Fuel Cells - Science topic

R2 is varied according to the calibration curve and not the volume of gallic acid you must work in the same condition using increasing concentration in order to draw the curve once the curve is linear (straight) you get r2 of 0.99 or even 1

Based on this article:

and these guys:

Dear Tashfeen Alam ,

It depends on the extent of the damage caused by the cold temperature and the duration of the exposure. If the cold exposure caused severe damage to the plants, such as freezing of the tissues, then it is likely that the plants will not be suitable for biochemical and metabolite analysis. However, if the damage was minimal and the wilting was reversible, then the plants may still be suitable for analysis. It would be best to visually inspect the plants and assess the extent of the damage before deciding whether to use them for your experiments. Additionally, you may also want to consider performing a control experiment with plants that were not exposed to cold temperatures to compare the results.

To identify the potential dopant, you need to consider a number of factors. Like size, charge valance, mixed valences, etc. In addition, your research needs to be clear. Such as, where will be the material applicable, oxide ion base SOFC or H+ conducting SOFC. You know the oxygen permeability of cathode material significantly controls the performance. So, I think lower valance cations (Mg, Zn, Cu, etc) could be an interesting choice for oxide ion-based material. In the case of H+ conducting SOFC, additional issues are there.

Hi Zhaleh

First question:

1. I need a pilot study, or

2. A similar study to yours

Second question:

It is better but not must to be the same to increase homogeneity of variances between groups

Thank you for given a reliable journal link

Dear Yusuf Pradesar

Most probably, in modern times of fuel cells, the bipolar plates carry the electric current from one cell to an adjacent cell. Back then, you can find separate current collectors employed to get the job done.

Gaskets are just to prevent if there is any leak in reactants or product water.

Only some notes:

It is a great dissapointment to me that QUT have expelled me without notice when Prof. Ledwich retired.

In principle the structure given by Ali A. Al-Allaq is correct. About the degree of detail you should discuss with your referee because that's a question of the standards within your department/faculty:

Some want a "closed" document in which you find everything so that the thesis is self-explanatory and does not require actually checking out the references while others have the attitude that they don't want to read too much so they want you to just briefly summarize your method and then reference more detailed introductions.

I am 82 years old and would like to end my career by having my thesis accepted. I am rying to get a grant to build and prove the Traction Simulator which in my view is the most important part of the thesis.

Dear Shoaib Ajmal, the question is really broad and unspecific, so I just give general information. Agjusting pH value is by adding diluted solutions of acids to lower pH and alkaline solutions to increase the pH, and buffers to maintain the pH at a given value.

The third part, pH affect all features of NPs preparation. It is important for precursors dissolution, shape, size, and surface texture, agglomeration/dispersion, morphology, crystallinity and type of morphisms, ..... Please have a look at the following RG thread. My Regards

May be alexnet

ZFC means that the sample is cooled in zero field, thus magnetically in a virgin state, whereas FC means that the sample is cooled under a magnetic field.

In the case of ordered materials with a phase transition(such as AF), the two curves appear identical. But for those with remanent magnetization, the curves deviate as the blocking temperature approaches, such as in spin glasses (or also magnetized ferro ). The larger the gap between FC and ZFC, the greater the hysteresis...

Thank you for your prompt response. I did plate an experiment regarding the titration of anti-cd3 by soluble method and pre-coat method. I did get the cd3 staining by pre-coat method but the titration of anti-cd3 did not affect the stimulation very much.

Hello!!! This is an article that contains a standard protocol, explains step by step.

Y.B Kannan

See our articles for nickel and cobalt ferrites. They will help you solve your problems.

Follow the following procedure:

1. optimize the pure surface (*), and take its electronic energy

2. optimize the adsorption geometry of H atom (H*). You may need to test various adsorption sites.

3. run a vibrational calculation of H*, with only the hydrogen atom allowed for relaxation. Based on the results, calculate the Gibbs free energy of H*. The surface is fixed because the free energy of a solid surface is quite complicated to calculate.

4. Calculate G(H2), and the Grel(H*) = G(H*) - G(*) - 0.5G(H2). Its absolute value is the overpotential.

This procedure is called Norskov's computational hydrogen electrode model.

