This description relates to asymmetric systems.
In a Brownian ratchet, for example, a force that is not directional in space, e.g., its average over space is zero, generates a directional motion of particles in a system.
In
An external electric field (constant in time) is applied to the system to create a saw-tooth-shaped energy profile 12 to which the molecule is subjected as shown in
When the field is turned off, a molecule that is at one of the points of minimum energy, say A0, is subjected to an energy profile 13 that is flat as shown in
Assume that the field is kept off until the probability of the molecule diffusing at least a distance (B0−A0) is significant, but the probability of the molecule diffusing at least a distance (B+1−A0) is still low. When the electric field is turned back on to restore the energy profile of
However, because the distance (B0−A0) is shorter than the distance (B+1−A0), at the instant the field is turned on, the probability of the particle being to the left of B0 will be greater than of being to the right of B+1 because the diffusion is not statistically preferential in either direction. In other words the probability is higher that the molecule will have taken a step to the left than to the right (by a step we mean a distance that puts it beyond the next energy peak along the direction in which it diffuses).
When this cycle (of turning the field on and off) is repeated many times, the molecule will, on average, have taken more steps to the left than to the right, and therefore have experienced directional motion to the left, even though the applied force (induced by the electric field) is not directional when averaged over space.
Such directional motion can overcome even an opposing load (e.g., a force tending to push the molecule to the right). In that case, the applied non-directional force of the electric field would be doing directional work, pushing the molecule to the left despite the opposing force.
Another known type of Brownian ratchet is a flashing ratchet [Astumian R D and Bier M, “Fluctuation driven ratchets—molecular motors”, Phys. Rev. Lett. 72 1766-9, 1994]. In a flashing ratchet, instead of applying an asymmetric voltage profile externally to a system (as in
Brownian ratchets have been applied in Brownian motors and Brownian pumps respectively to move particles directionally, e.g., against an opposing force, and to pump particles (e.g., ions) against a concentration and/or a voltage gradient. A review of Brownian ratchets can be found in various articles (e.g., Astumian and Derenyi, “Fluctuation driven transport and models of molecular motors and pumps”, European Biophysics Journal, vol 27, pp 474-489, 1998, and the references mentioned in that article).
Another ratchet mechanism is the Feynman ratchet [R. P. Feynman, R. B. Leighton, M. Sands, The Feynman Lectures on Physics (Addison-Wesley, Reading, Mass., 1966), vol. 1, chap. 46]. In this example, a ratchet and a pawl are in two thermally separated reservoirs at different temperatures. An asymmetry in the system—a difference in temperature between the two reservoirs—leads to a directional rotation of the ratchet mechanism (which can do work against a load).
There are also mechanical ratchets that achieve linear or rotary motion in one direction, while preventing motion in the opposite direction (Ref http://en.wikipedia.org/wiki/Ratchet_(device)).
In general, in an aspect, a combination comprises interaction with a system that has a perturbation. In such perturbed system, a non-directional input is applied to a first variable of the system. Based on an asymmetry of the perturbed system, a directional effect is achieved in a second variable of the system, the first and second variables comprising a conjugate pair of variables. At least one of the following pertains: the interaction occurs other than by an apparatus and other than in a way that actually achieves the directional effect, or the conjugate pair is other than position and momentum, or the input or the asymmetry is in a dimension other than spatial coordinates, or the directional effect is other than one-dimensional translational motion and other than one-dimensional rotary motion.
Implementations may include one or more of the following features. The interaction comprises causing the system to actually achieve the directional effect. The interaction includes an apparatus. The interaction comprises designing the system. The interaction comprises manipulating the system. The manipulating comprises analyzing the system. The manipulating comprises optimizing the system. The system is optimized for work done, for energy efficiency, for operation in a desired regime, or for a particular load.
The manipulation comprises implementing a function in the system. The function comprises filtering. The function comprises adaptive filtering. The function comprises compression. The function comprises de-compression. The function comprises sampling. The function comprises de-sampling. The function comprises feature extraction. The function comprises spectrum analysis. The function comprises storage. The function comprises modulation.
The interaction is based on signal processing. The signal processing comprises description of an aspect of the system. The signal processing comprises interpretation of an aspect of the system.
The signal processing comprises taking the transform of a variable. The transform comprises an integral transform. The integral transform comprises a Fourier transform. The integral transform comprises a Laplace transform. The integral transform comprises a wavelet transform. The integral transform comprises a Hilbert transform. The transform comprises a discrete transform. The discrete transform comprises a binomial transform. The discrete transform comprises a discrete Fourier transform. The discrete transform comprises a fast Fourier transform. The discrete transform comprises a Z-transform. The transform comprises a data-dependent transform. The transform comprises a transform other than an integral, discrete or data-dependent transform. The transform comprises a one-variable transform. The transform comprises a multi-variable transform.
The system comprises a physical system. The system comprises a chemical system. The system comprises a chemical reaction. The chemical reaction comprises an intermediate chemical reaction. The chemical reaction comprises a surface reaction. The chemical reaction comprises a bulk reaction. The chemical reaction comprises a membrane reaction. The chemical reaction comprises an organic reaction. The chemical reaction comprises an inorganic reaction. The chemical reaction comprises an enzymatic reaction. The chemical reaction comprises catalytic reaction. The chemical reaction comprises a non-catalytic reaction. The chemical reaction comprises a spontaneous reaction. The chemical reaction comprises a non-spontaneous reaction. The chemical reaction comprises an exothermic reaction. The chemical reaction comprises an endothermic reaction. The chemical reaction comprises a single chemical path. The chemical reaction comprises multiple possible chemical paths.
The system comprises a biological system. The system comprises a social system. The system comprises an economic system. The system comprises a combination of two or more of physical, chemical, biological, social and economic systems.
The conjugate pair of variables comprises position and momentum. The conjugate pair of variables comprises time and energy. The conjugate pair of variables comprises temperature and entropy. The conjugate pair of variables comprises pressure and volume. The conjugate pair of variables comprises electric field and polarizability. The conjugate pair of variables comprises magnetic field and magnetization. The conjugate pair of variables comprises stress and strain. The conjugate pair of variables comprises rotation angle and angular momentum. The conjugate pair of variables comprises chemical potential and particle number. The conjugate pair of variables comprises electric potential and electromotive force. The conjugate pair of variables comprises two orthogonal polarization vectors of an electromagnetic beam. The conjugate pair of variables comprises surface area and surface tension. There are two or more conjugate pairs of variables in the system.
