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Emissions from a dry bulk vessel operating on a biofuel blend were measured. Although marginal differences were observed in CO2 emissions from combustion compared to conventional marine fuels, life cycle CO2 emissions can be reduced by up to 40%.

Cutting it close for radical coupling In principle, electrochemistry is an ideal method for radical coupling: One precursor oxidized at the anode pairs up with a counterpart that has been reduced at the cathode. The trouble is that either or both coupling partners might not stay stable long enough to meet in the middle. Mo et al. resolved this issue by closely spacing the electrodes in a microfluidics platform (see the Perspective by Liu et al. ). They showcase coupling of dicyanobenzene as the cathodic radical precursor with a variety of oxidatively generated partners. Science , this issue p. 1352 ; see also p. 1312

We introduce a discrete approach to robotic construction that enables the integration of structure, mechanism, and actuation and offers a promising route to on-demand robot fabrication. We demonstrate this with the assembly of two centimeter-scale electromechanical systems: a Discretely Assembled Walking Motor (DAWM) capable of producing large scale linear or rotary motion from five millimeter-scale part types as well as a Modular Tiny Locomoting Element (MOTILE) that can locomote on a variety of ferrous surfaces. The five part types each embody a limited capability including rigid (strut and node), flexural, magnetic, or coil. Through their arrangement in a three-dimensional lattice, we demonstrate the assembly of actuated mechanical degrees-of-freedom in useful small-scale machines. This work extends prior research in discrete material systems with the inclusion of flexural and actuation components. Actuation is accomplished with the use of voice coil actuator components that produce up to 42 mN of force and strokes of 2 mm. This performance compares well with other millimeter scale actuators and provides sufficient force to lift 28 connected nodes in our assembled lattice, or 7 other actuator components. DAWM is capable of stepping at rates of up to 35 Hz, resulting in velocities of up to 25 mm/s. Multiple DAWM systems can be stacked to add force and can be driven in-phase or out-of-phase to produce intermittent or continuous force, respectively. MOTILE can climb vertical surfaces at speeds of 2.46 body-lengths per second, representing the fastest vertical climbing robot in recently reported research. This approach to robot fabrication discretizes robotic systems at a much finer granularity than prior work in modular robotics and demonstrates the possibility of assembling useful small-scale machines from a limited set of standard part types.

Rapid-prototyping processes are being extended to increasingly large scales, including 3D printing from gantries, and robotic arms for cutting, milling and winding. These all use designs that are digital, but materials that are not: they are continuously deposited or removed. Neil Gershenfeld, Matthew Carney, Benjamin Jenett, Sam Calisch and Spencer Wilson of the MIT Center for Bits and Atoms explore the implications of the use of digital materials, reversibly assembled from a discrete set of parts with a discrete set of relative positions and orientations, for applications on scales ranging from aerostructures to geoprinting. Here, they discuss the production of the parts, the modelling of structures made with them, and their automated assembly.

We demonstrate universal computation in an all-fluidic two-phase microfluidic system. Nonlinearity is introduced into an otherwise linear, reversible, low–Reynolds number flow via bubble-to-bubble hydrodynamic interactions. A bubble traveling in a channel represents a bit, providing us with the capability to simultaneously transport materials and perform logical control operations. We demonstrate bubble logic AND/OR/NOT gates, a toggle flip-flop, a ripple counter, timing restoration, a ring oscillator, and an electro–bubble modulator. These show the nonlinearity, gain, bistability, synchronization, cascadability, feedback, and programmability required for scalable universal computation. With increasing complexity in large-scale microfluidic processors, bubble logic provides an on-chip process control mechanism integrating chemistry and computation.

It has been observed that a linear-feedback shift-register (LFSR) sequence can be synchronized by feeding the modulated sequence into a "soft" (or "analog") version of the LFSR. In this correspondence, the "soft LFSR" is derived as forward-only message passing in the corresponding factor graph. A continous-time analog (suitable for realization as a clockless electronic circuit) is then given of both the LFSR and the soft LFSR. A connection is thus established between statistical state estimation and the phenomenon of entrainment of dynamical systems, which opens the prospect of deriving dynamical systems (such as electronic circuits) with strong entrainment capabilities from more powerful message passing algorithms

The assumptions behind Internet architectures do not scale to small devices — they have a baseline cost that is still too high for small, few-dollar, embedded objects. This barrier either leaves many devices network disenfranchised or encourages the creation of segmented networks. Internet 0 attempts to enable pervasive computing and networking on the embedded level by providing the Internet protocol as a communications substrate, and, through the use of an end-to-end modulation scheme, to speak to devices. I0 is a framework to bridge together heterogeneous devices via IP in a manner that is still compatible with designing globally large computer networks.

We report on a project that explored emerging technologies for intuitive and unobtrusive information interfaces in a compelling setting. An installation at the Museum of Modern Art, New York, was part of a public exhibit and included an interactive table that presented information associated with the exhibit to the gallery visitors without visible conventional computing elements. The enabling devices included noncontact sensing of low-cost tags in physical icons, electrostatic detection of hand location in three dimensions, and sensor fusion through lightweight Internet Protocol access.

