The Cold War Essay -- American History Papers

The Cold War When World War II in Europe finally came to an end on May 7, 1945, a new war was just beginning. The Cold War: denoting the open yet restricted rivalry that developed between the United States and the Soviet Union and their respective allies, a war fought on political, economic, and propaganda fronts, with limited recourse to weapons, largely because of fear of a nuclear holocaust.1 This term, The Cold War, was first used by presidential advisor Bernard Baruch during a congressional debate in 1947. Intelligence operations dominating this war have been conducted by the Soviet State Security Service (KGB) and the Central Intelligence Agency (CIA), representing the two power blocs, East and West respectively, that arose from the aftermath of World War II. Both have conducted a variety of operations from large scale military intervention and subversion to covert spying and surveillance missions. They have known success and failure. The Bay of Pigs debacle was soon followed by Kennedy's ft handling of the Cuban missile crisis. The decisions he made were helped immeasurably by intelligence gathered from reconnaissance photos of the high altitude plane U-2. In understanding these agencies today I will show you how these agencies came about, discuss past and present operations, and talk about some of their tools of the trade. Origin of the CIA and KGB The CIA was a direct result of American intelligence operations during World War II. President Franklin D. Roosevelt recognized the need to coordinate intelligence to protect the interests of the United States. In 1941, he appointed William J. Donovan to the head of the Office of Strategic Services (OSS) with headquarters in London. Fo... ...or the enemy and ally alike so as to be able to understand their capabilities and shortcomings without intelligence agencies. The CIA and KGB by themselves cannot assure peace. With the knowledge supplied by each to its leaders, intelligent decisions can be made in the world's best interest. Moreover, the status quo and power base remains relatively stable with the East and West on opposing sides. There can never be true and utterly complete peace, these organizations will continue to exist contrary ignorant ideals of the public for peaceful coexistence. Works Cited 1Encyclopedia Britannia index page 237 2KGB/CIA, Jonathon Bloch page 12 3KGB/CIA, Jonathon Bloch page 21 4CIA: The Inside Story, Andrew Tully page 113 5CIA: The Inside Story, Andrew Tully page 119 6General Thomas R. Phillips, U.S. Army, retired. 7Bay of Pigs, Peter Wyden page 59

Solder Joint In Electronic Engineering Essay

Electronic makers throughout the universe have a long history of utilizing lead-based solders. These solders have proven to be cost effectual and high reliable, and are solidly integrated into fabricating methods and procedures. Driven by statute law chiefly in the European Union i.e. WEE, RoHS, EEE Directives, makers are concrete the manner for taking lead solder from all electronics assemblies. However, the credence of nonleaded solder posses many draw dorsums. Conversion to RoHS ( Restriction of Hazardous Substance ) compliant parts must include the full merchandise development and fabrication procedure. To electronics makers, one of the most of import facets in the procedure is guaranting the nonleaded solder articulation dependability is equal to or greater than that of their current leaded solder composings. Manufacturers are working independently to formalize dependability for their nonleaded electronic constituents and systems. Likewise, industry organisations and other research workers have developed proof plans that attempt to understand failure mechanism associated with nonleaded merchandises, generate dependability acceleration theoretical accounts, and predict the dependability of nonleaded solder articulations. Several theoretical accounts of lead free solder articulation dependability non mature plenty yet to enable alone demand of aerospace and military intent. Several factors affect solder articulation dependability, i.e. portion geometry, solder drosss, and external environmental emphasiss. Rapid thermic cycling has been an effectual environmental stimulation capable of bring oning weariness on solder articulations, peculiarly with stuffs holding mismatched thermic enlargement coefficients. Mechanically induced quiver is another external emphasis that efficaciously evaluates solder joint dependability. Thermal cycling can bring forth high supplanting emphasiss at low rhythm frequences, whereas mechanical quiver can supply low supplanting emphasiss at high frequences and high rhythm counts. A peculiar type of trial equipment and methodological analysis capable of using a combination of rapid thermic cycling and quiver is Highly Accelerated Life Testing ( HALT ) . Circuit boards range from simple individual moulded plastic boards with Cu music directors on one or both sides to multilayer boards with Cu music directors, each bed being separated by a insulator and interconnected by metal music directors. Minimum line breadth and spacing between lines is less than 100 A µm. The board typically is made from a composite such as an epoxy with superimposed sheets of woven fiberglass. The dielectric stuff between beds of music directors is normally a polymer, for illustration polyimide. To keep solder ability, the exposed Cu may be coated with an inhibitor such as benzotriazole or with a solder greatcoat. Components are attached to the board with solder or metal-filled conductive adhesives. Fully assembled boards may be farther protected against wet, taint, and mechanical harm by a screen coat. ( Steinberg D,1988 )1.2 SOLDER JOINT RELIABILITY AND FAILURESolder articulations widely used in the electronic packaging industry to bring forth good electri cal, thermic, and mechanical connexions between the bundle and the printed circuit board. Twenty per centums of the mechanical failure in airborne and mechanization electronic cause by quiver and daze. Design appropriate step to guarantee the survival equipment in the daze and quiver environment is necessary to make so. Staying 80 per centum of mechanical failure related to thermic emphasiss ensuing from high thermic gradients, coefficient of thermic enlargement and high coefficient of snap. Solder joint failure occurs in several grounds: Poor design of the solder articulation A bad solder articulation intervention Solder stuff Excessive emphasis applied to solder articulations. In general, nevertheless, the solder articulation failures are merely graded harmonizing to the nature of emphasis that have caused. Most joint failure falls into three major classs: Fatigue failure due to cyclic emphasis application Due to the execution of a long term or lasting burden The emphasis is due to overloading in the short term Reflow profile besides has a important function on solder articulation reliablity. Because It besides has a high influence micro construction of the solder articulation. Vibration failure of solder articulations is assessed for dependability utilizing high accelerated life trial, which is represented by a GRMS- clip curve. For surface saddle horse microelectronic constituents, an estimate of printed circuit board ( PCB ) theoretical account analysis can be made by presuming PCB as a bare unpeopled thin home base because the addition in stiffness of PCB due to the climb of the constituents is about offset by the addition in entire mass of the populated PCB. However, this estimation can direct to mistakes in natural frequence