The Phytochemical Composition of Medicinal Plants: Brazilian Semi-Arid Region (Caatinga)

Carnauba wax, the most important vegetable wax under the economic and extracted from the leaves of the carnauba (Copernicia prunifera (Miller) H. E. Moore), is extensively applied in food due to its physiochemical characteristics with a majority of esters. p-Methoxycinnamic acid diesters obtained from the ceriferous powder of carnauba wax (PCO-C) have been associated with biological actions. However, being a versatile product, many types of research have been carried out seeking to expand the possibilities of applications of this raw material. Furthermore, different experimental studies on the pharmacological activities have also been undertaken in recent years and have tested various biological activities, such as hypolipidemic, hypocholesterolemic and hypoglycemic effects in mice. Therefore, in this book chapter, it is reviewing the development of a process of extraction of 4-hydroxycinnamic acid diesters of carnauba wax powder and investigates their biological actions and physical and chemical characteristics

In vitro Assessment of Neonicotinoids and Pyrethroids against Tea Mosquito Bug, Helopeltis antonii Sign. (Hemiptera: Miridae) on Guava

The tea mosquito bug (TMB), Helopeltis antonii, is an emerging pest of horticultural crops, specially on guava and moringa. Insecticides are indispensable component for the management of insect pests. Exploration of new molecules with shortest waiting period may pave way for managing TMB in fruit and vegetable crops with nil/low residue. Until now there are no recommended insecticides available under Central Insecticides Board & Registration Committee (CIB&RC) against TMB on guava. In view of the above facts, new molecules with a low waiting period and are recommended by CIB&RC on tea, viz., Clothianidin 50% WDG, Thiacloprid 21.7% SC, Bifenthrin 10% EC, and Thiamethoxam 12.60% + Lambda-Cyhalothrin 9.5% ZC, were chosen and evaluated against TMB under in vitro condition. Clothianidin 50% WDG recorded the highest mortality of 100.00 per cent at 72 hours after treatment (HAT), and the lowest LC50 value (0.328 ppm, fiducial limits: 0.144-0.515 ppm) and LT50 value (10.49 h, fiducial limits: 5.444-14.551 h), followed by Thiamethoxam 12.60% + Lambda-Cyhalothrin 9.5% ZC, Thiacloprid 21.7% SC, and Bifenthrin 10% EC. The results showed that the Clothianidin 50% WDG and Thiamethoxam 12.60% + Lambda-Cyhalothrin 9.5% ZC, were highly effective, with the lowest LC50 and LT50 values. Since TMB occurs from new flushing to fruiting stage of guava, a minimum of two sprays are mandatory to have quality fruit yield. Hence, application of Clothianidin 50% WDG followed by Thiamethoxam 12.60% + Lambda-Cyhalothrin 9.5% ZC on need basis will help to reduce the impact of TMB on guava

Optimizing Gas-Turbine Operation using Finite-Element CFD Modeling

Gas turbine engines are generally optimized to operate at nearly a fixed speed with fixed blade geometries for the design operating condition. The performance of gas turbine reduces when operated at different operating condition. In this work, we present a parametric study to optimize gas-turbine performance under off-design conditions by articulating the rotor blades in both clockwise and counterclockwise directions. Articulating the pitch angle of turbine blades in coordination with adjustable nozzle vanes can improve performance by maintaining flow incidence angles within the optimum range at certain off-design conditions. To observe the effect of rotor pitching on the performance of the gas turbine, a computational fluid dynamics (CFD) study is performed using the finite element formulation for compressible flows with moving domain. Results obtained from the CFD simulation for different rotor pitch angles are presented in this paper

Experimental Analysis and Material Characterization of Ultra High Temperature Composites

Proceedings of ASME Turbo Expo 2021 Turbomachinery Technical Conference and Exposition GT2021Ultra high temperature ceramic (UHTC) materials have attracted attention for hypersonic applications. Currently there is significant interest in possible gas turbine engine applications of UHTC composites as well. However, many of these materials, such as hafnium carbide, zirconium carbide, and zirconium diboride, have significant oxidation resistance and toughness limitations. In addition, these materials are very difficult to manufacture because of their high melting points. In many cases, SiC powder is incorporated into UHTCs to aid in processing and to enhance fracture toughness. This can also improve the materials’ oxidation resistance at moderately high temperatures due to a crack-healing borosilicate phase. ZrB₂-SiC composites show very good oxidation resistance up to 1700 °C, due to the formation of SiO₂ and ZrO₂ scales in numerous prior studies. While this may limit its application to hypersonic applications (due to reduced thermal conductivity and oxidation resistance at higher temperatures), these UHTC-SiC composites may find applications in turbomachinery, as either stand-alone parts or as a component in a multi-layer system.This research was supported in part by an appointment to the Postdoctoral Research Participation Program at the U.S. Army Research Laboratory administered by the Oak Ridge Associated Universities through an interagency agreement between the U.S. Department of Energy and DEVCOM ARL. Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-16-2-0008. The first author would like to acknowledge the support of DoD Laboratory University Collaborative Initiative (LUCI) Fellowship [2016-2019]. The UHTC specimen fabrication via Spark Plasma Sintering processing was done at UCSD by UCSD and DEVCOM ARL. The ablation experimental testing was conducted at DEVCOM ARL. The microstructure analysis and characterization were performed at NPS.W911NF-16-2-000

