Science topic

Carbonates - Science topic

Carbonates are in chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, CO2− 3. The name may also means an ester of carbonic acid, an organic compound containing the carbonate group C(=O)(O–)2.
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exploring potential instrument for organic carbon and carbonate analysis
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Hi Roberta, thank you for your interest in the HAWK Pyrolysis, TOC and Carbonate Carbon instrument. Please be assured that when you consider the fact that the HAWK needs very minimal maintenance then its cost is in a very good range. We can send you a quote if you would like us to do so. Please let me know. Our website is www.wildcattechnologies.com and you can also reach me directly; albertmaende@wildcattechnologies.com
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it is assumed that interpreting 4D seismic data shot over hydrocarbon reservoirs made of carbonates is more challenging than for clastic reservoirs. Then what could improve the value of 4D seismic for carbonates?
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Rock physics modeling of reservoir changes is required before the firs 4D seismic acquisition using the available well log data. This will indicate if there is a 4D signature for the expected reservoir changes.
The methods startinf from the Gassman theory are mostly applicable to the sandstone reservoir. Care has to be taken when the carbonate reservoirs are considered. See, for example, Øystein et al. (2005 SEG, Adam, Batzle and Brevik (2006), Vanorio, Scotellaro and Mavko (2007) -SEG, Sain et al. (2008) SEG, and Jiang et al., (2013) SEG.
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Please forgive my curiosity and interest. Does deep-sea and shallow-sea sedimentation always correspond exactly to the sequence stratigraphy we currently know? Let's take carbonate sequence stratigraphy as an example, reef formers are shaped by both hrm sea level change and relief as far as we know. So, if we encounter a contradictory sequence of this in the field, how should we interpret it? What we really want to ask is, could there be time intervals where the sequence does not depend on sea level or relief? thanks for your attention.
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Thanks Mr. Carlos Echevarria
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Hai everyone....
I have a medium with added Na2CO3 for algal growth...after somedays algal cells will utilize the Carbonate for its growth...i need to find out how much carbonate ion is consumed by algae after 15 days of growth...Any one kindly tell me the titration procedure for this...
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Hi Divya, you'll most likely want to do a simple acid-base titration, using a standardized concentration of sulfuric acid (maybe starting in the range of 0.01 M H2SO4) and use a pH meter for the end point (can be 4.5 or down to 4.2 depending on composition of ions and expected alkalinity result. Results below 20 ppm CaCO3 usually would use an endpoint of 4.2). You can also use a dye as an indicator for pH endpoint, such as bromocresol green. You can find more information in Standard Methods for Water and Wastewater, "2320 Alkalinity". I would assume some of your carbonate would convert to bicarbonate with atmospheric CO2.
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I need the CIF file of Na2CO3 having space group C2/m with cell parameters (a=9.0107, b=5.2443, c=6.3053, alpha=90, beta=97.3490 and gamma=90) and cell volume of 295.50. This file is present in COD and AMCSD but it has incomplete information i.e. scattering coefficient of C is missing, which is causing problem in Rietveld refinement. Does anyone can provide the CIF file or the source from where I can find the complete detail of this system.
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Hello. This can be more complicated. Apparently it is the gamma phase of Na2CO3 and it is said to be an incommersurately modulated structure. Some structural data is available for download at http://rruff.geo.arizona.edu/AMS/amcsd.php, there type "natrite" in the mineral field and search.
When it is an incommensurately modulated structure, it will work only approximately in most Rietveld's software.
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I was told that anions can not exist in air and always decompose. Is this correct?
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Well this is more than an over-simplification!. Atmospheric carbonates usually correspond to some of the mineral components of airborne particulate matter, actually fragments of rocks resuspended from soil and/or desert dust in the form of calcium and to a lesser extent, magnesium carbonates to which omologues from human activities must be added locally (cement, building excavating...) which are remobilized and mixed in the air like all the particles. This class of particles are mostly coarse (> 1 µm) with a high probability of being fast dry removed to the ground by gravitational settling . However we have to remind the concept of environmental fate for anything recirculated across the planet which includes not only transport but also physical chemistry and chemistry ( even biochemistry) during motion. For carbonate you can expect dissolution by collision with droplets during wet removal processes (therefore a strong influence of meteorolofical processes) and acid- base reactions which may actually bring to carbonate dispacement. One possible reaction of acid displacement of carbonates may be traced to HCl which is fairly volatile, after release from emissions (eg volcanoes) or atmospheric chemistry. However, airborne particulates are historically known to possess predominantly acid properties due to traces of H2SO4, HNO3 and mono and di-carboxylic acids (all substances with high vapour pressure) from atmospheric oxidation of gaseous precursors. In case of collision between carbonates and other aerosol particles more or less loaded with moisture, acidity can be expressed and release CO2. It is clear that any generalization is not allowed. Proof is therfore given in decades of aerosol science and not just research, but also in basic textbooks of atmospheric chemistry such as Fynlayson-Pitts & Pitts, and Seinfeld Pandis From the first through the third edition
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Dear Colleagues.,
I ask about a very strange case that not very common but maybe some body faced it or suggest a reliable interpretation. Is it possible to find diagenetic unmetamorphosed phanerozoic carbonate sandwiched between old assemblage of precambrian volcanics that underwent metamorphism ? and there is no conglomerate or breccia lies at the contact between the basement and the sediments ? noteworthy is the presence of faults is a familiar case in that area.
i attach a simplification sketch cross-section for the case
I would like to hear from you all
Best regards
Ahmed Morad
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I agree with Federico Lucci Federico Lucci, a photo would be really helpful.
In general, what I observe in the field is that faults in carbonates can form as very thin structures. There´s not necessarily a breccia or a large damage zone involved.
So, it´s worth having a closer look for any markers, i.e. striation, gauge.
In other words: I can not imagine that the carbonate is not metamorphosed if the contact is original.
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In order to perform Michaelis-Menten plot to calculate Km for oxa beta lactamase , I used nitrocefin as substrate , 100mM sodium phosphate di basic and 25mM sodium carbonate as buffer pH 7.3
Enzyme concentration 20nM
Substrate concentrations
1 uM
5 uM
10 uM
20 uM
30 uM
40 uM
50 uM
70 uM
80 uM
100 uM
Wavelength 490 nm
In order to calculate Vo ,
I plotted the absorbance values of each concentration vs time. The problem is , the slope for all the concentrations are same which means that Vo of all substrate concentrations are same.
Where is my mistake?
concentrations of the enzyme?
Concentration of the substrate?
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Ok, looking at your progress curves a few things spring to mind. Firstly, V0 is initial rate and should be taken from the first linear part of the curve, before it starts to level off. This is in practice somewhat arbitrary, but if you do this for your experiment here you should get different inital rates.
However, in your case this brings us to another issue, which is that, particularly in the higher substrate tests, your reaction is essentially over before you start measuring, so you will not get accurate initial rate estimates with this data. I would reduce the enzyme concentration or lower the temperature to get curves that look linear for longer (you need to slow down the reaction). Ideally, you highest substrate concebtration curve should look something like your lower concentrations do now.
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This foraminifera is the only specimen found in a Maastrichtian small isolated carbonate platform in Costa Rica, Central America.
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I would try with bryozoans...no foraminifera!
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Hello, Could anyone help me identify these fossils, please ?. These fossils inside Early Cretaceous age carbonate rocks. Are these fossils algae?
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Please provide us with a more detailed investigation of
a) lithology (carbonates, sulfates..)
b) body fossils and trace fossils others than this
c) existing environment analysis.
I suggests algal growth forms (?)
For more details and for comparison also of images see the study:
DILL, H.G., BOTZ, R. , BERNER, Z., STÜBEN, D., NASIR, S. and AL-SAAD, H. (2005) Sedimentary facies, mineralogy and geochemistry of the sulphate -bearing Miocene Dam Formation in Qatar.- Sedimentary Geology, 174: 63-96.
