Cent CO2 Research Articles

Evaluation of Elevated CO2 on Nutritional Quality of Green Gram for the Management of Callosobruchus chinensis (L.) during Storage

An experiment was conducted to study the assessment of nutritional quality parameters of green gram treated with elevated levels of carbon dioxide to manage Callosobruchus infestation during 2020-21 at Seed Entomology Laboratory, Seed Research and Technology Centre, College of Agriculture, Rajendranagar, Hyderabad, India. Nutritional quality of Callosobruchus chinensis infested green gram seeds exposed to four different concentrations of CO2 viz., 20, 40, 60 and 80 per cent was studied. The results revealed that the 80 per cent CO2 concentration maintained high carbohydrate content (62.93 per cent) and crude fat (4.51 per cent) besides less protein (25.26 per cent) content after two months of storage. The 80per cent CO2 treatment was consistently found to be the best treatment when it was retested in bulk quantity (25 kg of seed) after two months of storage period. High carbohydrate, crude fat content and low protein content were observed in all the CO2 treatments (20, 40, 60 and 80 per cent) when compared to untreated control. These findings suggest that using elevated CO2 levels could be a viable alternative to synthetic pesticides chemical fumigants for preserving green gram during storage.

Marine CSEM synthetic study to assess the detection of CO2 escape and saturation changes within a submarine chimney connected to a CO2 storage site

SUMMARY Carbon capture and storage (CCS) within sealed geological formations is an essential strategy to reduce global greenhouse gas emissions, the primary goal of the 2015 United Nations Paris Agreement. Large-scale commercial development of geological CO2 storage requires high-resolution remote sensing methods to monitor CO2 migration during/after injection. A geological formation containing a CO2 phase in its pore space commonly exhibits higher electrical resistivity than brine-saturated (background) sediments. Here, we explore the added value of the marine controlled-source electromagnetic (CSEM) method as an additional and relevant geophysical tool to monitor moderate to significant changes in CO2 saturation within a fluid conduit breaking through the seal of a CCS injection reservoir, using a suite of synthetic studies. Our 2-D CSEM synthetic models simulate various geological scenarios incorporating the main structural features and stratigraphy of two North Sea sites, the Scanner Pockmark and the Sleipner CCS site. Our results show significant differentiation of leakage through the seal with CO2 saturation ($S_{{\rm CO}_2}$) ranging between 20 and 50 per cent, while our rock physics model predicts that detection below 20 per cent would be challenging for CSEM alone. However, we are able to detect with our 2-D inversion models the effects of saturation with 10 and 20 per cent CO2 within a chimney with 10 per cent porosity. We demonstrate that simultaneous inversion of Ey and Ez synthetic electric field data facilitates a sharper delineation of a CO2 saturated chimney structure within the seal, whereas Ez synthetic data present higher sensitivity than Ey to $S_{{\rm CO}_2}$ variation, demonstrating the importance of acquiring the full 3-D electric field. This study illustrates the value of incorporating CSEM into measurement, monitoring and verification strategies for optimal operation of marine CCS sites.

Quantum mechanical modelling of the grain-surface formation of acetaldehyde on H2O:CO dirty ice surfaces

ABSTRACTAcetaldehyde (CH3CHO) is one of the most detected interstellar complex organic molecules (iCOMs) in the interstellar medium (ISM). These species have a potential biological relevance, as they can be precursors of more complex species from which life could have emerged. The formation of iCOMs in the ISM is a challenge and a matter of debate, whether gas-phase, grain-surface chemistry, or both are needed for their synthesis. In the gas-phase, CH3CHO can be efficiently synthesized from ethanol and/or ethyl radical. On the grain-surfaces, radical–radical recombinations were traditionally invoked. However, several pitfalls have been recently identified, such as the presence of energy barriers and competitive side reactions (i.e. H abstractions). Here, we investigate a new grain-surface reaction pathway for the formation of acetaldehyde, namely the reaction between CH3 and a CO molecule of a dirty water/CO ice followed by hydrogenation of its product, CH3CO. To this end, we carried out ab initio computations of the reaction occurring on an ice composed of 75 per cent water and 25 per cent CO molecules. We found that the CH3 + CO(ice) reaction exhibits barriers difficult to overcome in the ISM, either adopting a Langmuir–Hinshelwood or an Eley–Rideal mechanism. The subsequent hydrogenation step is found to be barrierless, provided that the two reacting species have the correct orientation. Therefore, this pathway seems unlikely to occur in the ISM.