Thank you for your clarification on the area, Mr Braun. I updated the cell picture and showed the electrodes in it.

Dear Umar Farooq,

The open circuit voltage of a fuel cell is the maximum functioning voltage (while no current flows) and is defined by the chemical thermodynamics of overall cell reaction. The Nernst equation establishes the relationship between cell reaction's standard potential and the open circuit voltage. I. e., if the standard potential at the desired temperature is determined, the open circuit voltage at other partial pressures of products and reactants at that temperature may be calculated.

Hi,

Very good points Szymon! To me also it seems sometimes impossible to compare the results in electrocatalysis due to different measurement and calculation procedures.

Talking about degradation tests, I am not sure about ORR, but in water splitting electrocatalysis the reason why different procedures are all accepted may be that these tests are usually performed in much harsher conditions that is required for industrial applications and they all pass the criteria defined for them to be called "stable".

I suggest reading this paper which is in water splitting electrocatalysis but can be a help for you too!

"Anantharaj, S., et al. "Precision and correctness in the evaluation of electrocatalytic water splitting: revisiting activity parameters with a critical assessment." Energy & Environmental Science 11.4 (2018): 744-771."

Good luck!

Arash

You can get details in paper

Harnisch, F., & Freguia, S. (2012). A basic tutorial on cyclic voltammetry for the investigation of electroactive microbial biofilms. Chemistry–An Asian Journal, 7(3), 466-475.

Even I can help you out for CV measurement & analysis -MFC

Dear Dr. Grigorios Kyriakopoulos,

I appreciate you for your helpful answer in enumerating an energy-efficient and eco-friendly energy coupling technology that is beneficial in exploiting geothermal energy.

Best regards,

Omid

Hello Arjun,

If you plan to work with design and developing activities, try to learn software. Otherwise you can join or develop on-job related to O&M perceptive. At present, Energy sector is at high end.

Dear Arjun, Your passion for learning is admirable. I'm not an expert to help you decide, but as a good friend, I recommend that you gain knowledge about incorporating AI and ML, especially in the energy sector (notably fuel cells and electrolyzers, as the rest already are progressing at their own rhythm with fierce competition). In fact, you should be aware that renewable energy companies (wind, solar, hydro, nuclear) had already significantly aided from the strength of AI and ML so over years, despite the reality that they still have a long road ahead to go in the energy sector. With developed nations intending for a totally green economy, a resourceful and reliable energy power system is a key focus, and there are still a lot to be said about you collaborating with the strategic and tactical level to guarantee the best results.

As of now go through those few research papers, and eventually we must have this discussion prolonged in a positive way to brainstorm ourselves.

Oxygen saturation means the concentration of oxygen in solution at given pressure of O2 in the gas phase. This is called a solubility of oxygen. "how exactly the oxygen concentration can affect the ORR activity?" I would expect an increase of the reaction rate with an increase of oxygen pressure in the gas phase.

You better try Pressure Plate apparatus. Where you can maintain 0.33 bar Pressure. And can determine FC easily.

Faisal Ur Rahman Awan

I could argue with those scientists who argue that the hydrogen wettability of the pores is of great importance. It is better to talk about hydrogen adsorption rather than wettability. After all, hydrogen is not a liquid. Hydrogen adsorption will be in one or two layers, and then, possibly, capillary condensation of hydrogen molecules, but this is also not wettability. If they are stored in storage facilities where there was oil, then hydrogen will dissolve in the pores. It is completely forgotten that hydrogen with various elements forms hydrides. The reaction will be biased towards their formation, since hydrogen will be stored at high pressure (concentration).

Dear Siva Moorthy, please specify the type of the membrane (filtration, electrochemical celles, ...). Please have a look at the attached file. My Regards

The total phenolic content was determined quantitatively using the Folin Ciocalteu reagent, with Gallic acid as the standard.

Yurii V Geletii commenting on a research platform like an amateur social media user is neither professional nor ethical either.

