Sandblasting nozzle

A nozzle for use with abrasive and/or corrosive materials is formed of sintered ceramic compositions having high temperature oxidation resistance, high hardness and high abrasion and corrosion resistance. The ceramic may be a binary solid solution of a ceramic oxide and silicon nitride, and preferably a ternary solid solution of a ceramic oxide, silicon nitride and aluminum nitride. The ceramic oxide is selected from a group consisting of Al2O3, Y2O3 and Cr2O3, or mixtures of those compounds. Titanium carbide particles are dispersed in the ceramic mixture before sintering. The nozzles are encased for protection from external forces while in use by a metal or plastic casing

Experimental Evaluation of Steady-State Control Properties of an Electron-Bombardment Ion Thrustor

Examined in this report are the experimental steady-state gains, or changes, in beam-current output with changes in thrustor inputs for a 10-centimeter-diameter electron-bombardment ion thrustor. A general leveling off of beam current as a function of an input variable was found at the upper range of each variable, At the design operating point, the filament-heating current exhibited the greatest sensitivity, or percentage beam-current output change for a percentage change in the input (2 to 4). Accelerator voltage showed the least effect (0.04) while discharge voltage, magnetic field, and neutral propellant flow exhibited about the same sensitivity (0.4 to 0.5). Some effects of nonlinearity are shown that may require consideration in the design of a closed-loop control system

Liquid crystal hyperbolic metamaterial for wide-angle negative-positive refraction and reflection

We show that nanosphere dispersed liquid crystal (NDLC) metamaterial can be characterized in near IR spectral region as an indefinite medium whose real parts of effective ordinary and extraordinary permittivities are opposite in signs. Based on this fact we design a novel electrooptic effect: external electric field driven switch between normal refraction, negative refraction and reflection of TM incident electromagnetic wave from the boundary vacuum/NDLC. A detailed analysis of its functionality is given based on effective medium theory combined with a study of negative refraction in anisotropic metamaterials, and Finite Elements simulations

Solar electric propulsion system tests

Design and performance of solar-powered electric propulsion system for interplanetary space exploratio

Young's Moduli of Cold and Vacuum Plasma Sprayed Metallic Coatings

Monolithic metallic copper alloy and NiCrAlY coatings were fabricated by either the cold spray (CS) or the vacuum plasma spray (VPS) deposition processes. Dynamic elastic modulus property measurements were conducted on these monolithic coating specimens between 300 K and 1273 K using the impulse excitation technique. The Young's moduli decreased almost linearly with increasing temperature at all temperatures except in the case of the CS Cu-23%Cr-5%Al and VPS NiCrAlY, where deviations from linearity were observed above a critical temperature. It was observed that the Young's moduli for VPS Cu-8%Cr were larger than literature data compiled for Cu. The addition of 1%Al to Cu- 8%Cr significantly increased its Young's modulus by 12 to 17% presumably due to a solid solution effect. Comparisons of the Young s moduli data between two different measurements on the same CS Cu- 23%Cr-5%Al specimen revealed that the values measured in the first run were about 10% higher than those in the second run. It is suggested that this observation is due to annealing of the initial cold work microstructure resulting form the cold spray deposition process

Magnetization Reversal Processes in the Nanocrystalline Fe-Co-Zr-Ti-Pr-B Magnets

Magnetization reversal processes in the magnets derived from the Fe 60 Co 13 Zr 1 Ti 3 Pr 9 B 14 alloy were investigated. It was shown that the processing technique affects the magnetization reversal processes. For the nanocrystalline ribbon samples pinning of the domain walls arises at low external magnetic fields while nucleation of reversed domains occurs at higher fields. However, the nucleation fields are lower than the pinning fields for the nanocrystalline rod and tube samples produced by suction-casting technique

Monte Carlo study of tunable negative-zero-positive index of refraction in nanosphere dispersed liquid crystals

Khoo et al.1, 2 have shown that nanosphere dispersed nematic liquid crystal (NDLC) constitutes a new type of metamaterial with index of refraction tunable from negative to positive values. Recently3 we have combined this approach with Monte Carlo simulations of inhomogeneous molecular order in planar NLC cells. Lebwohl - Lasher effective hamiltonian with Rapini - Papoular term for anchoring forces was used. Electric field and amplitude of anchoring forces are control parameters which determine the profiles of order parameter. In this paper we study, using the same approach, local spatial distribution of refractive index in NDLC planar cell. We show that NDLC material consists of layers with negative-zero-positive index of refraction. The spatial organization of those layers strongly depends on incident light wavelength. The role of spatially modulated external electric field for tuning of refractive index of NDLC is briefly discussed

The role of the light source in antimicrobial photodynamic therapy

This work was financially supported by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant (agreement no. 764837) and NCN Opus grant no. 2019/35/B/ST4/03280. We are also grateful to the Engineering and Physical Sciences Research Council of the UK for financial support from grants EP/R511778/1 and EP/L015110/1.Antimicrobial photodynamic therapy (APDT) is a promising approach to fight the growing problem of antimicrobial resistance that threatens health care, food security and agriculture. APDT uses light to excite a light-activated chemical (photosensitiser), leading to the generation of reactive oxygen species (ROS). Many APDT studies confirm its efficacy in vitro and in vivo against bacteria, fungi, viruses and parasites. However, the development of the field is focused on exploring potential targets and developing new photosensitisers. The role of light, a crucial element for ROS production, has been neglected. What are the main parameters essential for effective photosensitiser activation? Does an optimal light radiant exposure exist? And finally, which light source is best? Many reports have described the promising antibacterial effects of APDT in vitro, however, its application in vivo, especially in clinical settings remains very limited. The restricted availability may partially be due to a lack of standard conditions or protocols, arising from the diversity of selected photosensitising agents (PS), variable testing conditions including light sources used for PS activation and methods of measuring anti-bacterial activity and their effectiveness in treating bacterial infections. We thus sought to systematically review and examine the evidence from existing studies on APDT associated with the light source used. We show how the reduction of pathogens depends on the light source applied, radiant exposure and irradiance of light used, and type of pathogen, and so critically appraise the current state of development of APDT and areas to be addressed in future studies. We anticipate that further standardisation of the experimental conditions will help the field advance, and suggest key optical and biological parameters that should be reported in all APDT studies. More in vivo and clinical studies are needed and are expected to be facilitated by advances in light sources, leading to APDT becoming a sustainable, alternative therapeutic option for bacterial and other microbial infections in the future.Publisher PDFPeer reviewe

Hydrologic and Water Quality Monitoring on Turkey Creek Watershed, Francis Marion National Forest, SC

2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio