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As renewable electricity prices continue to decline, interest grows in alternative routes for the synthesis of sustainable fuels and chemicals, including ammonia. Considering demand for fertilizers, as well as its future potential as a dispatchable energy vector, sustainable synthesis of ammonia is being explored as an alternative to the capital- and carbon-intensive fossil-fuel-driven Haber–Bosch process. Here we assess stages along a transition to the sustainable synthesis of ammonia, looking at economic feasibility and climate impacts compared to the incumbent Haber–Bosch without and with CO2 capture. This analysis enables us to suggest technological thresholds for sustainable synthesis of ammonia to become economically and environmentally favourable. When driven by renewable energy sources, the water electrolyzer (near $400 per kW) coupled Haber–Bosch process will reach cost parity near 2.5 cents per kWh electricity. In the case of direct electrochemical ammonia synthesis, achieving cost-parity using the same 2.5 cents per kWh electricity will rely on achieving major advances in performance: an electrolysis full-cell energy efficiency exceeding 40% at a current density of 0.5 A cm−2. Once this operating performance is reached, electrically-powered ammonia synthesis will bring climate benefits when coupled with low-carbon electricity (

The concept of density-graded foams has been proposed to simultaneously enhance strain energy dissipation and the load-bearing capacities at a reduced structural weight. From a practical perspective, the fabrication of density-graded foams is often achieved by stacking different foam densities. Under such conditions, the adhesive interlayer significantly affects the mechanical performance and failure modes of the structure. This work investigates the role of different adhesive layers on the mechanical and energy absorption behaviors of graded flexible foams with distinct density layers. Three adhesive candidates with different chemical, physical, and mechanical characteristics are used to assemble density-graded polyurea foam structures. The mechanical load-bearing and energy absorption performances of the structures are evaluated under quasi-static and dynamic loading conditions. Mechanical tests are accompanied by digital image correlation (DIC) analyses to study the local strain fields developed in the vicinity of the interface. Experimental measurements are also supplemented by model predictions that reveal the interplay between the mechanical properties of an adhesive interlayer and the macroscale mechanical performance of the graded foam structures. The results obtained herein demonstrate that the deformation patterns and macroscale properties of graded foam composites can be tuned by selecting different bonding agents. It is also shown that the proper selection of an adhesive can be a practical way to address the strength-energy dissipation dichotomy in graded structures.

Summary Integrated carbon capture and utilization (CCU) is appealing for in situ production of fuels and chemicals. Here, we propose and subsequently assess an integrated electrochemical CCU process and compare it with a carbon capture and storage (CCS) route from economic and environmental perspectives. This analysis reveals that under a baseline CCU scenario, carbon products reap either economic (67% and 10% gross margin increase for carbon monoxide [CO] and n-propanol, respectively) or environmental benefits (formic acid production would reduce ∼721 thousand ton carbon dioxide equivalent [CO2e]/year) relative to the CCS route. Under an optimistic scenario, while all of the carbon dioxide (CO2)-derived products are economically compelling over the CCS route, only formic acid production would reduce ∼1,465 thousand ton CO2e/year over CCS (∼575 thousand ton CO2e/year). This study may serve as a framework to decide whether a CCS or a CCU pathway would be compelling under a given scenario when fuel-cell-based CO2 capture technology is used to reduce carbon emissions and create economic value from fossil fuel-based power plants.

Open educational resources (OER) have become increasingly popular in recent times. Here, the aim was to synthesise the lessons learned through the development of OER materials for a university-level course called &ldquo, environmental modelling&rdquo, Consequently, the topics of discussion included: (i) how to choose an appropriate creative commons license, (ii) ways of incorporating materials from other sources, such as publicly available sources, other open access materials, and an author&rsquo, s own published materials if not published under a creative commons license, (iii) the impact of the developed OER in the field of environmental modelling, and (iv) the challenges in developing OER material. Upon developing the materials, we observed the following: (i) students enrolled in the course did not purchase textbooks, (ii) our OER materials ranked as one of the most accessed (i.e., number 7) materials according to the usage data that summed the number of file downloads and item views from PRISM (i.e., the hosting platform maintained by the University of Calgary), (iii) the students learned relatively better as per the data acquired by the University of Calgary&rsquo, s universal student ratings of instruction (USRI) instrument, and (iv) other universities expressed interest in adopting the materials.