Universal “Plug and Play” Real-Time Entire Automotive Exhaust Effluents, Industry Vents and Flue Gas Emissions Liquefiers: The Game Changer Approach-Phase Two Category

Universal “Plug and Play” Real-Time Entire Automotive Exhaust Effluents, Industry Vents and Flue Gas Emissions Liquefiers: The Game Changer Approach-Phase Two Category

Modeling of reverse water–gas shift reaction in a membrane integrated microreactor

CO2 hydrogenation to syngas via reverse water–gas shift (RWGS) is modeled in a membrane decorated microchannel reactor. Coated CuO/ZnO/Al2O3 catalyst exists in the reaction channel which is physically separated from the neighboring permeate channel by a layer of supported sodalite (SOD) membrane selective to H2O and H2 transport. Pure H2 is used as the sweep gas. Two–dimensional, steady state, isothermal operation of the reactor is quantified by the momentum and mass conservations in the entire flow domain, membrane material transfer and catalytic reaction. Upon its benchmarking with the literature–based experimental data, the reactor model is used to study the effects of inlet velocities and partitioning of the reactive mixture and sweep streams, reactor pressure, and molar inlet H2:CO2 ratio. At 523 K, 15 bar and H2:CO2 = 3, the per cent CO2 conversion exceeds the thermodynamic limit of 16.8% and can be maximized to 52% when the inlet velocity of the H2 + CO2 mixture is minimized. Decreased dosing of the reactive mixture, however, limits the molar amount of CO2 converted and reduces reactor capacity. Both metrics are positively correlated with reactor pressure and the inlet velocity of the sweep gas but remain insensitive to flow direction. Syngas composition (molar exit (H2 – CO2)/(CO + CO2) ratio) can be varied between 1.7 and 9.8. The proposed reactor can deliver ∼2.5 times higher volume and catalyst mass–based productivity and ∼33% higher CO2 conversion than an equivalently operated packed–bed membrane reactor.

Developmental competence of bovine oocytes in maturation media supplemented with follicular fluid exosomes

The present study evaluated the role offollicular fluid exosomes on the developmental competence of bovine oocytes. Ovaries from slaughtered crossbred cattle were collected, all visible surface follicles aspirated, and culture-grade oocytes were subjected to further study. Exosomes were isolated from bovine follicular fluid by differential ultracentrifugation. A total of 358 oocytes selected for the study were randomly divided into two groups. Group I constituted 111 oocytes, in which normal maturation was carried. Group II constituted 247 oocytes, in which in vitro maturation (IVM) medium was supplemented with follicular fluid exosomes at 1 μL/100 μL IVM medium. Maturation was assessed after 24h of culture in a CO2 incubator maintained at 38.5°C in 95 per cent humidified atmosphere of 5 per cent CO2. Following IVM of oocytes for 24 h, in vitro fertilisation (IVF)was carried out by co-incubating with capacitated spermatozoa for 18 h and embryo culture was carried out subsequently. In group II oocytes supplemented with exosomes, a significantly higher maturation rate (p ≤0.01) (95.80 ±1.67 vs76.10 ± 0.95), fertilisation rate (53.68 ± 3.02vs37.85 ± 7.01) and cleavage rate (p ≤0.01) (43.66 ± 2.13vs(32.47 ± 5.23) was noticed compared to oocytes in group I without any supplementation.The present study established that supplementation of follicular fluid exosomescould improve the developmental competence of bovine oocytes.

Cyclic adenosine monophosphate modulator supplementation on in vitro maturation of bovine oocytes

Study evaluated the role of cAMP modulator (Forskolin and 3-isobutyl-1- methyl xanthine) supplementation on developmental competence of bovine oocytes. Cumulus oocyte complexes recovered from bovine ovaries of unknown reproductive status were used for the study. Oocytes retrieved by aspiration method were graded based on cumulus cell distribution and culture grade oocytes were selected for the study. A total of 414 culture grade oocytes were taken and divided into two groups. Group I constituted of 201 oocytes in which pre-maturation was carried out for a period of 2 h. In group II, 213 oocytes were selected in which normal maturation was carried out. Maturation was assessed after 24h of culture in CO2 incubator maintained at 38.5o C in 95 per cent humidified atmosphere of 5 per cent CO2 . Fertilisation was carried out using frozen thawed semen and the presumptive zygotes were then transferred to culture media and cleavage was assessed 48 h after insemination. A significantly higher maturation rate (p ?0.05) was observed in group I compared to group II (86.85 ± 1.19 vs 79.88 ± 2.67). There was a highly significant increase (p ?0.01) in cleavage rate in group I (65.92 ± 1.23) compared to group II (59.29 ± 1.50). A higher fertilisation rate was observed in group I (75.35 ± 1.19) than group II (71.88 ± 2.56). It could be concluded that pre-maturation with cAMP modulators improved the developmental competence of bovine oocytes.

