Effect Of Double Injection Research Articles

A Double-Injection Control Strategy For Partially Premixed Combustion

Partially Premixed Combustion has shown to be a promising internal combustion concept in terms of engine efficiency and emission levels, however, since the combustion process is partly kinetically controlled, unacceptably high pressure-rise rates could occur at various operating points. A remedy to this problem is the use of a pilot-fuel injection. This paper characterizes double injection effects on combustion through experimental results and presents a double injection closed-loop model predictive control strategy where the combustion phasing is controlled arbitrarily as the pressure rise rate is controlled below a upper bound. Experimental results show promising response times during set-point changes as well as load and speed disturbances.

Effect of double injection on combustion, performance and emissions of Jatropha water emulsion fueled direct-injection diesel engine

The experimental study was carried out using a four-stroke, high speed, DI (direct-injection) diesel engine with double fuel injections. In this study, Jatropha water emulsion was made by mixing a mass ratio of 10% of water. While fixing the first injection timing, we tested the engine on JWE (Jatropha water emulsion) with various injection timings and quantities of second injections. The acquired data was analyzed for various combustion parameters such as heat release rate, combustion center (timing of 50% of total heat release), ignition delay, and combustion duration; for performance parameters such as in-cylinder temperature, exhaust gas temperature, brake thermal efficiency; and emissions of CO (carbon monoxide), CO2 (carbon dioxide), HC (hydrocarbons), NOx (nitrogen oxides), as well as dust and smoke opacity. When using a large second injection amount, we found a significant reduction in the peaks of the in-cylinder pressure, HRR (heat release rate), and average in-cylinder temperatures. We also found a drastic increase in the ignition delay, combustion duration, and a shift in the combustion center toward the later combustion stage, as well as increased exhaust gas temperatures, and reduced brake thermal efficiency compared with those of the Light oil. A large second injection amount reduced NOx emissions up to 48%, and drastically reduced HC emissions at higher loads of the engine.

Hole-transport properties of a low-band gap alternating polyfluorene

The bulk transport properties of positive carriers in thin films of a low band-gap conjugated polymer, called APFO-Green5, have been investigated in the ac regime. The frequency-dependent impedance of an ITO/PEDOT:PSS/APFO-Green5/Al structure (where ITO is indium tin oxide and PEDOT:PSS is poly(3,4-ethylenedioxythiophene)/polystyrene sulphonic acid) was measured as a function of the dc applied bias. The capacitance response at low frequency gave indication of a combination of trapping and double-injection effects, while in the intermediate-high frequency range was determined by the transit time of injected holes. Hole mobility in APFO-Green5 thin films exhibited a Frenkel-like dependence on the applied electric field, with a field-dependent coefficient of around 8×10−3 (V cm−1)−1/2. A hole mobility close to 2×10−5 cm2 V−1 s−1 was achieved at the field of 3.5×105 V cm−1, in excellent agreement with that already reported by using a different bulk investigation technique.

EFEITO DA SINCRONIZAÇÃO DO ESTRO COM DUPLA APLICAÇÃO DE D-CLOPROSTENOL ASSOCIADA OU NÃO À eCG SOBRE O DESEMPENHO REPRODUTIVO DE CABRAS ½ BOER/SRD EXPLORADAS NA REGIÃO SEMIÁRIDA DO NORDESTE DO BRASIL

he aim of this study was to evaluate the effect of double injection of d-cloprostenol associated or not with equine chorionic gonadotrophin (eCG) over the reproduction performance of ½ Boer/non-genotype goats raised in the semi-arid region of North-eastern Brazil. Forty goats were distributed into two estrus synchronization protocols, as following: T1 (n = 20) two injections of 75 µg d-cloprostenol at seven days interval; T2 (n = 20), similar to the previous protocol, differing only by the addition of 300 IU eCG at the last d-cloprostenol injection. Percentage of animals in estrus (65% vs. 85%) and interval from the end of treatment to estrus onset (22.8 ± 13.4 h vs. 17.2 ± 7.6 h) did not differ (P>0.05) between T1 and T2, respectively. However, T2 showed a larger estrus length (P KEY WORDS: Estrus synchronization, goats, gonadotrophin, productive performance, prostaglandin.

A.C. and D.C. conduction in lightly substituted anthracene Langmuir films

The a.c. and d.c. properties of short-chain derivatives of anthracene prepared by using the Langmuir-Blodgett technique are reported; these thin films display interesting conduction effects on account of their unusual molecular structure. Emphasis is placed on the 9-alkyl-10-anthrylpropionic acid derivatives in which the alkyl chain is either C 4H 9 (C4 anthracene) or C 6H 13 (C6 anthracene). As expected, the dark conduction properties are markedly different from those of unsubstituted crystalline anthracene. For example, there is a marked anisotropy in the conductivity of C4 anthracene, the in-plane value exceeding that in a direction perpendicular to the layers by a factor of 10 8. By use of appropriate electrodes double injection effects accompanied by blue light emission were found. The admittance data for these novel films differ slightly from those of films of conventional fatty acid salts.

Third Side of the Lampert Triangle: Evidence of Traps-Filled-Limit Single-Carrier Injection

Rosental and Kalda have pointed out that the full theoretical solution of the Lampert triangle in the traps-filled-limit region predicts a more gentle slope than the experimentally observed results reported by Henderson and Ashley in neutron-irradiated silicon. While this is true, the experimental results are consistent with the simple space-charge-limited model. Although Rosental and Kalda suggest that the experimental results are due to high-field or double-injection effects, further experimental data tend to confirm the original assertion of traps-filled-limit behavior.

Double injection effects and electroluminescence in CdS

Observations on the negative resistance of insulating crystals of CdS with indium cathodes and gold anodes are reported. With applied voltages below the critical voltage for the onset of negative resistance a crystal can be switched from a low current to a high current state by light of wavelengths shorter than 8100 A. This effect is attributed to the presence of hole traps about 1 eV above the valence band. With pulsed applied voltages the current shows a steep rise to a highly conducting state after an induction time during which holes are being accumulated at the hole traps. At low temperatures visible light is emitted when a crystal is in the highly conducting state. The spectral distribution of this radiation is compared with the photoluminescence.

Double Injection Diodes and Related DI Phenomena in Semiconductors

Experimental studies of double injection (DI) negative resistance phenomena in GaAs, Si, and Ge are presented. V-I characteristics, switching, trapping, and photosensitivity properties of GaAs DI p-i-n diodes, fabricated by diffusion and alloying processes on semi-insulating crystals and in other cases fabricated via epitaxial processes with Cu-doped i regions, are described. Similar studies and data are presented on Si DI p-i-n diodes prepared via diffusion and/or alloying processes. Silicon DI p-i-n diodes are described which have been doped with various deep level impurities such as Au, Zn, Cd, or Co and which, depending upon the kind and concentration of deep level impurities, display a wide range of behavior including useful photosensitivity, switching, and voltage regulation properties. Brief mention is made of Ge DI p-i-n diodes fabricated on n-type crystals counter-doped with Cu, Fe, Ni, Co, or Mn. A comparison is made between experimental results and current theories of double injection effects. As might be expected, existing theories do not completely account for the experimental situation, e.g., breakdown to constant voltage in certain units and phenomena which seem closely related to plasma effects. In addition to various practical implications, including possibilities for a noninteracting diode negative resistance matrix, low voltage regulator diodes, photosensitive charge-storage diodes, and higher power microwave switching p-i-n diodes, the significance of deep level doping and possible and actual effects (e.g., secondary switching effects) on epitaxial Si devices are described.