A low cost air hybrid concept

This article is a pre-print version of the full and final article which is available at the link below.Copyright © 2010 Institut français du pétrole Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than IFP must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee: Request permission from Documentation, Institut français du pétrole, fax. +33 1 47 52 70 78, or [email protected] air hybrid engine absorbs the vehicle kinetic energy during braking, stores it in an air tank in the form of compressed air, and reuses it to propel a vehicle during cruising and acceleration. Capturing, storing and reusing this braking energy to give additional power can therefore improve fuel economy, particularly in cities and urban areas where the traffic conditions involve many stops and starts. In order to reuse the residual kinetic energy, the vehicle operation consists of 3 basic modes, i.e. Compression Mode (CM), Expander Mode (EM) and normal firing mode. Unlike previous works, a low cost air hybrid engine has been proposed and studied. The hybrid engine operation can be realised by means of production technologies, such as VVT and valve deactivation. In this work, systematic investigation has been carried out on the performance of the hybrid engine concept through detailed gas dynamic modelling using Ricardo WAVE software. Valve timing optimization has been done for the more efficient operation of air hybrid operation and obtaining higher braking and Motoring mean effective pressure for CM and EM respectively.EPSR

Managing amphibians in agricultural wetlands in South China: effects of fertilizers on Tadpole Performance

Abstract no. 0192 SSAR Siebert Conservation Award, Session IpostprintThe 2011 Joint Meeting of Ichthyologists and Herpetologists, Minneapolis, MN., 6-11 July 2011

Thermal stability of β-lactoglobulins A and B: Effect of SDS, urea, cysteine and N-ethylmaleimide

Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to monitor changes in the secondary structure and thermal stability of β-lactoglobulin A and B in the presence of sodium dodecyl sulphate (SDS), N-ethylmaleimide (NEM), urea and cysteine. An increase in the thermal stabilities of both proteins was noted in the presence of 10 mM-SDS. In the presence of 50 mM-SDS, there was extensive denaturation of both variants. In general, the β-strand/β-sheet regions in the secondary structure of both variants were very susceptible to denaturation by SDS and cysteine, suggesting that these regions may be held by hydrophobic and disulphide bonds. At ambient temperature and physiological pH, a notable difference was observed in the 1636 and 1627 cm -1 regions of the FTIR spectra of the two β-Ig variants. The results suggest possible differences in the nature of the β-sheet/β-strand distribution/content of the two proteins. Urea and NEM at a concentration of 50 mM, had little effect on the secondary structure and denaturation of both variants. New findings are presented which further indicate that although the β-Ig B variant showed greater thermal stability than the A variant in all the cases studied, its denaturation temperature and secondary structure were affected to a greater extent by the protein perturbants than ß-Ig A.published_or_final_versio

Modelling and simulation of counter-current and confined jet reactors for hydrothermal synthesis of nano-materials

A confined jet mixer and a counter-current mixer for the continuous hydrothermal flow synthesis of TiO2 nano-materials under supercritical water conditions have been investigated using computational fluid dynamics (CFD). The fluid flow and heat transfer behaviour, including velocity and temperature profiles in both reactor configurations, are studied using the CFD tool ANSYS Fluent. The tracer concentration profiles are also simulated via solving species equations from which the mixing behaviour in the reactors is examined. A combined CFD and population balance model is used to predict the size distribution. The predicted temperature distributions for both reactors were found to be in good agreement with experimentally measured data. Detailed comparison of the hydrodynamic and thermal behaviours, and particle size distributions between the two reactors helped in the identification of key factors that affect the reactor performance, and also provided suggestions for reactor design optimisation and scale-up

Effect of Crystallization Conditions on the Metastable Zone Width and Nucleation Kinetics of p ‐Aminobenzoic Acid in Ethanol

A detailed knowledge of the metastable zone width (MSZW) and nucleation kinetics is vital for the design of batch cooling crystallization processes. Factors such as cooling rate and impeller speed affect the MSZW and nucleation kinetics. Crystallization and dissolution temperatures were measured as a function of cooling rate and impeller speed during the batch cooling crystallization of p ‐aminobenzoic acid (pABA) from ethanol in a 0.5‐L stirred‐tank crystallizer. The polythermal experimental data were analyzed using the Nyvlt and first principles‐based Kashchiev‐Borissova‐Hammond‐Roberts (KBHR) methods. In all experimental cases, the latter model revealed that the nucleation process of pABA in ethanol was dominated by an instantaneous nucleation mechanism. The Nyvlt and KBHR analyses delivered a range of parameter values associated with a power‐law model describing the nucleation rate as well as the concentration of nuclei

