Microstructure and wear resistance of spray-formed supermartensitic stainless steel

Directory of Open Access Journals (Sweden)

Guilherme Zepon

2013-06-01

Full Text Available Since the early 90's the oil industry has been encouraging the development of corrosion and wear resistant alloys for onshore and offshore pipeline applications. In this context supermartensitic stainless steel was introduced to replace the more expensive duplex stainless steel for tubing applications. Despite the outstanding corrosion resistance of stainless steels, their wear resistance is of concern. Some authors reported obtaining material processed by spray forming, such as ferritic stainless steel, superduplex stainless steel modified with boron, and iron-based amorphous alloys, which presented high wear resistance while maintaining the corrosion performance1,2. The addition of boron to iron-based alloys promotes the formation of hard boride particles (M2B type which improve their wear resistances3-9. This work aimed to study the microstructure and wear resistance of supermartensitic stainless steel modified with 0.3 wt. (% and 0.7 wt. (% processed by spray forming (SF-SMSS 0.3%B and SF-SMSS 0.7%B, respectively. These boron contents were selected in order to improve the wear resistance of supermartensitic stainless steel through the formation of uniformly distributed borides maintaining the characteristics of the corrosion resistant matrix. SF-SMSS 0.7%B presents an abrasive wear resistance considerably higher than spray-formed supermartensitic stainless steel without boron addition (SF-SMSS.

Vision-aided Monitoring and Control of Thermal Spray, Spray Forming, and Welding Processes

Science.gov (United States)

Agapakis, John E.; Bolstad, Jon

1993-01-01

Vision is one of the most powerful forms of non-contact sensing for monitoring and control of manufacturing processes. However, processes involving an arc plasma or flame such as welding or thermal spraying pose particularly challenging problems to conventional vision sensing and processing techniques. The arc or plasma is not typically limited to a single spectral region and thus cannot be easily filtered out optically. This paper presents an innovative vision sensing system that uses intense stroboscopic illumination to overpower the arc light and produce a video image that is free of arc light or glare and dedicated image processing and analysis schemes that can enhance the video images or extract features of interest and produce quantitative process measures which can be used for process monitoring and control. Results of two SBIR programs sponsored by NASA and DOE and focusing on the application of this innovative vision sensing and processing technology to thermal spraying and welding process monitoring and control are discussed.

The effect of particles in different sizes on the mechanical properties of spray formed steel composites

DEFF Research Database (Denmark)

Petersen, Kenneth; Pedersen, A. S.; Pryds, N.

2000-01-01

particle size of 46 and 134 μm were carried out with respect to their mechanical properties e.g. wear resistance and tensile strength. It was found that the addition of Al2O3 particles to the steel improves its wear properties and reduces the elongation and tensile strength of the material......The main objective of the work was to investigate the effect of addition of ceramic particles with different size distributions on the mechanical properties, e.g. wear resistance and tensile strength, of spray formed materials. The experiments were carried out in a spray-forming unit at Risø...... National Laboratory, Denmark, where composites with a low alloyed boron steel (0.2 wt.% carbon) matrix containing alumina particles were produced. A comparison between cast hot-rolled material without particles, spray formed material without particles and the spray formed composites with an average ceramic...

Improved the microstructures and properties of M3:2 high-speed steel by spray forming and niobium alloying

Energy Technology Data Exchange (ETDEWEB)

Lu, L. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Xueyuan Road 30, Haidian District, Beijing 100083 (China); Hou, L.G., E-mail: lghou@skl.ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Xueyuan Road 30, Haidian District, Beijing 100083 (China); Zhang, J.X.; Wang, H.B.; Cui, H.; Huang, J.F. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Xueyuan Road 30, Haidian District, Beijing 100083 (China); Zhang, Y.A. [State Key Laboratory of Non-Ferrous Metals and Process, General Research Institute for Non-Ferrous Metals, Beijing 100088 (China); Zhang, J.S. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Xueyuan Road 30, Haidian District, Beijing 100083 (China)

2016-07-15

The microstructures and properties of spray formed (SF) high-speed steels (HSSs) with or without niobium (Nb) addition were studied. Particular emphasis was placed on the effect of Nb on the solidification microstructures, decomposition of M{sub 2}C carbides, thermal stability and mechanical properties. The results show that spray forming can refine the cell size of eutectic carbides due to the rapid cooling effect during atomization. With Nb addition, further refinement of the eutectic carbides and primary austenite grains are obtained. Moreover, the Nb addition can accelerate the decomposition of M{sub 2}C carbides and increase the thermal stability of high-speed steel, and also can improve the hardness and bending strength with slightly decrease the impact toughness. The high-speed steel made by spray forming and Nb alloying can give a better tool performance compared with powder metallurgy M3:2 and commercial AISI M2 high-speed steels. - Highlights: • Spray forming can effectively refine the microstructure of M3:2 steel. • Niobium accelerates the decomposition of M{sub 2}C carbides. • Niobium increases the hardness and bending strength of spray formed M3:2 steel. • Spray-formed niobium-containing M3:2 steel has the best tool performance.