If you don't have to recommend the research it's ok, but commenting on why someone is recommending it, reflects your false ego. [Breakdown:

17.54% Publications out of 229.93]

Hello,

Following an irrigation until saturation of the surface layer (about 30 cm), the reading of the humidity sensor gives you the field capacity moisture (FC) 24 hours after the irrigation. The maximum allowable deflection (MAD) should be estimated at about 30% of the AWC (available water holding capacity - AWC - that you can estimate with FC). For an average soil (less than 8% clay) the wilting point would correspond to a sensor reading after 4 days following the irrigation without any rain or watering during these 4 days.

Best regards.

The difference is ionization efficiency. Some ions 'fly' better than others in the same mode in MS. There is lots of speculation about why this is so, which occasionally breaks out in shouting matches (reaching the point of fist-a-cuffs) at ASMS and other MS conferences. Consequentliy, I will leave my speculations out of this response. However, just like some ions will only be seen in positive ion mode and others only in negative ion mode, the differences in relative ionization between molecules in a single mode can easily give you the result you see. If you really want to see if the molecule is upregulated or downregulated, you can spike the sample with a 13C or 18O-analog of the compound and deconvolve the isotopic patterns quantitatively. see reference attached.

Congratulations!

Hello,

There are so many hydrocarbon membranes have been demonstrated as an alternative for Nafion membranes in PEM fuel cells. However, the durability of such hydrocarbon membranes are lower compared to Nafion membrane because they are highly vulnerable to hydroxy and hydroperoxyl radicals generated in fuel cells. For the research purpose, sulfonated poly (ether ether ketone) (SPEEK) membrane is one of the notable alternative with low cost. To synthesize SPEEK, you may directly buy PEEK and perform the sulfonation.

Thank you very much for the answer

Best Regards

This article might be useful

Dear Vishnu,

many thanks for sharing this interesting and important technical question with the RG community. In view of the extremely high current prices of noble metals like Pt, Ru etc. it is not surprising that researchers make serious efforts to replace these platinum-group metals by cheap transition metals or even non-metallic materials. In this context I can suggest to you the fowlloing very interesting literature reference:

Fortunately this article has been posted by the authors as public full text on RG. Thus it can be freely accessed and downloaded as pdf file. Please also check the references 18 and 19 in this article. They also describe cheap replacements of expensive platinum-group metals for use in methanol fuel cells (DMFCs).

Good luck with your research and best wishes, Frank Edelmann

Many special thanks Prof. Dariusz Prokopowicz for your question! The great reset of energy resources began with the Paris Agreement to which the vast majority of states have acceded, and agreeing to revise their energy strategies at the national level. Along with wind energy, solar energy, hydro energy, hydrogen-based energy seems to be at least now one of the resources optimized by the human factor and can be controlled by the human factor in the production process. Moreover, being a green energy, it agrees with the two Agreements, namely the European Green Agreement 2050 and the UN Green Agreement 2050, which is why it also supports a predictability in the strategic direction of action of any state. Accidents will definitely be part of the process as well. But starting from the personal motto feel-think - act and these types of green energies I appreciate that they must be treated in a balance.

Solvent extraction

Direct aqueous injection

Head space extraction

Hi

In my opinion, the stoichiometry of reactant gas (O2 /H2) is most dependent on the flow field and manifold. To control gas velocity and manage the water content in the channel, in some flow fields you must increase the stoichiometry.

There is no clear rule for correcting stoichiometry but you consider that the best stoichiometry is the minimum amount of it which the PEMFC works stable and has maximum performance.

Most of the time, the recommended stoichiometry of the PEMFC stack is given by the stack manufacturer or power system integrator.

Yes, we have three methods for PEMFC stack operation: Flow-through, Dead-end, and Recirculation. In the third method what you said is happening.

Dear Dr. Yashwant Pratap and

Akula Komuraiah

Thank you very much

My Regards

Annacia Jeffers Thank you for the suggestion. The CV is run on a single cell which has already been conditioned. I will try to scan at a lower rate. Other observation was higher hydrogen evolution current or higher hydrogen desorption in the anode side of CV curve because of that there is a shift in CV curve.

Dear Brian,

I suggest you to search articles about the prediction of field working days based on soil moisture. Good researches can be found. As a research line related to Agricultural Machinery, most of papers deal also with soil mechanics.

