A STUDY OF STRUCTURAL PROPERTIES AND PERFORMANCE OF Ni-Co-Mg-Al-Ox CATALYST FOR CARBON DIOXIDE REFORMING OF METHANE

Previous work from our group has established Ni-Co-Mg-Al-Ox catalyst to be an active and stable catalyst for CO2 reforming of Methane, also known as dry reforming of Methane (DRM). Additionally, bimetallic Ni-Co showed better performance compared to individual monometallic catalysts of Ni or Co. Further studies revealed that Ni and Co showed different extent and kinetics of reduction. The relationship between the bulk structure and reducibility of active metals (Ni and Co) has not yet been studied. The individual interaction of the active metals with the component of the support is yet to be examined. Likewise, exploration of other feed source for DRM or dry reforming of higher hydrocarbon on Ni-Co-Mg-Al-Ox catalyst has not been studied. The primary aim of this research work is to study the effects of Mg/Al ratio (support) on the bulk structure, basicity, metal support interaction, metal site formation and site performance of Ni-Co-Mg-Al-Ox catalyst for CO2 reforming of CH4 (DRM). The research plan for this project is divided into two parts. Part one focuses on understanding the relationship between bulk structure, site formation and catalytic performance of monometallic (Ni or Co) and bimetallic Ni-Co-Mg-Al-Ox for DRM, as the Mg/Al ratio in the support changes. The second part focuses on the exploration of DRM using simulated coal gas feed and CO2 reforming of C2H6 (shale gas contains appreciable amount of C2H6). For part one, the effects of Mg/Al ratio on the bulk structure, site formation and performance of Ni-Co-Mg-Al-Ox for dry reforming were studied. High Mg/Al ratio showed NiCoO2 + MgO-solid phase + spinel structure, compared to the lower ratio that showed a complete spinel structure. This additional MgO phase improved the basicity and the easy of reduction of the active metals, leading to better activity and stability of catalyst to DRM reaction. With respect to the monometallic catalysts, supported Ni and Co showed similar structure, but different metal reducibility and site performance for DRM. The Al-Ox supported Co catalyst showed no reducibility and activity, appreciable amounts of both properties was found in the corresponding Ni catalyst. Introduction of MgO into the support improved metal reduction and basicity of support, making the performance of the catalysts better. These observations were related to the different interaction and distribution of the metals within the support system. For part two, DRM was studied using simulated coal feed gas at higher temperature (900 oC) using larger catalyst loading. Better activity, stability and product selectivity were observed in bimetallic Ni-Co with higher Mg/Al ratio compared to the lower ratio and monometallic Ni catalyst. Also, appreciable amount of activity was found using the coal gas feed, even though the amount of CO2 and CH4 were small compared to other components of the feed. The difference in the activity of catalysts using both feed was related to the difference in the composition of CH4 and CO2 in both feeds. For CO2 reforming of Ethane (CRE), two main points were addressed in this study; C2H6 dissociation study and CO2 reforming of C2H6. Results showed that the catalyst support, catalyst in oxide form and reduced catalysts can activate CO2 reforming of C2H6, unlike DRM that needs reduced catalyst for the reaction to proceed. Additionally, higher Mg/Al ratio catalysts showed preference for CRE over C2H6 dissociation, while lower Mg/Al ratio catalysts showed preference for C2H6 dissociation over CRE. In conclusion, variation of the composition of Mg/Al ratio in the support led to changes in the bulk structure, basicity, metal support interaction, active metal distribution, reducibility and performance of monometallic (Ni, Co) and bimetallic (Ni-Co) catalysts for DRM. Higher Mg/Al ratio improved the basicity of support leading to easy activation of CO2, which helped in the conversion of deposited carbon to CO. The presence of sufficient active site helped (synergistically with support) in the activation of the CH4, leading to better catalytic performance

Influence of Tillage Systems on Diversity and Abundance of Insect and Nematode Pests of Maize in Malete, Kwara State, Nigeria

