Fuel consumption and emission comparison of conventional and hydrogen feed vehicles

Current environmental concerns on nitrogen oxides (NO_x) and particulate matter (PM) emissions caused by diesel engines have led researchers to be interested in investigating vehicles with alternative power sources. Because of this reason, vehicle models with SI engine were adopted in the conducted study. Firstly, as an initial step, 1-D SI engine models were created with use of AVL Boost software. A four-cylinder engine model was created for conventional vehicle model, while a two-cylinder downsized engine was adopted as a subsystem of hybrid vehicle model. The models were based on experimental data obtained from a laboratory test setup with a single-cylinder engine. Subsequently, detailed engine maps on emissions and fuel consumption were generated with the developed ANN model. The fuel consumption and emission data, which were gathered from NEDC and WLTC simulations, were compared for conventional ICE, PEM FC and PEM FC + ICE powered vehicles with the help of the vehicle model which was developed by using Matlab Simulink software. Based on the results, it was concluded that there might be sufficient improvement in fuel consumption and significant improvement in emissions with the use of PEM FC that a hybrid driving system (PEM FC + ICE) can be utilized, and that emissions can be at 0 with the sole use of PEM FC.     

Molecular Determinants for Protein Stabilization by Insertional Fusion to a Thermophilic Host Protein

A universal method that improves protein stability and evolution has thus far eluded discovery. Recently, however, studies have shown that insertional fusion to a protein chaperone stabilized various target proteins with minimal negative effects. The improved stability was derived from insertion into a hyperthermophilic protein, Pyrococcus furiosus maltodextrin‐binding protein (PfMBP), rather than from changes to the target protein sequence. In this report, by evaluating the thermodynamic and kinetic stability of various inserted β‐lactamase (BLA) homologues, we were able to examine the molecular determinants of stability realized by insertional fusion to PfMBP. Results indicated that enhanced stability and suppressed aggregation of BLA stemmed from enthalpic and entropic mechanisms. This report also suggests that insertional fusion to a stable protein scaffold has the potential to be a useful method for improving protein stability, as well as functional protein evolution.     

Failure analysis of support during profile cutting process using horizontal milling machine

In this study, the effects of cutting forces on the support of horizontal woodworking milling machine are examined during profile cutting process using both experimental and analytical approaches. The support modeled in 3D using SolidWorks software is a crucial component of the horizontal milling machine used to locate and fix the wood workpiece during the cutting process on the workbench. The effects of cutting forces on the support specimens are measured experimentally considering vibration and failure analyses. Analytical stresses and modal analyses of the support were also calculated using finite element-based analysis approach. Chatter vibration forces of the cutting tool which resulted from cutting forces in x-, y-, and z-directions were calculated analytically during the profile cutting process. The results showed that both cutting and chatter forces are highly effective on the support component failure of the woodworking milling machines.     

An efficient finite element with layerwise mechanics for smart piezoelectric composite and sandwich shallow shells

In this work, we present a new efficient four-node finite element for shallow multilayered piezoelectric shells, considering layerwise mechanics and electromechanical coupling. The laminate mechanics is based on the zigzag theory that has only seven kinematic degrees of freedom per node. The normal deformation of the piezoelectric layers under the electric field is accounted for without introducing any additional deflection variables. A consistent quadratic variation of the electric potential across the piezoelectric layers with the provision of satisfying the equipotential condition of electroded surfaces is adopted. The performance of the new element is demonstrated for the static response under mechanical and electric potential loads, and for free vibration response of smart shells under different boundary conditions. The predictions are found to be very close to the three dimensional piezoelasticity solutions for hybrid shells made of not only single-material composite substrates, but also sandwich substrates with a soft core for which the equivalent single layer (ESL) theories perform very badly.     

Analysis of an unconventional cycle as a new comparison standard for practical heat engines: the circular/elliptical cycle in T–S diagram

An unconventional cycle analysis in the T–S diagram has been carried out and the cycle characteristics such as thermal efficiency, work density (defined as the ratio of the network output to the maximum volume in the cycle), maximum volume and maximum pressure are determined. The obtained results for the unconventional cycle are compared with those of the Carnot cycle. It is proposed that the analysed unconventional cycle may be used as a better comparison standard than the Carnot cycle for practical heat engines when both size and thermal efficiency are considered. Copyright © 2004 John Wiley & Sons, Ltd.     

Time-interleaved SAR ADC design with background calibration

In this article, a low power time-interleaved SAR (TI-SAR) ADC is presented. Background calibration is used to improve the linearity of the ADC. Offset, gain, and capacitor mismatches between interleaved channels are calibrated by postprocessing the ADC output. Besides, a novel trimming-based calibration algorithm is used to calibrate the timing mismatches between channels. The proposed calibration algorithm is more power-efficient compared with most of its counterparts. The ADC consists of 18 parallel channels, a reference channel with two dummy channels, and a channel for timing calibration. The timing calibration channel is clocked only when the reference channel samples. The dummy channels are utilized to equalize the input load over time as they sample one after another to fill the gap where the reference channel does not sample. There is no need for any other dummy channels for timing calibration channel since it has low kickback noise over input driver. Each parallel channel operates at 111 ms/s while the reference channel runs at 105 ms/s. The aggregate sampling speed of the converter is 2 GS/s, and 52-dB SNDR is accomplished near Nyquist frequencies.