HGD
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Hello,
I am trying to measure Fe (II) with the 1-10-Phenanthroline method in my water samples that will come from hydrothermal experiments containing CO2. Preliminary testing show that carbonate interferes with the measurement. Does anyone know of a work around to this?
Thanks,
Victoria
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At first blush, I would suggest acification and/or vacuum degassing. Sparging with an inert gas is also usually effective in removing active gases like oxygen and carbon dioxide. These should generelly not influence the oxidation state of Fe(II) in solution.
Though of course the ease of this depends on your amount of avalaible sample I would presume.
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When I do the PPC-PC reverse dry transfer method, PPC and the sample fall on the PC, and then I melt the PC/ sample /PC onto the silicon chip, how do I remove both PPC and PC to get the sample?
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The process of removing both PPC (photoresist) and PC (protective coating) layers after the reverse dry transfer method involves applying a suitable solvent to the sample to dissolve both layers. After dissolution, the layers are gently removed through rinsing with an appropriate cleaning agent, such as a solvent stream or a soft brush, followed by rinsing with isopropyl alcohol or deionized water. Once dried, the sample is inspected to ensure complete removal of the layers and is ready for further processing or analysis.
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Reservoir Geology
As against ‘sandstone reservoirs’, ‘carbonate reservoirs’ are usually characterized by ‘extreme’ and more often ‘random’ variations of porosity, permeability and rock-type within a field (associated with the highly-soluble nature of carbonate rocks). Since, the original character of the sedimentary sequence – in a carbonate reservoir - gets ‘greatly’ altered by either solution; cementation; fracturing; or, by mineral replacement; would it remain feasible by ML/AI to deduce any sensible correlation of logical patterns of porosity and permeability distribution of various carbonate reservoirs?
Whether the knowledge of ‘original sedimentary patterns’ (recognition of specific depositional events in a carbonate reservoir that could possibly lead to the major flow paths and to deduce the effect of various types of reservoir energies on ultimate oil recovery) could be of any help – while using ML/AI - towards deducing fruitful insights on characterizing fluid flow through a carbonate reservoir?
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The complexity and heterogeneity of carbonate reservoirs make them particularly challenging to model and predict. While machine learning (ML) and artificial intelligence (AI) methods have proven valuable in a range of geoscience and reservoir engineering tasks, their efficacy in deducing sensible correlations of logical patterns of porosity and permeability distribution in carbonate reservoirs may vary depending on the quality and diversity of available data.
Key considerations include:
  1. Data Availability: ML/AI techniques thrive on large, diverse datasets. Predicting porosity and permeability patterns in carbonate reservoirs would rely on access to comprehensive, high-quality data that captures the reservoir's characteristics. This might include well logs, core data, seismic data, reservoir production history, and any other available geoscience data. The more comprehensive and diverse the data, the better the ML/AI model can learn the complexities and randomness inherent in carbonate reservoirs.
  2. Feature Selection: The key to creating a successful model is identifying the features that impact the target outcome most (in this case, porosity and permeability). Understanding the original sedimentary patterns and their relationship to flow paths and oil recovery could certainly be valuable. Other features might include mineralogy, diagenetic history, grain size, sorting, bedding characteristics, fracturing, etc. Advanced ML techniques can also help to identify non-obvious relationships between features.
  3. Modelling Approach: Various ML/AI techniques might be suitable depending on the nature of the data and the problem. Supervised learning methods such as random forest, support vector machines, or deep learning might be used if there are labelled examples (e.g., core measurements of porosity and permeability). Unsupervised learning methods, like clustering or principal component analysis, might be used to identify natural groupings or patterns in the data.
  4. Validation: Any model developed should be rigorously validated using independent datasets. This is particularly important given the complexity and heterogeneity of carbonate reservoirs.
In summary, while predicting porosity and permeability distribution in carbonate reservoirs using ML/AI methods is challenging due to their highly complex and variable nature, it is not infeasible. The key lies in the quality and diversity of the data, careful feature selection, appropriate model selection, and rigorous validation. However, it's important to remember that ML/AI models are tools to assist with interpretation and decision-making, and their outputs should always be assessed critically in the context of broader geological understanding.
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Electrochemical cell. Sandwich-like structure: Conductive FTO electrode 1, Tungsten oxide layer 2, LiClO4 propylene carbonate solution electrolite 3, and FTO counterelectrode 4. Isolated system with no contact with air. Li+ intercalation into Tungsten oxide gives electrochemical reaction on applied direct current.
So the question is: EIS gives such unordinary result (watch Aftermath project below, or xls file). How on Earth could this be? What could explain low frequency small semicircles or inductive loops? What equivalent circuit could you suggest?
P.S. I suppose some of intercalated ions could deintercalate (or vice versa) during one way low frequency AC, otherwise the reaction goes slower. Let me know your suggestion
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1. Is this result repeatable ?
2. Did you check the linearity of your system?
3. Is your data consistent with the Kramers-Kronig relations?
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Effective Porosity: Feasible to measure?
Since, most of a 'petroleum reservoir cross section' remains occupied ‘by rock’ and ‘by oil and water’ that remains securely attached to the rock surfaces by molecular attraction, the ‘actual’ area through which ‘the water and oil keeps flowing’ is definitely going to be lesser than the ‘total’ reservoir cross sectional area of the oil and water bearing petroleum reservoir. In this context, would it remain feasible to deduce this ‘reduced cross-sectional area’ through the fluid (oil and water) keeps flowing?
Is there a way to grab the details on the effects of ‘attached water and oil’ that would probably help us to deduce the extent by which the ‘effective-porosity’ has been reduced from its actual value?
To what extent, this effective porosity would influence the resulting migration of ‘water flow’ and ‘oil flow’?
To what extent, the 'reservoir pressure' would influence the resulting 'effective porosity' associated with a sandstone and a carbonate reservoir?
Is there 'a straight-forward method' to determine the effective-porosity of a petroleum reservoir? If any such direct method exists, then, what exactly (which force) is supposed to drain ‘water and oil’ from those inter-connected pore-spaces?
Feasible to precisely estimate the volume of water and oil that remains retained by the petroleum reservoir as ‘specific retention’ (volume of oil and water that cannot easily drained by free gravity)?
In the absence of precise value on effective porosity, how do we deduce the ‘oil flow rate’ and ‘water flow rate’ exactly?
How do we have a control over the details on
(a) the degree of compaction encountered by matrix-porosity (microscopic porosities); and on
(b) the degree of intensity of fracturing – resulting from overlying rock mass – as a function of depth - towards estimating 'effective porosity'?
To what extent, the extent of ‘effective porosity’ associated with the matrix (primary) and fracture (secondary porosity) in soluble carbonate reservoirs 'gets modified' by 'the process of karstification or dissolution of carbonate minerals' by 'flowing brine containing weak carbonic acid' (assuming major oil fields around the globe remain hosted in limestone and dolomite reservoirs, which keep encountering various depositional environments and processes of its diagenesis)?
When the diameter and throat size, in general, have no relation to sedimentary particle size or sorting in a carbonate reservoir, how do we then deduce the ‘average pore sizes’ in a carbonate reservoir associated with low-permeable rock-matrix; and how exactly, we deduce the 'average fracture aperture thickness' associated with the high-permeable fracture-network?
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  1. Is it feasible to measure effective porosity in a petroleum reservoir?
Yes, it is feasible to measure the effective porosity of a petroleum reservoir using various techniques such as core analysis, well logging, and seismic imaging. However, it is important to note that effective porosity is a dynamic property that changes over time due to fluid flow and rock deformation.
2. Is there a way to determine the extent to which effective porosity is reduced by attached water and oil?
Yes, laboratory experiments can be conducted to determine the impact of attached water and oil on effective porosity. These experiments involve saturating rock samples with fluids and measuring the resulting change in porosity.
3. How does effective porosity influence water and oil flow in a reservoir?
Effective porosity is a critical property that determines the ability of fluids to flow through the rock matrix. A higher effective porosity generally leads to a higher flow rate of oil and water.
