Let K/k be a finite extension of a global field. Such an extension can be generated over k by a single element. The aim of this article is to prove the existence of a ”small” generator in the function field case. This answers the function field version of a question of Ruppert on small generators of number fields.

Pyroelectric neutron generators are a recent development utilizing the pyroelectric effect to produce an accelerating electric field and thus enabling creation of small electron and ion accelerators without external high voltage power supply. The principle of operation includes a pyroelectric crystal (LiTaO3 for example) placed in vacuum and simple heating (or cooling) of the crystal to cause a...

the hcci combustion process is initiated due to auto-ignition of fuel/air mixture which is dominated by chemical kinetics and therefore fuel composition has a significant effect on engine operation and a detailed reaction mechanism is essential to analysis hcci combustion. a single zone-model permits to have a detailed chemical kinetics modeling for practical fuels. in this study a single-zone ...

The preparation of air–fuel mixture is considerably dependent on fluid flow dynamics to achieve improved performance, efficiency, and engine combustion in the appearance of flow. In this study, the effects of mixtures of hydrogen and compressed natural gas (CNG) on a spark ignition engine are numerically considered. This article presents the results of a direct-injection engine using methane–hy...

In order to use gaseous fuels in Diesel Engines, Dual-Fuel Diesel Engine (D. F. D. E) the pilot injection approach is chosen. To predict its performance, an engine cycle model, based on limited-pressure Diesel cycle, is constructed. The model predicts D. F. D. E performance with LPG, and CNG gases. Comparing with pure Diesel engine, by increasing gas proportion in dual-fuel, indicated power and...

The gas flow estimation is crucial for the proper operation and monitoring of turbocharged (TC) engines with a torque structured engine control unit (ECU). This paper presents mean value models developed for modeling gas flow over the compressor, the turbine and the wastegate (WG) in a TC gasoline engine not equipped with a hot film air-mass flow meter (HFM). The turbine flow ...

This paper presents the results of experimental work carried out to evaluate the distribution of cold and hot exhaust gas recirculation between cylinders in a DI diesel engine. The experiments have been conducted on a 3.99 liters turbocharged DI diesel engine under full load condition at 1900rpm in order to distinguish and quantify some effects of hot and cooled EGR with various rates on the EG...

The paper presents the results of modelling thermal cycle of internal combustion engine including exhaust gas recirculation. The test engine can not achieve the optimum parameters of work due to occurrence of the knock combustion. The influence of EGR on the limits of the knock occurrence in the engine was studied. It turned out that few percent of exhaust gases in the fresh charge effectively ...