The effects of electricity pricing on PHEV competitiveness

Plug-in hybrid electric vehicles (PHEVs) will soon start to be introduced into the transportation sector, thereby raising a host of issues related to their use, adoption and effects on the electricity sector. Their introduction has the potential to significantly reduce carbon emissions from the transportation sector, which has led to government policies aimed at easing their introduction. If their widespread adoption is set as a target it is imperative to consider the effects of existing policies that may increase or decrease their adoption rate. In this study, we present a micro level electricity demand model that can gauge the effects of PHEVs on household electricity consumption and the subsequent economic attractiveness of the vehicles. We show that the electricity pricing policy available to the consumer is a very significant factor in the economic competitiveness of PHEVs. Further analysis shows that the increasing tier electricity pricing system used in California will substantially blunt adoption of PHEVs in the state; and time of use electricity pricing will render PHEVs more economically attractive in any state.     

The First Step of Biodegradation of 7-Hydroxycoumarin in Pseudomonas mandelii 7HK4 Depends on an Alcohol Dehydrogenase-Type Enzyme

Coumarins are well known secondary metabolites widely found in various plants. However, the degradation of these compounds in the environment has not been studied in detail, and, especially, the initial stages of the catabolic pathways of coumarins are not fully understood. A soil isolate Pseudomonas mandelii 7HK4 is able to degrade 7-hydroxycoumarin (umbelliferone) via the formation of 3-(2,4-dihydroxyphenyl)propionic acid, but the enzymes catalyzing the α-pyrone ring transformations have not been characterized. To elucidate an upper pathway of the catabolism of 7-hydroxycoumarin, 7-hydroxycoumarin-inducible genes hcdD, hcdE, hcdF, and hcdG were identified by RT-qPCR analysis. The DNA fragment encoding a putative alcohol dehydrogenase HcdE was cloned, and the recombinant protein catalyzed the NADPH-dependent reduction of 7-hydroxycoumarin both in vivo and in vitro. The reaction product was isolated and characterized as a 7-hydroxy-3,4-dihydrocoumarin based on HPLC-MS and NMR analyses. In addition, the HcdE was active towards 6,7-dihydroxycoumarin, 6-hydroxycoumarin, 6-methylcoumarin and coumarin. Thus, in contrast to the well-known fact that the ene-reductases usually participate in the reduction of the double bond, an alcohol dehydrogenase catalyzing such reaction has been identified, and, for P. mandelii 7HK4, 7-hydroxycoumarin degradation via a 7-hydroxy-3,4-dihydrocoumarin pathway has been proposed.     

Comparison of energy and material recovery of household waste management from the environmental point of view – Case Kaunas,Lithuania

The results of life cycle assessment of five different energy recovery-based waste management system options are presented. The system options were designed for the city of Kaunas, Lithuania. The Kaunas model was formed according to the Simple Integrated System Management concept developed at Lappeenranta University of Technology. CML2001 was selected as the method according to which the life cycle impact assessment profiles were compiled and analyzed.The results suggest that energy recovery from biowaste, paper and cardboard derived from households could be a more recommendable waste management option than material recovery of the fractions (composting of biowaste and recycling of paper and cardboard). The calculations were carried out with limited process information, and cannot thus be generalized in all parts.     

Thiophene-based hydrazones as hole-transporting materials

The synthesis, optical, thermal and photoelectrical properties of thiophene-based hydrazones are reported. The HOMO levels in a solid state of thiophene-based hydrazones measured by the electron photoemission technique are ?5.25 eV and ?5.28 eV. Hole-drift mobilities of the solid solutions in bisphenol-Z polycarbonate (PC-Z) of the synthesized hydrazones were studied by the time-of-flight technique. Room temperature hole mobilities in the solid solution of thiophene-2-carbaldehyde N,N-diphenylhydrazone in PC-Z exceeded 10^?5 cm²/(V s) at high electric fields.     

Computer aided flowsheet drawing—I: Equipment layout

A computer aided methodology is presented for determining the positions of equipment symbols in a flowsheet given only the equipment connection information. A two pass logic is used. In the first pass the location of process sections is determined by reducing the process section level flowsheet and generating a mesh structure using a modification of Rubin's algorithm. The approximate dimensions of each section are determined using a depth first search, and, the locations of the process section centroids are selected heuristically. In the second pass, the equipment symbols are positioned within the sections taking into account external equipment connections to other process sections as well as the flow patterns within the section. An experimental program has been developed and some test examples are presented.     

On Geometric Programming with Slack Constraints and Degrees of Difficulty

This note reviews the effects of singularity, degeneracy, and zero decision variables on the constrained derivative algorithm for solving generalized geometric programs presented in an earlier work. It is shown that the first two pathologies are easily accommodated and that the third may require the application of the algorithm in several successive stages.     

Electron transient response and impact-ionized plasma instability in GaAs at very high electric fields

Dynamic behavior of electrons in GaAs under impact ionization conditions is studied by the Monte Carlo technique. The relaxation time of impact ionization generation rate is estimated. The linear stage of instability caused by the generation rate lagging the electric field is investigated. The nonlinear regime of this instability is numerically simulated. The electric field and plasma density oscillations with a frequency of the order of 50–1000 GHz are obtained.     

The Purdue-Dow Styrene-Butadiene Polymerization Simulation

Abstract An interactive computer module for the simulation of the Dow Chemical Company styrene-butadiene polymerization process has been developed at Purdue University for use as a project in the senior laboratory course. After first viewing the process on video, the students must design experiments and choose process parameters such as flow rate, temperature and concentration to determine the characteristic constants of the underlying model. Realism is introduced into the assignment by incorporating budget and time constraints, and also statistical fluctuations in the simulation results. Student results are presented in both a written report and an oral presentation. Academic colleagues at other universities report success in using the Purdue-Industry modules, not only in laboratory courses, but also in kinetics, reactor design and process control courses.     

A Bayesian Approach to Batch Process Scheduling

The problem of decision timing in the context of batch scheduling is addressed in this paper. The representation of time in any scheduling model affects the number of integer variables and the convexity of the model. The usual procedure in batch process scheduling is to divide the scheduling horizon into equal size intervals to achieve the required accuracy. This construction generates a formulation with a potentially large number of binary variables. In this paper, the time events arising in the schedule are modeled directly, and thus the use of binary variables over periods during which no changes in system state occur is avoided. The problem is formulated as a mixed integer nonlinear program (MINLP). The Bayesian heuristic (BH) approach is used to implement a global optimization algorithm which effectively solves the resulting model. Computational comparisons using two text examples are made against a UDM (uniform discretization model) formulation. The results suggest that the BH approach combined with the nonuniform time discretization formulation shows promise for the solution of batch scheduling problems.