Optimal modelling and experimentation for the improved sustainability of microfluidic chemical technology design

Optimization of the dynamics and control of chemical processes holds the promise of improved sustainability for chemical technology by minimizing resource wastage. Anecdotally, chemical plant may be substantially over designed, say by 35-50%, due to designers taking account of uncertainties by providing greater flexibility. Once the plant is commissioned, techniques of nonlinear dynamics analysis can be used by process systems engineers to recoup some of this overdesign by optimization of the plant operation through tighter control. At the design stage, coupling the experimentation with data assimilation into the model, whilst using the partially informed, semi-empirical model to predict from parametric sensitivity studies which experiments to run should optimally improve the model. This approach has been demonstrated for optimal experimentation, but limited to a differential algebraic model of the process. Typically, such models for online monitoring have been limited to low dimensions. Recently it has been demonstrated that inverse methods such as data assimilation can be applied to PDE systems with algebraic constraints, a substantially more complicated parameter estimation using finite element multiphysics modelling. Parametric sensitivity can be used from such semi-empirical models to predict the optimum placement of sensors to be used to collect data that optimally informs the model for a microfluidic sensor system. This coupled optimum modelling and experiment procedure is ambitious in the scale of the modelling problem, as well as in the scale of the application - a microfluidic device. In general, microfluidic devices are sufficiently easy to fabricate, control, and monitor that they form an ideal platform for developing high dimensional spatio-temporal models for simultaneously coupling with experimentation. As chemical microreactors already promise low raw materials wastage through tight control of reagent contacting, improved design techniques should be able to augment optimal control systems to achieve very low resource wastage. In this paper, we discuss how the paradigm for optimal modelling and experimentation should be developed and foreshadow the exploitation of this methodology for the development of chemical microreactors and microfluidic sensors for online monitoring of chemical processes. Improvement in both of these areas bodes to improve the sustainability of chemical processes through innovative technology. (C) 2008 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved

B→ϕπB\to \phi \pi and B0→ϕϕB^0 \to \phi\phi in the Standard Model and new bounds on R parity violation

We study the pure penguin decays $B \to \phi\pi$ and $B^0 \to \phi\phi$. Using QCD factorization, we find ${\cal B}(B^\pm \to\phi\pi^{\pm} )=2.0^{+0.3}_{-0.1}\times 10^{-8}$. For the pure penguin annihilation process $B^0 \to \phi\phi$, analyzed here for the first time, ${\cal B}(B^0 \to\phi\phi)=2.1^{+1.6}_{-0.3}\times 10^{-9}$. The smallness of these decays in the Standard Model makes them sensitive probes for new physics. From the upper limit of $B\to \phi\pi$,we find constraints on R parity violating couplings, $| \lambda{''}_{i23}\lambda{''}_{i21}|<6\times10^{-5}$, $| \lambda'_{i23}\lambda'_{i21}|<4\times10^{-4}$ and $| \lambda'_{i32}\lambda'_{i12}|<4\times10^{-4}$ for $i=1,2,3$. Our new bounds on $|\lambda{''}_{i23}\lambda{''}_{i21}|$ are one order of magnitude stronger than before. Within the available upper bounds for $| \lambda{''}_{i23}\lambda{''}_{i21}|$, $|\lambda'_{i23}\lambda'_{i21}|$ and $|\lambda'_{i32}\lambda'_{i12}|$, we find that ${\cal B}(B\to\phi\phi)$ could be enhanced to $10^{-8}\sim 10^{-7}$. Experimental searches for these decays are strongly urged.Comment: 5 pages, 3 figures embede

Sources of CP Violation in the Two-Higgs Doublet Model

Assuming CP violation arises solely through the Higgs potential, we develop the most general two-Higgs doublet model. There is no discrete symmetry that distinguishes the two Higgs bosons. It is assumed that an approximate global family symmetry sufficiently suppresses flavor-changing neutral scalar interactions. In addition to a CKM phase, neutral boson mixing, and superweak effects, there can be significant CP violation due to charged Higgs boson exchange. The value of $\epsilon'/\epsilon$ due to this last effect could be as large as in the standard model.Comment: 8 pages, RevTex, (appear in Phys. Rev. Lett. 73, (1994) 1762 ), CMU-HEP94-1

Generation of the Baryon Asymmetry of the Universe within the Left--Right Symmetric Model

Fermions scattering off first-order phase transition bubbles, in the framework of $SU(2)_L\otimes SU(2)_R\otimes U(1)$ models, may generate the Baryon Asymmetry of the Universe (BAU), either at the $LR$-symmetry-breaking scale, or at the weak scale. In the latter case, the baryon asymmetry of the Universe is related to CP violation in the $K_0$--$\bar K_0$ system.Comment: 17 pages, CERN--TH 6747/92, ULB--TH--07/92, UAB-FT-298/9

A simple inert model solves the little hierarchy problem and provides a dark matter candidate