computation for different bundle profiles, for flip-chip-on-board ( FCOB ) and plastic-ball-grid-array ( PBGA ) assemblies. When the constituent has little profile, the estimate of PCB assembly as a bare PCB can supply acceptable average analysis consequences because the stiffness and mass part of little constituent to PCB assembly is non considerable. In this trial, changing GRMS-level random quiver trial for PCB assemblies were conducted. In order to cipher the dependability of PCB assembly, it is necessary to carry on the dynamic analysis.1.3 PROJECT PURPOSEIn this modern universe due to the causes of wellness and environmental issues the electronic fabrication industries confronting a challenging job of necessity to bring forth dependable solder merchandises in really high denseness with really low cost. Solder articulations are really of import to the dependability of Printed Circuit Boards ( PCB ) . This is a 1 of the taking factor in transmittal of electrical and thermic connexions. In instance of every PCB even a smaller solder articulations are really of import. So this undertaking investigates the Effect of quiver on solder articulation dependability in electronics assembly applications. Solder articulation of an electronic assembly is really of import measuring because of this theoretical account based survey might assist applied scientists efficaciously better the PCB mechanical design and therefore better dependability of electronics attached to the PCB by sing practical uncertainnesss and inauspicious quiver environments. This experiment attempted to research the usage of HALT to measure the dependability of solder articulations. For this trial, samples of PCB ‘s arranged and tested on an Environmental testing chamber. The trial program included a response where, as samples become displaced from the printed circuit board ( PCB ) , . In add-on, a solder joint life distribution would be bring forthing depicting comparative public presentation between Sn95.5/Ag4.0/Cu0.5 vs. Sn42Bi57Ag1 solder paste. The consequence of this trial did non bring forth the sequence of failures necessary to be after the life informations ; nevertheless the procedure of proving revealed near by into the application of HALT as a technique to contrast the public presentation of PCB soldered constituents. ( Steinberg D,1988 ) The overall research methodological analysis that has been followed during the undertaking is illustrated in Figure 1.1. There are six distinguishable stairss: Literature Survey, Project Planning, Design of Experiments, Experimental work, Analysis of consequence and Conclusion, and Documentation and Presentation. Literature Survey Design of Experiments Undertaking planning Experimental Work Analysis of Results and Conclusion Documentation and Presentation Figure 1.1: Undertaking MethodologyChapter 2LITERATURE REVIEW2.1 SINUSOIDAL VIBRATION TESTINGDynamic warps of stuffs caused by quiver can do jobs and malfunctions including failed electrical constituents, deformed seals, optical and mechanical misalignment, cracked or broken constructions, inordinate electrical noise, electrical trunkss, chafed wiring. Because sine quiver represent largely a certain cardinal frequence and the harmonics of that cardinal, in its pure province, this type of quiver is generated by a limited important figure of beginnings. Expressed as amplitude versus frequence, sine quiver is the type of quiver generated in the field by beginnings such as engine rotational velocities, propellor and turbine blade transition frequences, rotor blade transition and launch vehicles. While much of â€Å" existent universe † quiver is random, sine quiver proving accomplishes several of import ends in merchandise ability and proving. Much stuff and completed merchandise was modelled on some type of sine quiver signature. A sine expanse of frequences will reason whether the premises were right and if the divergences are considerable plenty to do design alterations. In other words, expanse will set up if the imagined frequence has been met and/or discovers the trial point cardinal frequence. Similarly, a expanse will assist place the trial capable resonance frequences, which may be the points at which the point experiences peculiarly nerve-racking warps. Some of the undermentioned trials include fixed frequence at higher degrees of the commanding variable ( displacement, speed, acceleration ) , and random quiver. Another typical sinusoidal quiver trial, sine explosion such as the teardrop, goes quickly to top out pulsation and so decays at lower rate ( to forestall harm to the unit ) . The burst trial puts a maximal burden into an object at a rapid rate and peculiarly emphasiss articulations and seams to place craft and design issues.2.2 RANDOM VIBRATION TESTINGThe genuineness of random quivers an effectual tool of testing craft defects came about during fabrication. Up until that limited hertz sine was applied during dependability proving. Pure sinusoidal quiver is composed of a individual frequence at any given clip. Comparisons trials revealed that to be the effectivity of random quiver. The trial point will hold to be subjected to many sine frequences over a longer period of clip, and may by happenstance weariness the trial point. Random quivers undercover defect faster. Another fluctuation would be a swept sine on random trial. In random quiver nevertheless, all frequences happening at the same time. Because of this, random quiver analysis normally performed over a big scope of frequences, say from 20Hz to 2000Hz. Research workers are non looking at a specific frequence, specific minute in clip or specific anything else ; They are statistically looking at a construction response to a given random quiver environment. Decidedly be cognizant about any natural frequences that cause a big random response at any open frequence degree, but largely all the experiments taking the overall response of the construction. Random quiver analysis looks at random accelerations or forces over a scope of frequences, which we call the frequence sphere. ( These random inputs are merely sustained over a period of clip, but are non time-dependent ; i.e. , the longer the period of clip, the better the statistical sampling in the frequence sphere. ) The scope of frequences is called a spectrum. Therefore, this is called by Spectral Density. Normally, if accelerations consider in trial, for that Acceleration Spectral Density ( ASD ) have to utilize.2.3 SINE ON RANDOM VIBRATION TESTINGVibration sine on random testing is executing by superposing a sine moving ridge on top of a random environment. A sine on random quiver trial replaces the combined environment of a spinning chopper blade with its distinguishable resonant degrees and the remainder of the aircraft which generates random engine and aerodynamic induced quiver. Gunfire on board an aircraft causes sine quiver while the remainder of the aircraft generates random excitements. These types of trials are doubling quiver Characterized by dominant extremums ( sinusoids ) superimposed on a broadband background. 