Pests are major biotic factors causing up to 45% yield reduction in maize production in sub-Saharan Africa. To develop improved methods for maize management, the species and abundance of insects and nematodes associated with ten quality protein maize varieties (QPMVs) were evaluated with two commonly used tillage practices, ‘plough only plots (POP)’ and ‘plough and harrow plots (PAHP)’. The experiment was carried out using QPMVs at the Teaching and Research Farm of the Kwara State University, Malete, Nigeria, and arranged in a randomized complete block design with 11 treatments replicated 3 times, including local check “pambo”. A total of 833.1±4.0 and 799.3±3.4 arthropods specimens were collected from POP and PAHP, respectively, comprising 8 orders and 18 families. Ootheca mutabilis was the most abundant species with 5.47% (POP) and 5.68% (PAHP) and the least abundant was Rhopalosiphum maidis 1.82% (POP) and 1.80% (PAHP). As indicated by Shannon Wiener (3.46±0.023) and Simpson indices (0.97±0.0008) there are even distribution in the tillage practices. Three genera of plant parasitic nematodes (PPNs) were identified, Meloidogyne spp. (POP (78.33±19.65), PAHP (1.33±0.33), Pratylenchus spp. (POP (41.67±9.26), PAHP (5.00±2.31), and Helicotylenchus spp. (POP (58.33±38.35), PAHP (23.33±14.50). The use of PAHP tillage practices is effective in reducing insects and nematodes associated with maize in Nigeria and therefore recommended for the management of both pests in maize production

ANN-derived equation and ITS application in the prediction of dielectric properties of pure and impure CO₂

High-performing equation has been step-wisely extracted from artificial neural network (ANN) simulation and subsequently applied for the prediction of the dielectric properties of pure and impure CO2. Data of relative permittivity (εr) for pure and impure CO2 were used in the ANN to train different ANN structures so that the network can recognise and predict CO2 property under different conditions. Analyses of the results from the training showed that single-layer ANN model [3-6-1] outperformed others. From this best-performing ANN structure, a single mathematical equation was extracted that can be employed in predicting εr for pure CO2 and CO2-ethanol mixture, even without access to ANN software. Using this ANN-based mathematical model, predictions of the relative permittivity (εr) for pure CO2 and CO2-ethanol mixture were performed, under different temperatures and pressures and at different ethanol concentrations. Under similar conditions, the output of the model provides good match with the original experimental εr. With increment in ethanol concentration, the model correctly predicted the rise in εr for the mixture. Also, it was shown that the εr rises with an increase in pressure but decreases with a rise in temperature. The work showed the reliability and applicability of the ANN in characterizing and predicting the dielectric property of pure CO2 as well as its mixture or impurities. The model developed and the techniques demonstrated in this work offers immense benefits and guides for researchers, who may want to explore the behaviours of a pure compound and its mixtures/impurities using ANN, as well as those interested in derived mathematical model from statistical computation tool like ANN

Transient sensor errors and their impact on fixed-bed regenerator (FBR) testing standards

This is an Accepted Manuscript of an article published by Taylor & Francis in Science and Technology in Build Environment on 14 December 2020, available at: https://doi.org/10.1080/23744731.2020.1846428.National Science and Engineering Research Council (NSERC), Tempeff North America Inc., Winnipeg, Canada, (Project No: 533225-18)Peer ReviewedFixed-bed regenerators (FBRs) are a favorable option for energy recovery in building HVAC systems due to their high sensible effectiveness. Unlike other types of energy recovery exchangers, the air temperature at the outlet of FBRs varies with time, which creates challenges when measuring the outlet temperature and effectiveness of FBRs since the actual outlet air temperature will include the transient response of the FBR and the temperature sensor. In this article, a validated numerical model of FBRs that takes into account the sensor response is used to quantify the temperature and effectiveness errors that result due to sensors’ response characteristics over a wide range of design parameters. The main contributions of this article are the practical recommendations for the temperature measurement for different types of FBRs developed for HVAC applications. The recommendations presented in this article could be implemented in future versions of the current standards (ASHRAE 84 and CSA C439-18 standards) for performance testing of air-to-air energy exchangers