Microstructure Based Material-Sand Particulate Interactions and Assessment of Coatings for High Temperature Turbine Blades

Gas turbine engines for military/commercial fixed-wing and rotary wing aircraft use thermal barrier coatings in the high-temperature sections of the engine for improved efficiency and power. The desire to further make improvements in gas turbine engine efficiency and high power-density is driving the research and development of thermal barrier coatings and the effort of improving their tolerance to fine foreign particulates that may be contained in the intake air. Both commercial and military aircraft engines often are required to operate over sandy regions such as in the Middle-East nations, as well as over volcanic zones. For rotorcraft gas turbine engines, the sand ingestion is adverse during take-off, hovering near ground, and landing conditions. Although, most of the rotorcraft gas turbine engines are fitted with inlet particle separators, they are not 100 percent efficient in filtering fine sand particles of size 75 microns or below. The presence of these fine solid particles in the working fluid medium has an adverse effect on the durability of turbine blade thermal barrier coatings and overall performance of the engine. Typical turbine blade damages include blade coating wear, sand glazing, Calcia-Magnesia-Alumina-Silicate (CMAS) attack, oxidation, plugged cooling holes, all of which can cause rapid performance deterioration including loss of aircraft. The objective of this research is to understand the fine particle interactions with typical ceramic coatings of turbine blades at the microstructure level. A finite-element based microstructure modeling and analysis has been performed to investigate particle-surface interactions, and restitution characteristics. Experimentally, a set of tailored thermal barrier coatings and surface treatments were down-selected through hot burner rig tests and then applied to first stage nozzle vanes of the Gas Generator Turbine of a typical rotorcraft gas turbine engine. Laser Doppler velocity measurements were performed during hot burner rig testing to determine sand particle incoming velocities and their rebound characteristics upon impact on coated material targets. Further, engine sand ingestion tests were carried out to test the CMAS tolerance of the coated nozzle vanes. The findings from this on-going collaborative research to develop the next-gen sand tolerant coatings for turbine blades are presented in this paper

Interfacial characteristics and microstructural evolution of ceramics exposed to high temperature sand laden combustion environments

Sand laden combustion environments are a current challenge plaguing ceramic thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs) on metallic and emerging ceramic matrix composite (CMC) turbomachinery components. Exposure of thermal and environmental barrier coatings on ceramic matrix composites to environmental particulate laden deteriorates the ceramic structure via chemical reactions and infiltration into pore structures. The challenge of environmental particulates, collectively referred to as calcium-magnesium-aluminosilicate (CMAS), is expected to be exacerbated in future components that utilize ceramic matric composites (CMCs), since the higher operating temperatures will accelerate particulate melting, infiltration, and diffusion kinetics. This study first presents efforts at ARL to develop sandphobic coatings resistant to CMAS infiltration and deposition. The results of a recent full scale sand ingestion engine test used to evaluate several ARL layered and blended coating compositions are presented. The study also includes the evaluation of interactions of CMAS plasma sprayed environmental barrier coatings and HfO2-Si bond coats on SiC/SiC CMCs in rig simulated engine test conditions. The focus is on the microstructural evolution of the coatings and the interfacial characteristics between the TBCs and EBCs and CMAS. Interfaces between coating constituents are also of interest in order to tailor coatings with superior thermal, structural, and chemical characteristics. Controlled studies on YSZ-based ceramic compacts are also performed in order to gain a more fundamental understanding of the effect of porosity on infiltration kinetics, as well as the nature of interfaces and interfacial products wrought by CMAS infiltration into YSZ ceramic grain boundaries. These model studies on YSZ are conducted by immersing the ceramic compacts into AFRL-02 sand and exposing the system to temperatures of up to 1300 °C. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, electron back scattered diffraction, and focused ion beam (milling and imaging) are utilized for microstructural and interfacial characterization of the CMAS reacted thermal and environmental barrier coating systems