4. How does reservoir pressure influence effective porosity in sandstone and carbonate reservoirs?
Reservoir pressure can have a significant impact on effective porosity, particularly in carbonate reservoirs. Increased pressure can lead to the dissolution of carbonate minerals and the creation of new porosity, while decreased pressure can cause compaction and reduction of porosity.
5. Is there a straightforward method to determine effective porosity, and what force drains oil and water from pore spaces?
There is no one-size-fits-all method for determining effective porosity, and multiple techniques may need to be used to obtain accurate measurements. The force that drains oil and water from pore spaces is generally a combination of capillary forces and gravity.
6. Is it feasible to estimate the specific retention volume of water and oil in a reservoir?
Yes, it is feasible to estimate the specific retention volume of water and oil in a reservoir using laboratory experiments and reservoir simulation software.
7. How do we determine oil and water flow rates in the absence of precise effective porosity values?
In the absence of precise effective porosity values, flow rates can be estimated using empirical correlations based on well log data or reservoir simulation software.
8. How do we control the degree of compaction and intensity of fracturing in estimating effective porosity?
The degree of compaction and intensity of fracturing can be controlled by using advanced drilling techniques and optimizing production strategies based on reservoir properties and geomechanical models.
9. How does karstification or dissolution of carbonate minerals impact effective porosity in carbonate reservoirs?
Karstification and dissolution can significantly increase effective porosity in carbonate reservoirs by creating new pore spaces and enlarging existing ones. However, the impact of these processes can be complex and depend on various factors such as the type of carbonate minerals present and the fluid chemistry.
10. How do we determine average pore sizes and fracture aperture thickness in a carbonate reservoir?
Average pore sizes and fracture aperture thickness can be determined using various techniques such as core analysis, well logging, and imaging. However, it is important to note that these properties can vary significantly across different regions of a reservoir and at different depths.
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Chemical EOR
1. What exactly dictates the economic viability of a surfactant-aided chemical EOR - despite it's retention of surfactants through adsorption, precipitation, degradation & phase-trapping?
2. How exactly are we able to upscale - the observed physical/chemical processes associated with the ‘surfactant adsorption’ (van der Waals interactions between non-polar surfactant chains, hydrogen bonding, chemisorption, surface precipitation, electrostatic interaction, ion exchange, hydrophobic tail-solid interactions) from ‘sub-pore-scale’ to Darcy-scale?
Feasible to bridge the gap, if the cores are aged with crude oil in the presence of connate-water?
3. Feasible to quantify the magnitude of adsorbed surfactants as a function of formation brine-composition, reservoir rock-type and its mineralogical composition, pH & salinity of in-situ and injected fluid phases, surface-redox potential and the fundamental chemical structure of the injected surfactants?
4. What is the fraction of ‘total adsorbed surfactants’ that tend to get desorbed as a function of time (sorption kinetics)?
Does it depend on ‘surface wettability’ and ‘redox state’ of the used cores?
5. How do we ensure whether the rate at which surfactants get adsorbed remain the same - throughout the surfactant-aided chemical EOR treatment?
6. How about the desorption of surfactants?
Whether, do we have a correlation between surfactant adsorption and desorption rates?
7. Under what circumstances, are we supposed to expect
(a) non-equilibrium adsorption?;
(b) non-linear adsorption?; &
(c) sorption kinetics of the surfactants
associated with the surfactant-aided chemical EOR?
8. To what extent, are we able to restore a sandstone core from an oxidized- to a reduced-state towards replicating anaerobic reservoir conditions @ lab-scale in the absence of impacting core-mineralogy and pore-structure?
Feasible to quantify the reduction in surfactant adsorption in cores under anaerobic conditions - resulting from oxide removal and calcite dissolution?
9. Considering reservoir surface hydrophobicity as a function of time, how about the natural correlation between ‘the oil or water-wet surfaces of a sandstone/carbonate reservoir rock’ and ‘the adsorption of surfactants’?
10.                   How about the rate of wettability alterations for a sandstone and a carbonate reservoir?
11.                   How exactly the ‘specific surface area’ and the ‘adsorption density per unit surface area’ gets altered in a typical sandstone and carbonate reservoirs – resulting from wettability treatment of cores at the laboratory-scale – before and after reaching CMC?
12.                   Whether the observed ‘arrival time of surfactant front’ @ lab-scale would match with the field-scale scenario?
13.                   To what extent, the observed results on the surfactant concentration @ lab-scale reflect the real field scenario, particularly, following the surfactant breakthrough?
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You are facing a very difficult problem! In a multicomponent (polygenic) rock (without destruction), only physical and hydrophysical parameters can be studied. To study physical and chemical processes, it is necessary to decompose the rock into separate mineral and organomineral formations and study each separately, and then, most likely, model. But I foresee that the model will not give high accuracy.
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Phosphate, carbonate, chloride, and phosphate ions can all be found in simulated body fluids. What chemical process may be used to remove the corrosion product?
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  1. Surface Preparation: The surface of the magnesium alloy should be cleaned thoroughly before starting the cleaning procedure. The surface can be cleaned using a degreaser or a mild detergent. The surface can then be rinsed with distilled water and dried with a clean cloth.
  2. Chemical Bath: The magnesium alloy can be immersed in a chemical bath containing a solution of mild acid, such as dilute acetic acid or citric acid. The concentration of the acid solution may vary depending on the severity of the corrosion. The alloy should be left in the solution for a specific time, usually 5-30 minutes, depending on the type of acid and the severity of the corrosion.
  3. Neutralization: After the magnesium alloy has been immersed in the acid solution, it should be removed and rinsed with distilled water to remove any excess acid. The surface should then be neutralized by immersing the alloy in a bath of alkaline solution, such as sodium bicarbonate. This will help to neutralize any remaining acid and prevent further corrosion.
  4. Passivation: The magnesium alloy can then be immersed in a passivation solution to help prevent further corrosion. The passivation solution can be a chromate or phosphate-based solution, which will form a protective layer on the surface of the alloy.
  5. Final Rinsing and Drying: After the passivation process, the magnesium alloy should be thoroughly rinsed with distilled water to remove any remaining chemicals. The surface should then be dried with a clean cloth.
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My background is in geology/geochemistry so I have never dealt with preserved organic specimens before. I recently acquired some preserved modern crinoids that I would like to process and analyze for major/trace element concentrations (mainly Ca, Mg, Sr, Mn) and calcium isotopes. I will be analyzing the mineralized skeleton of the crinoids, which are composed of high-Mg calcite, and have an established procedure to eliminate the organic mater from the samples involving a multi-step treatment with HCl and hydrogen peroxide. However, this procedure was established for calcified algal mats that were stored in water in a fridge, and not alcohol/formaldehyde.
These crinoid samples were collected in the early 90s and have been sitting in alcohol/formaldehyde for the past ~30 years. While alive many crinoids are brilliant in colour (reds, oranges, yellows, etc); however the preserved samples I have are dull brown or pale white in colour. Does this mean the preservation solution has leached or broken down some of the organic pigments? If the preservation solution is leaching/breaking down the organic matter, would it also affect the mineralized skeleton? I will be analyzing the crinoid sample on an ICP-OES, so maybe it would be worth it to analyze some of the preservation solution?
Thanks for any help or insight!
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Alcohol and formaldehyde preservation solutions are commonly used in the preservation of skeletal carbonates. However, there is a concern that these solutions may leach elements from the skeletal carbonates, which could potentially affect the accuracy of isotopic and elemental analyses.Several studies have investigated the effects of alcohol and formaldehyde preservation solutions on skeletal carbonates. One study found that formaldehyde preservation did not significantly affect the stable isotopic composition of skeletal carbonates, but it did result in a slight decrease in calcium concentration. Another study found that alcohol preservation did not significantly affect the stable isotopic composition or elemental concentrations of skeletal carbonates. However, some studies have reported that both alcohol and formaldehyde preservation solutions can leach elements from skeletal carbonates. For example, one study found that alcohol preservation caused a significant loss of magnesium from coral skeletons. Another study found that formaldehyde preservation caused a significant loss of strontium from bivalve shells. Overall, the effects of alcohol and formaldehyde preservation solutions on skeletal carbonates appear to be dependent on several factors, including the type of carbonate, the concentration and duration of exposure to the preservation solution, and the specific element being analyzed.