Machining tools in AISI M2 high-speed steel obtained by spray forming process; Ferramentas de usinagem em aco rapido AISI M2 obtido por conformacao por 'spray'

Energy Technology Data Exchange (ETDEWEB)

Jesus, Edilson Rosa Barbosa de. E-mail: erbjesus@usp.br

2004-07-01

The aim of the present work was the obtention of AISI M2 high-speed steel by spray forming technique and the material evaluation when used as machining tool. The obtained material was hot rolled at 50% and 72% reduction ratios, and from which it was manufactured inserts for machining tests. The performance of inserts made of the spray formed material was compared to inserts obtained from conventional and powder metallurgy (MP) processed materials. The spray formed material was chemical, physical, mechanical and microstructural characterised. For further characterisation, the materials were submitted to machining tests for performance evaluation under real work condition. The results of material characterisation highlight the potential of the spray forming technique, in the obtention of materials with good characteristics and properties. Under the current processing, hot rolling and heat treatments condition, the analysis of the results of the machining tests revealed a very similar behaviour among the tested materials. Proceeding a criterious analysis of the machining results tests, it was verified that the performance presented by the powder metallurgy material (MP) was slight superior, followed by conventional obtained material (MConv), which presented a insignificant advantage over the spray formed and hot rolled (72% reduction ratio) material. The worst result was encountered for the spray forming and hot rolled (50% reduction ratio) material that presented the highest wear values. (author)

An Integrated Numerical Model of the Spray Forming Process

DEFF Research Database (Denmark)

Pryds, Nini; Hattel, Jesper; Pedersen, Trine Bjerre

2002-01-01

of the deposition model is accomplished using a 2D cylindrical heat flow model. This model is now coupled with an atomization model via a log-normal droplet size distribution. The coupling between the atomization and the deposition is accomplished by ensuring that the total droplet size distribution of the spray......In this paper, an integrated approach for modelling the entire spray forming process is presented. The basis for the analysis is a recently developed model which extents previous studies and includes the interaction between an array of droplets and the enveloping gas. The formulation...... is in fact the summation of 'local' droplet size distributions along the r-axis. A key parameter, which determines the yield and the shape of the deposit material, is the sticking efficiency. The sticking phenomenon is therefore incorporated into the deposition model. (C) 2002 Acta Materialia Inc. Published...

Spray forming and mechanical properties of a new type powder metallurgy superalloy

International Nuclear Information System (INIS)

Jia Chong-Lin; Ge Chang-Chun; Xia Min; Gu Tian-Fu

2015-01-01

The deposited billet of a new type powder metallurgy (PM) superalloy FGH4095M for use in turbine disk manufacturing has been fabricated using spray forming technology. The metallurgical quality of the deposited billet was analyzed in terms of density, texture, and grain size. Comparative research was done on the microstructure and mechanical properties between the flat disk preform prepared with hot isostatic pressing (HIP) and the same alloy forgings prepared with HIP followed by isothermal forging (IF). The results show that the density of the spray-formed and nitrogen-atomized deposit billet is above 99% of the theoretical density, indicating a compact structure. The grains are uniform and fine. The billet has weak texture with a random distribution in the spray deposition direction and perpendicular to the direction of deposition. A part of atomizing nitrogen exists in the preform in the form of carbonitride. Nitrogen-induced microporosity causes the density reduction of the preform. Compared with the process of HIP+IF, the superalloy FGH4095M after HIP has better mechanical properties at both room temperature and high temperature. The sizes of the γ′ phase are finer in microstructure of the preform after HIP in comparison with the forgings after HIP+IF. This work shows that SF+HIP is a viable processing route for FGH4095M as a turbine-disk material. (paper)

An Integrated Approach for the Numerical Modelling of the Spray Forming Process

DEFF Research Database (Denmark)

Hattel, Jesper; Thorborg, Jesper; Pryds, Nini

2003-01-01

In this paper, an integrated approach for modelling the entire spray forming process is presented. The basis for the analysis is a recently developed model which extents previous studies and includes the interaction between an array of droplets and the enveloping gas. The formulation of the depos......In this paper, an integrated approach for modelling the entire spray forming process is presented. The basis for the analysis is a recently developed model which extents previous studies and includes the interaction between an array of droplets and the enveloping gas. The formulation...... is in fact the summation of "local" droplet size distributions along the r-axis. Furthermore, the deposition model proposed in the paper involves both the sticking efficiency of the droplets to the substrate as well as a geometrical model involving the effects of shadowing for the production of billet...