Trunk muscle training, posture fatigue, and performance in laparoscopic surgery

Purpose: To investigate the effect of trunk muscle endurance training on the perception of back postural fatigue and performance of a laparoscopic task. Materials and Methods: Thirty-one medical students (18 men and 13 women) with no laparoscopic surgical experience were randomly assigned to either a training group or a control group. Participants in the training group underwent a 6-week, 18-session trunk (abdominal and back muscle) endurance training program, whereas participants in the control group did not. Performance by all participants was assessed on a simulated laparoscopic task under varying conditions of low back postural fatigue, both before and after the training program. Results: Participants in the training group showed significant improvements in trunk endurance after the 6-week trunk endurance training program (P 0.05). Conclusion: Increasing trunk endurance can reduce postural fatigue and discomfort during simulated laparoscopic tasks, which may assist in the management of errors during laparoscopy. © Mary Ann Liebert, Inc. 2008.published_or_final_versio

Analytical technology aided optimization and scale-up of impinging jet mixer for reactive crystallization process

Reactive crystallization is widely used in the manufacture of active pharmaceutical ingredients (APIs). Since APIs often have low solubility, traditional stirred tank reactors and the route of process operation and control using metastable zone width are not effective. The current work investigated the integration of an impinging jet mixer and a stirred tank crystallizer that can take advantage of both the reaction and crystallization characteristics, the focus being on design optimization and scale-up using process analytical techniques based on the Fourier transform Infrared spectroscopy and Focused Beam Reflectance Measurement, as well as X-ray diffraction and particle imaging Morphologi G3. The parameters for process operation and design of the impinging jet mixer were optimized. The research was carried out with reference to the manufacture of an antibiotic, sodium cefuroxime, firstly in a 1L reactor, then a 10L reactor. The crystals produced showed higher crystallinity, narrower size distribution, higher stability and purity

Seed Recipe Design for Batch Cooling Crystallization with Application to l-Glutamic Acid

In this paper, a seed recipe design is proposed for batch cooling crystallization to obtain the desired product attributes including product yield and product size distribution, based on simulation studies and experiments on β-l-glutamic acid (β-LGA) crystallization. The impact of seed recipe on product attributes is investigated based on the population balance model (PBM) simulations with respect to the size-dependent growth of crystals. It is found that the product yield is primarily affected by the seed loading ratio (SLR) and the batch time, but less affected by the mean size and variance of seeds. Smaller seeds could improve the product yield, and in contrast, larger seeds facilitate the growth into larger crystals but require a larger SLR to ensure the product yield. By introducing an objective function for optimization with the above PBM, a seed recipe design is given for obtaining the desired product attributes as above-mentioned. In addition, it is found that washing seeds by the solvent is necessary to ensure seed quality for quantitative seed recipe design and implementation, by comparing three different seed preparation methods. Simulation tests and experiments well demonstrate the effectiveness of the proposed seed recipe design for seeded batch cooling crystallization

Combining Morphological Population Balances with Face-Specific Growth Kinetics Data to Model and Predict the Crystallization Processes for Ibuprofen

A route map for modeling pharmaceutical manufacturing processes utilizing morphological population balance (MPB) is presented in terms of understanding and controlling particle shape and size for optimizing the efficiency of both the manufacturing process and final properties of the formulated drugs. This is applied to batch cooling crystallization of the pharmaceutical compound ibuprofen from supersaturated ethanolic solutions in which the MPB is combined with the known crystal morphology and associated face-specific growth kinetics (Nguyen et al. CrystEngComm 2014, 16, 4568-4586) to predict the temporal evolution of the shape and size distributions of all crystals. The MPB simulations capture the temporal evolution of the size and shape of ibuprofen crystals and their distributions at each time instance during the crystallization processes. The volume equivalent spherical diameter and crystal size distribution converted from MPB simulation are validated against the experimental studies on the 1 L scale size (Rashid et al. Chem. Eng. Res. Des. 2012, 90, 158-161), confirming the promise of this approach as a powerful simulation, optimization, and control tool for the digital design of precision pharmaceutical processes and products with the desirable properties, with potential applications in crystallization design for personalized medicines