2.4 Real WORLD SIMULATION. Most quiver in existent universe is random for illustration a vehicle traveling over route feels random quiver from the route abnormalities. Land launched projectile vehicles exposed to non stationary quiver during its flight, the motor ignites the projectile travel through the ambiance, the motor burn terminals and so forth even in flying when subjected to turbulent air flow, undergoes random quiver. Random quiver is composed of battalion of continues spectrum of frequences. Movement varies indiscriminately with clip. It can be accessible in the sphere by a power spectral denseness map [ G2/Hz ] .2.5 HIGHLY-ACCELERATED LIFE TESTING ( HALT )HALT involve quiver proving in all three axes with a random manner of frequences. at last, HALT proving can include the real-time cycling of multiple environmental variables, for illustration, temperature cycling plus quiver testing. This multi-variable proving attack provides a closer appraisal of real-world operating environments. Unlike usual testing, the end of HALT proving is to interrupt the specimen. When the merchandise fails, the weakest point is recognized, so applied scientists know closely what demands to be done to develop merchandise quality. After a merchandise has failed, the weak constituents are upgrade or toughened. The revised specimen is so subjected to an extra unit of ammunition of HALT proving, with the scope of temperat ure, quiver, or floor further increased, so the merchandise fails once more. This identify the following weakest point. By traveling through several proving like this, the merchandise can be made rather strong. With This familiar attack, merely the weak musca volitanss are identified for betterment. This type of proving supply so much information about the assembly and public presentation of a merchandise, that it can be rather supportive for newer applied scientists assigned to a merchandise which they are non wholly familiar. HALT proving must be performed during the design period of a merchandise to build the basic design is dependable. But it is indispensable to observe that the units being tested are likely to be hand-made technology paradigm. At suggestion, we have found that HALT proving should besides be performed on existent industry units, to guarantee that the passage from technology design to production design has non resulted in a loss of merchandise quality or hardiness. Some applied scientists may see this attack as scientifically sensible, but economically impractical. though, the cost of HALT proving is much a lesser sum of than the cost of field failures.2.6 HIGHLY-ACCELERATED STRESS SCREENING ( HASS )HASS testing is an ongoing showing trial, performed on usual production units. Here, the thought is non to damage the merchandise, but instead to verify that existent industry units continue to run decently when subjected to the cycling of ecological factors used during the HASS trial. The bounds used in HASS proving are based on a skilled probe of the HALT proving parametric quantities. The importance of HASS proving can be suited when 1 considers today ‘s typical production scenario. Natural stuffs are purchased from a seller who uses stuffs purchased from other sellers. Components and sub-assemblies are obtained from makers all over the universe. The finishing gathering of the merchandise is performed by a subcontractor. This manner that the quality of the concluding merchandise is a function of the quality of all the constituents, stuffs, and procedures which are a portion of that concluding merchandise. These constituents, stuffs, and procedures c an and make alter over clip, in that manner impacting the worth and dependability of the concluding merchandise. The best manner to guarantee that fiction units continue to run into dependability aims is through HASS testing.2.7 RELIABILITYDependability is definite as the chance that a device will execute its required map under stated conditions for a exact period of clip. predict with some grade of Confidence is really dependent on right specifying a figure of parametric quantities. For case, taking the sharing that matches the information is of primary importance. If a right distribution is non chosen, the consequences will non be dependable. The confidence, which depends on the sample size, must be adequate to do right determinations. Individual element failure rates must be based on a big adequate population and of import to truly reflect present twenty-four hours normal uses. There are experimental considerations, such as influential the incline of the failure rate and cipherin g the activation power, every bit good as ecological factors, such as temperature, humidness, and quiver. eventually, there are electrical stressors such as electromotive force and current. Dependability technology can be slightly conceptual in that it involves much statistics ; yet it is technology in its most reasonable signifier. Will the design execute its proposed mission? Product dependability is seen as a grounds to the stamina of the design every bit good as the unity of the category and fabricating committednesss of an societies. One of the rudimentss of understanding a merchandise ‘s dependability requires an apprehension of the estimation of the failure rate. The conventional method of finding a merchandise ‘s failure rate is through the usage of accelerated quiver runing life trials perform on a sample of Devicess. The failure rate obtained on the life trial sample is so extrapolated to end-use fortunes by agencies of prearranged numerical theoretical accounts to give an appraisal of the failure rate in the field application. even though there are many other emphasis methods engaged by electronic assembly makers to to the full separate a merchandise ‘s dependability, the informations generated from operational life trial sampling is the major method used by the production for gauging the failure rate of a electronic assembly in field service.Failure Rate ( I » )Measure of failure per unit of clip. The utile life failure rate is based on the exponential life distribution. The failure rate typically decreases somewhat over early life, so stabilizes until wear-out which shows an increasing failure rate. This should happen beyond utile life.Failure In Time ( FIT )Measure of failure rate in 109 device hours ; e. g. 1 FIT = 1 failure in 109 device hours.Entire Device Hours ( TDH )Th e summing up of the figure of units in operation multiplied by the clip of operation.Average Time between failures ( MTBF )Dependability is quantified as MTBF ( Average Time Between Failures ) for repairable merchandise and MTTF ( Average Time To Failure ) for non-repairable merchandise. A right apprehension of MTBF is of import. A power supply with an MTBF of 40,000 hours does non intend that the N = Number of units under trial. If the MTBF is known, one can cipher the failure rate as the opposite of the MTBF. The expression for ( I » ) is: where R is the figure of failures. Once a MTBF is calculated, chance can deduce from following equation:R ( T ) = e-t/MTBFConfidence Level or Limit ( CL )Probability degree at which population failure rate estimations are derived from sample life trial. The upper assurance degree interval is used.Acceleration Factor ( AF )A changeless derived from experimental informations which relates the times to failure at two different emphasiss. The AF allows extrapolation of failure rates from accelerated trial conditions to utilize conditions. Since dependability informations can be accumulated from a figure of different life trials with several different failure mechanisms, a comprehensive failure rate is desired. The failure rate computation can be complicated if there are more than one failure mechanisms in a life trial, since the failure mechanisms are thermally activated at different rates. Equation 1 histories for these conditions and includes a statistical factor to obtain the assurance degree for the resulting failure rate.The Bathtub CurveThe life of a population of units can be divided into three distinguishable periods. Figure 1 