiled writer should hope to achieve. Though Slate, and the reader, may find some fault with Hosseini’s novel, The Kite Runner’s ability to take risks, an amazing job is done at filling two massively important pieces of Rushdie’s philosophy in its universal appeal and ability to open one’s minds. In doing so, the clear answer to the titular question of this essay, â€Å"Does Khaled Hosseini’s Writing Matter? † is yes. Works Cited: Hosseini, Khaled. The Kite Runner. New York: Riverhead, 2003. Print. ORourke, Meghan. â€Å"Do I Really Have To Read The Kite Runner?. † Slate, 07/25/2005. Slate Magazine. Web. 20 Nov 2011. Rushdie, Salman. â€Å"Imaginary Homelands. † London Review of Books 4. 18 (1982): 18-19. 21 Nov. 2011 .

What Is Materials Science College Courses, Jobs, Salaries

Materials science is a multi-disciplinary STEM field that involves the creation and manufacture of new materials with specific desired properties. Materials science sits at the boundary between engineering and the natural sciences, and for that reason, the field is often labeled with both terms: materials science and engineering. The development and testing of new materials draws upon numerous fields including chemistry, physics, biology, mathematics, mechanical engineering, and electrical engineering. Key Takeaways: Materials Science Materials science is a broad, interdisciplinary field focused on creating materials that have the specific properties.Specializations within the field include plastics, ceramics, metals, electrical materials, or biomaterials.A typical materials science curriculum emphasizes math, chemistry, and physics. Specializations in Materials Science The glass of your cell phone screen, the semiconductors used to generate solar energy, the shock-absorbing plastics of a football helmet, and the metal alloys in your bicycle frame are all the products of materials scientists. Some materials scientists work at the science end of the spectrum as they design and control chemical reactions to create new materials. Others work much more on the applied science and engineering side of the field as they test materials for specific applications, develop methods for producing new materials, and match the properties of materials to the specifications required for a product. Because the field is so broad, colleges and universities typically break down the field into several subfields. Ceramics and Glass Ceramic and glass engineering is arguably one of the oldest science fields, for the first ceramic vessels were created around 12,000 years ago. While everyday objects such as tableware, toilets, sinks, and windows are still part of the field, many high-tech applications have emerged in recent decades. Cornings development of Gorilla Glass—the high-strength, durable glass used for nearly all touch screens—has revolutionized many technological fields. High strength ceramics such as silicon carbide and boron carbide have numerous industrial and military uses, and refractory materials are used anywhere high temperatures are in play, from nuclear reactors to the thermal shielding on spacecraft. On the medical front, the durability and strength of ceramics has made them a central component of many joint replacements. Polymers Polymer scientists work primarily with plastics and elastomers—relatively lightweight and often flexible materials that are made up of long chain-like molecules. From plastic drinking bottles to car tires to bullet-proof Kevlar vests, polymers play a profound role in our world. Students who study polymers will need strong skills in organic chemistry. In the workplace, scientists work to create plastics that have the strength, flexibility, hardness, thermal properties, and even optical characteristics necessary for a given application. Some current challenges in the field include developing plastics that will break down in the environment, and creating custom plastics for use in life-saving medical procedures. Metals Metallurgical science has a long history. Copper has been used by humans for over 10,000 years, and much stronger iron goes back over 3,000 years. Indeed, advances in metallurgy can be connected to the rise and fall of civilizations thanks to their uses in weapons and armor. Metallurgy is still an important field for the military, but it also has a significant role in the auto, computer, aeronautic, and construction industries. Metallurgists often work to develop metals and metal alloys with the strength, durability, and thermal properties required for a given application. Electronic Materials Electronic materials, in the broadest sense, are any materials used for creating electronic devices. This subfield of materials science can involve the study of conductors, insulators, and semiconductors. The computer and communication fields rely heavily on specialists in electronic materials, and the demand for experts will remain strong for the foreseeable future. Well always be looking for smaller, faster, more reliable electronic devices and systems of communication. Renewable energy sources such as solar also depend upon electronic materials, and there is still significant room for advancements in efficiency on this front. Biomaterials The field of biomaterials has been around for decades, but it has taken off in the twenty-first century. The name biomaterial can be a bit misleading, for it does not refer to biological materials such as cartilage or bone. Instead, it refers to materials that interact with living systems. Biomaterials can be plastic, ceramic, glass, metal, or composite, but they serve some function related to medical treatment or diagnosis. Artificial heart valves, contact lenses, and artificial joints are all made of biomaterials designed to have specific properties that allow them to work in conjunction with the human body. Artificial tissues, nerves, and organs are some of the emerging research areas today. College Coursework in Materials Science If you major in materials science and engineering, youll most likely need to study math through differential equations, and the core curriculum for a bachelors degree will probably include classes in physics, biology, and chemistry. Other courses will be more specialized and might include topics such as these: Mechanical Behavior of MaterialsMaterials ProcessingThermodynamics of MaterialsCrystallography and StructureElectronic Properties of MaterialsMaterials CharacterizationComposite MaterialsBiomedical MaterialsPolymers In general, you can expect a lot of chemistry and physics in your materials science curriculum. You will have many electives to choose from as you decide on a specialty such as plastics, ceramics, or metals. The Best Schools for Materials Science Majors If you are interested in materials science and engineering, you are likely to find the best programs at comprehensive universities and technological institutes Smaller regional universities and liberal arts colleges dont tend to have robust programs in engineering, especially an interdisciplinary field like materials science that requires significant laboratory infrastructure. Strong programs in materials science can be found at the following schools in the United States: California Institute of Technology (Caltech)Carnegie Mellon UniversityCornell UniversityGeorgia Institute of Technology (Georgia Tech)Massachusetts Institute of Technology (MIT)Northwestern UniversityStanford UniversityUniversity of California at BerkeleyUniversity of Illinois at Urbana-ChampaignUniversity of Michigan at Ann Arbor Keep in mind that all of these schools are highly selective. In fact, MIT, Caltech, Northwestern, and Stanford rank among the 20 most selective colleges in the country, and Cornell isnt far behind. Average Materials Scientist Salary Nearly all engineering graduates have good job prospects in our technological world, and materials science and engineering is no exception. Your potential earnings, of course, will be tied to the type of job you pursue. Materials scientists can work in private, government, or education sectors. Payscale.com states that the average salary for an employee with a bachelors degree in materials science is $67,900 early in a career, and $106,300 by mid-career.