SPRAY CASTING

OpenAIRE

SALAMCI, Elmas

2010-01-01

ABSTRACT This paper is designed to provide a basic review of spray casting. A brief overview of the historical development of spray  casting and the description of plant and equipment have been given. Following metallurgical characteristics of spray formed alloys, process parameters and solidification mechanism of spray deposition have been discussed in detail. Finally, microstructure and mechanical properties of the selected spray cast Al-Zn-Mg-Cu alloys have been presented and comp...

X-ray photoelectron spectroscopy study of the passive films formed on thermally sprayed and wrought Inconel 625

Energy Technology Data Exchange (ETDEWEB)

Bakare, M.S. [Materials, Mechanics and Structures Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Voisey, K.T., E-mail: Katy.voisey@nottingham.ac.uk [Materials, Mechanics and Structures Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Roe, M.J.; McCartney, D.G. [Materials, Mechanics and Structures Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom)

2010-11-15

There is a well known performance gap in corrosion resistance between thermally sprayed corrosion resistant coatings and the equivalent bulk materials. Interconnected porosity has an important and well known effect, however there are additional relevant microstructural effects. Previous work has shown that a compositional difference exists between the regions of resolidified and non-melted material that exist in the as-sprayed coatings. The resolidified regions are depleted in oxide forming elements due to formation of oxides during coating deposition. Formation of galvanic cells between these different regions is believed to decrease the corrosion resistance of the coating. In order to increase understanding of the details of this effect, this work uses X-ray photoelectron spectroscopy (XPS) to study the passive films formed on thermally sprayed coatings (HVOF) and bulk Inconel 625, a commercially available corrosion resistant Ni-Cr-Mo-Nb alloy. Passive films produced by potentiodynamic scanning to 400 mV in 0.5 M sulphuric acid were compared with air-formed films. The poorer corrosion performance of the thermally sprayed coatings was attributed to Ni(OH){sub 2}, which forms a loose, non-adherent and therefore non-protective film. The good corrosion resistance of wrought Inconel 625 is due to formation of Cr, Mo and Nb oxides.

On the prediction of spray angle of liquid-liquid pintle injectors

Science.gov (United States)

Cheng, Peng; Li, Qinglian; Xu, Shun; Kang, Zhongtao

2017-09-01

The pintle injector is famous for its capability of deep throttling and low cost. However, the pintle injector has been seldom investigated. To get a good prediction of the spray angle of liquid-liquid pintle injectors, theoretical analysis, numerical simulations and experiments were conducted. Under the hypothesis of incompressible and inviscid flow, a spray angle formula was deduced from the continuity and momentum equations based on a control volume analysis. The formula was then validated by numerical and experimental data. The results indicates that both geometric and injection parameters affect the total momentum ratio (TMR) and then influence the spray angle formed by liquid-liquid pintle injectors. TMR is the pivotal non-dimensional number that dominates the spray angle. Compared with gas-gas pintle injectors, spray angle formed by liquid-liquid injectors is larger, which benefits from the local high pressure zone near the pintle wall caused by the impingement of radial and axial sheets.

Method of forming a leak proof plasma sprayed interconnection layer on an electrode of an electrochemical cell

Science.gov (United States)

Kuo, Lewis J. H.; Vora, Shailesh D.

1995-01-01

A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an electrode structure of an electrochemical cell by: (A) providing an electrode structure; (B) forming on a selected portion of the electrode surface, an interconnection layer having the general formula La.sub.1-x M.sub.x Cr.sub.1-y N.sub.y O.sub.3, where M is a dopant selected from the group of Ca, Sr, Ba, and mixtures thereof, and where N is a dopant selected from the group of Mg, Co, Ni, Al, and mixtures thereof, and where x and y are each independently about 0.075-0.25, by thermally spraying, preferably plasma arc spraying, a flux added interconnection spray powder, preferably agglomerated, the flux added powder comprising flux particles, preferably including dopant, preferably (CaO).sub.12. (Al.sub.2 O.sub.3).sub.7 flux particles including Ca and Al dopant, and LaCrO.sub.3 interconnection particles, preferably undoped LaCrO.sub.3, to form a dense and substantially gas-tight interconnection material bonded to the electrode structure by a single plasma spraying step; and, (C) heat treating the interconnection layer at from about 1200.degree. to 1350.degree. C. to further densify and heal the micro-cracks and macro-cracks of the thermally sprayed interconnection layer. The result is a substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode structure. The electrode structure can be an air electrode, and a solid electrolyte layer can be applied to the unselected portion of the air electrode, and further a fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell for generation of electrical power.