Hello,

I am using EIS for finding the equivalent circuit for a cell that I have used in the experiment for measuring dielectric data.

For this circuit model relaxation time for higher and lower frequencies, I am getting almost identical data of different relaxation times to my calculated data.

What could be the reason?

Indeed the external resistance should be comparable to the internal resistance. However, during the starting stage, the internal resistance is supposed to gradually decrease due to the development of functional microbial film on electrodes. So there is no rule, and you may yield different MFCs when apply different resistors.

There are some advices: The internal resistance depends on the surface area of the electrodes and the distances between the electrodes. If the area is huge and the distance is close, choose a resistor less than 1 k ohm, If not, choose more than 1k ohm. If you have no idea, just use any resistor and monitor the CCV for several days. For a conventional MFC, the OCV varies from 0.5 to 0.8. The CCV will decrease dramatically when loaded and slowly recover. If not recover, use bigger resistor; if no significant decrease, use smaller resistor.

Also depends on the purpose. If you want to obtain the maximum power output, the external resistance should be similar to the internal resistance. If the objective is the maximum exolectrogenic biomass growth, the external resistance should be lower to avoid current limitations. Exoelectrogenic activity is proportional to the current intensity; if your intensity is low (higher external resistance), exoelectrogens growth will be limited. When the cell is working at OCV (infinite resistance), intensity is zero and no exoelectrogenic activity is possible.

So you could benefit from these two valuable articles:

First....

"Microbial Fuel Cells: Influence of External Resistors on Power, Current and Power Density".

By: Kamau JM, Mbui DN, Mwaniki JM, Mwaura FB and Kamau GN.

Abstract:

The effect of external resistance on voltage, current, power, power density and current density is investigated in a microbial fuel cells using cowdung is investigated. This involves use of varying resistance resistors. The fuel cells

were operated under anaerobic condition for 9 days. PVC pipe was used to make a salt bridge using lamp wicks and potassium chloride. The obtained results indicated that the maximum voltage was on day 7 with 0.153 V across 33 kΩ resistor. The power was in the range of 0.000001 to 0.01 mW, current density was in the 0.1 to 23.29 mA/m2 range while the power density was in 7.5 × 10-7 to 3.1036 mW/m2 range.

And this is the second article:

"The Influence of External Load on the Performance of Microbial Fuel Cells"

By: Szymon Potrykus , Luis Fernando León-Fernández , Janusz Niezna ´nski

, Dariusz Karkosi ´nski.and Francisco Jesus Fernandez-Morales.

Abstract:

In this work, the effect of the external load on the current and power generation, as well as on the pollutant removal by microbial fuel cells (MFCs), has been studied by step-wise modifying the

external load. The load changes included a direct scan, in which the external resistance was increased from 120 Ω to 3300 Ω, and a subsequent reverse scan, in which the external resistance was decreased back to 120 Ω. The reduction in the current, experienced when increasing the external resistance, was maintained even in the reverse scan when the external resistance was step-wise decreased.

Regarding the power exerted, when the external resistance was increased below the value of the internal resistance, an enhancement in the power exerted was observed. However, when operating

near the value of the internal resistance, a stable power exerted of about 1.6 µW was reached. These current and power responses can be explained by the change in population distribution, which shifts to a more fermentative than electrogenic culture, as was confirmed by the population analyses.

Regarding the pollutant removal, the effluent chemical oxygen demand (COD) decreased when the external resistance increased up to the internal resistance value. However, the effluent COD increased

when the external resistance was higher than the internal resistance. This behavior was maintained in the reverse scan, which confirmed the modification in the microbial population of the MFC.

I have attached the pdf files ....

I hope it will be helpful...

The error lies in this assumption: "Partial Pressure is equal to mole fraction when operating pressure is 1 atm". That is only true, if you disregard the units. However, in order to fulfil the units of the equations you take from Haberman and Young, you really need to be careful with the units:

The partial pressure of each component i calculates from the molar fraction and the pressure, which you assume to be the atmospheric pressure:

X_i = x_i p_(atm) = x_i * 101325 (Pa)

Neglecting this leads to too low reaction rates. Thus, nearly no reaction occurs in your simulation.

