tamat jua final exam ak..

alhamdulillah..setelah bermingu2 perah otak, akhirnye tiba jua tarikh akhir exam final ak utk sem5..walaupon pelbagai masalahdan rintangan dihadapi sepanjang sem nie, tapi tetap tabah hadapinye..syukur pd tuhan krn mberi ak kekuatan yang utuh..

jiwa kacau..after final pcom..trsempak dgn skandal mmg satu situasi yang paling sedih dlm hidup..orang pernah ak sayang suatu ketika dulu skarg dh xblh ditegur atau senyum..huhuuu..terasa janggal tapi itu adalah kenyataan..ak paling xsuka bila terserempak dgn dia walaupon hati sentiasa berdoa agar ak selalu berjumpa dgn nya..jiwa kacau..segala memory lama menghantui diri..berat sungguh hati ini utk melupakan dia mahupon mbuang segala memory lama..itu sahaja harta yang paling istimewa dari dia utk ku..akan ak jaga dan kunci rapat dlm hati ni bersama nama nye kukuh terpahat..

p/s: kata2 mcm sengal aje kan..maaf sbb ayat xdisusun dgn btl..jiwa kacau..haha..

pcom oh pcom..

exam pcom seperti yang dijangkakan amat lah menderita kerana subjek ini amat lah memeningkan kepala dan agak xpaham kerana terlalu kyusuk dlm kelas..lec kt depan mmg berkualiti dan dijangka akan mengantikan penolong dekan tapi pelajar dikerusi pening2 lalat akibat xstdy sblm msk kelas..bila balik kls aje terus mkn dan tido..bila ilmu nk kekal..tambah plak mlm2 g merayau2 mencari makan ditempat yang jauh dan ditemani oleh teman2 hidup yang sejati konon nye..wah wah..sedap btl kehidupan mcni..tapi skrg kerana ms lalu yang tidak tfikir penting nye telah memberi kesan negatif yang amat ketara time last minute nak exam final esok..hahahaha...itu adalah kehidupan ku sebagai pelajar pcom..

p/s: jng contohi aku..^_^

kerinduan..

kdg2 time stdy2 mcni..teringat ms dulu2 ak dgn dia..stdy bersama..bergurau..makan bersama..time2 stdy tu adalah yang kn cubit..kn ketuk kepala..time2 stdy xblh bercakap, so tulis ape yang ckp kt kertas..hihii...mcm2 kenangan dulu mhimpit jiwa..sunyi plak rasanye diri ini tanpa dia..

biomedical material

difference btween atomic structure and crystal: bohn model, consist proton, electron, & arragement of atom.

ionic bonding: transfer electron
covelent bonding: share electron
metallic bonding: cloud of electron

density: nA/VNa
APF: n(4/3pia^3)/volume
volume: a^3
A=atomic mass
nSC=1, nBCC= 2, nFCC=4, nHCP=6
Asc= 0.5a, BCC= punca 3a/4, FCC= punca 2a/4
APF: sc=0.52, BCC=0.68, FCC= 0.74, HCP= 0.74

metal: close packing,metallic bonding,large atomic mass
ceramic: less dense packing density, lighter
polymer: low packing density, lighter element

diffusion: J=-D dc/dx

defect: point, line, area
point defect: vacancy atim, interstitial, subtitutional atom
line defect: dislocation: edge & screw
area defect: twin boundary

stress: tho(psi)= sigma cos lamda cos phi

increasing strength:
1 reduse grain size
2 solid solution(alloying)
3 precipitation
4 cold work

%cw = A0-Ad/Ad *100%
cw up, yield strength up, tensile up, ductility down

effect of cold work
1 recovery
2 recrystallization
3 grain growth

mechanical properties:
stress: force / area
strain: stress/ length displacement
elastic: reversible
plastic: permenent
toughness: energy to break a unit volume material
ductility: plastic tensile strain at failure
resilience: ability material store enrgy
hardness: resistance to permanent indenting surface

modulus elastic: E= stress/ strain
elastic shear modulus: G= tonsion stress/ shear strain

saturated hydrocarbon: single bond
unsaturated hydrocarbon: double or triple bond (less stable)

degree of polumerization:
Mn= sum XM
Mw= sum WM
nn= sum Xn/m
nw= sum Wn/m
m= average molecular weight= sum fm

increasing strength:
linear-branched-crosslinked-network
copolymer: 2 or more monomer polymerized together

thermoplastic:
little crosslinked, ductile, soften when heating, small e, large kc
thermoset:
more crosslinked, brittle,does not soft when heat, lagre e, small kc

defect in ceramic:
1 frenkel defect: a cation is out of place
2 shotty defect: a pair of cation and anion missing

advance ceramic application: SiC
1 heat engine
2 ceramic armor
3 electronic device

heat engine:
advantages: run in higher temperature, excelent wear and corrosion resistance, ability run without cooling system
disadvantages: brittle, too easy to have void-weaken engine, diffucult to machine

purpose matrix: transfer stress to other phase, and protect phase from enviroment
purpose dispersed phase: help enhance matrix properties

MMC= up stress, tensile strength and creep resistence
CMC=up kc
PMC= up e stress, tensile strength

Ec=VmEm+VpEp
1/Ec= Vm/Em + Vp/Ep

definition biocompatibility: the ability of material to perform with an aprociated host response in a specific application

implant factor:
1 bulk properties
2 surface properties
3 mechanical properties
4 long term condition

host factor:
1 species
2 age and healthy
3 immunology

stainless steel:
1 ferritic (BCC)
2 austenitic (FCC)
3 martensitic (BCT)
*kurang stdy bab nie..mlm nie br nk ingat all

bab seterus nye ak dh xdpt ingat sgt..atas nie pon penat ak recall br dpt ingat..definition and rumus kn remember lagi..otak ku kn terima semua ini..huuhuuu...