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I have amount of Hcl used and it's concentration
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Carbonate and bicarbonate are important ions in water chemistry. The concentration of these ions can provide information about the water's pH, alkalinity, and hardness. Here are the equations for calculating carbonate and bicarbonate concentrations in water: 1. Carbonate (CO3^-2) Calculation: Carbonate ion concentration can be calculated from the total alkalinity (TA) and pH of the water using the following equation: CO3^-2 = TA / (10^(pH-pKa1) + 10^(pH-pKa2) + 1) where pKa1 and pKa2 are the dissociation constants for carbonic acid (H2CO3). The values of pKa1 and pKa2 are 6.35 and 10.33, respectively, at 25°C. 2. Bicarbonate (HCO3^-) Calculation: Bicarbonate ion concentration can be calculated from the total alkalinity (TA) and pH of the water using the following equation: HCO3^- = (TA - CO3^-2) / (1 + 10^(pKa1-pH)) where pKa1 is the dissociation constant for carbonic acid. It is important to note that these equations assume that only carbonate, bicarbonate, and hydroxide ions contribute to the alkalinity of the water. Other ions such as phosphate, silicate, borate, and organic acids may also contribute to alkalinity and affect the accuracy of these calculations.
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The sample to be activated is for use in adsorption test experiment
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It depends on the starting concentration and the reagent, I think it's too general to say either all must be concentrated or not. I would look at reagent concentrations from past literature to inform your decision as that will likely dictate what your starting concentration should be for the activating agent.
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I want the correct method to infiltrate the carbonate mixture into a ceramic hollow fibre membrane. Based on some of the publications stated that the carbonate mixture needs to be pre-heated at 600oC before the addition of membrane in a vertical furnace. Do I need to pre-heated the carbonate mixture, or can I just put the membrane in the carbonate mixture and heat at 600oC?
I also need to know how to put the mixture in a vertical furnace. How can a vertical furnace hold the sample?
I appreciate any help you can provide.
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For step 2, the membrane should be submerged in the carbonate mixture at room temperature, after the mixture has been prepared and any required pre-heating has been completed. The carbonate mixture should not be in a molten state, as this would likely damage the membrane.
For step 3, the infiltration process typically takes place at room temperature or slightly above room temperature, and the temperature is not usually raised until the membrane has been fully infiltrated with the carbonate mixture. Once the infiltration is complete, the membrane is typically cured at a high temperature, such as 500-800°C, to ensure proper setting and bonding of the carbonate mixture.
I hope this helps.
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This the XRD Spectrum of the polymer being carbonized.
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Hello,
The X-ray diffraction pattern of a material can reveal information about the crystalline/amorphous structure and phase composition of the materials. In the case of biopolymers, they typically show broad peaks due to the overlapping of different crystal planes within the polymer chains and also because of their semi-crystalline nature whereas, the carbonates, typically show well-defined and sharp diffraction peaks due to their highly ordered structure.
Thus, depending on the relative quantities of the two components and the level of crystallinity in each component, the diffraction spectra in a biopolymer-carbonate composite may exhibit both broad and sharp peaks. The peaks may also show shifting or broadening due to the interaction between both components in the composite. Based on this spectral analysis, one can determine the information regarding the phase composition and crystalline structure of the material.
Hope this information might help you in your XRD analysis.
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I am new to modeling, i am only familiar with Gaussian (quantum mechanics only)
And I want to model the adsorption mechanism of Dye Methylene blue on metal carbonate because therir are many psoible mechanisms like elecrostatic attraction force or Hydrogen bond. I don't know if it works with quantum mechanics or classical mechanics.
plz advice me
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You're welcome Aly Reda.
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CARBONATE RESERVOIR CHARACTAERIZATION
1.   As against primary porosity - either inter-granular or intra-particle porosity (which mostly remain insensitive to stresses and thereby not actively participating in dictating the resultant preferred orientation),
(a) if the spatial distribution and alignment of primary fractures and secondary fractures (micro-cracks) in a given direction could contribute to the anisotropic behavior of carbonate reservoirs – as a function of regional stress distribution; and
(b) if the presence of secondary pores such as vuggy/fenestral/moldic/inter-crystalline porosity could contribute the stiffness (leading to a significant difference between acoustic log porosity and neutron-density log porosity) and strength to the carbonate reservoirs; then,
to what extent, are we successful in characterizing the quality (and elasticity) of a carbonate reservoir by measuring the various in-situ secondary pore-types?
And, how easy/difficult would it remain, if the secondary porosity keeps varying as a function of (varying) effective stress?
Can we still manage to characterize the above system with the data from neutron-porosity and sonic-logs (albeit, their inability to directly measure the rock’s pore-types)
or
an averaging between HSW/Reuss lower bound and Voiget upper bound would sound better for a carbonate reservoir?  
2.   In the presence of a formation damage, will we be able to qualify fracture porosity when VDL remains negative;
or,
Formation/Electrical micro-imagers would remain better (or a micro-CT)?
3.   Leaving aside the micro-cracks associated with the fracture-porosity, which one of the following three:
(a) clay-related pores;
(b) inter-grain and inter-crystal pores; and
(c) stiff pores;
would predominantly aid
in migrating the mobility of oil
from low-permeable rock-matrix to high-permeable fractures?
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Dr. Govindarajan, greetings. If you are trying to characterize a reservoir with permeability anisotropy related to natural fractures, your biggest challenge is the inadequacy of borehole data to describe the fracture system. Several tasks must be undertaken to provide the context to extrapolate borehole data to the drainage area that would be sampled by dynamic well production data for history matching. The first task is to understand the relation of the reservoir-scale geologic structure to the regional stress field. Second, find suitable outcrop analogues to your reservoir based on what you know from the first task. Third, some attempt to develop a probabilistic geostatistical understanding of the fracture geometry and intensity at the reservoir scale from the outcrop analogue would help understand the range of uncertainty to apply to your wellbore data. The amount of uncertainty inherent in using just the wellbore data without a context to extrapolate it makes successful prediction difficult. John Lorenz has published data comparing vertical and horizontal cores that sampled fractured reservoirs. His work on the Multi-Well Experiment in Colorado would be a starting point.
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Why do you use a coating buffer containing carbonate / b-carbonate for ELISA?
Do you use a combination of carbonate and bi-carbonate?
Or do you just use one of them? If yes, when do you use carbonate and when b-carbonate?
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I think that the relatively high pH of the bicarbonate/carbonate buffer that is often used for coating ELISA plates destabilizes protein structure sufficiently to expose the hydrophobic interior, which makes the protein more prone to sticking to the hydrophobic surface of the plate.
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Although formed over thousands of years, carbonate ramps forming where ocean sediments accumulate multicellular algae may be affected by ocean chemistry in such a way as to have a unique morphology.
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Hi Tristan, in my experience with carbonate ramps the role of algae would be secondary to other factors that would, in fact, control the type and distribution of algae. These factors would include the slope of the surface that the ramp grows on and climatic conditions. One good outcrop example comes to mind that you might want to check out: The Permian San Andres (note: not a misspelling of San Andreas) carbonates occur as a series of ramps that gradually give way upward into a rimmed shelf capped by the famous Capitan Reef of Guadalupe Mountains National Park. The literature is voluminous so you could research the role of algae in the ramps vs. rimmed shelves and maybe see something no one has thought of before. Cheers!
