Résumé -Effet de la composition du gaz naturel sur les performances d'un moteur GNCLe Gaz Naturel Comprimé (GNC) est considéré comme un carburant pour véhicule alternatif en raison de ses avantages économiques et environnementaux. Cependant, il est prouvé que la composition variable des gaz naturels produits dans diverses régions du monde affecte les performances et les taux d'émissions des moteurs GNC. Ainsi, l'objectif de cet essai est de corroborer l'effet de la composition du carburant sur la combustion et sur le taux d'émissions des moteurs GNC. Cet essai présente les caractéristiques de combustion globales obtenues en faisant fonctionner un moteur GNC de 2,5 L de quatre cylindres, posé en deuxième monte sur la base d'un moteur diesel à injection directe et équipé d'un dynamomètre. La puissance du moteur, la consommation de carburant spécifique au freinage, la pression de combustion et les émissions ont été mesurées dans des conditions de fonctionnement constantes en pleine charge et en charge partielle. Les résultats de l'expérience ont montré que la composition du GNC a un impact considérable sur les performances du moteur, sur la consommation de carburant et sur la vitesse de combustion. Une corrélation a été suggérée pour mieux comprendre la relation qui existe entre l'indice de Wobbe (IW) et la puissance du moteur. Elle propose une méthode pratique pour estimer la puissance du moteur lorsque la composition des gaz naturels varie. Abstract -Effect of Natural Gas Composition on the Performance of a CNG Engine -Compressed Natural Gas (CNG) is considered an alternative vehicle fuel because of its economical and environmental advantages. However, the varying composition of natural gases produced in different parts of the world is known to affect the performance and emissions of CNG engines. Thus

This experiment was conducted to investigate the effects of palm kernel expellers on growth performance, nutrient digestibility, and blood profiles of weaned pigs. A total of 88 weaned pigs (6.94±0.76 kg body weight [BW]; 28 d old) were randomly allotted to 2 dietary treatments (4 pigs/pen; 11 replicates/treatment) in a randomized complete block design (sex as a block). The dietary treatments were a typical nursery diet based on corn and soybean meal (CON) and CON added with 20% of palm kernel expellers (PKE). Pigs were fed for 6 wk using a 3-phase feeding program with declining diet complexity and with phases of 1, 2, and 3 wk, respectively. Blood was collected from randomly selected 2 pigs in each pen before weaning and on d 7 after weaning. Pigs were fed respective dietary treatments containing 0.2% chromic oxide from d 29 to 35 after weaning. Fecal samples were collected from randomly selected 2 pigs in each pen daily for the last 3 days after the 4-d adjustment period. Measurements were growth performances, digestibility of dry matter, nitrogen and energy, white and red blood cell counts, packed cell volume, and incidence of diarrhea. The PKE increased average daily gain (ADG) (246 vs 215 g/d; p = 0.06) and average daily feed intake (ADFI) (470 vs 343 g/d; p<0.05) and decreased gain-to-feed ratio (G:F) (0.522 vs 0.628 g/g; p<0.05) during phase 2 compared with CON, but did not affect growth performance during phase 1 and 3. During overall experimental period, PKE increased ADG (383 vs 362 g/d; p = 0.05) and ADFI (549 vs 496 g/d; p<0.05) compared with CON, but did not affect G:F. However, no differences were found on digestibility of dry matter, nitrogen, and energy between CON and PKE. The PKE reduced frequency of diarrhea (15% vs 25%; p = 0.08) for the first 2 wk after weaning compared with CON. Similarly, PKE decreased white blood cells (8.19 vs 9.56×103/μL; p = 0.07), red blood cells (2.92 vs 3.25×106/μL; p = 0.09), and packed cell volume (11.1% vs 12.6%; p = 0.06) on d 7 after weaning compared with CON. In conclusion, addition of 20% palm kernel expellers to nursery diet based on corn and soybean meal had no negative effects on growth performance, nutrient digestibility, and blood profiles of weaned pigs.