shows the dependability â€Å" bathtub curve † which theoretical accounts the cradle to sculpt instantaneous failure rates vs. clip. If we follow the incline from the start to where it begins to flatten out this can be considered the first period. The first period is characterized by a decreasing failure rate. It is what occurs during the early life of a population of units. The weaker units die off go forthing a population that is more strict. This first period is besides called baby mortality period. The following period is the level part of the graph. It is called the normal life. Failures occur more in a random sequence during this clip. It is hard to foretell which failure manner will attest, but the rate of failures is predictable. Notice the changeless incline. The 3rd period begins at the point where the incline begins to increase and extends to the terminal of the graph. This is what happens when units become old and get down to fail at an increasing rate.Figure 2.1 bath bath curveReliability Predictions MethodsA batch of clip has been spent on developing processs for gauging dependability of electronic equipment. There are by and large two classs: ( 1 ) anticipations based on single failure rates, and ( 2 ) demonstrated dependability based on operation of equipment over clip. Prediction methods are based on constituent informations from a assortment of beginnings: failure analysis, life trial informations, and device natural philosophies. For some computations ( e.g. military application ) MIL-HDBK-217 is used, which is considered to be the standard dependability anticipation method. A simple failure rate computation based on a individual life trial would follow equation 1. I »iˆ = failure rate. TDH = Total Device Hours = Number of units x hours under emphasis. AF = Acceleration factor, Since dependability informations can be accumulated from a figure of different life trials with several different failure mechanisms, a comprehensive failure rate is desired. The failure rate computation can be complicated if there are more than one failure mechanisms in a life trial, since the failure mechanisms are thermally activated at different rates. Equation 1 histories for these conditions and includes a statistical factor to obtain the assurance degree for the resulting failure rate where, I » = failure rate in FITs ( Number fails in 109 device hours ) I? = Number of distinguishable possible failure mechanisms K = Number of life trials being combined eleven = Number of failures for a given failure mechanism I = 1, 2, †¦ I? TDHj = Total device hours of trial clip for life trial J, J = 1, 2, †¦ K AFij = Acceleration factor for appropriate failure mechanism, I = 1, 2, †¦ K M = I §2 ( I ± , 2r +2 ) / 2 where, I §2 = qi square factor for 2r + 2 grades of freedom R = entire figure of failures ( I? xi ) I ± = hazard associated with CL between 0 and 1.2.2 SOLDER PASTERole Of Solder Paste In ReflowingSolder paste is a combination mixture of a flux composing and a extremely grinded, powdered solder metal metal that is usually used in the electronics industry to soldering procedures. And besides it is call as a attachment medium between the device interconnectedness characteristics and the PCB itself. The constituents of a solder paste are specially designed for first-class printing and reflow features. In normal instance of the surface saddle horse soldering procedure involves puting the substrate and a little sum of solder paste in a printed circuit board. After that the system will be heated until the solder reflows, forms an electrical connexion between the solder tablet and the electrical contact of electronics portion. After this reflow finished it forms both an electrical and mechanical connexion between the electronics constituents and the printed circuit board.Selection Criteria Of A Solder PasteChoice of a solder paste is really of import factor for reflowing procedure, dependability & A ; its quality. The undermentioned factors are considerable for a good solder paste [ 6 ] . The size of the solder metal atoms which are in the solder paste The inclination to organize nothingnesss The belongingss of the flux medium of the solder paste Alpha atom emanation rate The design of the stencil to be used for publishing Thermal belongingss of the solder paste Electrical belongingss of the solder pasteChapter 03MATERIALS AND EXPERIMENT METHODOLOGY3.1SOLDER PasteThe inside informations of solder paste used in the experiment are given in the undermentioned tabular arrayPCB noAlloy1 & A ; 2 Sn95.5Ag4Cu0.5 3 & A ; 4 Sn42Bi57Ag1 Table 3.1. types of solder paste used in experiment For this undertaking all above solder paste should be in a container with appropriate labelling and designation on it to separate it from the Tin – lead solder paste. The solder paste should be stored in a icebox between 35 – 45F. and should be allowed to come room temperature for minimal four hours before making the solder paste printing. Once it has finished the utilizing solder paste must replace to the icebox since it can non be at room temperature over 24 hours. The self life of the lead free solder pastes may be cut downing from the typical six month. The above guidelines are purely followed in this undertaking. Because it is non merely for warrant the quality of solder paste but besides a good manner to cut down the mistakes that may impact the concluding consequences of the undertaking.3.2 SOLDER PASTE PrintingImportant of Solder Paste PrintingSurface mount engineering ( SMT ) is used extensively in the electronics industry. Surface saddle horse constituents are potentially more dependable merchandises can be designed and manufactured utilizing the SMT. The solder paste stencil publishing procedure is really critical and of import measure in the surface saddle horse manufacting procedure. Most of all the bonding defects are due to jobs covering with the showing procedure. Stencil printing procedures have major cautiousnesss in operation and put up stairss. When we are supervising these factors carefully we can minimise the defects. The chief intent of publishing solder paste on PCB is to provide solder metal to solder joint to rectify sum. That merely publish must be aligned right and can acquire a perfect constituent arrangement.Printing Procedure ParametersSome of the undermentioned parametric quantities are really of import to publishing procedure. Stencil Stencils are utilizing for the solder paste slip easy off the aperture edges and thereby secures a unvarying print. For this procedure we utilizing electro formed stencils. Because of these stencils have really shape border and somewhat conelike. By and large a stencil is mading from cuppa or Ni. ENVIRONMENTAL Dust and soil from the air that will make the PCBs and stencils can be defects hapless wet ability in the reflow bonding procedure. So PCBs should be stored in certain bundles and cleaned before usage. SOLDER PASTE Solder paste characterise must be controlled to accomplish a maximal production consequences. Some of the factors are given below [ 12 ] . Percentage of metal Viscosity Slump Solder balls Flux activity working life and shelf lifeSolder Paste Printing Equipment and ProcessStencil printing parametric quantities are really of import factors in publishing procedures to accomplish a best output. The undermentioned parametric quantities must be proctors and controlled in a printing procedure. Squeegee force per unit area = 8kg Squeegee speed = 20 mm/s Separation speed = 100 % Printing spread = 0.0 millimeter These factors and bound can be adjust for our undertaking