Dear all, nice details are summerized by Dr. Manuel Gómez. The attached chapter is an additional support. My Regards

The differential equations for diffusion of phosphoric acid water flows both convective and diffusive rates of evaporation and current flows for different voltages can be relatively easily assembled using a high level program such as Berkeley Madonna which will allow you to graphically connect the elements and parameterize them. BM can be obtained from https://www.berkeleymadonna.com/downloads/ and a trial version is free.

Unknown parameters can be estimated and by fitting graphical outputs of voltage versus currents for different temperatures etc and acid concentrations you will be able obtain best fits. This process is not trivial and will require some work to collect the various constants coefficients and parameters you require. But well worth doing as you will learn much in the process.

In case you are still interested, I have a kW-scale SOFC teat rig, with a range of stacks at Cranfield University.

you can try measuring the temperature of stack or cell at max voltage/current. and try to maintain that. temperature is important to remove the byproduct water and it should be optimized ... some water is also need for ion movement

I agree with @ H.-P. Schulze, you can also see this article for more information about polarity...

If you are looking for an open-source fuel cell framework, I would recommend openFCST. You can download it at www.openfcst.org.

I agree with Ftwi Yohaness Hagos

Hello. DMSO makes the problem in the fluorescence spectrum.

Phaco with low parameters and good viscoelastics.

Any way just watch this if u want

"I Made a Hydrogen Fuel Cell - Infinite Energy!" On youtube

U will find your answer

Maximum efficiency is depended to methods which are used.

Hi, have a look at SweepMe! (sweep-me.net). The Keithley 236 driver works for Keithley 237 as well as for Keithley 238. The program is made to quickly create arbitrary IV sweeps without programming.

Dear all, Electrolysis water spliting and steam reforming of natural gas are the most efficient technological processes. Please check the following documents. My Regards

I totally agree with you

Dear Li Zhou, it is a common problem in LCMS analysis when one wants to assign an identification to observed chromotographic peaks. Unlike in GCMS analysis, ionization of the eluting compounds is not standarized and the resulting mass spectra are not library searcheable. Your options to identify the compounds depend for a large part on the technical parameters of the equipment used and the skills of the operator. For instance, if a well calibrated Orbitrap is used as the MS, chemical composition calculations can shed light on the chemical formula of the eluting compound. Accurate mass can help inmensely, but is not a panacee. The fragmentation pattern, knowledge about the preferred ionization (M+H, M+Na, M-H etc) may help excluding unlikely candidates. The most simple way is to run the verified standards and compare the retention time, accurate mass and fragmentation pattern (which is heavily dependent on the ionization potential of possible coeluting compounds!). I hope this is helpful. Feel free to ask for clarification wherever needed. Kind regards, Harrie Verhoeven

Alex Gupta , Please do share your findings/observations/comments on the same.

Thanks and regards

Mainak

Emmanuele Frasci Thank you very much for the response

Could be bound or hydrogen-bonded water to the surface, which is normal. There are several steps involved in ORR, and protons are needed. Perhaps the bound waters are more acidic than bulk water and act as the proton in PCET during ORR?

Dear Dr.

Cell improvement can be achieved through several influencing points to increase hydrogen production

first. The quality of the electrodes must be of high porosity and conductivity.

Second, the distance between the electrodes.

Third, the concentration of the electrolyte solution is very influential

My regards

Hi.

Yes. may be used and dbyproduct only water vapor

I want a recent update on the practical application. Thank you Ahmad K. Sleiti

Examples can be found here:

DOI:10.1016/j.jpowsour.2010.03.044

Hi.

Chemical reactions that happen at both ends of the fuel cell

At the anode

2H2 => 4H ++ 4e--

At the cathode

O2 + 4H ++ 4e - => 2H2O

Overall reaction

2H2 + O2 => 2H2O

Through this, we notice that the heat is coming out of the cell in the form of water vapor

Best Regards

Dear Dr.

Yes, it is possible to manufacture. The most important notes, first, the design of the cell, second, the type of electrodes used, and the shape of the electrodes made, third, the provisions of the cell so that it is completely closed to avoid leakage

Best Regards