Poisoning of ammonia synthesis catalyst considering off-design feed compositions

Activity of ammonia synthesis catalyst in the Haber-Bosch process is studied for the case of feeding the process with intermittent and impurity containing hydrogen stream from water electrolysis. Hydrogen deficiency due to low availability of renewable energy is offset by increased flow rate of nitrogen, argon, or ammonia, leading to off-design operation of the Haber-Bosch process. Catalyst poisoning by ppm levels of water and oxygen is considered as the main deactivation mechanism and is evaluated with a microkinetic model. Simulation results show that catalyst activity changes considerably with feed gas composition, even at exceptionally low water contents below 10ppm. A decreased hydrogen content always leads to lower poisoning of the catalyst. It is shown that ammonia offers less flexibility to the operation of Haber-Bosch process under fluctuating hydrogen production compared to nitrogen and argon. Transient and significant changes of catalyst activity are expected in electrolysis coupled Haber-Bosch process

3d polyaniline nanofibers anchored on carbon paper for high-performance and light-weight supercapacitors

In the field of advanced energy storage, nanostructured Polyaniline (PANI) based materials hold a special place. Extensive studies have been done on the application of PANI in supercapacitors, however, the structure–property relationship of these materials is still not understood. This paper presents a detailed characterization of the novel sodium phytate doped 3D PANI nanofibers anchored on different types of carbon paper for application in supercapacitors. An excellent relationship between the structures and properties of the synthesized samples was found. Remarkable energy storage characteristics with low values of solution, charge transfer and polarization resistance and a specific capacitance of 1106.9 ± 1.5 F g$^{−1}$ and 779 ± 2.6 F g$^{−1}$ at current density 0.5 and 10 Ag$^{−1}$, respectively, was achieved at optimized conditions. The symmetric supercapacitor assembly showed significant enhancement in both energy density and power density. It delivered an energy density of 95 Wh kg$^{−1}$ at a power of 846 W kg$^{−1}$. At a high-power density of 16.9 kW kg$^{−1}$, the energy density can still be kept at 13 Wh kg$^{−1}$. Cyclic stability was also checked for 1000 cycles at a current density of 10 Ag$^{−1}$ having excellent retention, i.e., 96%

Digitalization Platform for Mechanistic Modeling of Battery Cell Production

he application of batteries in electric vehicles and stationary energy-storage systems is widely seen as a promising enabler for a sustainable mobility and for the energy sector. Although significant improvements have been achieved in the last decade in terms of higher battery performance and lower production costs, there remains high potential to be tapped, especially along the battery production chain. However, the battery production process is highly complex due to numerous process–structure and structure–performance relationships along the process chain, many of which are not yet fully understood. In order to move away from expensive trial-and-error operations of production lines, a methodology is needed to provide knowledge-based decision support to improve the quality and throughput of battery production. In the present work, a framework is presented that combines a process chain model and a battery cell model to quantitatively predict the impact of processes on the final battery cell performance. The framework enables coupling of diverse mechanistic models for the individual processes and the battery cell in a generic container platform, ultimately providing a digital representation of a battery electrode and cell production line that allows optimal production settings to be identified in silico. The framework can be implemented as part of a cyber-physical production system to provide decision support and ultimately control of the production line, thus increasing the efficiency of the entire battery cell production process

Inquérito soro-epidemiológico anti-Brucella abortus em rebanhos caprinos na região semi-árida do Submédio São Francisco, PE.

A brucelose é uma doença infecto-contagiosa crônica comum a diversas espécies animais. O animal infectado é a principal fonte de infecção para o homem e outros animais. Objetivou-se com este estudo realizar um levantamento soro-epidemiológico da brucelose nos rebanhos caprinos na região semi-árida do Submédio São Francisco. Foram coletadas 144 amostras de soros de caprinos, rocedentes de três propriedades localizadas em municípios da região Submédio São Francisco no Estado de Pernambuco. As amostras foram obtidas por meio de venopunção da jugular e encaminhadas ao Laboratório de Microbiologia e Imunologia Animal da Universidade Federal do Vale do São Francisco, para realização do teste do antígeno acidificado tamponado (TAAT). Neste trabalho, todas as amostras analisadas (n=144), mostraram resultado negativo no TAAT. A infecção natural pela Brucella abortus não ocorre nos rebanhos de caprinos estudados na região semi-árida do Submédio São Francisco. No entanto, em virtude da presença de caprinos sororeagentes para esta enfermidade em estados vizinhos, salienta-se a importância de estudos como esse no Estado de Pernambuco e em outros estados geograficamente próximos

Species Distribution During Solid Electrolyte Interphase Formation on Lithium Using MD/DFT-Parameterized Kinetic Monte Carlo Simulations

