Analytical Simulation of the Cloud Combustion of Corn Starch Microparticles

Knowledge of the fundamentals of dust combustion is necessary for designing safety technologies such as flame arrestors. The structure of flame propagation in a uniformly distributed cloud of volatile fuel particles was simulated. A model based on energy and mass conservation laws was generated. The obtained system of equations was nondimensionalized and solved according to the introduced boundary conditions. Comparison of the results with the existing experimental data in the literature showed remarkable agreement. Finally, the effect of parameters such as particle size and Lewis number on the characteristics of the cloud combustion of biomass microparticles under both lean and rich conditions was studied.     

Development of a maturity model for electronic invoice processes

The digitalization of invoice processes provides a good opportunity for companies to pare down expenses, optimize administrative tasks, and increase efficiency and competitiveness. But the digitalization is limited by a variety of software solutions, legal uncertainties, heterogeneous demands, lack of know-how, and information system infrastructure incompatibilities. A holistic map of electronic invoice processes is mandatory, especially to demonstrate different levels of process integration and optimization. A maturity model puts this into practice and provides companies with a tool to identify their current situation and to derive recommendations to optimize that situation. In this paper, a maturity model for electronic invoice processes will be developed using exploratory data from focus groups. A theoretical approach that is based on a procedure-model for developing maturity models is applied. Four categories (strategy, acceptance, processes & organization, and technology) are identified and enriched by sub-categories. Future research requires the development of detailed maturity metrics.     

An Ovine Model for Percutaneous Pulmonary Artery Laser Denervation: Perivascular Innervation and Ablation Lesion Characteristics

Background: Pulmonary artery denervation (PADN) is an evolving interventional procedure capable to reduce pulmonary artery (PA) pressure. We aimed to compare PA nerve distribution in different specimens and assess the feasibility of an ovine model for a denervation procedure and evaluate the acute changes induced by laser energy. Methods: The experiment was divided into two phases: (1) the analysis of PA nerve distribution in sheep, pigs, and humans using histological and immunochemical methods; (2) fiberoptic PADN in sheep and postmortem laser lesion characteristics. Results: PA nerve density and distribution in sheep differ from humans, although pigs and sheep share similar characteristics, nerve fibers are observed in the media layer, adventitia, and perivascular tissue in sheep. Necrosis of the intima and focal hemorrhages within the media, adventitia, and perivascular adipose tissue were evidenced post laser PADN. Among the identified lesions, 40% reached adventitia and could be classified as effective for PADN. The use of 20 W ablation energy was safer and 30 W-ablation led to collateral organ damage. Conclusions: An ovine model is suitable for PADN procedures; however, nerve distribution in the PA bifurcation and main branches differ from human PA innervation. Laser ablation can be safely used for PADN procedures.     

Kinetic Model of the Formation of Protein Crystals in Capillaries by Counterdiffusion

A kinetic model of crystallization of lysozyme is proposed, and computer calculations of this process are carried out. The conditions for the formation of such crystals are determined. Under these conditions, individual crystals were grown that were suitable for X-ray examination. The developed model enables prediction of the quantity, size, and place of crystal nucleation inside the capillary.     

A kinetic model of amino-acid polymer growth in sodium and potassium aqueous solutions

A kinetic model was proposed and computing calculations of formation of short polymer chains (oligomers) from monomers (amino acids) in aqueous solutions with sodium and potassium ions for which energies of monomer addition to the chain were carried out. It is shown that formation of longer chains of monomers in potassium medium, in comparison with sodium medium, is caused by a smaller value of the energy of addition.     

Micellar Hyaluronidase and Spiperone as a Potential Treatment for Pulmonary Fibrosis

Concentration of hyaluronic acid (HA) in the lungs increases in idiopathic pulmonary fibrosis (IPF). HA is involved in the organization of fibrin, fibronectin, and collagen. HA has been proposed to be a biomarker of fibrosis and a potential target for antifibrotic therapy. Hyaluronidase (HD) breaks down HA into fragments, but is a subject of rapid hydrolysis. A conjugate of poloxamer hyaluronidase (pHD) was prepared using protein immobilization with ionizing radiation. In a model of bleomycin-induced pulmonary fibrosis, pHD decreased the level of tissue IL-1β and TGF-β, prevented the infiltration of the lung parenchyma by CD16⁺ cells, and reduced perivascular and peribronchial inflammation. Simultaneously, a decrease in the concentrations of HA, hydroxyproline, collagen 1, total soluble collagen, and the area of connective tissue in the lungs was observed. The effects of pHD were significantly stronger compared to native HD which can be attributed to the higher stability of pHD. Additional spiperone administration increased the anti-inflammatory and antifibrotic effects of pHD and accelerated the regeneration of the damaged lung. The potentiating effects of spiperone can be explained by the disruption of the dopamine-induced mobilization and migration of fibroblast progenitor cells into the lungs and differentiation of lung mesenchymal stem cells (MSC) into cells of stromal lines. Thus, a combination of pHD and spiperone may represent a promising approach for the treatment of IPF and lung regeneration.     

In vivo assessment of effect of fermented milk diet on course of infection in mice with bioluminescent Salmonella

A novel method for assessing the effect of fermented milk and its components on the course of Salmonella infection in live mice is described. Following a period of feeding with whole fermented milk (group W), a cell-free fraction of fermented milk (group S), or saline (group C, control), mice were challenged by oral gavage with a bioluminescent strain of Salmonella Enteritidis. Colonization of the gastrointestinal tract and subsequent infection could be followed by bioluminescent imaging of live mice with a cooled slow-scan CCD camera. Each group of mice was fed for 7 days with the appropriate product. On the eighth day, all mice were orally infected with 10(6) Salmonella cells. On the sixth day after infection, mice in groups W and C showed evidence of disease. No bioluminescent signal was observed for any of the mice in group S. The physical condition of the mice in groups W and S was normal, but some deterioration in the health of the mice in the control group (group C) occurred. On the eighth day after infection, a weak bioluminescence signal was observed for the mice in group W, but still no signal was observed for any of the mice in group S. Mice in both of these groups appeared normal, but the mice in group C showed strong evidence of infection and marked deterioration in their physical condition accompanied by a bioluminescence signal. This method allows the assessment of the effects of potential nutraceutical agents on the course of infection by foodborne pathogens in live animals in real time.     

Initial stages of the MBE growth of silicon carbide nanoclusters on a silicon substrate

The growth of silicon carbide (SiC) nanoclusters by molecular beam epitaxy on silicon substrates has been studied using a combination of experimental and theoretical methods. The first results concerning the initial stages of this growth are presented.     

Improving the reliability of ball grid arrays under random vibration by optimization of module design

Abstract

In this work, three different arrangements of circuit board in an electronic device were designed and the effects of random vibration frequencies on the reliability of ball grid arrays (BGA) in these arrangements were evaluated. The failure criterion in solder balls was the root mean square of peeling stress exerted during the dynamical loadings. According to the finite element method (FEM) results, the uttermost stress concentration was generated at the interface of printed circuit board (PCB) and the solder balls. It was also revealed that the increase of input power spectral density (PSD) decreased the fatigue life of solder joint in all the arrangements. Considering the arrangements of circuit boards, it was found that the maximum domain of peeling stress had a minimum effect on the solder balls when the heat sinks were away from the packages. The microstructural characterization of critical zone in solder balls indicated that with the increase of maximum peeling stress, the crack initiated and propagated along the interface.