intent Figure 3.1 DEK 260 stencil printing machine The DEK 260 stencil printing machine is used to publish solder paste on the circuit board. This DEK 260 stencil printing machine has two chief maps. Registers the place of the merchandise screen with in the print caput Positioning the circuit board below the stencil, to cook for the print rhythm. The boards to be print are supported on magnetic tooling and held by vacuity caps arranged on the home base to vouch the board steady during the printing on to the board. The first measure of the experiment is to make the solder paste publishing on to the board.Figure 3.2 Stencil printing by manusIn this undertaking unable to acquire metal stencil, so circuit boards are printed by manus, below process followed to publish PCB Put weights onto the stencil to repair it turn over the squeegee over the stencil solder paste presses through the aperture onto PCB separate stencil Two circuit boards are printed with solder paste for each solder paste types. Wholly 4 circuit boards printed.Pick and PlaceComponent of PCB placed by choice and topographic point machine ( APS Gold-Place L20 ) . robotic weaponries are used to put surface-mount devices onto PCB. Pick and topographic point process as follow. pneumatic suction noses taken by caput of arm, so moved to feeder where the constituent is loaded. The suction nozzele picks it up utilizing vacuity, and moves to the arrangement location so centers the constituent with focus oning fingers. After justified aligned point, it places the constituent onto solder paste.Figure 3.3 APS Gold-Place L203.3 SOLDER PASTE REFLOWPROCESS & A ; PROFILEFigure 3.4 reflow ovenReflow procedure is really of import to accomplish a good dependable solder articulation. Novastar 2000 HT convectional reflow oven is used in research lab for the probe. When making the reflow procedure with lead free solder paste it has to be performed at a m inimal peak temperature of 150.It is by and large accepted that lead free solders requires a higher reflow temperature up to 230 – 240.reflow oven has six warming zones and chilling zone. ( Wu J.2000 ) Reflow profile will be impacting the dependability of a solder articulation. Because it is a major factor that influence the formation of the intermettallic beds in a solder articulation. Intermettalic bed is a critical portion of a solder articulation. An intermettalic bond thickness should be thin. Therefore a good reflow profile must bring forth solder bumps with a thin intermetallic layer.. ( Zhang RR.2001 )PREHEAT ZONEIn this zone indicates how the temperature is altering fast on the printed circuit board. The ramp-up rate is normally between 1-3 per second. If this rate exceeds there will be harm to constituents from thermic daze. Merely In this preheat zone the solder paste begins to vaporize. So if the rise rate is excessively low the vaporization of flux is non uncomplete. This will impact the quality of the solder articulation.THERMAL SOAK ZONEIt is besides called the flux activation zone. In this thermic soak zone it will take 60-120 seconds for remotion of solder paste an d activation of fluxes. Solder splatter and balling will be go on if the temperature is excessively high or excessively low. End of this thermic daze zone a thermic equilibrium will finish the full circuit board.REFLOW ZONEIn this reflow zone merely the maximal temperature will be reached. In this zone we have to see about the peak temperature that is the maximal allowable temperature of full procedure. It is really of import to supervise this maximal temperature exceeds the peak temperature in this zone. It may do harm to the internal dies of SMT constituents and a block to the growing of intermetalic bonds. we have to see the profile clip besides. If clip exceeds than the industries specification it besides affect the circuit board ‘s quality.Cooling ZoneIn the reflow procedure the last zone is chilling zone. A proper chilling inhabits extra intermetallic formation or thermic daze to the constituents. By and large the chilling zone temperature scope is 30 – 100. In this undertaking, the undermentioned temperature profiles were selected. This temperature profile is stranded reflow profile for lead free bonding. Zone 1 220 Zone 2 180 Zone 3 170 Zone 4 190 Zone5 233 Zone 6 233 Wholly 4 circuit boards were printed. Choosing of good reflow profile was non involves any defects or amendss in the printed circuit board.Figure 3.5 Reflow profileFigure 3.6 printed circuit board after reflowSET UP EVENT DETECTORFigure 3.7 Event sensorThe constructed PCB ‘s were connected with event sensor by thread informations overseas telegram. Ribbon overseas telegram addressed harmonizing to `Analysis tech STD series event sensors manual ‘ . pins 1 to 32 map as beginning terminus and pins 33 to 37 map as land terminus.Figure 3.8 Ribbon overseas telegram pin referenceTo obtain closed cringle circuit to supervise the behavior of PCB constituents, PCB boards 1, 2, 3 and 4 connected to impart 1,2,33 and 34 severally.Ribbon overseas telegramAfter connected thread overseas telegram with event sensor and environment chamber, channels are assigned in â€Å" WIN DATA LOG † package which supplied with event sensor. For this trial following scenes define for informations acquisition.Figure 3.9 set up trial informations in event sensor3.5 INVESTICATING RELIABILITY OF SOLDER JOINT UNDER VIBRATION CHAMERFigure 3.10 Design Environmental FS800-70SVIn this survey, PCB ‘s were used in Variable Frequency Vibration Test to analyze the dynamic response of PCB assembly subjected to random quiver burden. The PCB specimens were tested at different acceleration degrees to measure the solder articulation dependability subjected changing G-level quiver tonss ( G is the gravitative acceleration ) , severally. Vibration trials were accomplished by utilizing an electro dynamic Shaker ( Design Environmental FS800-70SV ) and event sensor. One accelerometer was used to find the dynamic response of the specimen, Daisy concatenation cringles were monitored at the same time by an Event Detector during quiver trial. Any opposition alteration transcending a preset threshold with minimal continuance of 200ns can be d etected by the Event Detector. When a cleft is initiated in the solder articulation during the quiver trial, the opposition will increase. The failure standards recommended by IPC – 785 criterion is defined as daisy concatenation opposition by thermic or mechanical transients or perturbations in the signifier of short continuance ( ~ 1 A µsec ) high opposition spikes ( & gt ; 300 a„ ¦ ) . During thermic alterations the solder articulations are capable to shear, non tensile, lading ; hence, fracture surfaces of fractured solder articulations slide relative to each other bring forthing the characteristic short continuance intermittent. Therefore, in this context, the practical definition of solder joint failure is the break of electrical continuity ( & gt ; 300 ohms ) for periods greater than 1 microsecond. Figure 3.11 PCB ‘s was mounted inside the Environment chamber in this mode. Figure 3.12 Above tabular array exemplifying trial program.Figure 3.13 Trial programFigure 3.14 graphs obtained from chamberChapter 4ConsequencePCB board Failure rate ( % ) Operation clip ( hours ) Dependability 1 24.0 5 0 2 63.0 13.04 0 3 1.6 0.3305 0.5893 4 2.5 0.5083 0.2806Table 4.1 dependability of solder pasteThe proving began with 1 GRMS. The intent of this to observe any gross issues in solder articulations, every bit good as with the informations acquisition system. No failures were detected at