Effects of EGR rate on performance and emissions of a diesel power generator fueled by B7

This paper analyses the impacts of the application of an exhaust gas recirculation (EGR) system on the performance and emissions of a stationary, direct-injection diesel engine operating with diesel oil containing 7% biodiesel (B7). Experiments were carried out in a 49-kW diesel power generator with the adapted EGR system, and engine performance and emissions were evaluated for different load and EGR settings. The results were compared with the engine operating with its original configuration without the EGR system, and revealed a reduction of peak cylinder pressure and fuel conversion efficiency, mainly at high engine loads. The use of EGR caused opposite effects on carbon dioxide (CO2), carbon monoxide (CO) and total hydrocarbons (THC) emissions, depending on load and EGR rate, showing an increase in most situations. The application of EGR consistently reduced oxides of nitrogen (NOX) emissions, reaching a maximum reduction close to 30%. In general, the use of EGR increased CO2, CO and THC emissions at high loads. The use of 7.5% EGR was found to be at an adequate rate to simultaneously reduce CO, THC and NOX emissions at low and moderate loads, without major penalties on CO2 emissions and engine performance

Bacteria-inducing legume nodules involved in the improvement of plant growth, health and nutrition

Bacteria-inducing legume nodules are known as rhizobia and belong to the class Alphaproteobacteria and Betaproteobacteria. They promote the growth and nutrition of their respective legume hosts through atmospheric nitrogen fixation which takes place in the nodules induced in their roots or stems. In addition, rhizobia have other plant growth-promoting mechanisms, mainly solubilization of phosphate and production of indoleacetic acid, ACC deaminase and siderophores. Some of these mechanisms have been reported for strains of rhizobia which are also able to promote the growth of several nonlegumes, such as cereals, oilseeds and vegetables. Less studied are the mechanisms that have the rhizobia to promote the plant health; however, these bacteria are able to exert biocontrol of some phytopathogens and to induce the plant resistance. In this chapter, we revised the available data about the ability of the legume nodule-inducing bacteria for improving the plant growth, health and nutrition of both legumes and nonlegumes. These data showed that rhizobia meet all the requirements of sustainable agriculture to be used as bio-inoculants allowing the total or partial replacement of chemicals used for fertilization or protection of crops

Straddle injuries to the bulbar urethra: management and outcome in 53 patients

Objective: To describe our experience with blunt injuries to the bulbar urethra and their late sequelae to identify factors that may affect patient outcome. Materials and Methods: A retrospective study was performed on 53 male patients who presented, between January 2001 and December 2005, with blunt traumatic injury to the bulbar urethra. The definitive diagnosis of urethral rupture was made by retrograde urethrography, where urethral rupture was classified into partial or complete. The minimum follow-up period was 3 years. The initial management was either suprapubic cystostomy or endoscopic urethral realignment over a urethral catheter using a cystoscope to pass a guide-wire over which the catheter was inserted. Stricture formation was managed by visual internal urethrotomy (VIU) for passable strictures and urethroplasty (stricture excision and re-anastomosis) for impassable strictures or recurrence after VIU. The follow-up period was three years. The results were analyzed by SPSS software (chi-square and Student's-t-test). Results: Stricture formation occurred in 19 of 22 patients (86%) with complete urethral rupture and in 10 of 31 (32%) with partial rupture (p < 0.001). Strictures occurred in 11 of 31 (35%) patients treated initially with suprapubic cystostomy and in 18 of 22 (82%) treated with primary urethral realignment (p < 0.001). The success rate after VIU was 15% (4 of 26 patients) and after urethroplasty it was 96% (24 of 25 patients) (p < 0.001). Conclusions: Suprapubic cystostomy is better than urethral realignment and catheterization as primary management after straddle injury to the bulbar urethra. Stricture excision and re-anastomosis is better than VIU as delayed management for strictures that develop after straddle injury to the bulbar urethra

First and second thermodynamic law analyses applied to spark ignition engines modelling and emissions prediction

A mathematical and numerical model of flow and combustion process for spark ignition engines is developed using the principles of the first and second law of thermodynamic. Availability (exergy) analysis is applied to cylinder of a spark ignition engine during the combustion process using a two-zone combustion model. Special attention is given to identification and quantification of irreversibility of combustion process and energy available basing on the isooctane fuel explosion. To predict emissions generation (greenhouse gases) a skeletal mechanism including 32 species and 61 reactions was developed and tested for different engine operations and exergy destructions