Overview of Environmental Problems Caused by Logistics Transportation

Logistic transportation works is considered the main pollutant for the environment, with over 25 per cent CO2 emissions in the EU. This situation has raised concerns for the EU and governments to find solutions and impose regulations to diminish the environmental impact. The purpose of this paper is to investigate two questions regarding environmental issues connected to transportation; “What are the recent trends for establishing sustainable logistics for different transportation methods?” “Which alternatives can be incentivized to decrease the environmental impact of transportation activities?” These projects among the most noteworthy environmental benefits, which are also the case studies of this research are The Viking Concept, The WestMed Bridge, Scandinavian Shuttle and Baxter Inland Sea Transport. The result highlighted in this research is that shifting transportation modes has been successfully implemented, with considerable positive outcomes in terms of environment impact, cost and lead times in several European Union funded projects.

Cytotoxic and antiproliferative potential of methanolic extracts of Asparagus racemosus in MDAMB231 cells

The present study was carried out to evaluate the cytotoxic and antiproliferative activity of methanolic extract of Asparagus racemosus in MDAB-231 cells. The qualitative phytochemical analysis of the extract revealed the presence of steroids, alkaloids, flavonoids, glycosides, saponins and diterpenes. MDAMB-231 cells were maintained in RPMI media containing 10 per cent serum and 1 per cent antibiotic and antimycotic solution. The cells were harvested and seeded to 96 well plate at 5×103 cells/mL, incubated for 24 hours at 37˚C with 5 per cent CO2. The cells were treated with 160, 80, 40, 20 and 10µg/mL of the extract for 24 hours and viability was accessed using MTT Assay. Also cells were plated in 6 well plates at concentrations 3×105 cells/mL and exposed to 80, 40, 20 and 10µg/mL of the extract of Asparagus racemosus for acridine orange ethidium bromide (AO/EB) staining. There was a dose dependent decrease in viability of cells exposed to methanolic extracts of Asparagus racemosus with a viability of 15.55+0.193 per cent for cells treated with 160µg/mL. The IC50 was found to be 91.36+ 0.87 µg/mL. The AO/EB staining revealed that most of the cells were dead in extract treated with 80µg/mL where more than 90 per cent of cells were live when treated with 10µg/mL of the extract.

Total quality index of commercial oyster mushroom Pleurotus sapidus in modified atmosphere packaging

PurposeThe purpose of this paper is to identify the strain of oyster mushroom (OM) Pleurotus sapidus cultivated in a local (commercial) farm, and to generate a total quality index (TQI) on the strain using different modified atmosphere packaging (MAP) gas mixtures.Design/methodology/approachA phylogenetic tree was constructed using the MEGA software to identify the specific strain of P. sapidus grown in a local farm. The effects of MAP on fresh fruiting bodies of the identified strain were determined under three conditions: high carbon dioxide packaging (HCP: 20 per cent CO2, 15 per cent O2), low carbon dioxide packaging (LCP: 2 per cent CO2, 30 per cent O2) and high nitrogen packaging (HNP: 85 per cent N2, 15 per cent O2). All samples were stored at 4 oC for up to ten days, and subjected to total phenolic content (TPC), colour retention (CR) and sensory analysis. Quality parameters such as chewiness and odour were used to obtain the TQI.FindingsFrom the phylogenetic analysis, a new strain (P. sapidus strain QDR) with 99 per cent similarity to P. sapidus was identified. Among the three MAP treatments, HCP recorded the highest TPC (2.85 mg GAE/g) and CR (60.36) after ten days, although only its CR was significantly different (p<0.05) from the control. Feedback from 30 sensory panellists indicated that both HCP and LCP were generally more effective in retaining the colour–odour of OM. The optimum TQI for HCP was obtained based on the observed parameters, which is useful for the large-scale packaging of OM.Originality/valueScientific evidence has revealed that packaging trend for commercially grown OM affects consumer’s acceptance.