Spray forming: A numerical investigation of the influence of the gas to melt ratio on the billet surface temperature

DEFF Research Database (Denmark)

Pryds, Nini; Hattel, Jesper

2005-01-01

atomisation taking thermal coupling into consideration and the deposition of material at the surface of the billet taking geometrical aspects such as shading into account. The coupling between these two models is accomplished by ensuring that the total droplet size distribution of the spray is the summation......The relationship between the Gas to Melt Ratio (GMR) and the surface temperature of an evolving billet surface in spray forming is investigated numerically. The basis for the analysis is an integrated approach for modelling the entire spray forming process. This model includes the droplet...... of "local" droplet size distributions along the r-axis of the spray cone. The criterion for a successful process has been a predefined process window characterised by a desired fraction solid range at a certain distance from the atomizer. Inside this process window, the gas and melt flows have been varied...

Microstructural features and heat flow analysis of atomized and spray-formed Al-Fe-V-Si alloy

International Nuclear Information System (INIS)

Srivastava, A.K.; Ranganathan, S.; Ojha, S.N.

1998-01-01

Microstructural features of rapidly solidified powders and preforms of Al 80 Fe 10 V 4 Si 6 alloy produced by spray forming process have been studied. The atomization and spray deposition were carried out using a confined gas atomization process and the microstructural features were characterized using scanning electron microscopy and transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. The microstructure of a wide size range of atomized powders invariably revealed cellular and dendritic morphology. The extent of dendritic region and the dendritic arm spacing were observed to increase with power particle size. The TEM investigations indicated the presence of ultrafine second-phase particles in the intercellular or interdendritic regions. In contrast, the spray deposits of the alloy showed considerable variation in microstructure and size and dispersion of the second-phase particles at specific distances from the deposit-substrate interface and the exterior regions of the deposit. Nevertheless, considerable homogeneity was observed in the microstructure toward the center of the spray deposit. The formation and distribution of a cubic phase α-Al(Fe, V)Si has been characterized in both atomized powders and spray deposits. A one-dimensional heat flow model has been used to analyze the evolution of microstructure during atomization and also during spray deposition processing of this alloy. The results indicate that thermal history of droplets in the spray on deposition surface and their solidification behavior considerably influence the microstructural features of the spray deposits

Relating porosity and mechanical properties in spray formed tubulars

International Nuclear Information System (INIS)

Payne, R.D.; Naval Surface Warfare Center, Annapolis, MD; Moran, A.L.; United States Naval Academy, Annapolis, MD; Cammarata, R.C.

1993-01-01

Because the spray forming process holds the potential to reduce the cost of alloy production, there is significant interest in developing methods to industrialized and automate this process through advanced sensing techniques. These advanced sensing techniques will observe the process real-time and give inputs to a process controller. By determining relationships between part quality, process parameters and sensor inputs, the process controller will be able to determine the quality of a part while it is being made and make adjustments if necessary. A Tinius-Olsen Tensile Tester was used to test five tensile specimens. The five tensile specimens were taken from five alloy 625 (60% Ni, 20% Cr, 8%Mo, 5% Fe) tubulars with varying properties. Among the advanced sensing techniques currently used to monitor the spray forming process is a surface roughness sensor. It consists of an argon laser, a charge coupled device (CCD) camera and roughness determination software. The laser emission is expanded into a long, thin line and projected onto the substrate as the molten metal consolidates on the surface. The roughness determination software will grab a frame with the laser stripe, digitize it and calculate the root mean square (RMS) value of the roughness in that particular frame. Each frame has a time stamp and can be related back to other time stamped process parameters. Recent sensor work has tried to find correlations between RMS values and porosities determined after processing. This venture has met with limited success. The object of this paper is to link porosity with mechanical properties and therefore define quality. Eventually the input from all sensors and process parameters will be entered into a process controller. If there is a link between sensor data and quality, this controller will be able to determine the quality of a forming material from sensor inputs and make changes in the process parameters if the quality is poor

Hardening mechanisms of spray formed Al-Zn-Mg-Cu alloys with scandium and other elemental additions

International Nuclear Information System (INIS)

Sharma, M.M.; Amateau, M.F.; Eden, T.J.