Objective: Mouse mast cell protease-4 (mMCP-4, also known as chymase) has both pro- and anti-inflammatory roles depending on the disease model. However, its effects have not been studied in surgically wounded skin. Given the significant clinical applications of modulating the inflammatory response in wound healing, we examined the role of mMCP-4 and the effect of its inhibitor chymostatin on leukocyte and polymorphonuclear cell (PMN) recruitment in our skin model. Approach: Recruitment was assessed on day-1 postwounding of three groups of mice (n = 10 each): mMCP-4 null mice, wild-type (WT) mice treated with the mMCP-4 inhibitor chymostatin, and WT with no other intervention. Leukocytes were stained with CD-45 cell marker, and PMN cells were stained with chloroacetate esterase. Results: The WT mice had 27 ± 9 leukocytes per field compared with 11 ± 6 for the mMCP-4 nulls, a decrease of 60% (p = 0.03), whereas the chymostatin-injected group had a count comparable with the uninjected WT controls at 24 ± 9. The WT group had a PMN count of 96 ± 12 cells, compared with just 24 ± 8 in the mMCP-4 null group, a decrease of 75% (p = 0.001), whereas the chymostatin-treated group had 60 ± 18 cells, a decrease of 38% compared with the WT group (p = 0.03). Innovation: We showed that the inflammatory process can be influenced by impeding the arrival of PMNs into the surgically injured site using the mMCP-4 inhibitor chymostatin. Conclusion: Chymase contributes to the recruitment of white blood cells in surgically wounded skin.

Introduction: Accelerating progress in reducing child deaths is needed in order to achieve the Sustainable Development Goal child mortality target. This will require a focus on vulnerable children–including young children, those who are undernourished or with acute illnesses requiring hospitalization. Improving adherence to inpatient guidelines may be an important strategy to reduce child mortality, including among the most vulnerable. The aim of our assessment of nine sub-Saharan African and South Asian hospitals was to determine adherence to pediatric inpatient care recommendations, in addition to capacity for and barriers to implementation of guideline-adherent care prior to commencing the Childhood Acute Illness and Nutrition (CHAIN) Cohort study. The CHAIN Cohort study aims to identify modifiable risk factors for poor inpatient and post discharge outcomes above and beyond implementation of guidelines. Methods: Hospital infrastructure, staffing, durable equipment, and consumable supplies such as medicines and laboratory reagents, were evaluated through observation and key informant interviews. Inpatient medical records of 2–23 month old children were assessed for adherence to national and international guidelines. The records of children with severe acute malnutrition (SAM) were oversampled to reflect the CHAIN study population. Seven core adherence indicators were examined: oximetry and oxygen therapy, fluids, anemia diagnosis and transfusion, antibiotics, malaria testing and antimalarials, nutritional assessment and management, and HIV testing. Results: All sites had facilities and equipment necessary to implement care consistent with World Health Organization and national guidelines. However, stockouts of essential medicines and laboratory reagents were reported to be common at some sites, even though they were mostly present during the assessment visits. Doctor and nurse to patient ratios varied widely. We reviewed the notes of 261 children with admission diagnoses of sepsis (17), malaria (47), pneumonia (70), diarrhea (106), and SAM (119); 115 had multiple diagnoses. Adherence to oxygen therapy, antimalarial, and malnutrition refeeding guidelines was >75%. Appropriate antimicrobials were prescribed for 75% of antibiotic-indicative conditions. However, 20/23 (87%) diarrhea and 20/27 (74%) malaria cases without a documented indication were prescribed antibiotics. Only 23/122 (19%) with hemoglobin levels meeting anemia criteria had recorded anemia diagnoses. HIV test results were infrequently documented even at hospitals with universal screening policies (66/173, 38%). Informants at all sites attributed inconsistent guideline implementation to inadequate staffing. Conclusion: Assessed hospitals had the infrastructure and equipment to implement guideline-consistent care. While fluids, appropriate antimalarials and antibiotics, and malnutrition refeeding adherence was comparable to published estimates from low- and high-resource settings, there were inconsistencies in implementation of some other recommendations. Stockouts of essential therapeutics and laboratory reagents were a noted barrier, but facility staff perceived inadequate human resources as the primary constraint to consistent guideline implementation.

Difficulty adhering to evidence-based guidelines is an important driver of inpatient child mortality. A mixed method assessment was conducted in eight district or national referral hospitals in Bangladesh (2), Kenya (3), Malawi (1), Pakistan (1) and Uganda (1) between July and November 2016. Key informants (administrators, clinicians, nurses, nutritionists, pharmacists) were interviewed and essential hospital infrastructure, equipment and medicines was assessed by direct observation. The clinical notes of 240 children aged 2-23 months were reviewed and indicators of adherence to guidelines for common pediatric conditions, including severe acute malnutrition (SAM), pneumonia, diarrhea, and anemia were abstracted.