This experiment was conducted to investigate the effects of palm kernel expellers on productive performance, nutrient digestibility, and changes in white blood cells (WBC) of lactating sows. A total of 14 sows (200±12 kg of average body weight [BW]; 2.5 of average parity) were used and moved from gestation room to farrowing room on d 109 of gestation. Sows were randomly assigned to 2 dietary treatments in a completely randomized design. The treatments were a diet based on corn and soybean meal (CON) and CON added with 20% of palm kernel expellers (PKE). Sows were fed the treatments for 28 days (weaning) after farrowing. Blood was collected from each sow and 4 randomly selected piglets from each sow before farrowing or on d 3, 7, or 14 of lactation. Sows were fed respective treatments containing 0.2% chromic oxide from d 15 to 21 of lactation. Fecal samples were collected daily for the last 3 days after the 4-d adjustment period. Measurements were performances and WBC changes of sows and litter, nutrient digestibility of sows, and daily diarrhea of litter. Sows fed PKE had greater average daily feed intake (7.38 vs 7.10 kg/d; p<0.05) and lost less BW (−6.85 vs −8.54 kg; p<0.05) and backfat depth (−0.42 vs −0.71 mm; p<0.05) than those fed CON. However, there were no differences on digestibility of dry matter, nitrogen, and energy and weaning to estrus interval of sows fed either CON or PKE. Piglets from sows fed PKE gained more BW (203 vs 181 g/d; p = 0.08) and had less frequency of diarrhea (6.80 vs 8.56%; p = 0.07) than those from sows fed CON. On the other hand, no difference was found on preweaning mortality of piglets from sows fed either CON or PKE. Sows fed PKE had lower number of WBC (9.57 vs 11.82 ×103/μL; p = 0.09) before farrowing than those fed CON, but no difference on d 3 and 7. Similarly, piglets from sows fed PKE had also lower number of WBC (7.86 vs 9.80 ×103/μL; p<0.05) on d 14 of lactation than those from sows fed CON, but no difference on d 3 and 7. In conclusion, addition of 20% palm kernel expellers to lactation diet based on corn and soybean meal had no negative effects on productive performance, nutrient digestibility, and WBC changes of lactating sows.

The effects of magnesia (MgO) addition on the ionic conductivity and thermal stability of CaOstabilised zirconia (CSZ) was investigated by structural and morphological analysis. MgO was added to CSZ using a solid-state reaction, and a secondary phase was not observed via XRD of all specimens sintered at 1600°C. However, Mg 2 SiO 4 and Mg-rich phases were detected in the microstructure of CSZ doped with 5 and 10 mol-% MgO, respectively. Ionic conductivity increased with an increase in MgO content, and CSZ doped with 5 mol-% MgO exhibited a maximum value of 0.819 S cm −1 measured at 1500°C due to the scavenging of Si impurities. The thermal diffusivity increased from 0.517 (CSZ) to 0.649 mm 2 s −1 (5 mol-% doped CSZ), and the thermal expansion coefficient of 0.5 mol-% doped CSZ was maximal at 9.855 μm/m°C. The value of mol-% doped CSZ decreased to 8.937 μm/m°C as it was affected by the Mg-Si phase formation.

A high resolution core level photoemission study on the metal contact formed on S-passivated n-InGaP(100) surface reveals that the species produced by the chemical reaction of the deposited metal atoms with the surface atoms induce the gap states responsible for the Fermi level movement. The initial sulfur passivation of n-InGaP(100) surface efficiently reduced the gap states within the band gap and flattened the band bending by 0.6 eV relative to the sputter-cleaned surface. When the metals such as Al(Au) are deposited on the S/InGaP(100) surface, it was found that the deposited Al(Au) reacted with monosulfides resulting in the Al-sulfide (the remaining defective In-polysulfides) which seem to be the origin of the gap states.