25 Questions 63 Answers 0 Followers
Questions related from Omar Z. Sharaf
There seems to be a lot of arbitrary and sometimes contradictory explanations for the difference between the Isoelectric Point (IEP) and the Point of Zero Charge (PZC). Other times, the two terms...
02 February 2020 10,102 5 View
Up to my understanding, zeta potential is supposed to be the electrokinetic potential at the imaginary surface-of-shear in an EDL. The way it is estimated is by relating it to the measurable...
08 August 2019 5,925 4 View
Solid bridging (e.g., due to ambient-temperature sintering and solid-solid diffusion) often occurs between dried nanoparticles. My questions is: Upon the "physical" contact between two...
08 August 2019 5,416 7 View
Up to my knowledge, nanopowders are usually produced from synthesizing nanoparticles in gas phase or by drying them from liquid phase. In reality, this results in particle clusters that are not...
08 August 2019 9,377 7 View
If so, why are they defined as "suspensions" in the majority of literature, including high-ranked journals? Although both are heterogeneous two-phase systems, as far as I know, in suspensions,...
06 June 2019 6,133 12 View
Can ADI be used in this case? In all textbooks I went through, ADI is only used for 1D conduction or convection-conduction problems. I am interested in converting my current explicit code into an...
05 May 2019 6,819 8 View
I am aware that several definitions of stream-function in 3D flow do exist in the literature. But I am at a loss on what stream-function physically means in 3D.
05 May 2019 8,686 6 View
If the answer is yes, then does the charge acquisition mechanism change with respect to metallic, metal oxide, and carbon-based nanoparticles? And would it also change between totally pure water...
02 February 2019 8,879 6 View
Also, how do these hydrodynamic interparticle forces compare against hydration/depletion solvation-type interparticle forces? Are they all of the same nature? It seems to me that liquid bridging...
02 February 2019 7,879 7 View
Which would be useful in order to systematically estimate conditions under which radiation heat transfer can be neglected. Assume an absorbing/emitting fluid.
09 September 2018 9,404 8 View
Normally, to get the total radiative heat flux (qr) in W/m2 from the spectral radiative intensity (Ilamda) in W/(m2*um*str), Ilamda is integrated twice--with respect to solid angles and...
03 March 2017 3,427 5 View
Wavelength-dependent values for the complex index of refraction of many materials are available in the literature. However, temperature-dependent values seem to be quite scarce. Any clues to...
03 March 2017 9,288 2 View
I would like to confirm the soundness of a simple steady-state energy balance over a solar cell. Assume we take a solar cell as the control volume for an energy balance where the electrical...
03 March 2015 7,861 4 View
Do you have any relation for the wind convection heat transfer coefficient (i.e., external forced convection) from a parabolic surface? Specifically for a paraboloid of revolution (i.e., a solar...
03 March 2015 4,863 3 View
I need hourly measured weather data for different locations in the middle east, specifically in the United Arab Emirates (UAE). This includes hourly incident irradiance, ground-level temperature,...
02 February 2015 4,121 15 View
Why is the open-circuit voltage in a PV cell less than the bandgap voltage of the PV material? In other words, what is the physical interpretation of the voltage factor in a PV material? In which:...
02 February 2015 7,379 10 View
Could someone explain to me in details (or point me to appropriate sources) why the short-circuit current is less than the photogenerated current, resulting in an internal quantum efficiency less...
02 February 2015 2,258 6 View
Generally speaking, in electrical conversion efficiency calculations for PV and MJPV cells, is the input in the conversion efficiency definition the incident solar power (or power flux) on the...
02 February 2015 3,310 4 View
In multi-junction PV cell assemblies, why is it common for the substrate to be a metallic-ceramic-metallic structure? What purpose does each layer serve exactly?
02 February 2015 7,464 3 View
I am wondering if there's a way to do this since the gamultiobj function in MATLAB is limited to linear constraints. If not, could you recommend any alternatives?
01 January 2015 7,616 9 View
I would like to become more proficient using MATLAB's optimization toolbox in general and GA optimization in particular for solving non-linear constrained single- and multi-objective optimization...
01 January 2015 258 5 View
Will photons with sub-bandgap energies in both direct and indirect semiconductor solar cells turn into lattice vibration (phonon absorption) or pass through the semiconductor unaltered? I am...
10 October 2014 8,121 9 View
Why is it that at the wavelength corresponding to the bandgap of an indirect semiconductor, the internal quantum efficiency doesn't drop immediately to zero? But instead, it follows a sharp curve...
02 February 2014 815 2 View
Can someone guide me to some good references for the design and analysis of solar spectrum decomposition filters (beam splitters)?
01 January 2014 6,622 1 View
Illumination distribution profile, flux concentration ratio, and optical efficiency are the main results I need. Elements include parabolic and paraboloidal concentrators , Fresnel optics, and...
01 January 2014 9,690 8 View