The system comprises a feedback system. The system comprises a time-invariant system. The system comprises a time-variant system. The system comprises a linear system. The system comprises a nonlinear system. The system comprises a continuous-time system. The system comprises a discrete-time system.
The non-directional input comprises an intensive variable of a conjugate pair of variables. The non-directional input comprises a signal. The non-directional input comprises an externally applied signal. The non-directional input comprises a signal that is intrinsic to the system. The non-directional input comprises an input signal. The non-directional input comprises a noise signal. The non-directional input comprises a control signal. The non-directional input comprises an intermediate signal. The non-directional input comprises a time-independent signal. The non-directional input comprises a time-dependent signal. The non-directional input comprises a continuous-time signal. The non-directional input comprises a discrete-time signal. The non-directional input comprises a deterministic signal. The non-directional input comprises a stochastic signal. The non-directional input comprises more than one signal.
The non-directional input comprises an influence. The non-directional input comprises a chemical influence. The non-directional input comprises an electrical influence. The non-directional input comprises a magnetic influence. The non-directional input comprises a thermal influence. The non-directional input comprises an electromagnetic influence. The non-directional input comprises a flow influence. The non-directional input comprises a pressure influence. The non-directional input comprises a mechanical influence. The non-directional input comprises a gravitational influence.
The non-directional input comprises a combination of two or more influences. The influences are of the same type of influence. The influences are of at least two different types of influences. The influences have the same phase. The influences have different phases with a fixed relationship. The influences have different phases with a varying relationship. The influences have the same frequency. The influences have different frequencies with a fixed relationship. The influences have different frequencies with a varying relationship.
The asymmetry comprises an absence or a violation of a non-isometric symmetry. The asymmetry comprises an absence or a violation of a directional symmetry. The asymmetry comprises an absence or a violation of a reflection symmetry. The asymmetry comprises an absence or a violation of a rotational symmetry. The asymmetry comprises an absence or a violation of a translational symmetry. The asymmetry comprises an absence or a violation of a glide reflection symmetry. The asymmetry comprises an absence or a violation of a rotoreflection symmetry. The asymmetry comprises an absence or a violation of a helical symmetry. The asymmetry comprises an absence or a violation of a scale symmetry. The asymmetry comprises an absence or a violation of two or more symmetries. The asymmetry comprises an externally applied asymmetry. The asymmetry comprises an asymmetry that is intrinsic to the system. The asymmetry comprises a time-independent asymmetry. The asymmetry comprises a time-dependent asymmetry. The asymmetry comprises a one-variable asymmetry. The asymmetry comprises a multi-variable asymmetry. There is more than one asymmetry. All the asymmetries comprise an absence or a violation of the same type of symmetry or antisymmetry. The asymmetries comprise an absence or a violation of two or more types of symmetries or antisymmetries.
The directional effect comprises an extensive variable of the conjugate pair of variables. The directional effect comprises an output signal. The directional effect comprises a noise signal. The directional effect comprises a control signal. The directional effect comprises an intermediate signal. The directional effect comprises a time-independent signal. The directional effect comprises a time-dependent signal. The directional effect comprises a continuous-time signal. The directional effect comprises a discrete-time signal. The directional effect comprises a deterministic signal. The directional effect comprises a stochastic signal. More than one directional effect is achieved. The directional effects are in the same type of variable. The directional effects are in at least two different types of variables. The directional effect comprises doing mechanical work. Doing mechanical work comprises altering the kinetic energy of a system.
The directional effect comprises altering the potential energy of a system. The potential energy comprises gravitational potential energy. The potential energy comprises elastic potential energy. The potential energy comprises chemical potential energy. The potential energy comprises electric potential energy. The electric potential energy comprises electrostatic potential energy. The electric potential energy comprises electrodynamic potential energy. The electric potential energy comprises nuclear potential energy. The potential energy comprises thermal potential energy. The potential energy comprises rest mass energy.
The directional effect comprises doing thermodynamic work. Doing thermodynamic work comprises altering the enthalpy of a system. Doing thermodynamic work comprises altering the entropy of a system. Doing thermodynamic work comprises doing pressure-volume work.
The directional effect comprises doing organizational work. Doing organizational work comprises altering the order of a system. Doing organizational work comprises altering the complexity of a system. Doing organizational work comprises altering the pattern of a system. Doing organizational work comprises altering the structure of a system. Doing organizational work comprises altering the emergent property of a system. Doing organizational work comprises altering the behavior of a system.
The combination comprises one or more actions or steps in a method, one or more elements in an apparatus, one or more parts in a combination of matter, or sub-combinations thereof.
An input modulates a potential energy surface of the system. The potential energy surface is modulated vertically. The potential energy surface is modulated laterally. One or more inputs modulate the potential energy surface of a transition state in the system both vertically and laterally. A transition state of the potential energy surface is modulated. The input directly interacts with the reactants. The input modulates a property of the environment of the reactants. The environment comprises an active pocket of an enzyme. The environment comprises a supramolecular structure. The supramolecular structure comprises an aptamer. The supramolecular structure comprises a zeolite. The supramolecular structure comprises a polymer. The supramolecular structure comprises a carbon nanotube. The system comprises an influence mediator. The influence mediator comprises a charged bead or a magnetic bead. The influence mediator comprises a linker.
The system is designed using ab initio simulations, catalytic antibodies and/or in vitro evolution. The system comprises a modification to enhance an input. The modification comprises attaching an enzyme or a supramolecule to a surface of a reaction chamber with an electrical double layer formed at that surface. The modification comprises coating a surface of a reaction chamber with a flexible substrate.
In general, in an aspect, the invention features, an apparatus comprising a site for a reaction, and a device interacting with a system that has a perturbation. In the perturbed system a non-directional input is applied to a first variable of the system. Based on an asymmetry of the perturbed system, a directional effect is achieved in a second variable of the system, the first and second variables comprising a conjugate pair of variables. At least one of the following pertains: the interaction occurs other than by an apparatus and other than in a way that actually achieves the directional effect, or the conjugate pair is other than position and momentum, or the input or the asymmetry is in a dimension other than spatial coordinates, or the directional effect is other than one-dimensional translational motion and other than one-dimensional rotary motion.
