A direct hydrogen fuel cell uses hydrogen and air (oxygen) to produce electricity, as we showed in class.
If you wanted a voltage of 2.2 V for your fuel cell device (which can be made of multiple cells), what mix of conversion and/or number of cells would you want to use? Remember: the voltage of cells in series adds up. There are a variety of possible answers.
In: Chemistry
Solve this comp architecture problem:
Supposed you have an array int* arr = {3,7,6,4,5}. The values in arr store in the memory of 0(x21), 8(x21), .... , 32(x21). Transform the following RISC-V code into a C program.
ld x5, 16(x21)
addi x6, x0, 3
sll x5, x5, x6
sd x5, 8(x21)
In: Computer Science
A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25 ∘C. The initial concentrations of Pb2+ and Cu2+ are 5.00×10−2 M and 1.70 M, respectively. What is the cell potential when the concentration of Cu2+ has fallen to 0.250 M ? What are the concentrations of Pb2+ and Cu2+ when the cell potential falls to 0.37 V?
In: Chemistry
The voltage drop across an RLC circuit is:
v(t) = G*311.13*sine(377t) + 124.45*sine(1131t + 20) volts.
The current in the direction of the voltage drop is:
i(t) = 15.56*sine(377t) + 0.5*sine*(1131t - Φ)
Calculate:
a) The constants R, L, C of the circuit.
b) The angle value Φ
c) The average value of the power delivered to the circuit.
In: Electrical Engineering
The speed of a runner increased steadily during the first three seconds of a race. Her speed at half-second intervals is given in the table. Find lower and upper estimates for the distance that she traveled during these three seconds.
| t (s) | 0 | 0.5 | 1.0 | 1.5 | 2.0 | 2.5 | 3.0 |
| v (ft/s) | 0 | 6.2 | 10.8 | 14.9 | 18.1 | 19.4 | 20.2 |
In: Math
A circular loop in the plane of the paper lies in a 0.78 T magnetic field pointing into the paper.
A) If the loop's diameter changes from 16.6 cm to 6.4 cm in 0.63 s , what is the direction of the induced current? Clockwise or Counterclockwise?
B) What is the magnitude of the average induced emf? Answer in V.
C) If the coil resistance is 4.3 ohm , what is the average induced current? Answer in A
In: Physics
How does temperature affect the band structure and the I-V characteristics of semiconductor devices?
How does changing the carrier lifetime affect semiconductor devices?
For a GaAs PN junction, imagine that the device is to be used as a photo-diode. What width of intrinsic layer would you want to design the device with if the photons only absorb in the depletion/intrinsic regions? Assume: wavelength = 0.75um.
In: Electrical Engineering
11) 2NH3(g)+3O2(g)+2CH4(g) --->2HCN(g) +6H2O(g)
^=-45.9 kj ^=-74.87kj ^= 135.1kj ^= -241.8kj
a) Calculate delta H rxn
b) Calc q when 25.0 g CH4 reacts
c) If 10.0L of each reactant was used at STP what V of HCN would be formed?
d) If 6.0L of HCN was formed? calc % yield
In: Chemistry
A body of mass 7 kg is projected vertically upward with an initial velocity 18 meters per second. The gravitational constant is g=98m/s2. The air resistance is equal to k|v| where k is a constant.
Find a formula for the velocity at any time ( in terms of k ):
Find the limit of this velocity for a fixed time t0 as the air resistance coefficient k goes to 0.
In: Advanced Math
A Nd: YAG Laser with a length of 0.01m is coated on both sides so that R=0.95
wavelength= 1.0?m
the linewidth of the laser transition is v = 10/cm
Absorption coefficient a=0.01/cm
Lifetime of upper laser level l = 3ms
refractive index n = 1.77
A. What is the minimum invertsion population requirement for lasing?
B. What is the Q of the Cavity?
In: Physics