High Temperature Ceramic Microstructure and Interface Evolution during Exposure to Particulate Laden Combustion Flows in Gas Turbine Engines

Objective: To innovate sandphobic coating and surface modification for high temperature turbine blades to resist sand glaze build-up and related Calcia-Magnesia-Alumina-Silicate (CMAS) attack on Thermal/Environmental Barrier Coatings (T/EBCs)

Embedded Temperature Sensor Evaluations for Turbomachinery Component Health Monitoring

Current rotorcraft gas turbine engines typically use titanium alloys and steel for the compressor section and single-crystal nickel superalloys for the hot-section turbine stator vanes and rotor blades. However, these material selections are rapidly changing due to increased requirements of power-density and efficiency. Future U.S. Army gas turbine engines will be using ceramic matrix composites for many high temperature engine components due to their low density and improved durability in high temperature environments. The gas turbine industry is also actively developing adaptive concept technologies for production and assembly of modular gas turbine engine components with integrated sensing. In order to actively monitor engine components for extended seamless operation and improved reliability, it is essential to have intelligent embedded sensing to monitor the health of critical components in engines. Under this U.S. Army Foreign Technology Assessment Support (FTAS) program funded research project, embedded fiber-optic temperature sensors from U.K.-based company, Epsilon Optics Ltd (Fordingbridge, UK)., were experimentally evaluated to measure temperature responses on typical turbomachinery component material coupons. The temperature responses from this foreign technology sensor were assessed using a thermomechanical fatigue tester with a built-in furnace to conduct thermal cycling durability experiments. The experimental results obtained from the durability performance of this embedded fiber Bragg sensor are reported in this paper. This sensor technology, upon maturation to higher TRL (technology readiness level), can greatly reduce the lifecycle cost of future U.S. Army gas turbine engines

Embedded Temperature Sensor Evaluations for Turbomachinery Component Health Monitoring

Current rotorcraft gas turbine engines typically use titanium alloys and steel for the compressor section and single-crystal nickel superalloys for the hot-section turbine stator vanes and rotor blades. However, these material selections are rapidly changing due to increased requirements of power-density and efficiency. Future U.S. Army gas turbine engines will be using ceramic matrix composites for many high temperature engine components due to their low density and improved durability in high temperature environments. The gas turbine industry is also actively developing adaptive concept technologies for production and assembly of modular gas turbine engine components with integrated sensing. In order to actively monitor engine components for extended seamless operation and improved reliability, it is essential to have intelligent embedded sensing to monitor the health of critical components in engines. Under this U.S. Army Foreign Technology Assessment Support (FTAS) program funded research project, embedded fiber-optic temperature sensors from U.K.-based company, Epsilon Optics Ltd (Fordingbridge, UK)., were experimentally evaluated to measure temperature responses on typical turbomachinery component material coupons. The temperature responses from this foreign technology sensor were assessed using a thermomechanical fatigue tester with a built-in furnace to conduct thermal cycling durability experiments. The experimental results obtained from the durability performance of this embedded fiber Bragg sensor are reported in this paper. This sensor technology, upon maturation to higher TRL (technology readiness level), can greatly reduce the lifecycle cost of future U.S. Army gas turbine engines

Analytical Evaluation of Generalized Predictive Control Algorithms Using a Full Vehicle Multi-Body Dynamics Model For Mobility Enhancement

<p>ABSTRACT: This paper discusses research conducted by the U.S. Army Research Laboratory (ARL) - Vehicle Technology Directorate (VTD) on advanced suspension control. ARL-VTD has conducted research on advanced<br>suspension systems that will reduce the chassis vibration of ground vehicles while maintaining tire contact with the road surface. The purpose of this research is to reduce vibration-induced fatigue to the Warfighter as well as to improve the target aiming precision in-theater. The objective of this paper was to explore the performance effectiveness of various formulations of the Generalized Predictive Control (GPC) algorithm in a simulation<br>environment. Each version of the control algorithm was applied to an identical model subjected to the same<br>ground disturbance input and compared to a baseline passive suspension system. The control algorithms<br>considered include a GPC with Implicit Disturbances, GPC with Explicit Disturbances, and GPC with Preview<br>Control. A two-axle tactical vehicle with independent front and rear suspensions was modeled in the TruckSim<br>full-vehicle dynamics simulator. The control algorithms were compared based on their effectiveness in controlling peak acceleration and overall average acceleration over a range of vehicle speeds. The algorithms demonstrated significant reductions in the chassis acceleration and pitch of the full-vehicle model. Keywords: Vehicle vibration control, vehicle dynamics simulation, control algorithm, advanced suspension, generalized predictive control.</p> <p> </p