Suitability of bio-desiccants for energy wheels in HVAC applications

Government of the Saskatchewan (Ministry of Agriculture), Agricultural Development Fund: Project #20160266Peer ReviewedThis paper investigates the suitability of bio-desiccants for moisture recovery in energy wheels. Bio-desiccants are environment-friendly materials that have high water vapor adsorption capacities. The main contribution of this paper is that it reports the latent effectiveness of flax-fiber (bio-desiccant) coated energy wheels for a wide range of operating conditions and compares the effectiveness of the flax-fiber wheels with wheels that are coated with commercially available desiccants and other biomaterials. The moisture transfer performance of a flax-fiber coated exchanger is determined using a small-scale test facility and two different experimental methods: single step change tests and cyclic tests. The test results are used to verify the applicability of an effectiveness correlation from the literature. Using the energy wheel correlation and the sorption isotherms, the latent effectiveness of commercially available energy wheels coated with molecular sieve, ion exchange resin and silica gel desiccants are obtained and compared with that of bio-desiccants (flax fiber and starch particles). The highest latent effectiveness is obtained for silica gel followed by starch particles, ion exchange resin, flax-fiber and molecular sieve. The results from this study will be useful in research and development of bio-materials for energy recovery systems for building applications

Global impact of COVID-19 on stroke care and IV thrombolysis

Objective To measure the global impact of COVID-19 pandemic on volumes of IV thrombolysis (IVT), IVT transfers, and stroke hospitalizations over 4 months at the height of the pandemic (March 1 to June 30, 2020) compared with 2 control 4-month periods. Methods We conducted a cross-sectional, observational, retrospective study across 6 continents, 70 countries, and 457 stroke centers. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases. Results There were 91,373 stroke admissions in the 4 months immediately before compared to 80,894 admissions during the pandemic months, representing an 11.5% (95% confidence interval [CI] -11.7 to -11.3, p < 0.0001) decline. There were 13,334 IVT therapies in the 4 months preceding compared to 11,570 procedures during the pandemic, representing a 13.2% (95% CI -13.8 to -12.7, p < 0.0001) drop. Interfacility IVT transfers decreased from 1,337 to 1,178, or an 11.9% decrease (95% CI -13.7 to -10.3, p = 0.001). Recovery of stroke hospitalization volume (9.5%, 95% CI 9.2-9.8, p < 0.0001) was noted over the 2 later (May, June) vs the 2 earlier (March, April) pandemic months. There was a 1.48% stroke rate across 119,967 COVID-19 hospitalizations. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was noted in 3.3% (1,722/52,026) of all stroke admissions. Conclusions The COVID-19 pandemic was associated with a global decline in the volume of stroke hospitalizations, IVT, and interfacility IVT transfers. Primary stroke centers and centers with higher COVID-19 inpatient volumes experienced steeper declines. Recovery of stroke hospitalization was noted in the later pandemic months.Paroxysmal Cerebral Disorder

Kinetics of toluene alkylation with methanol catalyzed by pure and hybridized HZSM-5 catalysts

A kinetic study of toluene alkylation with methanol was performed over pure HZSM-5, mordenite/ZSM-5 (hybrid of mordenite and HZSM-5), and ZM13 (composite mixture of HZSM-5 and MCM-41 at pH 13). Experimental runs were conducted using a batch fluidized bed reactor at temperatures of 300, 350 and 400 °C and reaction times of 3, 5, 7, 10, 13, 15 and 20. s. The rate of toluene methylation and toluene disproportionation were studied on the three catalysts (toluene alkylation is usually accompanied by toluene disproportionation on acid catalyst). Based on the results obtained, a simplified power law kinetic model consisting of three reactions was developed to estimate the activation energies of toluene methylation and disproportionation simultaneously. Coke formation on catalysts was accounted for using both reaction time and reactant conversion decay functions. All parameters were estimated based on quasi-steady state approximation. Estimated kinetic parameters were in good agreement with experimental results. The order of alkylation ability of the catalysts was found to be ZM13 > HZSM-5 > mordenite/ZSM-5, while the reverse is for toluene disproportionation (mordenite/ZSM-5 > HZSM-5 > ZM13). Thus, alkylation of toluene is most favorable on ZM13 due to combined effect of mesoporosity induced through its synthetic route and acid content. Toluene/MeOH molar ratio of 1:1 was most suitable for toluene alkylation reaction.</p

