Jim Romeo

Bio: Jim Romeo is an academic researcher. The author has contributed to research in topics: Plastics engineering & Stewardship. The author has an hindex of 2, co-authored 9 publications receiving 30 citations.

Low Energy?: Reducing energy consumption for industrial facilities for stewardship and economy

Abstract: In view of ongoing experimental activities to determine the pion polarizabilities, we have started to recalculate the available two-loop expressions in the framework of chiral perturbation theory, because they have never been checked before. We make use of the chiral Lagrangian at order p 6 now available, and of improved techniques to evaluate the two-loop diagrams. Here, we present the result for the neutral pions. The cross section for the reaction γγ → π 0 π 0 agrees with the earlier calculation within a fraction of a percent. We present analytic results for the dipole and quadrupole polarizabilities, and compare the latter with a recent evaluation from data on γγ → π 0 π 0 .

Emergence of home manufacturing in the developed world: return on investment for open-source 3-D printers.

Abstract: Through reduced 3-D printer cost, increased usability, and greater material selection, additive manufacturing has transitioned from business manufacturing to the average prosumer. This study serves as a representative model for the potential future of 3-D printing in the average American household by employing a printer operator who was relatively unfamiliar with 3-D printing and the 3-D design files of common items normally purchased by the average consumer. Twenty-six items were printed in thermoplastic and a cost analysis was performed through comparison to comparable, commercially available products at a low and high price range. When compared to the low-cost items, investment in a 3-D printer represented a return of investment of over 100% in five years. The simple payback time for the high-cost comparison was less than 6 months, and produced a 986% return. Thus, fully-assembled commercial open source 3-D printers can be highly profitable investments for American consumers. Finally, as a preliminary gauge of the effect that widespread prosumer use of 3-D printing might have on the economy, savings were calculated based on the items’ download rates from open repositories. Results indicate that printing these selected items have already saved prosumers over $4 million by substituting for purchases.

Shadows of Bonnor black dihole by chaotic lensing

Abstract: We numerically study the shadows of a Bonnor black dihole through the technique of backward ray tracing. The presence of a magnetic dipole yields nonintegrable photon motion, which sharply affects the shadow of the compact object. Our results show that there exists a critical value for the shadow. When the magnetic dipole parameter is less than the critical value the shadow is a black disk, but when the magnetic dipole parameter is larger than the critical value the shadow becomes a concave disk with eyebrows possessing a self-similar fractal structure. These behaviors are very similar to those of the equal-mass and nonspinning Majumdar-Papapetrou binary black holes. However, we find that the two larger shadows and the smaller eyebrow-like shadows are joined together by the middle black zone for the Bonnor black dihole, which is different from that in the Majumdar-Papapetrou binary black hole spacetime where they are disconnected. With the increase of the magnetic dipole parameter, the middle black zone connecting the main shadows and the eyebrow-like shadows becomes narrow. Our results show that the spacetime properties arising from the magnetic dipole yield interesting patterns for the shadow cast by a Bonnor black dihole.

Optical interconnects for extreme scale computing systems

Abstract: Face-to-face comparison of major large scale HPC interconnects.Review of challenges and solutions for increased use of optics in HPC.Description of optical switching, in terms of principle, limitations, technical requirements and benefits. Large-scale high performance computing is permeating nearly every corner of modern applications spanning from scientific research and business operations, to medical diagnostics, and national security. All these communities rely on computer systems to process vast volumes of data quickly and efficiently, yet progress toward increased computing power has experienced a slowdown in the last number of years. The sheer cost and scale, stemming from the need for extreme parallelism, are among the reasons behind this stall. In particular, very large-scale, ultra-high bandwidth interconnects, essential for maintaining computation performance, represent an increasing portion of the total cost budget.Photonic systems are often cited as ways to break through the energy-bandwidth limitations of conventional electrical wires toward drastically improving interconnect performance. This paper presents an overview of the challenges associated with large-scale interconnects, and reviews how photonic technologies can contribute to addressing these challenges. We review some important aspects of photonics that should not be underestimated in order to truly reap the benefits of cost and power reduction.

Syngas Fermentation to Alcohols: Reactor Technology and Application Perspective

Abstract: One approach of Power-to-X is the coupling of the energy and chemical sector, using electrolysis for syngas generation and microbial gas conversion for the production of biochemicals. On the verge of commercialization, known challenges of gas fermentation technology are poor mass transfer of syngas, low cell concentration and productivity. These problems can be addressed by an intelligent reactor design. Thus, this article provides an overview on the current state of the art for reactor technology in syngas fermentation and discusses possible concepts with regard to an application at industrial scale.