Chương 2: thông số vật lý<br />
thực phẩm<br />
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Caùc thoâng soá vaät lyù cuûa thöïc phaåm<br />
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Ñoä daøi<br />
: L (m)<br />
Dieän tích : S (m2)<br />
Theå tích<br />
: V (m3)<br />
Khoái löôïng : m (kg)<br />
Khoái löôïng rieâng: ρ (kg/m3)<br />
AÙp suaát<br />
: P (N/m2)<br />
Vaän toác<br />
: v (m/s)<br />
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Caùc thoâng soá vaät lyù cuûa<br />
thöïc phaåm (tt)<br />
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Ñoä nhôùt<br />
: µ (Ns/m2)<br />
Nhieät löôïng rieâng : i, I (J/kg)<br />
Nhieät dung rieâng : c (J/kg.ñoä)<br />
Heä soá daãn nhieät : λ (W/m.ñoä)<br />
Heä soá truyeàn nhieät<br />
: k (W/m2.ñoä)<br />
Nhieät ñoä<br />
: T (ñoä C, ñoä F, ñoä<br />
K)<br />
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Dimensions<br />
(Thöù<br />
nguyeân)<br />
Dimensions are represented as symbols<br />
(kyù hieäu) by:<br />
• length [L],<br />
• mass [M],<br />
• time [t],<br />
• temperature [T]<br />
• force [F].<br />
All engineering quantities can be expressed in terms of these<br />
fundamental dimensions<br />
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Dimension<br />
s<br />
(Thöù nguyeân)<br />
• Length = [L], area = [L]2 , volume = [L]3.<br />
• Velocity = length travelled per unit<br />
time=[L]/[t]<br />
• Acceleration = rate of change of<br />
velocity=[L]/[t]x1/[t]=[L]/[t][t]=[L]/ [t]2<br />
• Pressure<br />
= force per unit area=[F]/[L]2<br />
• Density<br />
= mass per unit volume=[M]/[L]3<br />
• Energy<br />
= force times length=[F] x [L].<br />
• Power<br />
= energy per unit time=[F] x [L]/[t]<br />
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