Antimicrobial resistance (AMR) is a growing global concern. Antibiotic stewardship is being promoted to reduce AMR. However, few studies have documented inpatient antibiotic prescription practices in lowresource settings. We audited the 240 clinical notes of 2-23 month-old inpatient children in Bangladesh (2), Kenya (3), Malawi (1), Pakistan (1) and Uganda (1) as part of a baseline assessment in a study to identify risk factors for mortality in acutely ill inpatients, particularly in undernourished children. This analysis describes adherence to antibiotic guidelines during the first 48 hours of admission.

Currently, post-combustion carbon capture (PCC) is the only industrial CO2 capture technology that is already demonstrated at full commercial scale in the TMC Mongstad in Norway (300,000 tonnes per year CO2 captured) and BD3 SaskPower in Canada (1 million tonnes per year CO2 captured). This paper presents a comprehensive review of the most recent information available on all aspects of the PCC processes. It provides designers and operators of amine solvent-based CO2 capture plants with an in-depth understanding of the most up-to-date fundamental chemistry and physics of the CO2 absorption technologies using amine-based reactive solvents. Topics covered include chemical analysis, reaction kinetics, CO2 solubility, and innovative configurations of absorption and stripping columns as well as information on technology applications. The paper also covers in detail the post build operational issues of corrosion prevention and control, solvent management, solvent stability, solvent recycling and reclaiming, intelligent monitoring and plant control including process automation. In addition, the review discusses the most up-to-date insights related to the theoretical basis of plant operation in terms of thermodynamics, transport phenomena, chemical reaction kinetics/engineering, interfacial phenomena, and materials. The insights will assist engineers, scientists, and decision makers working in academia, industry and government, to gain a better appreciation of the post combustion carbon capture technology.

Ab initio (coupled-cluster and density-functional) calculations of Gibbs reaction energies in solution, with new entropy-of-solvation damping terms, were performed for the ether-catalyzed hydroboration of alkenes. The goal was to test the accuracy of continuum-solvation models for reactions of neutral species in nonaqueous solvents, and the hope was to achieve an accuracy sufficient to address the mechanism in the "Pasto case": B2H6 + alkene in THF solvent. Brown's SN2/SN1 "dissociative" mechanism, of SN2 formation of borane-ether adducts followed by SN1 alkene attack, was at odds with Pasto's original SN2/SN2 hypothesis, and while Brown could prove his mechanism for a variety of cases, he could not perform the experimental test with THF adducts in THF solvent, where the higher THF concentrations might favor an SN2 second step. Two diboranes were tested: B2H6, used by Pasto, and (9BBN)2 (9BBN = 9-borabicyclo[3.3.1]nonane, C8H15B), used by Brown. The new entropy terms resulted in improved accuracy vs traditional techniques (∼2 kcal mol(-1)), but this accuracy was not sufficient to resolve the mechanism in the Pasto case.

The dissociation constants of the conjugate acids of 14 amines (diethylethanolamine, monoethanolamine, n-butyldiethanolamine, t-butyldiethanolamine, n,n-dimethylpropanolamine, methyl-diethanolamine, ethyldiethanolamine, monoethylethanolamine, n,n-dimethylisopropanolamine, triethanolamine, 4-methylpiperazine-1-amine, 3-morpholino propylamine, 4,2-hydroxylethylmorpholine, and triethylamine) were measured over a temperature range between 293.15 and 333.15 K using the potentiometric titration method. The change in standard state thermodynamic properties was derived from the van’t Hoff equation. The influence of the steric hindrance, number of −OH groups, and length of alkyl chain on the dissociation constants was identified. Of the studied amines, few sterically hindered derivatives of piperazine, a secondary amine monoethylethanolamine, and a tertiary amine n,n-dimethylpropanolamine have high pKa values but lower standard enthalpy than those of the benchmark amine, monoethanolamine (MEA), and thus were deeme...

The solubility of carbon dioxide in three bis(trifluoromethylsulfonyl)imide-based ionic liquids: N-methyl-n-pentylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([p(5)mpyrr][Tf2N]), 1-butyl-2,3-dimethylimidazolium bis(trifluoromethyl sulfonyl)imide ([bmmim][Tf2N]), and tributylmethylphosphonium bis(trifluoromethyl sulfonyl)imide ([P4441][Tf2N]) was measured at 298.15, 313.15, and 343.15 K and pressures up to about 1.9 MPa. The data were well correlated with the Soave–Redlich–Kwong equation of state (SRK-EoS). Henry's law constants for CO2 in the three ILs ([p(5)mpyrr][Tf2N], [bmmim][Tf2N], and [P4441][Tf2N]) at 298.15 K were 3.1, 3.5, and 3.3 MPa, respectively.