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I am trying to prepare a bicarbonate buffer for TNBS analysis which requires a 0.1 M bicarbonate buffer of pH 8.5. Most of the chemical suppliers have a reagent of 1 M and of different pH. I have been told that I can use carbonate and bicarbonate to make the buffer using the Henderson-hasselbalch equation, but I am not sure how to calculate exactly how much concentration or volume must be added in order to obtain a specific pH buffer of the same. Can anyone point out the exact process to make the same? Thanks.
[I have also attached the protocol steps for reference.]
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In many formulation of silicate paint they add 1% of 'white spirit'. Other main ingredients are K-silicate - about 25-30%
Carbonate filler - about 30%
Water - 15-20%
TIO2 or pigment - about 10%
Polymer - 8%
So what is the reason to add white spirit?
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Kothapu GOPAL Reddy water is also controls the viscosity
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I have preserved my water samples with HNO3. The samples collected from field and brought to lab after 2 days. Now can I determine Carbonate and bicarbonate from HNO3 mixed sample?
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No. In acid medium , carbonate and bicarbonate may not be measured.
For the measurement of carbonate/ bicarbonate , some some standard methods are recommended and followed.
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I am working with polymer:salt aqueous two phase systems to purify a small organic chemical product. The distribution of the chemical depends on the pH of the solution, so I want to test different pH values and with different salts.
The first problem I have, is that the different salts (Potassium carbonate, Sodium sulfate, Potassium phosphate) will affect the pH due to their acidity/basicity. I thought I might formulate solutions with the desired pH values by mixing specific ratios of the acids and conjugate bases, but the desired pH values are sometimes far from the pKa values of the buffers (e.g. pH 10 in a potassium buffer). I am not sure if the Henderson Hasselbach equation can be used in such cases, and the predicted pH would still be off due to the high ionic strength (~1-2 M), beyond what the Debye Hückel theory can correct for.
Alternatively I thought I might just adjust the pH of the buffers with strong acid/base.
The second problem I have, is that I can't accurately measure the pH values of concentrated (~10-20% w/w) salt solutions with a standard glass electrode. I am considering using the specific salt as a filling solution in the electrode instead of KCl, or using a buffer with the salt for calibration. But I don't know how either approach will work in practice.
Any advice, input, or references would be welcomed!
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You need special electrode for salt solutions which mostly used in marine sciences.
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Dear all,
I have nepheline syenite gneisses, consisting of grossular-andradite (grandite) series garnets. Other minerals of these rocks are nepheline (seldom altered), plagioclase, k-feldspar, calcite, amphibole (Ca-rich), titanate, sodalite, and cancrinite. Pyroxene is however absent and the amount of biotite is quite low. In the field, highly weathered carbonate veins are also noticed. Do these garnets indicate any carbonate activity (metasomatism) in the alteration of the original minerals of protolith nepheline syenite or any metamorphic effect? Answers and suggestions are welcome.
Thank you
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Cancrinite is one of the most common replacement/alteration products in Ne-bearing magmatic and metamorphic rocks under hydrothermal conditions
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Does anyone know about a study where the concentrations of one or more redox-sensitive elements including uranium, molybdenum, and vanadium are reported for the silicates/carbonates rocks in the Himalayan regions?
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The Kathmandu-Banepa Basin is a "chemical waste-paper basket" for trace elements. We created a chemical atlas of that region collecting the elements of the Lesser and Higher Himalayas:
DILL, H. G., PIYA, B., ROETTGER B., TALLIG, A., DOHRMANN, R., WECK H.- D., SIEWERS, U., BUSCH, K., KHADKA, D.R. and KHANAL, R. (2002) Chemical and mineralogical compositions of fine-grained siliciclastics in the Kathmandu-Banepa Basins – Base maps for environmental and economic geology.-Zeitschrift für angewandte Geologie, 48: 30 – 48.
HGD
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Hai everyone...Can anyone help me how 1.3g/L of Na2CO3 is calculated for 5% CO2. from the below reference took from research article.
****Reference****
The values of sodium carbonate concentrations corresponding to 5%, 10%, 15%, 20% and 30% CO2 concentrations at pH 7 are 1.3 g/L, 2.6 g/L, 3.8 g/L, 5.1 g/L, and 7.6 g/L, respectively.
****Reference****
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Divya Ganesan I looked at the paper and another one (Upendar et al. 2018). The difference between your and their amounts of Na2CO3 could be from using different volumes of flasks. The exact amount of Na2CO3 without specifying other points is very strange, it is not professional. I would ignore this discrepancy, not everything published is correct! If you still have doubts, then just use any available gas analyzer: GC, IRGA, mass-spec, etc. As the last resort, if none is available in your laboratory, you can apply the 'ancient' method of absorbing CO2 with an alkali trap and titration. The dfference between 0.22 and 1.3 is more than 5 times! Also, you can take a pure compressed CO2 from a tank or from dry ice and inject 5 ml with a syringe into a 100 cc flask to have ~5%. Then you compare it with gas mixtures prepared from Na2CO3.
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Hi,
I would like to have the vdw force field parameters of different phosphate and carbonate ionic species (eg. PO4,3- / HPO4,2- / HCO3,-) for a molecular dynamics simulation.
I'm not well familiar with charmm and amber force fields. So, my question is if I can obtain the parameters from these FFs? and if yes, which one is more sound?
I would appreciate any specific articles and/or tutorials related to my question.
Thanks in advance,
Azade
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Gourav Shrivastav Can you elaborate on that response?
Because whenever I try to build a phosphate buffer imitation in CHARMM-GUI using AMBER or OPLS ff (even sometimes with the CHARMM36m ff) it responds that the HPO4 force field cannot be found.
I tried using solution builder with CHARMM-GUI's own ions and with multicomponent assembler with manually built HPO4 ligands through Ligand Modeler.
Both cases refuse to work with AMBER and OPLS force fields, mostly AMBER ff.
I was building a 100A wb, with a 11 amino acid peptide, for the GROMACS suite. Standard conditions: 303.15K, Monte-Carlo placing method, no additional modifications, ligands or HET molecules from what CHARMM-GUI loads by default.
Im guessing this was the question from Azade.
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From literature, I am aware that Ce anomaly in marine and carbonate sediments are good indicator of depositional setting, but this alone cannot be used for this purpose as it may be influenced by the detritus phase. I would like to know if there are other geochemical indicators which could be used to reliably predict depositional environments in carbonate sediments.
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First and foremost you should spend more time on describing the mineralogy/ petrography of your calcareous rocks. Are they impure limestones with a lot of detrital material or are they almost clean dolo- or limestones. Are the impurities only non-organic or also contain organic matter. In the latter case you can make use of biomarkers determined with organic chemical methods. But be cautious they can be formed in-situ or immigrated hydrocarbons. In case of true mineral impurities different mineralogical and chemical parameters can be harnessed.
Common limestones contain:
Ø calcite
Ø Mg calcite (MgCO3 = 0 to 6 %; > 11 % at T values > 15°C and higher- up 40 %)
Ø ferroan calcite (reducing environment)
Ø dolomite
Ø ferroan dolomite/ ankerite (reducing environment, late diagenetic)
Ø siderite (reducing environment, late diagenetic)
Ø collophanite/ hydroxyl-apatite
Ø clay minerals (e.g,. illite, smectite, sepiolite, glauconite...)
Ø alkaline feldspar
Ø siliceous compounds (derived from spicules, radiolarian tests, diatoms
Ø sulfate (gypsum, celestite)
Ø chloride (halite)
Now you must know which trace elements can be accommodated in the lattice of the major minerals and how can the substitute, e.g., for Ca, P etc.
Fe in calcite is a redox indicator
Cl, S, Mg and Sr are controlled by strong evaporation
Co, Ni, V, Cr are governed by the clay minerals and good redox indicators
In case of phosphates you can use the entire REE spectrum, Eu and Ce anomalies tetrad effects etc.
Feldspar is not relevant it is a diluter.
You can also use Ca, Sr and S isotopes for chemo-stratigraphy and some kind of age dating using the seawater curve.
