An integrated solution for an autonomous drone racing in indoor environments

Intelligent Service Robotics - The use of drones is becoming more present in modern daily life. One of the most challenging tasks associated with these vehicles is the development of perception and...     

N-fertiliser application or legume integration enhances N cycling in tropical pastures

Understanding the effects of N application or the introduction of a legume on N cycling is critical for achieving productive and sustainable grassland systems. This 2-year study assessed the N cycling of three pasture treatments: (1) mixed Marandu palisadegrass (Brachiaria brizantha) and forage peanut (Arachis pintoi) without N fertiliser (GRASS?+?LEGUME); (2) monoculture Marandu palisadegrass fertilised with 150 kg N ha^?1 year^?1 (GRASS?+?N); and (3) monoculture Marandu palisadegrass without N fertiliser (GRASS). Continuous stocking was used with a target canopy height of 0.20 to 0.25 m. Litter responses, forage and N intake, N livestock excretion and N cycling were measured. Existing litter and litter deposition rate were greatest in GRASS pasture (3030 and 84.3 vs. 2140 kg ha^?1 and 64.8 kg OM ha^?1 d^?1; average of GRASS?+?N and GRASS?+?LEGUME pastures, respectively; P?<?0.10). Litter decomposition rate in GRASS pasture was smaller 30.4 and 36.0% compared to GRASS?+?N and GRASS?+?LEGUME pastures, respectively (P?<?0.10). The GRASS?+?N obtained greatest (P?<?0.10) faecal N excretion (21.7 vs. 13.8 kg N ha^?1 season^?1), and urinary N excretion (32.0 vs. 14.2 kg N ha^?1 season^?1). In the GRASS?+?N and GRASS?+?LEGUME pastures, there was a positive overall change of N in the soil–plant–animal system of 13 and 33 kg N ha^?1 year^?1, respectively. In the GRASS pasture, there was an overall negative change of N in the soil–plant–animal system of ??41 kg N ha^?1 year^?1. Nitrogen application or the integration of forage peanut in a grass pasture increased the conservation of soil N reserves.

     

Carbon‐nanotube electron emitters for display applications

Abstract— The optoelectronic, mechanical, and thermal properties of carbon nanotubes have made them very attractive for a wide range of potential applications. However, many applications require the growth of aligned/micropatterned carbon nanotubes with or without a modified nanotube surface. We have developed several simple pyrolytic methods for large‐scale production of aligned carbon‐nanotube arrays perpendicular to the substrate surface. We have also used photolithographic and soft‐lithographic techniques to pattern our aligned carbon nanotubes with submicron resolution. These aligned carbon‐nanotube arrays can be transferred onto various substrates of particular interest (e.g., on conducting substrates as electron emitters for flat‐panel displays) in either a patterned or non‐patterned fashion. The well‐aligned structure further allows us to prepare aligned coaxial nanowires of carbon nanotubes sheathed with polymers and to modify the surface of individual carbon nanotubes by plasma treatment. These aligned/micropatterned carbon nanotubes with and without surface modification possess desirable properties for electron emission applications.     

Combining Intelligent Techniques for Sensor Fusion

Mobile robots rely on sensor data to build a representation of their environment. However, sensors usually provide incomplete, inconsistent or inaccurate information. Sensor fusion has been successfully employed to enhance the accuracy of sensor measures. This work proposes and investigates the use of Artificial Intelligence techniques for sensor fusion. Its main goal is to improve the accuracy and reliability of the distance measure between a robot and an object in its work environment, based on measures obtained from different sensors. Several Machine Learning algorithms are investigated to fuse the sensors data. The best model generated by each algorithm is called estimator. It is shown that the employment of estimators based on Artificial Intelligence can improve significantly the performance achieved by each sensor alone. The Machine Learning algorithms employed have different characteristics, causing the estimators to have different behaviors in different situations. Aiming to achieve an even more accurate and reliable behavior, the estimators are combined in committees. The results obtained suggest that this combination can further improve the reliability and accuracy of the distances measured by the individual sensors and estimators used for sensor fusion.     

Multifunctional Characteristics of Glass Fiber-Reinforced Epoxy Polymer Composites with Multiwalled Carbon Nanotube Buckypaper Interlayer

In this work, multiwalled carbon nanotube buckypaper (MWCNT-BP) was inserted at the middle-plane of glass fiber/epoxy resin prepregs to obtain three-phase nanostructured composite. Preliminary tests conducted by differential scanning calorimetry and thermogravimetric analyses (TGA) revealed that the proposed curing cycle to prepare the laminates in a hot compression-molding machine was appropriated. The mechanical properties of the BP-based composite studied by short beam shear and compression shear tests presented no improvements compared to the base laminate. On the other hand, the thermal properties of the nanostructured composite improved as demonstrated by dynamical mechanical analyses and TGA. Besides, the reflectivity results revealed an average value of −12.2 dB in the X-band with a maximum attenuation of 99.4% of the incident wave at 9.5 GHz. The improvements in both thermal and electromagnetic properties demonstrate the potential for both structural and multifunctional applications of the obtained BP-composite. POLYM. ENG. SCI., 60:740–751, 2020. © 2020 Society of Plastics Engineers     