beginning, nevertheless, after 1.5GRMS an review revealed that both PCBs 3 and 4 were failed. Following, quiver degrees were stepped bit by bit to 6GRMS increases over the period of five hours PCB 1 got failed, In 13.04 hr ‘s period the chamber reached degree of about 14GRMS, staying PCB besides got failed. However, the failure mechanism was attributed to a quiver moving on the solder connexion particular to these parts and was straight related to thermic mistakes. Failure rate Time elapsed Above graph illustrating failure rate vs. Time elapsed for Sn42Bi57Ag1 Failure rate Time elapsed Above graph illustrating failure rate vs. Time elapsed for Sn95.5Ag4Cu0.5Chapter 5RESULT ANALYSISFrom dependability analysis sample 3 has maximum dependability and sample 2 has minimum dependability. Each sample was subjected to nominal supply current and opposition value in conformity with the design and public presentation specification. Respective trial samples continued to vibrate with some public presentation abnormalities observed. The aim of this experiment was to utilize HALT quiver to set up the relationship between the life of similar parts soldered with different solder composings. The consequences proved inconclusive for the primary intent of â€Å" Sn95.5Ag4Cu0.5 † versus â€Å" Sn42Bi57Ag1 † articulation random quiver trial. Both composings demonstrated weak public presentation and the consequences may propose that with regard to this brief random quiver trial, solder articulation dependability is different between the two composings. No samples were separated from the trial vehicle as a consequence of the quiver applied. However, the trial procedure revealed insight into HALT and suggested factors which can impact consequences when soldered constituents are being compared. First, Printed circuit board kineticss would be understood and controlled so that acceleration hot musca volitanss and nothings are made more equal in amplitude. A flexible PCB will debar and bring forth bending emphasiss suited for measuring emphasis on solder articulations. But with a flexible board acceleration uniformity become hard to command and do a comparing trial less nonsubjective. Second, HALT random quiver is a good methodological analysis for bring forthing multi-axis wide spectrum energy for PCBs and their constituents. ( Wu J.2000 ) The typical method to analyze the functionality of a PCB in a quiver environment is to verify the quiver transmissibility. Normally the transmissibility at any location of PCB should be less than a factor of 10, i.e. , 1 G input will non bring forth more than 10 G end product at any location of the PCB. To accomplish this end, two methods can be applied to the PCB design. One is to restrain the PCB tightly to the fixture, which can be realized by bettering the boundary conditions in the finite component analysis theoretical account. The other is to relocate heavy affiliated constituents of the PCB board to allow optimum locations ( i.e. , mass re-distribution ) . ( Wu J.2000 ) Lead free solder assemblies have quickly been promote in the micro-packaging development to forestall the environmental pollution, issues on the dependability has non been clearly solved. Several experiments have been conducted on the soundness of alternate lead free soldering technique such as Sn-Ag-Cu solder. During the bumping procedure, a considerable thermic distortion is occurred and the chemical features of solder and bed qualities are besides changed in agreement with the surface completing method such as ET ( electric Sn ) , ENEPIG ( electro less nickel, electro less Pd and submergence gold ) etc. The IMC ( intermetallic compound ) bed is formed in a micro-scale part between the solder and the surface completing stuff under high temperature adhering procedure. In the field of micro-packaging together with IMC bed, one of the most hard issues is to mensurate width interface beds in a solder articulations. Since the IMC beds have been estimated as the weakest subdivision in th e solder articulations, a accurate finding of mechanical belongingss in the country of this critical part may supply direct and enhanced information to understand the break behavior. aˆ? . ( Zhang RR.2001 ) stringency of mounting bolt of PCB reduced during experiment. Due to this consequence the PCB stated to vibrate freely. Applied quiver force was non shared uniformly. From finite component analysis alterations in stringency of mountin bolt can be realize.Chapter 6DecisionThe decisions ensuing from this work are:.Interactions between temperature and quiver were found important and therefore had influence on concluding consequence. Stencil printing by manus affect the solder joint dependability. Better apprehension gained about electronic assembly behaviors when subjected to quiver. Gained cognition about electronic assembly procedure and how it is act uponing in solder articulation dependability. Gained good experience in managing event sensor and environmental proving chamber.Chapter 7FUTURE WORKSIn this undertaking investigated the consequence of quiver of solder articulation dependability in electronic assembly. For this probe two different types solder paste used, eventually all specimens were tested in environmental Chamber. In this undertaking when making quiver trial informations acquired by event sensor is non accurate value. From informations obtained from event sensor does non give proper analytical consequence. In sing about the hereafter works of this undertaking can be expand based on acquirable informations type, every bit good as finite component analysis because dependability of a solder articulation depends on assorted environmental factors, so result analysis will be more accurate and stand with more international criterions.

Theories about Personality by Freud, Rogers and Eysenck Free Essay Example, 2500 words

To explain that personality was a result of interaction with the components of the human mind, Freud categorized the human mind into three parts: the id, the ego, and the super-ego. The idea was that the mind with its distinct parts as illustrated above is ultimately responsible for personality and decision-making capabilities of the individual. Largely, Freud portrayed an individual as a captive of their mind, which denies them the free will to decide their preferred personalities. In essence, in the topographical dissection of the human mind, Freud sought to justify that human personality resulted from mind functions beyond the individual s control and hence denies the possibility of free will in developing personalities. For instance, the id that Freud considered to be the most primitive part of the mind operated unconsciously. However, even in the unconscious function of the id, it utilized the pleasure principle and often guided people towards attaining instant gratification (B aumeister, Dale, Sommer, 1998). Considering that the id operates unconsciously, individuals do not have control of unconscious processes and hence the result of an operation from the id part of the brain, which also affects personalities, is not willed. We will write a custom essay sample on Theories about Personality by Freud, Rogers and Eysenck or any topic specifically for you Only $17.96 $11.86/page Considering the superego was the only conscious part of the brain, Freud could have suggested that though the brain could function unconsciously and subconsciously, individuals still had a role to play in developing their preferred personalities, especially concerning acting morally.

Personality And The Development Of Karen Duvall. Evergreen...

