Interference of Data Transmission in Access and Backbone Networks by High-Power Sensor System

Currently, individual optical fibers are mostly used for each non-data application, which is very inefficient and uneconomical. Sharing a single fiber for multiple applications is a promising solution. However, in the case of a non-data application, the situation is much more complicated compared to data because of special application´s requirements. In laboratory setup, we performed a measurement with a standard G.652D optical fiber for analyzing possible interaction of stable frequency/accurate time transmission, 1.25/10Gbps data transmission (typical bitrates for access point-to-point networks), and high-power sensor signal for different channel spacing and different pulse duration of sensor signal.     

The Effect of Surface Site Ensembles on the Activity and Selectivity of Ethanol Electrooxidation by Octahedral PtNiRh Nanoparticles

Direct ethanol fuel cells are attractive power sources based on a biorenewable, high energy-density fuel. Their efficiency is limited by the lack of active anode materials which catalyze the breaking of the C−C bond coupled to the 12-electron oxidation to CO₂. We report shape-controlled PtNiRh octahedral ethanol oxidation electrocatalysts with excellent activity and previously unachieved low onset potentials as low as 0.1 V vs. RHE, while being highly selective to complete oxidation to CO₂. Our comprehensive characterization and in situ electrochemical ATR studies suggest that the formation of a ternary surface site ensemble around the octahedral Pt₃Ni₁Rh_x nanoparticles plays a crucial mechanistic role for this behavior.     

Real options and technology management: Assessing technology migration options in wireless industry

The wireless industry is currently undergoing a major transition from second generation (2G) to third generation (3G) wireless technologies. The paper attempts to assess wireless technology migration options using the real options approach (ROA) to support the wireless network operators’ strategic decisions: to migrate or not, if so, which migration path to take. The preliminary result shows that the evolution of wireless network technologies between generations is desirable, but not within generations. Finally, from a strategic perspective, we should consider the possible challenges that may hinder migration. By identifying these challenges, we can be more watchful of transition pitfalls and can choose a better alternative.     

Numerical simulation of acoustic holography with propagator adaptation: Application to a 3D disc

Acoustical holography can be used to identify the vibration velocity of an extended vibrating body. Such an inverse problem relies on the radiated acoustic pressure measured by a microphone array and on an a priori knowledge of the way the body radiates sound. Any perturbation on the radiation model leads to a perturbation on the velocity identified by the inversion process. Thus, to obtain the source vibration velocity with a good precision, it is useful to identify also an appropriate propagation model. Here, this identification, or adaptation, procedure rests on a geometrical interpretation of the acoustic holography in the objective space (here the radiated pressure space equipped with the L²-norm) and on a genetic algorithm.The propagator adaptation adds information to the holographic process, so it is not a regularisation method, which approximates the inverse of the model but does not affect the model. Moreover regularisations act in the variables space, here the velocities space. It is shown that an adapted model significantly decreases the quantity of regularisation needed to obtain a good reconstructed velocity, and that model adaptation improves significantly the acoustical holography results.In the presence of perturbations on the radiated pressure, some indications will be given on the interest or not to adapt the model, again thanks to the geometrical interpretation of holography in the objective space.As a numerical example, a disc whose vibration velocity on one of its sides is identified by acoustic holography is presented. On an industrial scale, this problem occurs due to the noise radiated by car wheels. The assessment of the holographic results has not yet been rigorously performed in such situations due to the complexity of the wheel environment made up of the car body, road and rolling conditions.     

Tuning Carbon Materials for Supercapacitors by Direct Pyrolysis of Seaweeds

The sea provides a large variety of seaweeds that, because of their chemical composition, are fantastic precursors of nanotextured carbons. The carbons are obtained by the simple pyrolysis of the seaweeds under a nitrogen atmosphere between 600 and 900 °C, followed by rinsing the product in slightly acidic water. Depending on the origin of the seaweed and on the pyrolysis conditions, the synthesis may be oriented to give an oxygen‐enriched carbon or to give a tuned micro/mesoporous carbon. The samples with a rich oxygenated surface functionality are excellent as supercapacitor electrodes in an aqueous medium whereas the perfectly tuned porous carbons are directly applicable for organic media. In both cases, the specific surface area of the attained carbons does not exceed 1300 m² g⁻¹, which results in high‐density materials. As a consequence, the volumetric capacitance is very high, making these materials more interesting than activated carbons from the point of view of developing small and compact electric power sources. Such versatile carbons, obtained by a simple, ecological, and cheap process, could be well used for environment remediation such as water and air treatment.     

Real-time quantification of viable bacteria in liquid medium using infrared thermography

Quantifying viable bacteria in liquids is important in environmental, food processing, manufacturing, and medical applications. Since vegetative bacteria generate heat as a result of biochemical reactions associated with cellular functions, thermal sensing techniques, including infrared thermography (IRT), have been used to detect viable cells in biologic samples. We developed a novel method that extends the dynamic range and improves the sensitivity of bacterial quantification by IRT. The approach uses IRT video, thermodynamics laws, and heat transfer mechanisms to directly measure, in real-time, the amount of energy lost as heat from the surface of a liquid sample containing bacteria when the specimen cools to a lower temperature over 2 min. We show that the Energy Content (EC) of liquid media containing as few as 120 colony-forming units (CFU) of Escherichia coli per ml was significantly higher than that of sterile media (P < 0.0001), and that EC and viable counts were strongly positively correlated (r = 0.986) over a range of 120 to approximately 5 × 10⁸ CFU/ml. Our IRT approach is a unique non-contact method that provides real-time bacterial enumeration over a wide dynamic range without the need for sample concentration, modification, or destruction. The approach could be adapted to quantify other living cells in a liquid milieu and has the potential for automation and high throughput.