Jeroen Schoenmaker

This manuscript gives a solution to the black hole information paradox by bringing to the debate a fundamental aspect of information science: the process of measurement by a receiver. Bekenstein and Hawking established the foundations of black hole thermodynamics based on previous works of Brillouin and Szilard on information physics. In this work, we demonstrate that the relation between energy and information established in communication technology by Shannon and Landauer has not been adequately applied to black hole physics. As Landauer states, a computation process is closely akin to a measurement. Our argument is grounded on the physical concepts of measurement, signal-to-noise ratio, energy dissipation during the switching process in computation, and hysteresis loops. We give special attention to the role of noise and energy dissipation in the process of information transmission. We demonstrate that Szilard’s work fails to establish a connection between information and entropy in agreement with the works of Landauer and Shannon. We also demonstrate that a quantum state cannot be directly equivalent to a unit of information. The entropy and temperature attributed to black holes are questioned, and a solution to the black hole information paradox is provided. Similarly to what happens with Maxwell’s demon, the black hole information paradox is “exorcised” once we account for the process of measurement and information processing.

In this work, we analyze the thermodynamic principles underlying modern data storage systems, including Random Access Memory (RAM), hard disk drive (HDD), flash memory, magnetic RAM (MRAM), ferroelectric RAM (FeRAM), and phase-change RAM (PCRAM), as well as other less well-known data storage mechanisms. The analysis is conducted in the context of data storage and processing in relation to Landauer’s principle, with special emphasis on hysteresis. Analogous to how heat engines are characterized by thermodynamic cycles, data storage systems are examined in terms of the hysteresis loop of their fundamental data unit. We explore the role of heat in data storage systems. Afterward, we introduce the concept of temperature gradient memory (TeGraM) along with a detailed layout of a realizable device. Experimental results demonstrating this technology are also presented.

This manuscript bridges the fields of jet propulsion, synthetic jets and thermoacoustic engines. We introduce the case that synthetic jets in air can be considered a consistent approach for propulsion systems. To date, studies on synthetic jet propulsion have been scattered and rather subsidiary. Furthermore, investigating the perspective of propulsion can provide new insights into the field of synthetic jets and the physics of propulsion. In this work, synthetic jet propulsion in air is demonstrated and studied for acoustic and thermoacoustic cases. We developed synthetic jet systems and characterized the resulting propulsion regarding several relevant parameters such as geometric factors and the frequency and power of acoustic jets electromechanically and thermally produced. We demonstrated the 10.4-mN and 2.7-mN thrust in the acoustic and thermoacoustic modes, respectively, using compact tabletop assemblies. The physical mechanism of the jets has been modeled, simulated, verified with Schlieren imaging and laid in the perspective of adherent literature. Similarities and differences regarding traditional jet propulsion systems are discussed. Synthetic jet propulsion in air using a thermal cycle is experimentally demonstrated for the first time.

This manuscript bridges the fields of jet propulsion, synthetic jets and thermoacoustic engines. We put forward the case that acoustic air jets can be considered as a consistent approach for propulsion systems. Hitherto, studies on synthetic jet propulsion have been scattered and rather subsidiary. Furthermore, investigating with the perspective of propulsion can give new insights to the field of synthetic jets, and the physics of propulsion. We developed and characterized the propulsion properties with regard to several relevant parameters such as geometric factors, frequency and intensity of acoustic jets produced electromechanically and thermally. We demonstrated 10.4 mN and 2.7 mN thrust in the acoustic and thermoacoustic modes respectively, using compact tabletop assemblies. The physical mechanism of the jets has been modelled, simulated, verified with Schlieren imaging and laid in the perspective of adherent literature. Similarities and differences with regard to traditional jet propulsion systems are discussed. As an essentially unexplored avenue, several improvement directions are indicated.

Recently, the Gauss rifle has gained attention as an interesting problem for physics and engineering education. In this manuscript we propose and analyze a novel problem that, while being related to the Gauss rifle, is rather simpler: the Gauss pendulum, which yields more consistent results and allows further agreement between model, simulation and experimental data. The Gauss pendulum, unlike the rifle, does not involve rotational movement of balls and the difference between the initial and final energy state of the system can be easily accessed by measuring the final height of the swinging projected ball. An extensive assessment of a Gauss pendulum has been developed using free software and accessible laboratory equipment. Focusing on the validation of the magnetic potential well model to understand the gain in kinetic energy, it was possible to obtain a remarkable agreement between the experimental and theoretically simulated data.

Organic Rankine Cycle (ORC) systems are increasingly gaining relevance in the renewable and sustainable energy scenario. Recently our research group published a manuscript identifying a new type of thermodynamic cycle entitled Buoyancy Organic Rankine Cycle (BORC) [J. Schoenmaker, J.F.Q. Rey, K.R. Pirota, Renew. Energy36, 999 (2011)]. In this work we present two main contributions. First, we propose a refined thermodynamic model for BORC systems accounting for the specific heat of the working fluid. Considering the refined model, the efficiencies for Pentane and Dichloromethane at temperatures up to 100 degrees C were estimated to be 17.2%. Second, we show a proof of concept BORC system using a 3 m tall, 0.062 m diameter polycarbonate tube as a column-fluid reservoir. We used water as a column fluid. The thermal stability and uniformity throughout the tube has been carefully simulated and verified experimentally. After the thermal parameters of the water column have been fully characterized, we developed a test body to allow an adequate assessment of the BORC-system's efficiency. We obtained 0.84% efficiency for 43.8 degrees C working temperature. This corresponds to 35% of the Carnot efficiency calculated for the same temperature difference. Limitations of the model and the apparatus are put into perspective, pointing directions for further developments of BORC systems.

We report a hierarchically ZnO micro/nanostructured material where ZnO microtubes are covered with ZnO nanowires. The synthesis process is partially driven by electrical current and accompanied in situ by electrical resistivity measurements. The thermal activated energy of the obtained semiconducting microtubes was estimated to be 0.5 eV. Microtubes topped with nanowires may have multifunctional nature and tailored properties for technological applications.

We performed an in depth analysis of the subjects of entropy and the second law of thermodynamics and how they are treated in astrophysical systems. These subjects are retraced historically from the early works on thermodynamics to the modern statistical mechanical approach and analyzed in view of specific practices within the field of astrophysics. As often happens in discussions regarding cosmology, the implications of this analysis range from physics to philosophy of science. We argue that the difficult question regarding entropy and the second law in the scope of cosmology is a consequence of the dominating paradigm. We further demonstrate this point by assuming an alternative paradigm, not related to thermodynamics of horizons, and successfully describing entropic behavior of astrophysical systems.

Tailoring magnetic flux distribution is highly desirable in a wide range of applications such as magnetic sensors and biomedicine. In this paper we study the manipulation of induced currents in passive devices in order to engineer the distribution of magnetic flux intensity in a given region. We propose two different approaches, one based on especially designed wire loops (Lenz law) and the other based on solid conductive pieces (eddy currents). The gain of such devices is mainly determined by geometry giving perspective of high amplification. We consistently modeled, simulated, and executed the proposed devices. Doubled magnetic flux intensity is demonstrated experimentally for a moderate aspect ratio.