The reaction comprises a chemical reaction. The reaction comprises a biochemical reaction. The device comprises one or more controlled inputs. An input comprises a controlled voltage. An input comprises a controlled mechanical force. An input comprises a controlled temperature. An input comprises a controlled pressure. The device comprises a surface.
The directional effect comprises converting a type of non-chemical energy into another type of non-chemical energy. Electrical energy is converted into rotary power or mechanical work. Rotary power or mechanical work is converted into electrical energy. The directional effect comprises converting a type of chemical energy into a type of non-chemical energy. A chemical fuel energy is converted into a non-chemical energy. A chemical energy is converted into electrical energy. A chemical energy is converted into rotary power or mechanical work.
The directional effect comprises converting a type of non-chemical energy into a chemical energy. Electrical energy is converted into a chemical energy. A non-chemical energy is converted into a high energy density chemical fuel. The high energy density chemical fuel comprises methane. The high energy density chemical fuel comprises ethane. The high energy density chemical fuel comprises hydrogen. A non-chemical energy is converted into a biofuel. The biofuel comprises methanol. The biofuel comprises ethanol. A non-chemical energy drives a chemical fuel process. The chemical fuel process comprises gasoline cracking The chemical fuel process comprises gasoline synthesis.
The directional effect comprises converting a type of chemical energy into another type of chemical energy. The conversion reaction comprises CO2 reduction. The conversion reaction comprises glucose to fructose conversion. The conversion reaction comprises ethylene production.
The directional effect comprises manipulating a chemical reaction. The chemical reaction is an intermediate chemical reaction. The chemical reaction is a biochemical reaction. The manipulation comprises controlling a direction of the reaction. The manipulation comprises altering a final substrate and/or a final product concentration or the ratio of the two concentrations. The manipulation comprises doing work on the system that the system would otherwise not do, including against or along other influences and/or gradients. The manipulation comprises catalyzing the reaction. The manipulation comprises specific enhancement and/or suppression of reactions and/or chemical paths. The manipulation comprises increasing, decreasing, or reversing a spontaneity of the reaction. The manipulation comprises changing a probability of a specific path and/or product, relative to another alternative path or product, to change a yield of the specific path and/or product.
A result of the method comprises new mixtures and/or products. A new mixture of product produced by applying the method.
The system is used in chemical manufacturing. The system is used in industrial processing. The system is used in catalysis. The system is used in chemical fuel production. The system is used in electricity generation. The system is used in rotary power or mechanical work generation. The system is used in energy storage. The system is used in reduction of undesired chemicals. The undesired chemical comprise greenhouse gases.
The directional effect comprises altering the negentropy of a system.
The system comprises a self-organizing system. The self-organizing system comprises a protein. The self-organizing system comprises a self-assembling molecule. The system comprises a process. The process comprises cell signaling. The process comprises homeostasis. The process comprises a developmental stage of a living organism.
The system is used in basic life science research. The system is used in medicine. The system is used in a synthetic life process or a product. The directional effect comprises transporting an object. The transportation is against an opposing force and/or gradient. The object comprises a micro-object. The object comprises an ion. The object comprises a molecule. The object comprises a biomolecule. The object comprises a biological cell. The object comprises a macro-object.
The object comprises a transportation vehicle. The system is used in mechanics. The system is used in biological transportation. The system is used in chemical transportation. The system is used in vehicular transportation.
The directional effect comprises altering a property of an object and/or a process. The property comprises structure. The property comprises complexity. The property comprises strength. The property comprises elasticity. The property comprises weight.
The system is used in material science. The system is used in manufacturing.
The directional effect comprises altering the electromagnetic property of an object and/or a process. The system is used in electronics. The system is used in communications.
The system comprises a pump that is driven by the dynamics of the system. The pump alters the concentration of an object. The pump alters the transfer speed of an object.
In general, in an aspect, a combination comprises interaction with a system that has a perturbation. In such perturbed system, an input is applied to a first variable of the system. Based on an asymmetry of the perturbed system, a directional effect is achieved in a second variable of the system. The first and second variables comprise a conjugate pair of variables.
In general, in an aspect, a combination comprises interaction with a system that has a perturbation. In such perturbed system, an input is applied to a first variable of the system. Based on an asymmetry of the perturbed system, a directional effect is achieved in a second variable of the system. The first and second variables comprise a conjugate pair of variables other than position and momentum.
In general, in an aspect, a combination comprises non-physical interaction with a system that has a perturbation. In such perturbed system, an input is applied to a first variable of the system Based on an asymmetry of the perturbed system, a directional effect is achieved indirectly in a second variable of the system, The first and second variables comprise a conjugate pair of variables.
In general, in an aspect, a combination comprises interaction with a system that has a perturbation. In such perturbed system, an input is applied to a first variable of the system. Based on an asymmetry of the perturbed system, a directional effect is achieved in a second variable of the system. The first and second variables comprise a conjugate pair of variables. The input or the asymmetry is in a dimension other than spatial coordinates.
In general, other aspects include combinations of these features useful for producing particular products, such as hydrogen.
These and other aspects and features, and combinations of them, can be expressed as systems, methods, compositions of matter, manufactures, methods of doing business, means or steps for performing functions, program products, methods of manufacture, methods of use, combinations, and in other ways.
Other aspects and features will be apparent from the following description and from the claims.
Here, we describe a broad concept and a broad understanding of a new energy transduction technique, in which a non-directional input or influence (we often use the words interchangeably) achieves a directional effect in a system.
We use the term non-directional very broadly to include, for example, that an average of an input or influence applied to the system by a signal, over one or more ranges of interest for a dimension or dimensions along which one or more effects is to be achieved, is zero.
And we use the term directional very broadly to include, for example, that an average influence applied to the system by a signal, over one or more ranges of interest for the dimension or dimensions along which the one or more effects is to be achieved, is not zero.
We use the term influence very broadly to include any kind or nature of influence, including, for example, a force, a torque, or an event that alters a state of a system or a property of a system, or any combination of influences.
We use the term signal also very broadly to include any function of one or more independent variables. The signal may contain, express, or imply information about a behavior or nature of a phenomenon. In some examples, the signals can be mathematical or abstract or other representations or implementations.
We use the term system very broadly to include, for example, two or more interacting or interdependent entities, real or abstract, which in some examples may form an integrated whole. The term system may also include, for example, any process that results in the transformation of signals. Thus, in some examples, a system has an input signal and an output signal which is related to the input through a system transformation. The term system may further include, for example, one or more of a subset of a system (e.g. a subsystem), an object or an element in a system, or a relationship between objects or elements of a system or its surroundings.