The solubility of carbon dioxide in three bis(fluorosulfonyl)imide-based ionic liquids: N-propyl-n-methyl-piperidinium bis(fluorosulfonyl)imide ([p(3)mpip][FSI]), N-propyl-n-methyl-pyrrolidinium bis(fluorosulfonyl)imide ([p(3)mpyrr][FSI]) and N-propyl-n-methyl-n,n-dimethyl-ammonium bis(fluorosulfonyl)imide ([N4441][FSI]) was measured at (298.15, 313.15, and 343.15) K and pressure up to about 2 MPa. The Henry's law constants for CO2 in the three ILs, ([p(3)mpip][FSI], [p(3)mpyrr][FSI] and [N4441][FSI]) at 298 K are (4.1, 4.0, and 3.8) MPa respectively, indicating the negligible effect of change of cation precursors on CO2 solubility. Solubility of CO2 in the present ILs with [FSI] anion is comparable with those in the ILs containing a more fluorinated common anion, [Tf2N]. The solubility data were correlated well with the Soave–Redlich–Kwong equation of state (SRK-EoS).

Ab initio molecular dynamics simulations of up to 210 ps have been performed on various aqueous intermediates postulated in the CO2 + amine reaction, important for CO2 capture. Observations of spontaneous deprotonation of aqueous carbamate zwitterions R1R2NHCOO(±) by bulk water (instead of additional amine, or via umbrella sampling) are reported apparently for the first time. Carbamic acid structures R1R2NCOOH were observed in some simulations, arising from zwitterions not via classical 1,3-H-shifts but via Grotthuss-style multiple-H(+) transfer pathways that involve bulk H2O and require carbamate anions R1R2NCOO(-) as an intermediate stage along the way. H(+)-bridging complexes, including not only Zundel ions [water·H(+)·water](+) but neutral carbamate complexes [carbamate(-)·H(+)·water], were observed in simulation. These results should assist efforts in improving underlying mechanisms for kinetic modeling.

Objective: Multiplex PCR assay was used for diagnosis of diarrheagenic Escherichia coli (DEC) in stool samples of children (under 5 years) with acute diarrhea. Methods: Samples were collected from January 2011 to December 2011, from Dhaka Medical College Hospital and Dhaka Shishu Hospital. Multiplex PCR with five specific primer pairs to detect enteropathogenic E. coli ( eae , bfp ), enterotoxigenic E. coli ( lt , st ) and enteroaggregative E. coli ( aat ) were used. However, enteroinvasive E. coli , enterohemorrhagic E. coli and diffusely adhererent E. coli were not sought. Result: In total, 135 (67.5%) E. coli were isolated from 200 stool samples. The prevalence of DEC was 68 (34%). Among DEC, most frequently isolated pathotype was EPEC 40 (58.82%), followed by ETEC 24 (35.29%) and EAggEC 18 (26.47%). Among the EPEC, 5 (12.5%) were typical EPEC. Among the 68 DEC positive cases, 22 samples contained more than one pathogenic gene in various combinations. Among the combination of DEC, EPEC+ETEC combination was 6 (27.27%) followed by ETEC+EAggEC 4 (18.18%), EPEC+EAggEC and ETEC+EPEC+EAggEC were both in 3 (13.6%). Conclusion: This study shows that DEC is a common cause of childhood diarrhea in Dhaka city of Bangladesh. By using multiplex PCR assay, DEC can be diagnosed in one PCR reaction that makes a conclusive diagnosis of diarrhea. DOI: http://dx.doi.org/10.3126/ajms.v5i2.8576 Asian Journal of Medical Science, Volume-5(2) 2014: 59-66

Concerns about climate change have propelled research efforts to develop affordable and environmentally benign technologies to capture CO2 from large emission sources, which can subsequently be used either for enhanced oil recovery or stored in other geological storage sites. The study of the solubility of CO2 in solvents is therefore of great interest, both from the theoretical and practical points of view. To screen solvents or to design CO2 capture processes, knowledge of the equilibrium solubility of CO2 in the solvents is necessary. A large body of solubility data of CO2 in aqueous and non-aqueous solutions of prominent industrial amines are available in literature. We present such data along with a description of the experimental techniques and thermodynamic models used. Innovations made to obtain an optimum solubility of CO2 and to minimize the energy cost of a desired CO2 capture system by adopting different kinds of solvents are also reviewed.

