photovoltaic energy conversion and sustainable energy

Written Part:
Q1. In Jan 2004 NASA's Mars Exploration Rover landed on the surface of Mars in search of answers about the history of water on the planet
(a) What is the solar irradiance (Wm^-2) entering the mars atmosphere, knowing R_sun=696 Mm, T_sun=5762 K, r_mars=230 Gm, σ=5.67x1^0-8 Wm^-2K^-4?
(b) What is the solar irradiance on the horizontally oriented solar panels (n=0°) of the Mars rover when the sun is in the zenith (z=0°), using the following properties of the Mars atmosphere: optical thickness αd=0.5 and s=0.8?
(c) The rover gets its energy from 1.3m² of solar cells with 27.5% overall conversion efficiency and it needs 100 W electrical power to drive. Calculate the direct, indirect, and total irradiation (Wm^-2) as well as the electrical output power when z=55° and panel is tilted towards the sun with n=10°. Will it be able to drive?

A1. 
(a) Calculate dilution factor, f, then get solar irradiance by Q=fσT⁴
(b) Calculate direct, indirect, and total irradiance.
(c) Calculate direct, indirect, and total irradiance and compare with Q_tot from η=W/Q_totA.

Q2. For the study of solar conversion we know that the spectral distribution n(E) follows from the emissivity ε(E), the number of photon modes h(E)dE, and the occupation probability f(E).
(a) Explain the greybody spectrum. What is emissivity?
(b) Derive h(E).
(c) Show that you can obtain the photon occupation probability from the electron occupation probability.

A2. See long derivation in course notes.

Q3. Forgot. Something about tandem cells and fill factors and output powers.

Q4. All about the window effect for heterojunction solar cells.
(a) Define the general current efficiency including all necessary parameters.
(b) Calculate the current efficiency as a function of u=amt. of light that can be absorbed in layer 2/amt. of light that can be absorbed in layer 1.
(c) Explain how the window effect comes to take place from (b).
(d) Sketch a graph of the current efficiency as a function of u.

A4. See long derivation in course notes.

Oral Part:
Q1. Derive and explain the equation for calculating a planet's temperature from the sun's temperature.
A1. See derivation in course notes.

Q2. Derive the (3) factors that affects the absolute efficiency, η^*, of a solar cell.
A2. See derivation in course notes.

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my brother, the poet

i am extremely amazed and surprised that my brother has come up with this piece.

yup, the same brother who hated doing book reviews he made our bunso read a book and tell him the summary. the same brother who writes things like "happy father's day pa! still have a long way to go!" (hahaha). the same brother who's more reluctant than me to write all the essays papa would demand from us.

i, myself, have not even attempted to write in vernacular and THIS is quite well phrased. so, yes, i am very proud :D

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latex: bibliography error

how to get the ieee bibliography template to work.

context:
ieee latex template for photonics journal using TeXworks editor.

procedure:

1. in file Optogenetics.tex: add "\cite{Deisseroth2006}" to random section.
2. in file Optogenetics.tex: define style and .bib file to the position where the references should be placed.
3. create file Optogenetics.bib with the following content:
4. execute.

error:
when adding references using ieee bibliography template, the following error occurs:

fix:
replaced procedure #2 with:
tried executing and it worked, .bib file loads perfectly. reverted to the code as written in procedure #2 (using IEEEtrans style) and the error no longer appeared, can't figure out why. i think it also helped that i restarted the editor but i'm not really sure.

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photonics in optogenetics

i enjoyed the recent trends in photonics course a lot particularly because it didn't require much effort owing to the fact that you only need to be present during the lectures, give a lecture on one topic of interest, and make a paper about it. on the other hand, you would need to read, read, read some more, study and talk about your chosen topic but you do learn a lot and get stimulated to think of new ideas in the process. taking the course with someone who works at the military defense industry is an added bonus especially when he drops out hints of some highly classified projects by the military every now and again.

our own topic was on optogenetics, i've read at least twenty papers on the photonics part yet i'm not even close to knowing a quarter of what there is to know about this field even though it started barely twenty years ago. however, i had such a great time reading up and i'm happy we've stirred up some discussion after our talk. for instance, following the example on sight restoration using optogenetics technology, pieterjan questioned the possibility of implanting IR-sensitive opsins to the human eye. i never even thought about that possibility as i have already discarded the use of IR light since it would cause a lot of heating in the human tissue. but of course, what are engineers for but to solve such kind of problems, right? :P i can imagine all sorts of applications for such technology already!

i am still in the process of writing the report in journal format but the slides we used for the presentation are as follows:

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faculteit letteren en wijsbegeerte bibliotheek

vanity trip, obviously. nobody reads engineering like this. this photo was taken as a token of the small, quiet, desk-less section of the library at the plateau where i usually stay when i want to rehearse before oral presentations.

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