High-order coplanar waveguide (CPW) filters implemented by means of open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs)

In this paper, it is demonstrated that transmission lines loaded with a combination of open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs) are useful for the design of high-order band pass filters subjected to standard responses. Specifically, we present a 7-pole Chebyshev band pass filter in coplanar waveguide technology. The device is compact and filter performance is good, including a wide stopband response. With this work, we extend our previous work on the applications of OSRR- and OCSRR-loaded lines to the design of highly selective filters.     

Characterization of Lactobacillus isolates from fermented olives and their bacteriocin gene profiles

Near one hundred isolates of Lactobacillus paraplantarum, Lactobacillus pentosus and Lactobacillus plantarum from table olives were studied. Strains were genotyped by rep-PCR. Although the technique failed to differentiate some isolates at the species level, it proved a robust and easy procedure that could be useful for distinguishing between related strains of L. paraplantarum, L. pentosus and L. plantarum from a large pool of unrelated strains of these species. A PCR-based screening revealed the presence of the plantaricin encoding genes plnA, plnB, plnC, plnD, plnE/F, plnF, plnI, plnJ, plnK, plnG and plnN in most isolates of the three species. Sequences of bacteriocin genes present in L. paraplantarum and L. pentosus were homologous to L. plantarum genes. Through a discriminating analysis of the bacteriocin gene profiles, it was possible to establish a relationship between the origin of isolation and the LAB isolates, regardless of species.     

Analysis and comparative study of factors affecting quality in the hemming of 6016T4AA performed by means of electromagnetic forming and process characterization

Hemming is commonly one of the last operations for stamped parts. For this reason it is of critical importance on the performance and perceived quality of assembled vehicles. However, designing the hemmed union is a complicated task and is deeply influenced by the mechanical properties of the material of the bent part. Significant problems can arise in this operation when bending aluminum alloys, because cracks can appear due to the localized strain during hemming as a result of the low ductility of automotive aluminum alloys. This paper presents the development of the electromagnetic forming (EMF) technology for auto body-in-white parts hemming. A relatively simple experimental procedure to perform a hemming operation based on the principle of EMF is presented in order to compare the variation in the quality parameters of a hemmed joint. The achieved results are compared with the corresponding geometry hemmed utilizing the conventional process. At the same time, the study is completed with the development of a new simulation method for the EMF technology. The results obtained during this study prove the capability of the EMF to obtain quality hem unions simplifying the complicated conventional hemming operation. In this study a loose coupling EMF hemming simulation method has been developed using Maxwell^® 3D to solve the electromagnetic field computation and Abaqus^® to solve the mechanical computation. This simulation method shows good agreement with the physical experiments. Finally, the EMF hemming process is characterized by analyzing the influence of main input parameters on the quality output parameters.     

Short communication: Signs of host genetic regulation in the microbiome composition in 2 dairy breeds: Holstein and Brown Swiss

This study aimed to evaluate whether the host genotype exerts any genetic control on the microbiome composition of the rumen in cattle. Microbial DNA was extracted from 18 samples of ruminal content from 2 breeds (Holstein and Brown Swiss). Reads were processed using mothur (https://www.mothur.org/) in 16S and 18S rRNA gene-based analyses. Then, reads were classified at the genus clade, resulting in 3,579 operational taxonomic units (OTU) aligned against the 16S database and 184 OTU aligned against the 18S database. After filtering on relative abundance (>0.1%) and penetrance (95%), 25 OTU were selected for the analyses (17 bacteria, 1 archaea, and 7 ciliates). Association with the genetic background of the host animal based on the principal components of a genomic relationship matrix based on single nucleotide polymorphism markers was analyzed using Bayesian methods. Fifty percent of the bacteria and archaea genera were associated with the host genetic background, including Butyrivibrio, Prevotella, Paraprevotella, and Methanobrevibacter as main genera. Forty-three percent of the ciliates analyzed were also associated with the genetic background of the host. In total, 48% of microbes were associated with the host genetic background. The results in this study support the hypothesis and provide some evidence that there exists a host genetic component in cattle that can partially regulate the composition of the microbiome.     