We use the term transduction very broadly to include, for example, the conversion, translation or alteration of one form of energy into another form of energy.
The energy which is subject to the transduction and the energy into which it is transduced can take a very wide variety of possible forms and amounts, in some cases different than, more effective or efficient than, or in other ways better than would be the case for known energy transduction techniques. We also use the term energy very broadly to include, for example, internal energy, negentropy (i.e. negative entropy), or a property of a system that is conserved and that can be related to an energy term (e.g. momentum, volume, enthalpy, entropy).
As an example, this new energy transduction technique can be used to enable a conversion from energy in one form (e.g., chemical) into energy in another form (e.g., electrical or another chemical form) without requiring an intermediate step of energy conversion to heat energy. This energy conversion is therefore more efficient, can be simpler and less expensive to implement, and can apply to an extremely broad range of energy conversion regimes. In some examples of the new energy transduction, the order and/or the complexity of a system may be increased (e.g. the entropy of the system may be reduced), which may lead to, for example, self-organization or an emergent property or behavior.
This new energy transduction technique offers the potential to change and benefit broad areas of activity and many disciplines.
Here, among other things, we describe interactions with a system. We use the term interaction very broadly to include, for example, using a system to achieve a desired outcome, designing a system for the purpose of achieving a desired outcome, manipulating a system (which may include analyzing the system, optimizing the system, or implementing a new function in the system), an apparatus that itself embodies all or part of the system, or any combination of those.
We use the term apparatus very broadly to include, for example, any tangible structure, instrument, appliance, device, machine, mechanism, setup, computer, software, network, equipment, or other thing of any kind.
The interactions with systems that we contemplate in this description include designing systems, manipulating systems, interacting based on signal processing, actually achieve a directional effect, and applications of the interactions. Any of these and combinations of these can be achieved with apparatus, including but not limited to apparatus examples that we describe here.
In many cases, the apparatus can be implemented in a wide variety of kinds of computing hardware, software, firmware, or combinations of them, in many cases with the aid of a wide variety of communication networks, user interfaces, interface devices, operating systems, databases, processes, process control and monitoring systems, and user applications.
An interaction in a system 28 may have multiple steps (
Also, the system is a perturbed system 34. We use the term perturbed very broadly to include any perturbations of the system, including perturbations that are caused by the input 30 to the system, or noise that is intrinsic to the system, or another kind of signal in the broadest sense.
Then, there's an asymmetry 36 in the system. In contrast to asymmetry, within the term symmetry, we very broadly include, for example, any invariance of values (e.g., a lack of any perceptible change) under a transformation over a range of interest. Also, within the term antisymmetry, we very broadly include, for example, a symmetry in which the values under the transformation are of opposite sign or sense. And, by asymmetry, we mean very broadly, for example, an absence or a violation of a symmetry or of an antisymmetry or of both.
When the non-directional input is applied to the perturbed system, based on an asymmetry of the system, the result (which we sometimes refer to as the system's output) is a directional effect 40 that occurs at least in part in a second variable of the system. Therefore, the system outputs an effect, for example, a desired effect (e.g., does work) in a directional manner.
We call each such system an asys (ASYmmetric System or Asymmetric SYStem), and we sometimes refer to a given asys with reference to its non-directional input, its asymmetry, and its directional effect, in that order. For example, if an electric field (E) is applied as an input, there's an asymmetry along a Q-axis of a chemical reaction (Q), and a particle number (N) of a particular output molecule (i.e., chemical yield) is changed, we sometimes call it an E-Q-N-asys.
For example, we described a Q-ratchet in the provisional patent application Ser. 61/090,028, filed Aug. 19, 2008, cited above. A Q-ratchet is an example of the systems illustrated in
Here, we elaborate on a Q-ratchet system, and provide examples for some of its variations.
In some examples, let's assume we have a chemical system (which we define very broadly and includes, for example, but is not limited to, any chemical reaction having one type of molecule in a left energy well 50 (molecule type A), another type of molecule in a right energy well 52 (molecule type B), and an energy barrier 54 between the two wells) (
Also assume that we apply a sinusoidal electric field 55 that modulates a potential energy of a transition state 56 of the molecules in the chemical reaction (
Now, let's assume the chemical system has the following asymmetry: the energy level 62 of the left well is higher than the energy level 64 of the right well (
In such a chemical reaction, the population of molecules at a given energy level is governed by a Boltzmann distribution. The energy levels of the molecules at various locations along the Q-axis (and thus, the populations of molecules at those locations along the Q-axis) are subject to thermal fluctuations, which constitute a perturbation to the system. In other words, the system is perturbed by thermal fluctuations.
In
In this example system, the input is an electric field, the asymmetry is a non-zero free energy of the chemical reaction (H0), and the directional effect is an alteration of a time constant for a particular chemical path (e.g., decreasing the time constant, τ, of that path). As such, we call it an E-H0-τ-asys.
In this example, to achieve catalysis or de-catalysis, the non-directional electric field input is applied over time, and the catalysis or de-catalysis directional effect is achieved along an energy dimension of the system (e.g., by a differential change in the effective barrier height of a particular chemical path). More broadly, this is an example of a very wide range of systems in which a non-directional input and a directional effect comprise a conjugate pair of variables (in this example, time and energy).
We use the phrase “conjugate pair of variables” very broadly to include, for example, any pair of variables of a system that are related to each other in accordance with a principle that governs the system. For example, in Hamiltonian formulations of physics, conjugate variables are coordinates whose Poisson brackets give a Kronecker delta (or a Dirac delta in the case of continuous variables) (e.g., position and momentum, time and energy). In a thermodynamic system, extensive energy transfer can be expressed as the product of a generalized force (in an intensive variable) and a displacement caused by the force (in an extensive variable). Thermodynamic potentials (including, but not limited to, internal energy, Helmholtz free energy, enthalpy, Gibbs free energy, Landau potential) can be expressed as conjugate pairs (including, but not limited to, pressure and volume, temperature and entropy, chemical potential and particle number). A very wide variety of other examples also fall within the phrase “conjugate pair of variables.”