This is a first approximation
HGD
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Seismic Inversion and Carbonate Reservoir Characterization
1. Feasible to precisely understand the rock properties – from the spatial variations in impedance contrasts – towards estimating the carbonate reservoir properties (away from production well) – using seismic amplitude data?
2. To what extent, the details on the fracture-size, fracture-shape distributions – could be deduced – using seismic responses (spatial variation of impedance contrasts) – towards identifying optimal drilling locations – in a carbonate reservoir?
3. To what extent, the details on the mineral composition and interaction among minerals – will influence – the fracability of a carbonate reservoir – using the approach of seismic acquisition, processing and pre-stack inversion?
If so, then, how exactly to relate the fracability of a carbonate reservoir to the seismic estimates – on the ratio of differential horizontal stresses; the pressure to initiate fractures; and the closure pressure?
4. Have any major limitations - associated with the ‘isotropic’ seismic inversion algorithm – towards estimating the continuous rock properties – of a carbonate reservoir - at the seismic-scale?
5. How sensitive will be – the coupling between ‘rock-physics modeling’ and ‘pre-stack seismic inversion’ – towards ‘value estimation from grid searching’ – in a carbonate reservoir?
6. Feasible to justify the assumptions of (a) linear approximation for reflectivity; and (b) the natural logarithms of P-impedance, S-impedance & density to have a linear correlation – in a carbonate reservoir – towards simultaneous inversion of pre-stack seismic data?
7. To what extent, the simultaneous investigation of rock properties of a carbonate reservoir – along with the interpretation of seismic attribute variations – would really mitigate the contradictions, if any – arising from – having both explicit and implicit relationships between rock and elastic properties of a carbonate reservoir?
8. To what extent, will we be able to achieve the ‘accuracy’ of ‘seismic inversion’ - in a carbonate reservoir?
What are the consequences of not inverting the elastic properties correctly – in a carbonate reservoir (apart from the difficulty of correlating the carbonate rock properties with the seismic attributes)?
Feasible to perform ‘anisotropic inversion’ – in a carbonate reservoir (in the absence of anisotropic measurements @ both log-scale and laboratory-scale, while the seismic data quality @ far offsets remaining poor)?
9. How easy/difficult will it remain - to capture the impedance contrast - at the fracture-matrix interface - in a carbonate reservoir?
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As a practicing geophysical consultant, my approach would be to find an established field with a 3D seismic survey, and see what I can see. This is what I did years ago, perhaps you should try it. The Texas Bureau of Economic Geology has several surveys available - I have no idea of what is available in India, but perhaps since your questions are very general - it doesn't matter.
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Hi, I have a doubt about making an equivalent %co2 solution with sodium carbonate. I have attached the reference equation quoted in the research article. If anyone knows how to derive the equation kindly help me.
****reference***
pH=6.30+log [ HCO3− ] −log [ CO2]
pH=10.09+log [ CO3 2- ] −log [ HCO3-]
The values of sodium carbonate concentrations corresponding to 5%, 10%, 15%, 20% and 30% CO2 concentrations at pH 7 are 1.3 g/L, 2.6 g/L, 3.8 g/L, 5.1 g/L, and 7.6 g/L, respectively.
****reference***
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Dalibor, I agree with you.
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Hi,
I have seen in recent literature that LiOH is preferencialy used to synthesized NCM811 whereas we can either use Li2CO3 or LiOH to synthesize NCM111 and 622. Is there any parasitic reactions with carbonate when nickel content is high ?
Regards,
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Thank you for bringing this discussion in the research gate. My question is on LiOH mass calculation. the chemical composition of commercial lithium hydroxide (merk) which I purchased is LiOH. but in papers, I find that they assume it is hydrated (LiOH.H2O). what should I calculate? the mass of LiOH or LiOH.H2O?
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I tried to tosylation glycerol carbonate with sodium hydride base in THF solvent. but C=O bond in glycerol carbonate was broken. can you help me what is the reason of that? is it becauce of the time or temprature of rection or order of adding materials?
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thank you so much for your help :)
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I'm an undergraduate student performing HCN production of PGPR, and we cannot prepare 2% sodium carbonate in 0.5% picric acid solution because we don't have a procedure can you please help us. thank you so much
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Perhaps help this.
Screening hydrogen cyanide (HCN) produced by rhizobacterial isolates
Assessment of HCN produced by rhizobacterial isolates was carried out. Appropriate amount of each isolate was inoculated in 250-ml flask (3 flasks/isolate), containing King’s B broth medium (100 ml) amended with 4.4 g/l glycine. Non-inoculated flasks were used as a control. Sterile filter paper strip was dipped in picric acid solution (0.5% picric acid in 2% sodium carbonate) and was attached to the neck of the flask. The flask was plugged and sealed off with Parafilm. Incubation was made at (28 ± 2 °C) for 4 days, with shaking at 140 rpm. A change in color of the filter paper strips from yellow to light brown, brown, or brick red was recorded as weak (+), moderate (++), or strong (+++) reaction, respectively. No change in color was recorded as a negative (−) reaction (Abd El-Rahman and Shaheen 2016).
Piric acid solution is a special substance.
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Everyone on the internet (almost) attributes Global Warming (GW) and Climate Change (CC) to CO2 in the atmosphere. It is like a mantra (or disclaimer :o/) applied to almost every study related to science, even those far removed from the subject of earth sciences.
As a Chemical Engineer I recognize that there is a strong correlation between earth's temperature and CO2 in the atmosphere. But Correlation does not prove cause and/or effect. And sometimes we tend to reverse cause and effect... A favorite poem of mine is this:
"I often pause to wonder at fates peculiar ways
So many very famous men were born on Holidays." (Author disputed)
The same correlation exists between the CO2 in a bottle of soda pop and the atmosphere captured above the liquid. In the Pop example the CO2 molecules constantly travels out-of and in-to the liquid, and the overall balance is based on the temperature. The same thing happens in the oceans (and even the carbonate rock of earth itself) and the atmosphere above both.
So I ask this: what if the earth was warming up (by some "unusual event" over several hundred years)? The CO2 in the atmosphere would increase... correct? So Heat would cause more CO2, rather than CO2 causing more heat. (Pause: I know the "greenhouse effect" has been shown in the Laboratory... but without the presence of the massive CO2 buffers, like the ocean, and rock. My pop bottle example suffers from the same limitations... I am just proposing an alternative to the mantra... that I would like someone to explore as a mental experiment.)
But what “unusual event” has occurred to warm the earth over recent centuries?
Could it be the magnetic pole shift that is now ongoing? I have searched for an explanation of how much energy would be generated (inside the earth) by a magnetic polar shift. I found only one article. And it said heat would be generated.
But it was just a guess as to how much heat is being produced and there was no attempt to correlate it with CO2 release. So little is known about the earth more than a few hundred feet down... if we knew more about the core of the earth we might even be able to predict earthquakes and volcanic eruptions... but so far we can't. If you can just imagine for a moment that 1/4 or 1/2 of the earths interior mass was rotating (or just moving a few microns) inside the earth, you can see the possibilities for friction and a huge amount of energy release.
The entire earth might only warn by a tiny fraction of a degree... but that would release massive amounts of CO2 from the rocks themselves. Then add the ocean's release of CO2 and/or its inability to absorb more CO2.
I think this is worth investigation by the Physicists and Geologists and Oceanographers, and Chemists of Research Gate. What do you think?
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Interesting question, Prof. Dj Flesher , in the tropic we are experiencing in some places the opposite effect "cooling and freezing", but I prefer to wait some answers from specialists.
Best Regards.
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We want to know the respiratory microbial activity of a soil sample.
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I am currently engaged in wastewater management-related work. Can carbonate and bicarbonate concentrations in water be calculated using alkalinity and pH? Please offer any empirical equations relevant to this, if any exist.
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The following equations might help, but you should clarify if they are valid or if they should be modified in your case study (depending on the system there are different approxiations).