A reduced chemical kinetic model for HCCI combustion of primary reference fuels in a rapid compression machine

A model for the Homogeneous Charge Compression Ignition (HCCI) of Primary Reference Fuels (PRFs) in a Rapid Compression Machine (RCM) has been developed. A reduced chemical kinetic model that included 32 species and 55 reactions was used and the affect of wall heat transfer on the temperature of the adiabatic core gas was taken into account by adding the displacement volume of the laminar boundary layer to the cylinder volume. A simple interaction between n-heptane and iso-octane was also included. The results showed the well-known two-stage ignition characteristics of heavy hydrocarbons, which involve low and high temperature cycles followed by a branched chain explosion. The first stage energy release decreases and the ignition delay increases nonlinearly with increasing octane number and decreasing the initial pressure. The energy release rate and total energy released were determined primarily by the rate of CO oxidation during the explosive phase following the ignition delay. The model reproduced the pressure curves obtained in the RCM experiments over a wide range of conditions remarkably well and was very sensitive to the fuel structure, the mixture composition and the initial temperature and pressure. Thus, the model can be easily adapted for predicting “knock” in spark-ignition engines and ignition-delays and burning rates in HCCI engines.     

Fe2O3-doped forsterite ceramics as a joining partner for ZrO2 in a laser brazing process

Gastight, high-temperature stable sealing between yttria-doped zirconia (ZrO₂) and an electrically insulating ceramic joining partner is necessary for a wide range of applications in oxygen sensing and energy conversion. To accomplish this, laser brazing with glass solders is an attractive alternative to existing joining processes. Due to a near-perfect match of its thermal expansion with the one of ZrO₂ up to high temperatures (～800 °C) and good thermal and electrical insulation properties, forsterite (Mg₂SiO₄) is chosen as a candidate joining partner. As the absorptivity of pure forsterite at the used diode laser wavelengths of 808 and 940 nm is quite low, increasing the energy absorption by doping forsterite with Fe₂O₃ appears to be a promising refinement of this technique. The optical properties of the resulting olivine ceramics are evaluated. The results show that Fe₂O₃-doped forsterite is both suitable as a joining partner for ZrO₂ and for tuning its absorptivity.     

Development of a kinetic model for the oxidation of methane over Pd/Al2O3 at dry and wet conditions

The kinetics of the oxidation of methane over a commercial 0.5% Pd on γ-Al₂O₃ catalyst has been studied in a lab-scale fixed-bed reactor, the effect of temperature, and methane, oxygen and water partial pressures being investigated, in a range of interest for environmental applications. Different Eley–Rideal, Langmuir–Hinshelwood and Mars–van Krevelen models were fitted to the experimental results, the best fitting being obtained for a Mars–van Krevelen model that considers slow desorption of the reaction products. The model parameters obtained both from differential and integral treatment of the experimental data are in good agreement with each other. A modification of the proposed model, taking into account that water is adsorbed over oxidised sites, is also able to model the inhibition produced by steam.     

Extraction methods and some physical properties of mesquite (Prosopis chilensis (Mol) Stuntz) seed gum

To evaluate the potential use of mesquite (Prosopis chilensis (Mol) Stuntz) seed gum, the behaviour of the gum was studied using two extraction methods (alkaline and acid), different pH values, two concentrations (0.2 and 0.4% w/v) and different temperatures. The capacity of the gum to stabilise food foams was also evaluated. The alkaline extraction yield (24.9%) was higher than the acid extraction yield (17.7%). Owing molecular to hydrolysis caused by the acid, acid extraction resulted in a lower protein content. Gum from acid extraction had a higher viscosity than that from alkaline extraction at all temperatures investigated (10, 20, 30, 40, 50 and 60 °C). There were no significant differences between the viscosities of mucilage dispersions at the different values of pH studied (3.0, 4.0 and 5.0). The addition of extracted mesquite gum (obtained by either method and at either concentration studied) to egg white foam provided a higher stability and decreased the liquid drainage and collapse of the foam. Copyright © 2004 Society of Chemical Industry     

Acute interstitial pneumonia (Hamman Rich syndrome)

We report the case of a 65-year-old woman with no history of respiratory disease who suffered onset of dyspnea after an episode of pseudoinfluenza. Dyspnea progressed such that within 15 days it was triggered by minimal effort. The patient died 15 hours after admission to our hospital, with a clinical picture of adult respiratory distress. Autopsy allowed us to rule out several diseases and arrive at a diagnosis of acute interstitial pneumonia, consistent with clinical course, anatomical and pathological findings as described in the literature.