Highly durable, flexible, and even washable multilayer electronic circuitry can be constructed on textile substrates, using conductive yarns and suitably packaged components. In this paper we describe the development of e-broidery (electronic embroidery, i.e., the patterning of conductive textiles by numerically controlled sewing or weaving processes) as a means of creating computationally active textiles. We compare textiles to existing flexible circuit substrates with regard to durability, conformability, and wearability. We also report on: some unique applications enabled by our work; the construction of sensors and user interface elements in textiles; and a complete process for creating flexible multilayer circuits on fabric substrates. This process maintains close compatibility with existing electronic components and design tools, while optimizing design techniques and component packages for use in textiles.

This paper demonstrates the use of software radio techniques in the context of sensing, rather than communications. It describes code-division multiplexing (CDMA) and time-division multiplexing (TDMA) of a receiver channel in an electric field sensing system. The only hardware used is a front-end gain stage consisting of two opamps and a microcontroller. The modulation and demodulation operations are implemented entirely in the microcontroller software. Multiple coded waveforms are transmitted simultaneously, and induce a combined signal on a single receive electrode. The combined signal, after passing through a single analog front end terminating in an analog-to-digital converter, is separated into the four original component signals by a software demodulation operation. The signal-to-noise ratio (SNR) achieved by the code-division multiplexed system given a fixed measurement time is compared to the SNR achieved by a time-division multiplexed implementation given the same total measurement time. The paper also compares the scaling of TDMA and CDMA performance with the number of transmitted channels and the number of demodulated channels.

The need to characterize and forecast time series recurs throughout the sciences, but the complexity of the real world is poorly described by the traditional techniques of linear time-series analysis. Although newer methods can provide remarkable insights into particular domains, they still make restrictive assumptions about the data, the analyst, or the application1. Here we show that signals that are nonlinear, non-stationary, non-gaussian, and discontinuous can be described by expanding the probabilistic dependence of the future on the past around local models of their relationship. The predictors derived from this general framework have the form of the global combinations of local functions that are used in statistics2,3,4, machine learning5,6,7,8,9,10 and studies of nonlinear dynamics11,12. Our method offers forecasts of errors in prediction and model estimation, provides a transparent architecture with meaningful parameters, and has straightforward implementations for offline and online applications. We demonstrate our approach by applying it to data obtained from a pseudo-random dynamical system, from a fluctuating laser, and from a bowed violin.

Quantum computation remains an enormously appealing but elusive goal. It is appealing because of its potential to perform superfast algorithms, such as finding prime factors in polynomial time, but also elusive because of the difficulty of simultaneously manipulating quantum degrees of freedom while preventing environmentally induced decoherence. A new approach to quantum computing is introduced based on the use of multiple-pulse resonance techniques to manipulate the small deviation from equilibrium of the density matrix of a macroscopic ensemble so that it appears to be the density matrix of a much lower dimensional pure state. A complete prescription for quantum computing is given for such a system.

Electronic computers currently have many orders of magnitude more thermodynamic degrees of freedom than information-bearing ones (bits). Because of this, these levels of description are usually considered separately as hardware and software, but as devices approach fundamental physical limits these will become comparable and must be understood together. Using some simple test problems, I explore the connection between the information in a computation and the thermodynamic properties of a system that can implement it, and outline the features of a unified theory of the degrees of freedom in a computer.

[ring, ring] Alice : Hello…Quantum Computer Associates. Bob : Quantum Computer? Quantum con-puter is more like it! That stuff will never work (other than as a make-work program for underemployed physicists). I wasn't calling for a quantum computer, just a faster one to help me find matches in a

We describe an inertial measurement device based on an electrodynamically trapped proof mass. Mechanical constraints are replaced by guiding fields, permitting the trap stiffness to be tuned dynamically. Optical readout of the proof mass motion provides a measurement of acceleration and rotation, resulting in an integrated six degree of freedom inertial measurement device. We demonstrate such a device—constructed without microfabrication—with sensitivity comparable to that of commercial microelectromechanical systems technology and show how trapping parameters may be adjusted to increase dynamic range.

The Theremin was one of the first electronic musical instruments, yet it provides a degree of expressive real-time control that remains lacking in most modern electronic music interfaces. Underlying the deceptively simple capacitance measurement used by it and its descendants are a number of surprisingly interesting current transport mechanisms that can be used to inexpensively , unobtrusively, robustly, and remotely detect the position of people and objects. We review the relevant physics, describe appropriate measurement instrumentation, and discuss applications that began with capturing virtuosic performance gesture on traditional stringed instruments and evolved into the design of new musical interfaces.

A musical instrument is an analog computer. It integrates equations of motion based on applied boundary conditions and generates acoustic and tactile outputs. Understanding why the equations of motion is liked is a very hard problem, fabricating traditional instruments that duplicate desired equations of motion is a hard problem, but using new technology to emulate and generalize them is an increasingly easy problem. The remarkable confluence of sensing, modeling, computing, and communications that is blurring the distinction between using wood and strings or silicon to solve the same equations will be discussed. This includes ideas such as the active remote interrogation of passive structures for sensing, state‐space reconstruction for building observational nonlinear models, cellular automata methods for efficient first‐principles solution of continuum equations, and tools for real‐time computing and communications on general‐purpose platforms.