Furthermore, when we use the phrase “a conjugate pair of variables” or “comprising a conjugate pair of variables” or phrases such as “comprising an intensive variable of a conjugate pair of variables”, we mean to include, not only the conjugate pair itself, but also variables that influence and/or are influenced by either or both of the variables of a conjugate pair. Thus, variables that serve as inputs to or outputs from the variables that are technically the conjugate pair are meant to be included in the concept of a conjugate pair of variables, for example, an electric field input that modulates a chemical potential that itself is the intensive variable of a conjugate pair.
In a second example of an asymmetric system, we assume the same electric field input and the same asymmetric potential energy surface for a chemical reaction as in
In
In this example, the input is an electric field, the asymmetry is the non-zero free energy of the chemical reaction (H0), and the directional effect is (in this example) the altered yield of a chemical reaction (e.g., changing the particle number, N, of a particular molecule). As such, we call it an E-H0-N-asys. And to achieve a directional effect in the form of an altered chemical yield (e.g., a change in the particle number of a particular molecule), a non-directional input is applied that modulates the chemical potentials of the molecules in the system. Then the non-directional input and the directional effect of this example system comprise a conjugate pair of variables, namely, chemical potential and particle number.
In a third example, we also use an asymmetric system having a sinusoidal electric field input, but this time the asymmetry is an off-center location 80 of a transition state along the Q-axis (i.e., Q0 is not equal to zero along the Q-axis) (
In
In this example, the input is an electric field, the asymmetry is an off-center location of a transition state (Q0), and the directional effect is a catalyzing of a particular chemical path, so we call it an E-Q0-τ-asys. And like the first example provided above, in this example, the non-directional input is applied over time, and the directional effect is achieved along an energy dimension of the system, so the input and effect comprise a conjugate pair of variables, namely, time and energy.
In a fourth example (
In this example, the input is an electric field, the asymmetry is an off-center location of a transition state (Q0), and the directional effect is the altered yield of a chemical reaction (i.e. particle number, N, of a particular molecule). As such, we call it E-Q0-N-asys. And similar to the second example above, the non-directional input and the directional effect in this example comprise the conjugate pair of variables of chemical potential and particle number.
In a fifth example, we have an asymmetric system using the asymmetry of the previous example (e.g., Q0 is not equal to zero, as in
In this example, the input is a mechanical force, the asymmetry is an off-center location of the transition state (Q0), and the directional effect is an altered yield of a chemical reaction (e.g., particle number, N, of a particular molecule). As such, we call it m-Q0-N-asys (we use the small letter m for mechanical, and the capital letter M for magnetic). And again, the non-directional input and the directional effect in this example comprise a conjugate pair of variables of chemical potential and particle number.
In another, sixth, example, a system does not have an intrinsic asymmetry in free energy of the chemical reaction (H0) or in Q space, i.e., H0 and Q0 are equal to zero (
Unlike the example of
In this example, there are two inputs, an electrical field and a mechanical force; an asymmetry is externally applied and is the existence of a direction of the applied loop. The directional effect is an altered yield of a chemical reaction (e.g., a particle number, N, of a particular molecule). As such, we call it an m&E-loop-N-asys. In this example, the non-directional inputs and the directional effect can be said to comprise two conjugate pairs of variables: time and energy, and chemical potential and particle number.
In another, seventh, example, we plot the negentropy, i.e. negative entropy, of a system on the vertical axis, rather than its internal energy. For this example, the system comprises a protein, and a higher negentropy implies a more ordered system. In
Below, we elaborate on an interpretation of the mechanism of operation of asymmetric systems. And even though the description focuses on manipulation of the internal energy of a system, the same concepts apply to entropy of a system or to another variable of a system that constitutes an extensive variable of a conjugate pair.
Chemical reactions happen on time scales ranging from ˜100 femtoseconds to hours or longer. Theoretical analysis of typical chemical reactions is complicated by a requirement to take into account the time evolution (on the femtosecond time scale) of a large number of nuclear degrees of freedom of a typical molecule/protein on the timescale of the reaction. This problem can be addressed in principle using molecular dynamic (MD) simulations. But current practical limitations of computing power prevent studying more than a microsecond of a reaction.
Theoretical chemists have developed methods that reduce the problem to a time evolution of a single reactive degree of freedom that represents the reaction, while other degrees of freedom are treated as a thermal bath. It is assumed that there is a least energy path along the potential energy surface (PES) from reactants (left well) to products (right well) that passes through a transition state barrier (see
We adopt a similar approach here. Note that the dynamics of the single reactive degree of freedom can involve motion of a larger number of atoms depending on the size of the system and, thus, in general, can be represented by a reactive coordinate vector q(t) which characterizes system configuration. For the reactions taking place in the ground electronic state and for large molecules, an approach based on classical mechanics is usually adequate.
To describe a time evolution of a molecular probability density function ρ(q,v,t) one can use the Klein-Kramers equation which is a variant of the Fokker-Plank equation appropriate for the description of the chemical system coupled to a thermal bath:
where V(q,t) is the PES, m is the effective mass along the reactive coordinate of interest (q), ξ is a friction coefficient, T is temperature, k is the Boltzman constant and v is the velocity along q.
This equation describes evolution of the molecular distribution function in the phase space (q, and v). Note, that in the absence of dissipation current, this description incorporates the dynamics described by Hamilton's equations.
If inertial effects can be neglected, then the Klein-Kramers equation simplifies to the Smoluchowski equation in configuration space only:
where D is the diffusion coefficient which is related to the friction coefficient through the Einstein relation:
This equation describes diffusion of the reactive coordinate in the presence of the field of force due to the PES. The absence of the dependence on mass and velocity indicates that the motion described by this equation is overdamped. This equation holds when coupling of the reaction to other degrees of freedom and the bath is strong and, hence, energy dissipation is fast.
Such description is appropriate to describe slow reactions that involve collective reactive motion of a significant number of atoms (e.g., domains of proteins) on up to microsecond time scale because the energy dissipation in the condensed phase happens on femtosecond-picosecond time scale. It may also be appropriate for small molecule reactions on surfaces (e.g., heterogeneous catalysis) if the coupling to the surface is strong.
When the PES is time-independent the steady-state solution of Smoluchowski equation yields the Boltzmann distribution of molecules on the PES which served as an initial distribution for finding time-dependent numerical solutions of the Smoluchowski equation in all simulation results presented below.
Here we are proposing to control the chemical reaction dynamics using externally applied time-dependent perturbations which can modify the PES of the reactive system. These perturbations may involve electrical or mechanical forces.
