Higher Poincare Lemma and Integrability

We prove the non-abelian Poincare lemma in higher gauge theory in two different ways. The first method uses a result by Jacobowitz which states solvability conditions for differential equations of a certain type. The second method extends a proof by Voronov and yields the explicit gauge parameters connecting a flat local connective structure to the trivial one. Finally, we show how higher flatness appears as a necessary integrability condition of a linear system which featured in recently developed twistor descriptions of higher gauge theories.Comment: 1+21 pages, presentation streamlined, section on integrability for higher linear systems significantly improved, published versio

Investigation of Microalgae Co-Cultures for Nutrient Recovery and Algal Biomass Production from Dairy Manure

Treatment of waste streams using algae can minimize eutrophication by removing inorganic nutrients while producing biomass which can be used for biofuels, animal feed, and fertilizer production. While there are many studies that report the growth of individual algal strains in different media, there are relatively few studies that examine the performance of algae coculture. The objective of this research was to determine the growth parameters and nutrient sequestration profiles of Chlorella vulgaris, Scenedesmus dimorphus, and their coculture in wastewater from a dairy facility at two dilutions (10% and 25%). Average specific growth rates (and biomass concentrations) the S. dimorphus, C. vulgaris, and their coculture were 0.263 d⁻¹ (0.290±0.059 g/L), 0.063 d⁻¹ (0.145±0.011 g/L), and 0.250 d⁻¹ (0.400±0.060 g/L) d⁻¹ at 10% manure, and 0.232 d⁻¹ (0.543±0.149 g/L), 0.234 d⁻¹ (0.364±0.113 g/L), and 0.289 d⁻¹ (0.612±0.255 g/L) at 25% manure, respectively. Based on the results it was evident that the strains S. dimorphus and C. vulgaris have different capacities for accumulation of biomass production (S. dimorphus is higher), lipid accumulation (S. dimorphus is higher), chlorophyll (C. vulgaris is higher), total suspended solids (TSS) (C. vulgaris is higher), and volatile suspended solids (VSS) (S. dimorphus is higher). It was found that mixed coculture had higher biomass growth, specific growth rate, and removal efficiency of nitrogen, phosphorous, and TSS for the 25% dairy wastewater. The results were similar for 10% dairy wastewater except for the specific growth rate and nitrogen removal efficiency which were higher for the S. dimorphus monoculture. These capacities can be leveraged in mixed coculture to achieve higher treatment efficiencies compared to monocultures. The results can inform managers of agricultural and municipal wastewater facilities as they make decisions about whether to include algal technology in future upgrades and expansion.This is the publisher’s final pdf. The published article is copyrighted by the American Society of Agricultural and Biological Engineers and can be found at: http://elibrary.asabe.org/toc_landing.asp?conf=aeaj.Keywords: Scenedesmus dimorphus, Wastewater, Phosphate removal, Nitrate removal, Microalgae coculture, Chlorella vulgari

Higher Structures, Self-Dual Strings and 6d Superconformal Field Theories

I summarize and discuss some recent results on formulating actions of six-dimensional superconformal field theories using the language of higher gauge theory. The latter guarantees mathematical consistency of our constructions and we review crucial aspects of this framework, such as $L_\infty$-algebras and corresponding kinematical data given by higher connections. We then show that there is a mathematically consistent non-Abelian extension of the self-dual string equation which satisfies many physical expectations. Our construction favors a particular higher gauge group leading us to higher principal bundles known as string structures. Using these, we manage to formulate a six-dimensional action which shares many properties with the famous $(2,0)$-theory but also still differs from it in some key points.Comment: 16 pages, Contribution to Proceedings of LMS/EPSRC Durham Symposium Higher Structures in M-Theory, August 201

Embedded ultrasonic transducer design and wireless communication for intelligent monitoring of structures

This paper describes a wireless demonstrator system designed for generation and detection of fundamental symmetrical Lamb waves (So) characterized by high velocity and low attenuation. The demonstrator comprises two piezoceramic transducers embedded within an epoxy plate, drive and pre-amplification electronics, a microcontroller and a communications interface. This arrangement can be configured to operate in an active pitch-catch or pulse-echo interrogation mode or as a passive acoustic emission (AE) sensor. The history of AE incidents, for example, may then be transmitted by Wireless link

Evaluating the performances of gridded satellite/reanalysis products in representing the rainfall climatology of Ethiopia

This study evaluated performances of the Climate Hazard Group Infrared Precipitation with stations version 2.0 (CHIRPS v2.0) and Multi-Source Weighted-Ensemble Precipitation version 2.8 (MSWEP v2.8) products against observed data. Rainfall climatology was simulated for different agro-ecological zones (AEZs) of Ethiopia during 1991–2020 at different temporal scales. Performance evaluations were made using continuous and statistical performance measures as well as Probability Density Function (PDF). CHIRPS v2.0 for estimating monthly, seasonal, and annual rainfall totals, and MSWEP v2.8 for daily rainfall have shown better performance over all AEZs. The two products display comparable performance for detecting daily rainfall occurrences over alpine AEZ, but MSWEP v2.8 is superior in the rest four AEZs. CHIRPS v2.0 outperforms MSWEP v2.8 for detecting most of the daily rainfall intensity classes over all AEZs. The findings will play a noteworthy role to improve the quality of hydro-climate studies in Ethiopia