Cognitive impairment among type 2 diabetic patients attending family medicine clinics, university of Ilorin Teaching Hospital, Ilorin, north central Nigeria

Background: Cognitive impairment (CI) is increasing worldwide with its burden affecting a wide range of adults. It is a less addressed and underdiagnosed complication of Diabetes Mellitus. This study aimed to determine the prevalence and pattern of cognitive impairment among type 2 diabetic patients in the primary care setting of a tertiary hospital. It also determined the relationship between CI and some socio-demographic factors among participants.Materials and method: It was a descriptive hospital-based cross-sectional study. Data was collected from 274 adult type 2 diabetic patients attending the Family Medicine clinics of the UITH, Ilorin from March through May 2017. Interviewer-administered structured and semi-structured questionnaires were used to obtain information from the respondents. The Mini-Mental State Examination (MMSE) was used to assess the prevalence and pattern of CI among respondents. Data was collated and analyzed using the Statistical Package for Social Sciences version 21 (SPSS-21).Results: The prevalence of CI in this study was 27%. Mild cognitive impairment (MCI) was commoner than severe cognitive impairment. CI had a statistically significant relationship with the age, level of education and employment status of the respondents (p-value of 0.001, 0.026 and 0.014 respectively).Conclusion: CI is common among type 2 diabetic patients in primary care. Physicians should routinely screen type 2 diabetic patients for CI as well as assess its pattern and risk factors. This would allow for the implementation of appropriate care to prevent CI or its worsening among type 2 diabetic patients.&nbsp; Keywords: Cognitive impairment, Type 2 Diabetes, Mini-Mental State Examination, Primary car

Global Impact of COVID-19 on Stroke Care and IV Thrombolysis

OBJECTIVE: To measure the global impact of COVID-19 pandemic on volumes of IV thrombolysis (IVT), IVT transfers, and stroke hospitalizations over 4 months at the height of the pandemic (March 1 to June 30, 2020) compared with 2 control 4-month periods. METHODS: We conducted a cross-sectional, observational, retrospective study across 6 continents, 70 countries, and 457 stroke centers. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases. RESULTS: There were 91,373 stroke admissions in the 4 months immediately before compared to 80,894 admissions during the pandemic months, representing an 11.5% (95% confidence interval [CI] -11.7 to -11.3, p &lt; 0.0001) decline. There were 13,334 IVT therapies in the 4 months preceding compared to 11,570 procedures during the pandemic, representing a 13.2% (95% CI -13.8 to -12.7, p &lt; 0.0001) drop. Interfacility IVT transfers decreased from 1,337 to 1,178, or an 11.9% decrease (95% CI -13.7 to -10.3, p = 0.001). Recovery of stroke hospitalization volume (9.5%, 95% CI 9.2-9.8, p &lt; 0.0001) was noted over the 2 later (May, June) vs the 2 earlier (March, April) pandemic months. There was a 1.48% stroke rate across 119,967 COVID-19 hospitalizations. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was noted in 3.3% (1,722/52,026) of all stroke admissions. CONCLUSIONS: The COVID-19 pandemic was associated with a global decline in the volume of stroke hospitalizations, IVT, and interfacility IVT transfers. Primary stroke centers and centers with higher COVID-19 inpatient volumes experienced steeper declines. Recovery of stroke hospitalization was noted in the later pandemic months. © 2021 American Academy of Neurology