Considering the thermodynamics of such a system, for an overdamped system, internal energy includes only potential energy as determined by the location of the molecules on the PES. Thus, internal energy is calculated according to:
U(t)=∫ρ(q,t)V(q,t)dq.
If the PES is time dependent, the change in internal energy can be calculated from the First law of thermodynamics:
where {dot over (W)}(t) and {dot over (Q)}(t) are the rate of work done by an external agent on the system and the heat exchange rate between the system and environment, respectively:
Total work done by the external agent (Ein) is:
E
in
=W(t)=∫{dot over (W)}(t)dt.
Change in the free energy ΔG(t)=ΔU(t)−TΔS(t) can be used as a measure of useful work performed by the external agent (e.g., useful energy stored in the system) because by definition, the free energy represents a maximal amount of work that can be performed by the system. We assume that temperature changes in the system are small because we focus on a system that is strongly coupled to the environment. Typical thermalization times (i.e., cooling) for molecules in solutions are in a picosecond domain; thus our approach is valid up to ˜10 GHz frequency range. For systems that are weakly coupled to the environment (e.g., gas at low pressures), the temperature changes could be taken into account, but we do not consider this case here.
In order to determine free energy changes we need to calculate entropy of the system. Our current treatment relies on classical mechanics therefore we use Shannon's definition of the entropy as applied to continuous configuration space determined by our model:
S(t)=−k∫ρ(q,t)ln [ρ(q,t)]dq.
Finally, efficiency is defined as:
Yield is defined as a relative change in the number of molecules in the left well (the reactant well).
Asymmetry can also be introduced into the system by appropriate choice of the relative phase between two external fields applied to the system as shown in
The inherently higher efficiency and yield of the two parameter modulation can be understood from the following simple picture based on the analysis of the population dynamics along the circular or rectangular trajectory. When the system is moved along the trajectory from the entry point A (see
Simulations presented in
Presented simulations were performed for specified sets of parameters only. Optimization of all the above parameters should further increase the performance. For example
There are multiple ways that transduction efficiency and yield could be further improved. For example instead of sinusoidal modulation (resulting in circular trajectory as shown in
Even higher performance is expected for slower reactions since the transduction efficiency peak appears at lower frequencies for larger reaction barriers (
The above description focused on chemical reactions and their dynamics to provide some insight into how ASYS operates and how it alters the internal energy of objects and/or systems. Another example of ASYS can be provided from biology, and this time, with the negentropy of a system and/or an object altered instead. Negentropy is the negative entropy, and is used as a measure of the level of order or complexity. In a self-organizing system, the interactions between sub-systems and/or objects occur such that the overall interaction energy is lowered, which then compensates an increase in the negentropy of a system to a more ordered state (e.g. protein folding, homeostasis). ASYS can be applied to such a system to manipulate its negentropy and alter its level of self-organization, and/or it can enable self-organization to occur in a system whose interaction energy would not otherwise lead to an increase in its negentropy, i.e., it would not self-organize in the absence of ASYS transducing an external energy towards the system's negentropy.
A convenient analogy to better describe the key concepts of our ASYS technique employs the basic concepts and equations that are used in Noether's theorem. Noether's theorem relates symmetries to conservation laws, with the two variables comprising a conjugate pair. For example, a system that is symmetric in time (e.g., that is invariant in time) leads to conservation of energy. Similarly, a system that is invariant in space (e.g., symmetric in position) leads to conservation of momentum, and so on.
The ASYS technique can be regarded as the inverse Noether's theorem, where the absence or violation of a symmetry (e.g., an asymmetry) leads to the non-conservation of another variable (e.g., a directional effect) with the input and output variables comprising a conjugate pair. In the example of yield manipulation in a chemical reaction provided above, there may be an asymmetry in chemical potential, which leads to a directional change in particle number (of a certain molecule), with chemical potential and particle number comprising a conjugate pair. Furthermore, sets of equations similar to those employed in Noether's theorem can also be used to optimize and quantify the ASYS technique for a particular asymmetric system, simply by assuming that a certain symmetry does not apply and then looking at how the variable to be conserved (or not) gets impacted and by how much.
One can interact (we use the term interact in a similar very broad sense as the term interaction, as explained earlier) with such a system (as described above) by, for example, using or causing the system to achieve the directional effect (including, but not limited to, a net yield change in a chemical reaction) from a non-directional input (including, but not limited to, a sinusoidal electric field), based on an asymmetry of the system (including, but not limited to, a nonzero free energy of the reaction).
The interaction may also include any apparatus that embodies such a system.
As shown in the flowchart of
As shown in
This manipulation may involve, for example, analyzing (including, but not limited to, magnitude of the yield change as a function of frequency) or optimizing the system (including, but not limited to, adjusting the frequency and/or the phase of two inputs relative to each other, to maximize the directional effect). The system may be optimized for work done, for energy efficiency, for operation in a desired regime, and/or for a particular load. This manipulation may also involve implementing a new function in the system. This function may be filtering (including, but not limited to, change the system response to an input at certain frequencies), adaptive filtering, compression, de-compression, sampling, de-sampling, feature extraction, spectrum analysis, storage or modulation.
A user 130 can identify or plan a desired interaction with an asymmetric system 132, and can plan and execute a physical embodiment 134 based on a design or manipulation. A computer 136 can be used. Signal processing software 138 and simulation software 140 are run by a processor 142 that has access to storage 144 as needed. The result of the computer-implemented process is a plan of how to achieve the desired interaction with the asymmetric system 146. Any of a wide variety of computer and software platforms can be used to implement the concepts described here.
For a given input and directional effect of a system, interaction can include, for example, signal processing concepts and methodologies. We refer to “signal processing” very broadly to include, but not be limited to, analysis, interpretation, and/or manipulation of signals. We can use signal processing to describe and/or to interpret any aspect or feature of a system and any combination of them.