Effect of additives in medium on in-vitro maturation of goat oocytes

Present study was carried out to find the effect of combining EGF with IGF, cysteine and sodium pyruvate singly as additive in a medium consisting of TCM-199 + 100 µl/ml foetal bovine serum + 100 µM/ml cysteamine + 1 µg/ml 17â- Oestradiol + 5 µg/ml pFSH + 5µg/ml oLH + 10 per cent follicular fluid and 10 per cent oestrous goat serum on in-vitro maturation (IVM) of caprine oocytes on incubation at 38.50C for 24 hours in a CO2 incubator maintaining 5 per cent CO2 under humidified condition. The additives comprised 10 ng/ml EGF + 50 ng/ml IGF-1, 10 ng/ml EGF + 600 µM/ml cysteine and 10 ng/ ml EGF + 0.2 mM/ml sodium pyruvate. The IVM rate of oocytes on the basis of cumulus cells expansion and nuclear maturation was found to be significantly higher (P less than 0.05) with EGF + IGF-1 (88.74 ± 1.85% and 61.71 ± 1.61%) than with EGF + sodium pyruvate (82.86 ± 0.97% and 54.62 ± 1.88%), EGF + cysteine ( 78.58 ± 1.45% and 49.02 ± 1.52%) and without additive (control) (75.27 ± 1.58% and 43.03 ± 1.48%).

Effect of growth factor on in-vitro maturation of porcine oocyte

The present study was aimed to evaluate the beneficial effect of different growth factors on in-vitro maturation of porcine oocytes. Ovaries were collected from a local abattoir immediately after slaughter of the animals and transported to the laboratory. A total of 618 type A and type B oocytes were cultured in TCM-199 containing additives with PMSG and hCG for the first 22 hrs and without hormones for subsequent 22 hrs of incubation at 39o C under 5 per cent CO2 level and 90-95 per cent humidity. The effects of supplementation of different growth factors viz., EGF, IGF-I and EGF + IGF-I in the medium were studied. The rate of oocytes with cumulus cells expansion was significantly higher (P less than 0.01) when growth factors were added as compared to control but it did not differ significantly between growth factors. The rate of nuclear maturation of oocytes was significantly higher (P less than 0.01) as compare to control for EGF and EGF + IGF-I but not for IGF-I. There was no significant difference in the rate of oocytes with nuclear maturation between the growth factors studied. It can be concluded from the present study that addition of EGF, IGF-I or EGF + IGF and additives along with hormones (PMSG and hCG for first 20-22 hrs) in TCM-199 Medium gives optimum in-vitro maturation rates in porcine oocytes.

Bartonella henselae infection in diverse clinical conditions in a tertiary care hospital in north India.

Background & objectives:Bartonella henselae causes infections which closely resemble febrile illness and chronic diseases such as tuberculosis and haematological malignancies. There are not many studies on Bartonella infections from India. The present study was undertaken to diagnose B. henselae infection in diverse clinical conditions in a tertiary care hospital in north India.Methods:A total of 145 patients including those with fever and lymphadenopathy, infective endocarditis and neuroretinitis were enrolled in the study. Whole blood, serum and lymph node aspirate and valvular vegetations if available, were obtained. Samples were plated on chocolate agar and brain-heart infusion agar containing five per cent fresh rabbit blood and were incubated at 35°C for at least four weeks in five per cent CO2 with high humidity. Immunofluorescent antibody assay (IFA) was done for the detection of IgM antibodies in the serum using a commercial kit. Whole blood was used to perform polymerase chain reaction (PCR) for the citrate synthase gene (gltA).Results:IFA was positive in 11 of 140 (7.85%) patients and PCR was positive in 3 of 140 (2.14%) patients. Culture was negative in all the cases. A higher incidence of Bartonella infection was seen in patients with fever and lymphadenopathy (n=30), seven of whom were children. In ophthalmological conditions, four cases were IFA positive.Interpretation & conclusions:The present study shows that the threat of Bartonella infection is a reality in India. It is also an important treatable cause of fever and lymphadenopathy in children. Serology and PCR are useful tests for its diagnosis. Clinicians should consider Bartonella infection in the differential diagnosis of febrile illnesses and chronic diseases.