Studies on the oxidation of enamines with molecular oxygen. I. Oxidation of Some Piperidino Alkenes

In the autoxidation of 1-piperidinocyclohex-1-ene ( 1 ), 1-piperidinobut-1-ene ( 2 ), 3-piperidinopent-2-ene ( 3 ), and 1-piperidino-2-methyl-prop-1-ene( 4 ) only products of an oxidative attack at the CC-double bond are formed. Both α-aminoketones, the products of the rearrangement of primarily formed epoxides, and products of the oxidative session of the CC double bond are obtained. As a side reaction some hydrolysis of the starting enamines takes place. This hydrolysis proves that some water must be formed during the enamine oxidation.     

Nutritional Value of Various Ray Fish Liver Oils to the Pacific White Shrimp <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>

A 32-day comparative feeding trial was performed to evaluate the nutritional value of four different ray fish liver oils to the Pacific white shrimp Litopenaeus vannamei. Four feeds were prepared with liver oil extracted from Dasyatis brevis, Rhinoptera steindachneri, Aetobatus narinari, and R. bonasus. A control feed was prepared with Menhaden fish oil. Ray fish liver oils were mainly composed of poly- and highly unsaturated fatty acids and contained levels of 20:5n-3 and 22:6n-3 comparable in magnitude to those of Menhaden fish oil, except for A. narinari liver oil, which had moderately low concentrations of 20:5n-3 and 22:6n-3 but showed a particularly high level of 20:4n-6, more than six times greater than that of Menhaden fish oil. Dietary fatty acids significantly influenced the fatty acid composition of shrimp muscle tissue, e.g., the diet with Menhaden fish oil elicited significantly higher shrimp muscle DHA level than diets with oil from D. brevis, and A. narinari, but not than diets with oil from R. steindachneri and R. bonasus. In spite of these differences, all four ray fish liver oils evaluated were as efficient in promoting growth and survival of L. vannamei as Menhaden fish oil, an ingredient known for its adequate nutritional quality to shrimp and fish. This study demonstrated one of the many possible applications of a locally-available resource that is currently being wasted.     

Influence of a joining helix on the BLUF domain of the YcgF photoreceptor from Escherichia coli

BLUF-domain-comprising photoreceptors sense blue light by utilizing FAD as a chromophore. The ycgF gene product of Escherichia coli is composed of a N-terminal BLUF domain and a C-terminal EAL domain, with the latter postulated to catalyze c-di-GMP hydrolysis. The linkage between these two domains involves a predominantly helical segment. Its role on the function of the YcgF photoreceptor domain was examined by characterizing BLUF domains with and without this segment and reconstituting them with either FAD, FMN or riboflavin. The stability of the light-adapted state of the YcgF BLUF domain depends on the presence of this joining, helical segment and the adenosine diphosphate moiety of FAD. In contrast to other BLUF domains, two-dimensional (1)H,(15)N and one-dimensional (1)H NMR spectra of isotope-labeled YcgF-(1-137) revealed large conformational changes during reversion from the light- to the dark-adapted state. Based on these results the function of the joining helix in YcgF during signal transfer and the role of the BLUF domain in regulating c-di-GMP levels is discussed.     

Lipophilic contributions to the solvatochromism of analogous betaines

A pair of solvatochromic phenolate betaines that differed only in their lipophilicity was synthesized. Their solvatochromic responses in pure solvents, in a DMSO–MeOH solvent mixture as well as in micellar solutions were different, an observation which confirmed the fact that sensor lipophilicity contributes to the interpretation of solvatochromism. Quantum mechanical calculations reproduced the observed spectral differences. Molecular dynamics simulations shed light on the solute–solvent interactions responsible for their differences in solvent mixtures.     

Exploiting abstraction relationships'' semantics for transaction synchronization in KBMSs

Currently, knowledge sharing is turning out to be a crucial area that needs to be supported by Knowledge Base Management Systems (KBMSs). We propose an approach for transaction synchronization in KBMSs-LARS (Locks using Abstraction Relationships' Semantics). We show how we obtain serializability of transactions thereby providing different locking granules. The main benefit of our technique is the high degree of potential concurrency, which is obtained by means of a logical partitioning of the knowledge base (KB) grounded in the abstraction relationships, and the provision of many lock types to be used on the basis of each partition. In this way, we capture the abstraction relationships' semantics which are contained in a KB graph for transaction synchronization purposes and enable the exploitation of the inherent parallelism in a knowledge representation approach.