We can also use signal processing to transform any such signal. We use the term transform very broadly. Without limitation, examples of transforms include an integral transform (including, but not limited to, Abel, Fourier, Short-time Fourier, Hankel, Hartley, Hilbert, Hilbert-Schmidt integral operator, Laplace, Inverse Laplace, Two-sided Laplace, Inverse two-sided Laplace, Laplace-Stieltjes, Linear canonical, Mellin, Inverse Mellin, Poisson-Mellin-Newton cycle, Radon, Stieltjes, Sumudu, Wavelet), a discrete transform (including, but not limited to, Binomial, Discrete Fourier, Fast Fourier, Discrete cosine, Modified discrete cosine, Discrete Hartley, Discrete sine, Hankel, the determinant of the Hankel matrix, Irrational base discrete weighted, Number-theoretic, Stirling, Z-transform), a data-dependent transform (including, but not limited to, Karhunen-Loéve), or another transform (Bäcklund, Bilinear, Box-Muller, Burrows-Wheeler, Wavelet, Distance, Fractal, Hadamard, Hough, Legendre, Möbius, Perspective, Y-delta). The transform may be a one-variable transform or a multi-variable transform. The signal processing may be used to effect more than one type of transform, including combinations and sequences of transforms and transforms that may be developed in the future.
The system may very broadly be any kind of system, including, for example, a physical system, a chemical system, a biological system, a social system, an economic system, or another system, or a combination of any two or more of such systems (including, but not limited to, a biochemical system or a biophysical system).
The chemical system may comprise a chemical reaction. The chemical reaction may comprise an intermediate chemical reaction. The chemical reaction may comprise a surface reaction, a bulk reaction, or a membrane reaction, or combinations of them. The chemical reaction may comprise an organic reaction or an inorganic reaction or a combination of the two. The chemical reaction may comprise an enzymatic reaction, a catalytic reaction, a non-catalytic reaction, or combinations of them. The chemical reaction may comprise a spontaneous reaction or a non-spontaneous reaction, or a combination of the two. The chemical reaction may comprise an exothermic reaction or an endothermic reaction, or a combination of the two. The chemical reaction may comprise a single chemical path or multiple possible chemical paths.
The conjugate pair of variables of interest in the system may be very broadly any conjugate pair, for example, position and momentum, time and energy, temperature and entropy, pressure and volume, electric field and polarizability, magnetic field and magnetization, stress and strain, rotation angle and angular momentum, chemical potential and particle number, electric potential and electromotive force, two orthogonal polarization vectors of an electromagnetic beam, surface are and surface tension, or another conjugate pair. There may be more than one conjugate pair of variables in the system and combinations of them that are of interest.
The system may be a feedback system. The system may be time-invariant or time-variant. It may be linear or nonlinear. The system may be a continuous-time system or a discrete-time system. The system may include a combination of such systems.
The non-directional input may comprise an intensive variable of a conjugate pair of variables.
The non-directional input may be a signal. It may be externally applied or may be intrinsic to the system. It may be an input signal, a noise signal, a control signal, or an intermediate signal. We intend the term intermediate to broadly refer to, for example, any signal that is not an external input signal into the system or an output signal out of the system. The non-directional input may be time-independent or time-dependent. It may be continuous-time or discrete-time. It may be deterministic or stochastic. There may be more than one input and any combination of them.
The non-directional input may be an influence.
An influence may be chemical, electrical, magnetic, thermal, electromagnetic, flow, pressure, mechanical, gravitational, or another influence. It may be a combination of two or more of the above mentioned influences. If two or more, the influences may be of the same type of influence or of at least two different types of influences. If two or more, the influences may have the same phase. They may also have different phases with a fixed relationship or different phases with a varying relationship. If two or more, the influences may have the same frequency. They may also have different frequencies with a fixed relationship or different frequencies with a varying relationship.
The asymmetry may be an absence or a violation of a non-isometric symmetry, a directional symmetry, a reflection symmetry, a rotation symmetry, a translational symmetry, a glide reflection symmetry, a rotoreflection symmetry, a helical symmetry, a scale symmetry, or a combination of two or more of the above mentioned symmetries.
The asymmetry may be externally applied or it may be intrinsic to the system. The asymmetry may be time-independent or time-dependent. It may be a one-variable asymmetry or a multi-variable symmetry. There may be more than one asymmetry in the system. If two or more, the asymmetries may be an absence or a violation of the same type of symmetry or antisymmetry, or of at least two different types of symmetries or antisymmetries.
The directional effect may comprise an extensive variable of a conjugate pair of variables.
The directional effect may be an output signal, a noise signal, a control signal, or an intermediate signal. It may be time-independent or time-dependent. It may be continuous-time or discrete-time. It may be deterministic or stochastic. There may be more than one directional effect achieved. If two or more, the directional effects may be in the same variable or they may be in at least two different types of variables.
The directional effect may include doing mechanical work. The mechanical work may be altering the kinetic energy of a system. The directional effect may include altering the potential energy of a system. The potential energy may be gravitational potential energy, elastic potential energy, chemical potential energy, electrical potential energy (e.g. electrostatic, electrodynamic or magnetic, nuclear), thermal potential energy, and/or rest mass energy. The directional effect may include doing thermodynamic work. Thermodynamic work may include altering enthalpy and/or entropy of a system and/or doing pressure-volume work on the system. The directional effect may be doing organizational work. The organizational work may be altering the order, complexity, pattern, structure, emergent property, and/or behavior of a system.
Implementation of the vertical and lateral modulation of the chemical PES relies on the ability to impose modulation of the binding interactions between atoms of the molecule. This can be achieved in multiple ways. First external fields can be used that directly interact with the electronic states of the molecule, thereby affecting energy of the selective configuration of the molecule (
Secondly, the modulation of the PES can be achieved by imposing modulation of the properties of the environment in which reacting molecules reside. The environment can include, for example, any other molecules/atoms in the surrounding area that are interacting with the reacting molecule. For example if the reacting molecule is the substrate of an enzyme, then the amino residues of the enzyme in the active pocket will interact with the reactive molecule and have a major effect on the transition state of the reactant enabling catalysis. Any external perturbation of the enzyme that results in changes of the geometry of the active pocket will modulate the PES of the reactant. In turn, the perturbation of the enzyme structure can be achieved in multiple ways, e.g., electric fields, acoustic fields, pressure, changes in pH, temperature, ionic strength or specific ligands; furthermore enzymes can be derivatized with external force “mediators” (or “influence mediators”) such as charged or magnetic beads or linkers that couple the externally applied force (e.g. electric or magnetic field or mechanical force) to the enzyme and thereby inducing changes in the structure of the active pocket.