We discuss a minimal extension to the standard model in which two singlet scalar states that only interacts with the Higgs boson is added. Their masses and interaction strengths are fixed by the two requirements of canceling the one-loop quadratic corrections to the Higgs boson mass and providing a viable dark matter candidate. Direct detection of the lightest of these new states in nuclear scattering experiments is possible with a cross section within reach of future experiments.Comment: Finite corrections included. Model modified. Conclusion unchange

Nonfactorization and the decays Ds+→ϕπ+,ϕρ+D_s^+ \to \phi \pi^+, \phi \rho^+ and ϕl+νl\phi l^+ \nu_l

In six chosen scenarios for the $q^2$ dependence of the form factors involved in $D_s^+ \rightarrow \phi$ transition, we have determined the allowed domain of $x = A_2(0) / A_1(0)$ and $y = V(0)/A_1(0)$ from the experimentally measured ratios $R_{sl} = \Gamma(D_s^+ \rightarrow \phi l^+ \nu_l)/\Gamma(D_s^+ \rightarrow \phi \pi^+)$ and $R_h = \Gamma(D_s^+ \rightarrow \phi \rho^+)/\Gamma(D_s^+ \rightarrow \phi \pi^+)$ in a scheme that uses the $N_c =3$ value of the phenomenological parameter $a_1$ and includes nonfactorized contribution. We find that the experimentally measured values of $x$ and $y$ from semileptonic decays of $D_s^+$ favor solutions which have significant nonfactorized contribution, and, in particular, $R_{sl}$ favors solutions in scenarios where $A_1(q^2)$ is either flat or decreasing with $q^2$.Comment: 15 pages, Latex, four figure (available on request)

Nonfactorization and Color-Suppressed B→ψ(ψ(2S))+K(K∗)B \to \psi (\psi(2S))+K(K^*) Decays

Using $N_c=3$ value of the parameter $a_2=0.09$ but including a modest nonfactorized amplitude, we show that it is possible to understand all data, including polarization, for color-suppressed $B\to\psi(\psi(2S))+K(K^*)$ decays in all commonly used models of form factors. We show that for $B\to\psi +K$ decay one can define an effective $a_2$, which is process-dependent and, in general, complex; but it is not possible to define an effective $a_2$ for $B\to\psi +K^*$ decay. We also explain why nonfactorized amplitudes do not play a significant role in color-favored B decays.Comment: 13 pages, Latex, one figure (not included

Adjustment of the electric current in pulsar magnetospheres and origin of subpulse modulation

The subpulse modulation of pulsar radio emission goes to prove that the plasma flow in the open field line tube breaks into isolated narrow streams. I propose a model which attributes formation of streams to the process of the electric current adjustment in the magnetosphere. A mismatch between the magnetospheric current distribution and the current injected by the polar cap accelerator gives rise to reverse plasma flows in the magnetosphere. The reverse flow shields the electric field in the polar gap and thus shuts up the plasma production process. I assume that a circulating system of streams is formed such that the upward streams are produced in narrow gaps separated by downward streams. The electric drift is small in this model because the potential drop in narrow gaps is small. The gaps have to drift because by the time a downward stream reaches the star surface and shields the electric field, the corresponding gap has to shift. The transverse size of the streams is determined by the condition that the potential drop in the gaps is sufficient for the pair production. This yields the radius of the stream roughly 10% of the polar cap radius, which makes it possible to fit in the observed morphological features such as the "carousel" with 10-20 subbeams and the system of the core - two nested cone beams.Comment: 8 pages, 1 figur

Transient domain walls and lepton asymmetry in the Left-Right symmetric model

It is shown that the dynamics of domain walls in Left-Right symmetric models, separating respective regions of unbroken SU(2)_L and SU(2)_R in the early universe, can give rise to baryogenesis via leptogenesis. Neutrinos have a spatially varying complex mass matrix due to CP-violating scalar condensates in the domain wall. The motion of the wall through the plasma generates a flux of lepton number across the wall which is converted to a lepton asymmetry by helicity-flipping scatterings. Subsequent processing of the lepton excess by sphalerons results in the observed baryon asymmetry, for a range of parameters in Left-Right symmetric models.Comment: v2 version accepted for publication in Phys. Rev. D. Discussion in Introduction and Conclusion sharpened. Equation (12) corrected. 16 pages, 3 figure files, RevTeX4 styl

Electroweak Phase Transitions in left-right symmetric models

We study the finite-temperature effective potential of minimal left-right symmetric models containing a bidoublet and two triplets in the scalar sector. We perform a numerical analysis of the parameter space compatible with the requirement that baryon asymmetry is not washed out by sphaleron processes after the electroweak phase transition. We find that the spectrum of scalar particles for these acceptable cases is consistent with present experimental bounds.Comment: 20 pages, 5 figures (included), some comments added, typos corrected and new references included. Final version to appear in PR