For pKa prediction of aliphatic amines (amines relevant to industrial CO2 capture), the performance of quantum-chemistry continuum-solvation methods is contrasted with the 1981 pencil-and-paper group-additivity method of Perrin, Dempsey, and Serjeant (PDS). We have optimized a quantum-chemistry continuum-plus-correction strategy, as well as updated the parameter values in the PDS method. The PDS method outperformed the continuum-based method: root-mean-square errors for a sample of 32 amines are 0.28 for the continuum-based method, 0.33 for the original PDS method, and 0.18 for the updated PDS method. Considering also that there is ambiguity in choice of cavity radii and molecular conformer for continuum-based methods, we recommend the pencil-and-paper PDS method over such methods.

Reaction kinetics is one of the most important parameters for the amine-based CO2 capture process because it indicates how fast CO2 reacts with amine, and it is one of the key parameters required for simulating and designing the absorption column. Reaction kinetics has been studied for several decades to aid the understanding of the reaction mechanism, obtaining the kinetics data and understanding the kinetics behavior. This article will comprehensively review these research activities from past to present and look at the future perspective of the study of CO2 absorption kinetics.

Densities (ρ) and viscosities (η) of aqueous 1-methylpiperazine (1-MPZ) solutions are reported at T = (298.15 to 343.15) K. Refractive indices (nD) are reported at T = (293.15 to 333.15) K, and surface tensions (γ) are reported at T = (298.15 to 333.15) K. Derived excess properties, except excess viscosities (Δη), are found to be negative over the entire composition range. The addition of 1-MPZ reduces drastically the surface tension of water. The temperature dependence of surface tensions is explained in terms of surface entropy (SS) and enthalpy (HS). The measured and derived properties are used to probe the microscopic liquid structure of the bulk and surface of the aqueous amine solutions.

The Henry's Law constants of CO 2 , CH 4 and N 2 in 2701 ionic liquids (ILs) of widely varying structures at (283.15, 298.15, and 323.15) K, the molar volumes and the relative polarity of ILs at 298.15 K are predicted using the thermodynamic method COSMO-RS. Structural variations in the cations and anions that enhance or diminish solubility and selectivity are identified. The trends in Henry's Law constants are explained in the light of molecular interactions qualitatively through sigma profiles and sigma-potentials of ILs. The relationships between the Henry's Law constants and the properties of ionic liquids are also investigated. In general, the Henry's Law constants of CO 2 decrease with increase in molar volume, and decrease in polarity of ILs. Both the solubility of CO 2 and selectivity decrease as temperature is increased. Activity coefficients at infinite dilution, enthalpies and entropies of solvation are also used to elucidate gas–liquid interactions. COSMO therm predictions are compared with experimental data. Ranking of cations, in terms of Henry's Law constants, is reported for each counterpart anion and vice versa. Such information is useful for designing and screening of ionic liquids for CO 2 capture.

Quantum chemistry computations with a semicontinuum (cluster + continuum) solvation model have been used to cure long-standing misprediction of aqueous carbamate anion energies in the industrially important CO2 + aqueous amine reaction. Previous errors of over 10 kcal mol(-1) are revealed. Activation energies were also estimated with semicontinuum modeling, and a refined discussion of the competing hypothetical mechanisms for CO2 + monoethanolamine (MEA) is presented. Further results are also presented to demonstrate that the basicity of an amine (aqueous proton affinity) correlates only with CO2 affinity within an amine class: secondary amines have an extra CO2 affinity that primary amines do not have.

This study investigates the interaction of natural organic matter with iron oxide (goethite) on chlorine decay, disinfection by-product (DBP) formation, and DBP compound speciation [total trihalomethanes (TTHM4) and haloacetic acids (HAA5)]. Batch experiments were conducted with goethite, multiple finished drinking waters, variable chlorine dose, and fixed pH 8. The overall objective was to assess natural organic matter (NOM) adsorption onto goethite and its effect on chlorine decay and DBP formation. Chlorine consumption always increased in the presence of goethite and is attributed to an increase in the reactivity and/or modification of adsorbed NOM. Adsorbed NOM also led to an overall increase in TTHM4, however, HAA5 formation was suppressed during the first 2 h. Chloroform was identified as the increasing species and dichloracetic acid was identified as the suppressed species. This study clearly shows that goethite, which is the predominant iron oxide of pipe deposits, alters both chlorine decay and DBP formation and should be considered when assessing water treatment plant operations and DBP monitoring site selection.