Structure and corrosion behavior of Al-Co-Ti alloy system

PurposeThis paper aims to investigate ternary Al-Co-Ti alloy system with various Co compositions. Structural characterization of AlxCoy-2Ti2 alloys were performed by means of light microscopy, scanning electron microscopy, X-ray diffraction and electrochemical test. The effect of the addition of 5, 10, 15, 20, 25, 30 per cent Co and 2 per cent Ti on the structural evolution shows that both intermetallic compounds formation and structure morphology are related to corrosion resistance at the as-elaborated state as after subsequent heat treatment at 500°C during short time. According to the microstructural characterizations, the authors can notice that the substitution of Co has an important effect on the corrosion resistance and plays a role for the formation of the passive film.Design/methodology/approachThe alloys in this study were obtained by a high-frequency induction fusion. Powders from Al, Co and Ti (99.999 per cent) in proportions defined according to the composition aimed of alloy have been used. The total mass of the sample to be elaborated lies between 8 and 10 g. Cold compaction was achieved for mixed powder intended for high fusion frequency (HF). For electrochemical tests, the sample was cut by a diamond wheel to obtain a square section of dimensions 1 cm2. Afterward, this sample was connected with a Cu electrical wire. The last stage is the envelope in an acrylic resin realized in a plastic mold. The used electrolyte is a salt environment of 3.5 per cent NaCl (35 g of NaCl by liter of distilled water at room temperature [25 ± 1°C], aerated and with moderated agitation V = 250 r.min−1). This mold is kept in ambient air for 10 min to allow the resin to solidify.FindingsThe aim of this work is to establish the influence of the addition of Co and Ti on structural change and related corrosion behavior improvement in Al. Particular attention is accorded to Al-15 per cent Co-2 per cent Ti alloy.Originality/valueAmong the studied alloys with different Co contents, a precise composition of 15 per cent Co and 2 per cent Ti appears to have interesting electrochemical characteristics regarding the corrosion potential, the corrosion current and particularly the corrosion rate, which is very small when compared to that of other alloys, as well in the as-solidified state than after heat treatment. This composition is located halfway between the stainless steel 304 and the Al-Fe and Al-Co-Ce alloys.

Effect of active packaging on sensory attributes of low sugar, low calorie and fibre enriched Lal Peda

Varanasi,the city of gallis and ghats is not only famous for its Banarasi saree and Banarasi paan , but also famous for the Lal Peda loaded with higher amount of sugar and loaded with Ghee , the Peda is shaped by hand and dusted with semolina and pistachios as a finishing touch. Lal Peda is a popular heat desiccated traditional dairy delicacy of eastern India specially Uttar Pradesh. It is prepared by blending of Khoa and sugar followed by heat desiccation until characteristic reddish brown colour appears. The Lal Peda is deficit in fibre so the developed Lal Peda was prepared with addition of oat. This product is manufactured since long time yet not glamorized as other Khoa based sweet products like Burfi , Peda etc. The main reason behind this is, these products centered into specific areas and have not proper focused by research scientists and extension workers. So the experiment was carried out on low calorie, low sugar and fibre enriched Lal Peda . The Lal Peda samples packed in polythene bags coated with nisin as a bio-preservative to check the preservation ability of the developed Lal Peda . The Lal Peda samples were packed in commercial Nasco sampling polyethylene bags using MAP equipment Reepack® and MAP mix 9000 Gas mixer, manufactured by PBI DAN5SENSOR A/S, Ringstead, Denmark. Three different combinations of gases i.e. 75 per cent CO 2 :25 per cent N 2 ,50 per cent CO 2 :50 per cent N 2 and 25 per cent CO 2 :75 per cent N 2 were used to pack the Lal Peda samples. The samples packed under air were kept as control. The samples were stored in a BOD incubator (Remi Elektrotechnik Ltd., New Delhi, India) at 20 and 37 o C and were analyzed for sensory attributes at an interval of 10 days. The sensory evaluation was carried out by 10 semi expert judges.

Effect of meiotic stages during in vitro maturation on the post thaw recovery of buffalo oocytes