Personality and the development of Karen Duvall Evergreen State College There are many factors that effect the way that children develop. Children progress through many stages as they grow and what happens in each of the stages can have an impact on their social and emotional well being. Many theorists have speculated as to what goes on in the depths of our psyche. Why do we make certain choices? How do our interactions within society impact our development? Self definition has been a studied from a variety of perspectives - historical, cultural and developmental (Kroger, 1996). Throughout history, we have asked ourselves the age old question, Who am I? Developmental psychologists study the way that we function. All the magnificent ways that are bodies work, the way we think and obtain new information and how these factors change across our life span. These theorists look at how these factors are affected by genetics, culture and experience (Wade, 2008). One such theorist was Erik Erikson. The central thesis of Erikson is the esta blishment of an ego-identity. Freud believed the ego could be described as the part of the psyche that develops in order to ensure the health and safety and sanity of the personality as it mediates between the demands of the Id (the unconscious) and external reality (Fadimen Frager, 2005, p. 50). Erikson postulated that the ego had a more important role, â€Å"a selective, integrating, coherent and persistent agency central to personality function†

Essay on Bipolar Disorder - 1279 Words

Mental illness comes in many forms one of the most prevalent forms facing people today is depression. The realm of depression encompasses many different types and forms, some of these are, Seasonal Affect Disorder commonly called SAD, Bipolar Disorder, Postpartum, Chronic Depression, and situational depression to name a few. When many people think about depression they think about a person who is stereotypically down on life. However they don’t see the people who suffer from extreme highs, as well as extreme lows. They don’t see the people who at one point in time can feel really optimistic, and have grad plans. They may be impulsive and make risky choices without thinking about their consequences. The next day they could have problems†¦show more content†¦During an episode of mania the person may feel very optimistic, they may have unrealistic beliefs about their abilities, they may also spend little time sleeping and yet have boundless energy, they may talk s o rapidly that others can’t keep up, racing thoughts and moving from topic to topic without any transition, distraction, impaired judgment impulsive actions, taking risky and reckless decisions without thinking about the consequences, and in severe cases delusions and hallucinations. During an episode of depression the person may experience, the feelings of sadness, hopelessness, as well as emptiness, irritability, inability to experience pleasure, loss of energy, mental/physical sluggishness, appetite/weight change, sleep problems, concentration/memory problems, feelings of worthlessness and guilt, and thoughts of suicide (Segal, 2). Both men and women are affected by bipolar at the same rate (Grohol, 1). Diagnosis of this disorder can be characterized into three different subtypes. The first type is Bipolar I in order for the disorder to be classified as type I it must include at least one episode of both mania and depression. The next face of bipolar is Bipolar II disorder this is identified by hypomania and severe depression. Hypomania is a lesser type of mania, these people can still carry-on with their everyday life. Another type of bipolar disorder is Bipolar disorder not otherwise specified (BP-NOS) these people may experience symptoms of bipolar but theyShow MoreRelatedBipolar Disorder ( Bipolar )847 Words   |  4 Pagesâ€Å"Bipolar Disorder† Bipolar Disorder is a mental illness, which involves hypomanic episodes, which are changes in someone’s usual mood. Originally, Bipolar Disorder was called manic depression because it does share similar symptoms with people diagnosed with depression. Bipolar Disorder is a severe condition because it can cause mania, which then causes hallucinations and paranoid rage. (Bipolar Disorder) Bipolar Disorder is classified into two categories, bipolar type 1 and bipolar type 2. BipolarRead MoreBipolar Disorder ( Bipolar )829 Words   |  4 PagesBipolar disorder is an often devastating mental illnesses, with high emotional, social and economic impact on the lives of patients and family members [Jin and McCrone, 2015; Miller et al., 2014]. In recent decades, there has been significant progress in developing diagnostic methods for reliably diagnosing severe bipolar disorder (bipolar disorder type I) and some related bipolar â€Å"spectrum† disorders (bipolar type II disorder), and there has also been recent progress in identifying some of the geneticRead MoreBipolar Disorder ( Bipolar )956 Words   |  4 PagesBipolar Disorder Definition Bipolar Disorder is an increasingly common mood disorder that effects millions of people worldwide. In order to understand the plight of any psychiatric patient suffering from this ailment or to be prepared to treat this disease, it is pertinent to first fully understand what this mental disorder truly is. The first misconception surrounding bipolar disorder is that it is just one disease, contrarily it can be divided into two different sub categories. The National InstituteRead MoreBipolar Disorder ( Bipolar )1010 Words   |  5 PagesIntroduction/Overview of Condition Bipolar Disorder (BD) is a severe mental illness (SMI) characterized by dramatic mood â€Å"swings† between manic and depressed states. In their manic states, individuals experience an abnormally elevated mood characterized by extreme, grandiose gestures and ideas, inflated self-esteem, lack of sleep, constant talking, distractibility, poor judgement, and even aggression (Griggs). Individuals can be characterized as having either a hypomanic episode or a manic episodeRead MoreBipolar And Bipolar Disorder ( Bipolar )1397 Words   |  6 Pagesâ€Å"Bipolar robs you of that which is you. It can take from you the very core of your being and replace it with something that is completely opposite of who and what you truly are† (A. Reyan 2015). Bipolar disorder is a mood disorder that alters a person’s life, they can never go back to who they were before. â€Å"It is estimated that more than 10 million Americans suffer from bipolar disorder† (everydayhealth.com 2015). Bipolar disorder is broken down into two types; bipolar I and bipolar II disorderRead MoreBipolar Disorder ( Bipolar )1536 Words   |  7 PagesBipolar disorder has been gaining more and more attention over the last few years. With shootings on the rise, or at least the publicity of them, people are often pointing their fingers at mental diseases including bipolar disorder. An ongoing issue regarding mental illnesses, however, is the population has failed to fully understand what they truly are, the symptoms, and how to treat them. Bipolar disorder, which is commonly referred to as manic-depressive illness, is a disorder within the brainRead MoreBipolar Disorder ( Bipolar )1447 Words   |  6 Pages Bipolar disorder is a serious mental illness in which common emotions become intensely and often unpredictably magnified. Individuals with bipolar disorder can quickly swing from extremes of happiness, energy and clarity to sadness, fatigue and confusion. Bipolar disorder more commonly develops in older teenagers and young adults; it can appear in children as 6. The exact cause of bipolar disorder is unknown; there are two types of this disease: Types of the bipolar disorder: People with bipolarRead MoreBipolar Disorder ( Bipolar )1155 Words   |  5 PagesBipolar Disorder Research Paper What is Bipolar Disorder? Bipolar Disorder is an increasingly common mood disorder that affects millions of people worldwide. In order to understand the plight of any psychiatric patient suffering from this ailment or to be prepared to treat this disease, it is pertinent to first understand what this mental disorder truly is. The first misconception surrounding bipolar disorder is that it is just one disease, contrarily it can be divided into two different sub categoriesRead MoreBipolar Disorder ( Bipolar )1541 Words   |  7 PagesManic depression, also known as Bipolar Disorder is not your normal up and down mood change; it’s not like what most people experience, getting a little sad and getting over it. Instead it is extreme mood swing that â€Å"usually going from EXTREMLY happy to EXTREMLY angry† also include emotional highs and lows such as, depression and mania. Mood changes can happen as little as a few times a year or as often as several times a week; it depends on the person and thei r environment. At times, you feel veryRead MoreBipolar Disorder ( Bipolar ) Essay1544 Words   |  7 PagesBipolar Disorder or manic-depressive disorder is a disorder characterized by highs, manias, and lows, depressions, and can therefore be easily distinguished from unipolar depression, a major depressive disorder in DSM-5, by the presence of manic or hypomanic episodes (Miklowitz Gitlin, 2014). Bipolar disorder is generally an episodic, lifelong illness with a variable course (American Psychiatric Association, 2010). There are two classifications of bipolar disorder; bipolar I disorder and bipolar