Lithium metal batteries are one of the promising technologies for future energy storage. One open challenge is the generation of a stable and well performing Solid Electrolyte Interphase (SEI) between lithium metal and electrolyte. Understanding the complex interaction of reactions at the lithium surface and the resulting SEI is crucial for knowledge-driven improvement of the SEI. This study reveals the internal species distribution and geometrical aspects of the native SEI during formation by model-based analysis. To achieve this, a combination of molecular dynamics, density functional theory, and stand-alone 3D-kinetic Monte Carlo simulations is used. The kinetic Monte Carlo model determines the SEI growth features over a long time and length scale so that the SEI can be analyzed quantitatively. The simulation confirms the frequently postulated layered SEI structure arising from the decomposition of an ethylene carbonate/lithium hexafluorophosphate (2 M) electrolyte with lithium metal. These layers are not clearly separated, which is contrary to what is often reported. The gradient distribution of the species within the SEI therefore corresponds to a partly mosaic structured SEI at the borders of the layers. At the lithium surface, an inorganic layer of lithium fluoride and then lithium carbonate is observed, followed by an organic, more porous SEI layer consisting of lithium ethylene dicarbonate. Simulations further reveal the strong prevalence of corrosion processes of the metal, which provide more than 99% of the lithium for the SEI reaction processes. The salt contributes less than 1% to the SEI formation. Additionally, SEI formation below and above the initial interface was observable. The here presented novel modeling approach allows an unprecedented in-depth analysis of processes during native SEI formation that can be used to improve design for high battery performance and durability

Mastite estafilocócica em um rebanho de caprinos leiteiros na região semi-árida do Submédio São Francisco, PE.

A mastite é uma enfermidade infecto-contagiosa de etiologia múltipla, de onde podem ser isolados microrganismos gram positivos e gram negativos. Objetivou-se avaliar o perfil de sensibilidade aos antimicrobianos dos principais agentes causadores de mastite em cabras leiteiras do Submédio São Francisco. Foram utilizados 30 animais explorados em sistema intensivo de produção. As amostras de leite foram coletadas e processadas no laboratório de Microbiologia e Imunologia Animal da UNIVASF. Do total de amostras analisadas 41,66% (25/60) apresentaram resultado positivo na lactocultura. Com relação aos animais estudados, observou-se que 60% (18/30) deles foram portadores de mastite e 40% (12/30) não apresentaram a doença. O Staphylococcus coagulase positiva foi isolado em 96% (24/25) das amostras positivas. Streptococcus spp. foi identificado em apenas uma das delas. Neste estudo, bserva-se uma alta prevalência de mastite na propriedade avaliada, bem como a ampla ocorrência de Staphylococcus coagulase positiva, como agente causador da enfermidade. Poucos são os antimicrobianos com uma eficácia acima de 90% para os microrganismos isolados, com destaque para a amicacina e gentamicina

Distribution of PLD and FagA, B, C and D genes in Corynebacterium pseudotuberculosis isolates from sheep and goats with caseus lymphadenitis.

Caseous lymphadenits (CL) is a chronic and subclinical disease that affects goats and sheep and, consequently, causes economic losses, especially to small producers. The purpose of this study, through use of Polymerase Chain Reaction (PCR), was to verify the presence of virulence genes of phospholipase D (PLD), integral membrane protein (FagA), iron enterobactin transporter (FagB), ATP binding cytoplasmic membrane protein (FagC) and iron siderophore binding protein (FagD) in 168 isolates of C. pseudotuberculosis obtained from cases of caseous lymphadenitis in goats and sheep. FagA, FagB and PLD genes were detected in all 145 strains isolated from abscesses in superficial lymph nodes and in 23 strains isolated from viscera. The FagC gene was positive in 167 (99.40%) isolates. The FagD gene was detected in 160 (95.23%) isolates. All virulence factors analyzed were found more frequently among isolates collected in the viscera of animals with CL, indicating a multifactorial nature, as well as variations, in the invasive potential of C. pseudotuberculosis strains.Ahead of print

Eficácia de três métodos empregados no controle da mastite estafilocócica em cabras leiteiras criadas no município de Santa Maria da Boa Vista, PE.

A mastite é a inflamação da glândula mamária, com alterações físicas, químicas e microbiológicas no leite e alterações no tecido da glândula mamária, o que promove prejuízos econômicos aos criatórios leiteiros. Dada a relevância dos estudos acerca das lternativas para o tratamento e controle da mastite, objetivou-se avaliar métodos de controle da enfermidade em pequenos ruminantes. Foram utilizados animais portadores de mastite subclínica, distribuídos em quatro grupos: grupo um (n = 15) foi o controle cujos animais não receberam nenhum tratamento contra a mastite. No grupo dois (n=11), fez-se a aplicação de uma vacina comercial usada para bovinos leiteiros (Mastaph® ). No grupo três (n=13), empregou-se antimicrobiano (cloxacilina) de aplicação intramamária e no grupo quatro (n=14), fez-se a aplicação da vacina comercial associada ao antimicrobiano cloxacilina. Na associação vacina e antibiótico (grupo 04), observou-se redução significativa (P<0,05) no número de tetos infectados. A utilização apenas do antibiótico cloxacilina (grupo 03) também foi eficiente em reduzir significativamente (P<0,05) a taxa de infecção. O antibiótico a base de cloxacilina pode ser usado isoladamente ou em associação a vacinas anti-mastíticas para controle da mastite estafilocócica em pequenos ruminantes