2 x TA (total alkalinity) = [HCO3^-] + 2 [CO3^-2] + [OH^-] (1)
and [CO3^-2] = K2 [HCO3^-] / [H^+] (2)
Substitute carbonate ion from equation (2) to equation (1).
Also pH = -log [H^+] (3), so you could solve to have the solution for [H^+]
If you then rearrange equation (1) to solve for [HCO3^-] you should be able to calculate the bicarbonate.
I hope this is a good start. More clarifications here:
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I am trying to find a method for FTIR analysis of carbonized textile surfaces. I could not be able to analyze by FTIR-ATR. Is the spectrum obtained with a powdered sample with KBr meaningful for the entire non-homogeneous surface? Is there any method for FTIR analysis of 3D carbonized fabric?
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Thank you very much for your valuable answer Thomas Mayerhöfer. I will change the accessory and try again.
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Is there some kind of empirical formula or some outcrop characteristics you can use to assess the duration a sandstone outcrop was subject to weathering? How big is the influence of the cementation material (clay, ferritic cement, carbonate, silicate, gypsum)? Are there any publication on this topic?
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Dear Dr. Ungewitter,
I am not sure whether luminescence dating could answer at least parts of that question - acknowledging that weathering and surface exposure are, of course, not the same. An overview of the technique and its applications is given by, e.g., Liritzis (2011).
Best,
Martin
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I want to use orbitolinids for the biostratigraphy of a Barremiam/Aptian carbonate platform, to support my chemostratigraphy data. I have used related publications for descriptions and pictures trying to identify the different species, but I would like to have the opinion of an expert to confirm my classification.
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Hi Dear Margherita
Barremian and Aptian limes contain abundant amounts of orbitolina and this is a good idea.But you have to make sure about the taphonomic effect of ostracoda on the chemical composition.
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Particularly in the absence of a Bouma sequence or evaporites.
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I refresh my suggestions with a slight modification. The marginal aspect with an increased detrital input will still exist in this sediment. In this case I would place also emphasis on the geochemistry of trace elements like zirconium (Zr) which is a good indicator of an increase in the detrital input. I used it very often successfully. On the opposite end and typical of a basinward facies is boron (B). While B is not part of routine XRF programs, Zr does so.
A good marker is the V/Cr ratio which increases with an increase of the reducing regime. Less sensitive but also helpful is the Ni/Co ratio. If you draw chemologs you will certainly get a chance to correlate them based on these elements and you can directly take a decision which way the detrital input will increase and find an antithetic correlation with the redox regime based on the V/Cr ratio that response to the bituminous organic matter.
I wish you much success.
HGD
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We know Ooids from variety of environments when water is agitated and microbial activity exists, such as tidal environments, also in high salinities they better compete with other carbonate forming grains, they are also known from salt lakes, such as the one in Utah. However are they also reported from freshwater lakes?
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Dear Jafar do you have also experience with Akchagyl and Apsheron Formations, they are reportedly mainly consist of lacustrian and fluvial sediments, and Gastropods and Ostracods are also reported, marine environment also apparently present, the sections I came across from Pahne Kala area consists of Ooids, Gastropods and Ostrocods I wonder the fossil assemblage belongs to Pliocene or Middle-Late Miocene. As you know benthic foraminifera of Late Cenozoic are long range and are not helpful in this case. Do you think palynological study of these Formations may help us to resolve this matter.
with many thanks
and best regards
Hesam
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In my lab, we measure clumped isotope on bioapatite carbonates. Our acid reaction is at 70deg.C. We are wondering if anyone knows the acid fractionation value that we need to use or can give me a ref? I only found for 90 and 110deg.C. Thank you!
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Decreased carbonate ions with increased bicarbonate ions reduce pH. But while measuring water quality, we estimate carbonate and bicarbonate ions as one of the parameters and a higher concentration of these ions indicates alkalinity. But how ocean acidification happens when bicarbonate concentration increases.
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I'd say it's just the opposite. The activity ratios of CO3-2, HCO3- and H2CO3* are controlled by the pH value and also by the partial pressure of CO2. It is carbonate equilibria.
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The HR ESIMS of a compound we obtained from natural source seems to exhibit a carbonate adduct. If this has already been reported, please kindly send me the paper.
Best regards,
Remy
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Thank you very much
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I am looking for an alternate method to measure percentage of carbonate impurity from sodium bicarbonate. The specification is <0.23% carbonate. There is a titration method using barium chloride to precipitate the carbonate and back titration for the bicarbonate. This will measure total carbonate/ bicarbonate and also bicarbonate only, in order to calculate the carbonate. I am not sure if this will be sensitive enough for small amount of carbonate, which is less than 0.23%. I try find other ideas or separation with different techniques, for example using ion chromatography, but it seemed that carbonate and bicarbonate not separable by IC by many articles. Any comment and suggested techniques or method for this quantitation. This was originally a project to find alternate method from the USP method using the carbonate apparatus (for sodium bicarbonate) since we have difficulty with the method.
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This is now an old question. What did you do? How satisfactory was it? Vogel's Quantitative Inorganic analysis also has a titration method
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I am looking for a lab methodology that would be suitable to arsenic sequential extraction in carbonates. Many of the papers I find are applied to siliciclastics and the strong acid reagents used can dissolve carbonates, hence yielding erroneous results.
Thanks
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Use an alkaline system with sodium hydroxide and sodium sulfide. Thank you.
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Am making carbonized biomass value chain analysis and for such work, I am calculating carbon footprint.
I would therefore appreciate if anyone can share one (carbon footprint calculator e.g., spreadsheet) with me or direct me to a link/website where I can access one.
Thank you!
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Recently there were published many “comment papers” in valid journals such as Palaeoworld, Geological Journal, Carbonates and Evaporites and ... regarding the larger benthic foraminifera where accurate identifications require a high level of experience and knowledge of their taxonomy, this is the main question who are really the cause of these mistakes and problems?
1- Authors
2- Reviewers
3- Editors
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Hello Mehdi Hadi
I return to your original question/heading/topic of "What makes bad articles". I think that bad articles are ones that do not adequately address the topic/aim/title of their study. That happens in many fields, unfortunately, and it is often quite a good thing that letters and comments are sent in response. If people stay silent, that is because people are lazy but should make an effort to point out the problem(s) with the study/paper. I support this approach and definitely do it myself. To answer your original question - the author(s) should be held responsible for this situation.
That, though, might still mean that it is a good paper and may be thought-provoking and draws responses from readers who have different points of view so I totally support what some - such as Suman Sarkar - have said that comments might actually mean it is a thought-provoking article.
As for transparent reviews, as mentioned by Suman Sarkar ,
Mike Simmons
and Lorenzo Consorti most recently - I can only think that as a reviewer, I like to remain anonymous for most times. I wonder if that would make potential reviewers less likely to accept the task when invited...?
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These specimens were found in carbonate sediments in Tunisia. Kasserine area
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If by ‘contiguous’ you mean as the original ‘paired shells‘, the answer is yes. However, this is most common for burrowing species. For surface dwelling species it is the exception that the two valves stay together upon death. For burrowing species it is quite common.
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In anticline structure carbonate Reservoir of areal extension 31x10 km with 24 to26 degrees. no compartments. And no faces alteration (hydraulic continuty exist) multiple Downhole samples, MDT, and well testing samples were taken the bubble point ranging from 2140 psi in one flank to 2746 psi as average.
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If rock samples from core or cuttings are available, it might be possible to see if the source rock interval is more complex than assumed. Taking samples throughout the interval for geochemical analysis might help. Comparing extracted hydrocarbons to pyrolysis results might be enlightening with regard to fluid prediction.
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Can the inorganic carbon isotopes measured in a sequence of deep-water profiles dominated by black shale be used as a stratigraphic correlation? If the absolute values are affected (possibly more negatively than shallow-water carbonates), can the isotopic trends be correlated?