Pure Heroine by Lorde free essay sample

The world was taken by storm when Lorde emerged, the throaty, tough eyed heroine behind the summer smash hit of 2013, â€Å"Royals.† You might also know her as the agitated buzz behind The Hunger Games’s â€Å"Yellow Flicker Beat,† or the sullen muse at the center of â€Å"Tennis Court.† Lorde first debuted her voice after two EP’s, The Love Club EP and Tennis Court EP, Pure Heroine being her first full length album. A masterwork mix of sound, Lorde cements her place in the music industry as an unstoppable tour de force. The rest, of course, is history. Toppling YouTube charts and heading an army of millions on Twitter, Lorde’s sheer celebrity and presence has exploded since the public discovered her raw, pulsing talent. But it isn’t just her personality that has captured the attention of thousands. Throughout Pure Heroine’s evolution of sound, Lorde’s singer-songwriting genius shines, intertwined with her taste for fresh, innovative beats. That moment when youre at a party and youre drunk and for a moment as you throw your hands in the air time ceases to exist. She captures this perfectly in her line: Were hollow like the bottles that we drain. But she then makes it more unbelievably beautiful in the most underwhelming of ways with her line: We might be hollow but were brave. Because we are. Were not just young. Were not just dumb. Were brave. Braver than we know. Honestly, its like shes reading my thoughts. Its like she has gone to my school. And you know she captures the spirit of empty, rebellious teens so well? Shes 16 years old. It bothers me when reviewers say she has surprising depth for a teenager. Because whos to say we dont have depth? Tennis Court may be one of her more popular songs, but that does not mean for one second it is not one of the best things Ive ever heard. In 400 Lux, she captures the utter nothingness, the utter emotional emptiness of millennials, in teens, but in Tennis Court, she captures t he rebellious side of that. My favorite line is: Its a new art form showing people how little we care. I love that. Because were expected to care about all this s***- s*** that yes, in the end, as she silently acknowledges, we may regret not caring about, but its so hard to care about it all. Being good little children. All those little daily things- being quiet when the adult tells you to be quiet. Answering endless questions on endless pieces of paper. Keeping your mouth shut because youre to young to count. And we just dont care. We care so little. We feel so little. Tennis Court also has that element of James Dean coolness, that element of swag, that element of slick sexiness, which makes it perfect. I love in her song Ribs when she talks about fears of getting old. Many people ignore it as the fears of growing old is a rather much used subject, but, whether we like to admit it or not, our youth is something we value, something we love. For a while, it is a part of our identity , and when youre young, even if you are emotionally empty and depressed and you party and maybe the people you love wont matter when you get old, you shine. Then you grow up and get a job and have kids and you forget about these cares. Its hard to let go of who we are. Before I finish up this review, Id like to acknowledge two more songs together, as they are very similar, though one is from her previous album, the Love Club. These two songs are The Love Club and White Teeth Teens. Both these songs are about that one group of handsome, beautiful, group of royals every school has. There have been different names for these types of groups at different schools, for example, at my high school, its The Crew. Maybe Im wrong, but in this case, I would like to think its the name of the previous song- The Love Club. One of the best lines from this song is: Im sitting pretty on my throne, theres nothing more I want, except to be alone. She is the queen bee, the prettiest, most popular girl at her high school. Although at some time in the future, her high school popularity will mean nothing, right now she is a queen on her throne, and she appears to have everything to everyone else- looks, the popular boy, everything- but she doesnt have true happiness, and she knows this. She (to bring back this word yet again) hollow. And you know every morning she probably gets up early to make sure she looks nice, every single morning, again and again, and for what? Approval from people that 15 years will have to think to remember her name? Shes hollow. And she knows it. White Teeth Teens is like part two- describing the Love Club. Her line: Ill let you in on something big- I am not a white teeth teen. Is a rare moment of honesty. Its not like we try to lie. But when we say hahaha and lol, were not really laughing out loud. We say things even if theyre not true to make everything good because everyday being told to be quiet and everyday living for the thrill of it, is makes everythi ng seem not good. We keep cool on the outside (Were so happy- even when were smiling out of fear- Tennis Court) but its all fake. So in that moment she was real. She wasnt in the Love Club, because like she says in the next line of White Teeth Teens, being in The Love Club, being in The Crew, its in the blood. This is a reference to how rulers are often chosen because of their blood- their ancestors. In Tennis Court she says Everythings cool when were all in line for the throne and (as mentioned before) in The Love Club she talks about sitting on her throne, so she is comparing the hierarchy that is high school (That sounds rather dull- its like this. In Lord of the Flies, when left alone, a group of adolescents lose all laws of society and form a hierarchy, they let that anger, that rebellious emotional hollowness rage- and who do they put as their lord? The most attractive kid.) to a kingdom, and to truly be queen, to truly be king, it has to be in the blood- you have to be wealth y. This society is focused on wealth- youre cool if you have the most expensive phone, the most expensive shoes, the most expensive clothes. As she makes clear in Royals, she doesnt come from money, so shes only fooling herself into thinking she is truly a part of the Love Club. I will leave with this. What Lorde captures so perfectly in this masterpiece is this- Were hollow and in many ways fake. (I live in a hologram with you- holograms are unreal, fake images- Buzzcut Season)Were shallow. We party and we live for moments of empty happiness. We can be so cool, but inside, were so afraid. But we are also capable of love and extreme emotional depth, we have insight because we know the way this world works- we know it can be cruel and love can be cruel and people will sell out and sometimes there is nothing but numbness. And maybe were rebels without any cause. But were brave.

Lab Report Questions Sample

Lab Report Questions Paper The melting point will be lower than expected. 5. Part B. 2. The solute dissociates slightly in the solvent. How will the slight dissociation affect the reported molar mass of the solute- too high, too low, or unaffected? Explain. The solute dissociating slightly will cause you to calculate a molar mass that is too small if you neglect the dissociation by assuming i=l instead of the correct value of i, which is 6. Part B. 3. The temperature versus time data plot shows no change in your temperature at the freezing point for a pure solvent; however, the temperature at the freezing point for a solution steadily decreases until the solution has completely solidified. Account for this decreasing temperature. The freezing point of the solution is always lower than the freezing point of the pure solvent because when a non-volatile solute is dissolved in a solvent, the vapor pressure of the solvent is lowered. A depression of the solvent freezing point occurs. 7. Part C. I . Interpretation of the data plots consistently shows that the freezing points of three solutions are too high. As a result of this misreading of the data, will the reported molar mass of the solute be too high, too low, or unaffected? Explain. -The change in temperature is suppose to increase because the freezing point from the cooling curves increases causing the molar mass to be lower. If three solutions are too high then the molar mass will be recorded as high. We will write a custom essay sample on Lab Report Questions specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Lab Report Questions specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Lab Report Questions specifically for you FOR ONLY $16.38 $13.9/page Hire Writer