The present study has been undertaken to assess the post thaw recovery of buffalo oocytes vitrified at different stages of in vitro maturation (IVM). Cumulus oocyte complexes (COCs) obtained from slaughterhouse ovaries were randomly divided into 6 different groups: control (non-vitrified oocytes were matured for 24 h in maturation medium (MM) consists of TCM-199 supplemented with 10 per cent w/v fetal calf serum (FCS) at 38±1 0 C and 5 per cent CO 2 in a humidified atmosphere, 0 h (vitrified before the onset of maturation), 6, 12, 18 and 24 h groups (vitrified at 6, 12, 18 and 24 h, respectively, after the onset of maturation). Oocytes were exposed to vitrification solution (VS) consists of 40 per cent w/v propylene glycol and 0.25 M trehalose in phosphate buffered saline (PBS) supplemented with 4 per cent w/v bovine serum albumin (BSA) for 3 min at 20-25 0 C. Oocytes in VS were loaded into 0.25 ml French mini straw with 1M sucrose solution separated by two airspace on either side of VS. The straws were sealed with hot forceps and plunged directly into liquid nitrogen (LN 2 ; -196 0 C). The straws were thawed after storage period of atleast 7 days by transferring them into a water bath at 37°C for 30 sec. The cryoprotectant was removed by exposing the oocytes to 1 M sucrose solution. Oocytes in 0, 6, 12, 18 and 24 h groups were further matured for additional 24, 18, 12, 6 and 0 h, respectively, to complete a total of 24 h maturation period.A sum of 495, 432, 457, 416 and 420 oocytes were vitrified in 0, 6, 12, 18 and 24 h groups, respectively. After thawing, 444 (89.70%), 384 (88.89%), 418(91.47%), 381 (91-59%) and 387 (92.14%) oocytes were recovered in 0, 6, 12, 18 and 24 h groups, respectively. It is evident that no significant difference was observed under different vitrification groups.

Mitigation of stress corrosion cracking of carbon steel exposed to CO-CO2-H2O environments through inhibitor addition

Purpose – This investigation aims to find the degree of passivation required to completely inhibit the stress corrosion cracking of carbon steel exposed to CO-CO2-H2O environments. Design/methodology/approach – A516 pressure vessel steel was exposed to distilled water with 25 per cent CO and 75 per cent CO2 at an overall pressure of 800 kPa with the introduction of potassium bichromate as an additional inhibitor. Slow strain-rate tests were performed to evaluate the steel for sensitivity to cracking. Electrochemical characteristics were investigated in parallel in order to determine the extent of passivation required with the addition of the inhibitor. Findings – Slow strain-rate tests showed that between 100 and 1,000 ppm potassium bichromate was required to completely mitigate cracking with a significant reduction in passivation current densities. Research limitations/implications – The chosen inhibitor is not ideal for practical applications as an inhibitor, but gave an indication of the passivation required. Practical implications – The results showed that the added inhibitor might even cause increased sensitivity to cracking in this environment, with significant passivation required for resistance to cracking. Originality/value – The degree of passivation required for complete resistance of carbon steel in 25 per cent CO-75 per cent CO2-H2O.

Model for Cameron-band emission in comets: a case for the EPOXI mission target comet 103P/Hartley 2

Abstract The CO2 production rate has been derived in comets using Cameron-band (a3Π→X1Σ) emission of CO molecules, assuming that photodissociative excitation of CO2 is the main production mechanism of CO in the a3Π metastable state. We have developed a model for the production and loss of CO(a3Π), which has been applied to comet 103P/Hartley 2: the target of the EPOXI mission. Our model calculations show that photoelectron impact excitation of CO and dissociative excitation of CO2 can together contribute about 60–90 per cent to Cameron-band emission. The modelled brightness of (0–0) Cameron-band emission on comet Hartley 2 is consistent with Hubble Space Telescope observations for 3–5 per cent CO2 (depending on the model input solar flux) and 0.5 per cent CO relative to water, where the photoelectron impact contribution is about 50–75 per cent. We suggest that estimation of CO2 abundances on comets using Cameron-band emission may be reconsidered. We predict a height-integrated column brightness of the Cameron band of ∼1300 Rayleigh during the EPOXI mission encounter period.

Health groups renew push for 30 per cent CO2 target

Health groups renew push for 30 per cent CO2 target

Optimal Performance from Electrochemical Devices Using Control Theory at the Surface Coverage Level

A method is presented for optimizing a desired electrochemical reaction in the presence of undesired reactions by the optimal choice of a time varying control variable, such as the current or voltage waveform. The method is illustrated by a PEM fuel cell example: computing the maximum power production from the oxidation of H2 on Pt/Ru in the presence of 1 per cent CO at 50 C and 1 atm. Dynamic programming, in combination with a surface coverage anode model, is used to show that the optimal solution yields a series of pulse-like overvoltage waveforms – a generalization of previous heuristic pulsing approaches to increasing power in PEM fuel cells in H2 with CO. Essentially, the solution indicates how to optimally allocate electrochemical resources between two competing tasks: investing electrical energy in freeing sites for the desired reaction and producing electrical energy from the desired reaction. Because dynamic programming is computationally intensive, an efficient technique is presented for implementing the method using a priori predictions of the family of optimal performance paths and using experimental feedback from estimates of surface coverage based upon observer theory. The observers are shown to converge to a limited set of experimental data.