Generally any supramolecular structure can be used to build an active environment 201 around the reactant 202, e.g., aptamers 204 or molecules/materials 206 with nanocavities (e.g. zeolites, polymers, cyclodextrins, carbon nanotubes and related) can be employed for this purpose (
The above approach enables selection of different external forces for induction of vertical or lateral modulation (e.g. electrical and mechanic), thereby allowing simultaneous modulation of multiple parameters. In order to achieve stronger electric field strengths, an enzyme 214 may be linked to a surface 216 of a reaction chamber 218 where formation of electrical double layer can be used for field enhancement (e.g.,
Similar approaches as above can be used for surface catalyzed reactions, which are common in energy and chemical manufacturing industries. The energy and location of the transition state for surface catalyzed reactions is sensitive to the details of coordinating interactions between the molecule and the surface catalyst. Deformation of the surface (e.g., compression or stretching) can lead to changes in the structure of the surface and are expected to affect both the energy and location of the transition state. For example, an electric field can be used to modulate the energy of the transition state while a mechanical deformation (e.g. by direct stretching/compression or by acoustic surface waves or using a piezoelectric substrate, 226,
A wide variety of physical implementations of an ASYS system are possible. Examples have been provided earlier. In general, the interaction with an ASYS system may comprise an apparatus with a site for a reaction and a device interacting with the system. The reaction may comprise a chemical reaction and/or a biochemical reaction and a wide variety of other possible reactions. The device may comprise one or more controlled inputs, such as voltage, mechanical force, temperature, and/or pressure, or others or combinations of them. The device may also comprise a surface on which or near where the reaction takes place.
The directional effect may comprise, for example, converting a type of non-chemical energy into another non-chemical energy. Electrical energy may be converted into rotary power or mechanical work, for example. Rotary power or mechanical work may be converted into electrical energy, for example.
Other examples are possible.
For example, the directional effect may comprise converting a type of chemical energy into a non-chemical energy. A chemical fuel energy may be converted into a non-chemical energy. A chemical energy may be converted into electrical energy or rotary power or mechanical work.
The directional effect may comprise converting a type of non-chemical energy into a chemical energy. Electrical energy may be converted into a chemical energy. A non-chemical energy may be converted into a high energy density chemical fuel (e.g. methane, ethane, or hydrogen), into a biofuel (e.g. methanol or ethanol), or it may drive a chemical fuel process (e.g. gasoline cracking, or gasoline synthesis).
The directional effect may comprise converting a type of chemical energy into another type of chemical energy. The chemical reaction may comprise CO2 reduction, glucose to fructose conversion, or ethylene production.
The direction effect may comprise manipulating a chemical reaction. The chemical reaction may be an intermediate chemical reaction. For example, the reaction for the combustion of methane is: CH4+2O2→CO2+2H2+heat; with intermediate reactions given as: CH4+2O2→CO+H2+H2O, 2CO+O2→2CO2, and 2H2+O2→2H2O.
The directional effect, in this example, may comprise running this reaction in reverse, i.e. CO2+2H2O→CH4+2O2, providing the necessary energy by transducing it from an externally applied input, e.g. electrical energy (
A wide variety of kinds of manipulation are possible. For example, the manipulation may comprise controlling a direction of the reaction. It may comprise altering a final substrate and/or a final product concentration or the ratio of the two concentrations. It may comprise doing work on the system that the system would otherwise not do, including against or along other influences and/or gradients. The manipulation may further comprise catalyzing the reaction. And/or it may comprise specific enhancement and/or suppression of reactions and/or chemical paths. The manipulation may also comprise increasing, decreasing, or reversing a spontaneity of the reaction. It may comprise changing a probability of a specific path and/or product, relative to another alternative path or product, to change a yield of the specific path and/or product.
A result of the method when used in chemical reactions or pathways comprises new mixtures and/or products.
The system may be used in chemical manufacturing, industrial processing, catalysis, chemical fuel production, electricity generation, rotary power or mechanical work generation, energy storage, and/or reduction of undesired chemicals (e.g. greenhouse gases).
The directional effect may comprise altering the negentropy (i.e., negative entropy) of a system. The system may comprise a self-organizing system, such as a protein or a self-assembling molecule. It may comprise a process, such as cell signaling, homeostasis, or developmental stages of a cell or a living organism (e.g. reproduction, growth, differentiation, death). The system may be at the molecular, cellular or behavioral scale. It may be used in basic life science research, medicine (e.g. discovery, treatment, or monitoring), and/or synthetic life processes and products.
The directional effect may comprise transporting an object. The object may be transported against an opposing force and/or gradient. The object may comprise a micro-object, such as an ion, a molecule, a biomolecule, and/or a biological cell, or it may comprise a macro-object, such as a transportation vehicle. The system may be used in mechanics, biological transportation, chemical transportation, and/or vehicular transportation.
The directional effect may comprise altering the property of an object and/or a process. The property may comprise structure, complexity, strength, elasticity, and/or weight. The system may be used in material science or manufacturing.
The directional effect may comprise altering the electromagnetic property of an object and/or a process. The system may be used in electronics or communications.
In addition to and based on all of the above, and combinations of them, other examples may also be included. For example, an electric field input may be applied to an asymmetric system, in which a spontaneous chemical reaction may also be an input, and the energy released from the reaction may be converted into electrical energy and extracted out of the system (e.g., the output electrical energy would be the directional effect). Another example is a similar asymmetric system, in which the external influence may be a magnetic field, rather than an electric field.
The techniques described here could be used to modify or improve existing asymmetric systems and/or the interactions with such systems. For example, a Brownian ratchet may be designed and/or manipulated using signal processing.
Many other systems can be interacted with, based on a wide variety of combinations of non-directional inputs, asymmetries, directional effects, systems, and conjugate pairs of variables.
Other implementations are also within the scope of the following claims.
This application is entitled to the benefit of the priority of U.S. provisional application Ser. 61/090,028, filed Aug. 19, 2008, U.S. provisional application Ser. 61/171,645, filed Apr. 22, 2009, U.S. provisional application Ser. 61/172,838, filed Apr. 27, 2009, U.S. provisional application Ser. 61/172,959, filed Apr. 27, 2009, and U.S. provisional application Ser. 61/179,233, filed May 18, 2009, all of which are incorporated here in their entireties by reference.
Number | Date | Country | |
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61090028 | Aug 2008 | US | |
61171645 | Apr 2009 | US | |
61172838 | Apr 2009 | US | |
61172959 | Apr 2009 | US | |
61179233 | May 2009 | US |