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I am a bit skeptical. We studied the Early Paleozoic Graptolite Shales which have almost worldwide extension on different continents and which are also of interest as "hot shales" (U) and deposits of a variegated "bunch" of rare metals. Even there facies the changes in this rather homogeneous argillaceous facies did not provide a good platform for a isotope stratigraphy. Chemical elements used as ratios such as V/Cr or NI/Co are in some cases much more enlightening than C isotopes, only.
HGD
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Dear colleagues,
I'm looking for a laboratory that measures clumped isotopes - Δ47. My research interests are carbonate minerals occurring in ultramafic rocks. I plan to reconstruct the formation conditions of various carbonates from ultramafic massifs from the north-east part of the Bohemian Massif. The carbonates were probably formed in both supergene and hydrothermal conditions and I aim to distinguish how these conditions had changed in terms of time and space. I would like to reconstruct magnesite precipitation conditions using clumped Isotope palaeothermometry.
Please let me know if you are open to collaboration and what are possible costs involved. Long-time scientific cooperation is possible :)
Contact me on Researchgate or blazej.cieslik2@uwr.edu.pl
Thanks!
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Hi! There is a clumped lab in ATOMKI, Debrecen, Hungary. Check it out.
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What type of marine carbonate factory is more predictable to be present in here ? what animals were responsible for the formation of the carbonates?
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If we take the facies diagram literally with actual slope deposits downdip from the platform, I will offer some alternative interpretations. In my experience, these are not large platforms and I suspect the stratal geometry is not purely depositional or the basin to shelf correlations are incorrect. Assuming, the correlations are correct, one could argue that the top of cycle 3 would have been flat at the time of deposition and that some uplift and subsidence occurred during the earlier cycles. The variation in facies patterns also argues for episodic changes in subsidence. Looking at the distribution of slope facies one can conclude that all the cycles are aggradational except cycle 2 which shows progradation due to slower subsidence. The overall stacking pattern of the cycles is also consistent with long-term creation of accommodation presumably driven by tectonics. This pattern is similar to the Pennsylvanian-Early Permian subsurface succession of the Midland Basin of Texas. During Ancestral Rockies deformation, middle Pennsylvanian shallow carbonate platforms evolved into the late Pennsylvanian/Early Permian Horseshoe Atoll capped by "pinnacle reefs" surrounded by organic-rich basinal sediments just like cycle 3. Within the Midland basin, direct indications of the adjacent basement tectonics are subtle except adjacent to uplifts. The huge volume of basinal deposits is also a clue that somewhere outside this basin there was an abundant sediment source terrain probably the result of tectonics.
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Dear, I need to prepare carbonate buffer for my ELISA work. It requires the pH of 9.6 to be used. In the ref. method, it is stated that bicarbonate/carbonate buffer is used. However, I ever done ELISA before this time, using just only bicarbonate dissolved in water and it has pH around 8.5. My advisor told me it is the same thinig between the two buffer system but somehow Im eager to know how the two is the same (or different). I already have tried to look for explanation anywhere but im not quite good at chemistry much.
Another question is that I see from "https://www.sigmaaldrich.com/TH/en/technical-documents/protocol/protein-biology/protein-concentration-and-buffer-exchange/buffer-reference-center" and I understand that 0.1 M of bicarbonate/carboante buffer has concentration of bicarbonate and carbonate both equal to 0.1 M. However, when I look into "https://www.aatbio.com/resources/buffer-preparations-and-recipes/carbonate-bicarbonate-buffer-ph-9-2-to-10-6" at pH 9.6 (which can be adjust), it shows that the concentration of those 2 chemicals are not equal but somehow give the summation into 0.1. I wonder which I am misunderstanding the concept. Thank you in advance for the reply ^^"
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The purpose of the alkaline bicarbonate/carbonate buffer is for binding the antigen to the ELISA plate. My understanding is that the alkaline pH is mildly denaturing to proteins, causing exposure of the hydrophobic interior of the protein, which enhances protein binding to the hydrophobic surface of the plate. I don't think the precise recipe is important. The moderately alkaline pH is the important thing.
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I am doing description of the Triassic carbonate description in terms of Diagenesis and facies analysis. where can I find the related paper or book? thanks for your recommendation
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There is also another book on carbonate diagenesis which can be helpful,
Carbonate Reservoirs
Porosity and Diagenesis in a Sequence Stratigraphic Framework
Edited by Clyde H. Moore, William J. Wade
Volume 67,
Pages 1-374 (2013)
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I am doing the synthesis of tert-butyl 6-(3-hydroxy-propyl-methy-lamino)quinoline-4-carboxylate, using Cesium carbonate, BINAP, and Pd2(dba)3 and N-methyl-1,3-propanolamine in Toulene.
TLC using different solvents and ratios didn't work out even using column chromatography, so does anyone know how to purify my compound ?
to get rid of Cesium Carbonate, BINAP and Pd2dba3 ?
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Thanks a lot @Vladimir Khlebnikov
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I want to know about the carbonization process related to electrospun fiber.
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Is there any effective way to reconstruct the thermal history of deep carbonate formations?
I know that there is a Δ47/(U-Pb) method, but is this method too harsh for the selection of carbonate samples?
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If you have regional knowledge, subsidence history can be restored by using 1D basin modeling (even if is a trusted carbonate sequence). In the process of restoring paleo-heat flow and parameters calibration, you will get the most precise thermal paleoenvironmental formation conditions (regardless of age, e.g. Paleozoic, Cretaceous, Tertiary, etc).
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I need to carbonize the NBR rubber sample. Can anyone explain the formation of graphitic structure from the carbonization of NBR? Is there any mechanism relevant for this formation?
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The yield of carbon will depend on the acrylonitrile (ACN) content of the polymer and is generally quite low (~12% for a 50% ACN NBR). The mechanism is very broadly as described for the manufacture of carbon fibre from polyacrylonitrile. If the Nitrile rubber is carbon black filled, then this will also contribute to the Carbon yield, as might polymeric plasticisers.
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Which method and which function is suitable to be used to get the target?
1. Productivity of single well at a different location in fractured cave carbonate reservoir
2. Productivity of multiple wells at a favorable location in fractured cave carbonate reservoir
Your help will be highly appreciated
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Mass balance calculations require that carbonates with δ13-C < -5 (per mil) contain some carbon derived from the oxidation of organic matter. Given that several negative isotopic anomalies much smaller than that (< -10) are recorded, notably in the Neoproterozoic, is it possible that there is another source for depletion in 13C?
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Carbonate isotopic compositions are largely a reflection of the environment in which they form. Methane oxidation by methanotropic bacteria at the anoxic interface of a stratified water column can contribute isotopically depleted CO2 to the environment where there is an active methane e.g., the Ancient lakes that deposited the Green River Formation or the Lacustrine oils in many Basins in China.
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What kind of carbonate minerals depression is preferrable for Au-bearing sulfides flotation (may be reverse flotation?) for such an ore:
  • quartz - 10-30%
  • feldspar (orthoclase) - 5-40%
  • clay&mica - 20-30%
  • Fe-dolomite&ankerite - 5-60% (!)
  • FeS2 - 1-8%
  • FeAsS - 0,5-3%
  • AsS - 0,2-2%
  • ZnS - 0,1-4%
  • PbS - 0,1-1%
Gold is mainly assotiated with Py and AsPy. There are also 0,5-5,0 mkm particles of electrum. Any advice for effective modern reagents?
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Maria, danke dir für deine Überlegungen! Ich kenne Lev Odysseyevich seit 20. Jahrhundert, noch von der Universität. Es scheint, muss ich ihn wirklich zu diesem Thema beiziehen.
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Hi,
I'm working on Late Cretaceous carbonates in central southern atlas of Tunisia. I think that these are longitidunal sections of Rudists but I need confirmation and a more detailed description.
Thank's
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As previously stated by Stevens and El Hassi, they are rudists. With those sections is not easy to precise genus or species, but in the first picture at the right side, one of the specimens shows a typical reticulate structure of the wall that copuld be usefulo to identify them.