2006-01-01

The hardening mechanisms in spray formed Al-Zn-Mg-Cu alloys with additions of chromium, zinc and scandium were studied. The microstructure of the spray formed alloys was analyzed by transmission electron microscopy. A range of tensile strengths were achieved, and varied based on elemental additions, and second phase particle strengthening. To explain the significantly higher strength in one alloy with scandium, theoretical results due to the yield stress of Al-Zn-Mg-Cu alloys as a function of volume fraction and precipitate particle size, were compared to experimental data. Both the possibilities of coherency and order strengthening are examined. The significant additional hardening achieved in the alloy with scandium is attributed to small ordered particles of Al 3 Sc, which precipitated during aging

Design and performance of a full-scale spray calciner for nonradioactive high-level-waste-vitrification studies

International Nuclear Information System (INIS)

Miller, F.A.

1981-06-01

In the spray calcination process, liquid waste is spray-dried in a heated-wall spray dryer (termed a spray calciner), and then it may be combined in solid form with a glass-forming frit. This mixture is then melted in a continuous ceramic melter or in an in-can melter. Several sizes of spray calciners have been tested at PNL- laboratory scale, pilot scale and full scale. Summarized here is the experience gained during the operation of PNL's full-scale spray calciner, which has solidified approx. 38,000 L of simulated acid wastes and approx. 352,000 L of simulated neutralized wastes in 1830 h of processing time. Operating principles, operating experience, design aspects, and system descriptions of a full-scale spray calciner are discussed. Individual test run summaries are given in Appendix A. Appendices B and C are studies made by Bechtel Inc., under contract by PNL. These studies concern, respectively, feed systems for the spray calciner process and a spray calciner vibration analysis. Appendix D is a detailed structural analysis made at PNL of the spray calciner. These appendices are included in the report to provide a complete description of the spray calciner and to include all major studies made concerning PNL's full-scale spray calciner

Cold spray nozzle design

Science.gov (United States)

Haynes, Jeffrey D [Stuart, FL; Sanders, Stuart A [Palm Beach Gardens, FL

2009-06-09

A nozzle for use in a cold spray technique is described. The nozzle has a passageway for spraying a powder material, the passageway having a converging section and a diverging section, and at least the diverging section being formed from polybenzimidazole. In one embodiment of the nozzle, the converging section is also formed from polybenzimidazole.

Method of forming a plasma sprayed interconnection layer on an electrode of an electrochemical cell

Science.gov (United States)

Spengler, Charles J.; Folser, George R.; Vora, Shailesh D.; Kuo, Lewis; Richards, Von L.

1995-01-01

A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO.sub.3 powder, preferably compensated with chromium as Cr.sub.2 O.sub.3 and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO.sub.3 layer to about 1100.degree. C. to 1300.degree. C. to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the unselected portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell.

Layered growth with bottom-spray granulation for spray deposition of drug.

Science.gov (United States)

Er, Dawn Z L; Liew, Celine V; Heng, Paul W S

2009-07-30

The gap in scientific knowledge on bottom-spray fluidized bed granulation has emphasized the need for more studies in this area. This paper comparatively studied the applicability of a modified bottom-spray process and the conventional top-spray process for the spray deposition of a micronized drug during granulation. The differences in circulation pattern, mode of growth and resultant granule properties between the two processes were highlighted. The more ordered and consistent circulation pattern of particles in a bottom-spray fluidized bed was observed to give rise to layered granule growth. This resulted in better drug content uniformity among the granule batches and within a granule batch. The processes' sensitivities to wetting and feed material characteristics were also compared and found to differ markedly. Less robustness to differing process conditions was observed for the top-spray process. The resultant bottom-spray granules formed were observed to be less porous, more spherical and had good flow properties. The bottom-spray technique can thus be potentially applied for the spray deposition of drug during granulation and was observed to be a good alternative to the conventional technique for preparing granules.

Microstructural characterization of spray formed Fe-based amorfizable alloy; Caracterizacao microestrutural de ligas ferrosas amorfizaveis processadas por conformacao por spray

Energy Technology Data Exchange (ETDEWEB)

Gabriel, A.H.G.; Ananias, M.Jr. da S.; Lucena, F.A.; Santos, L.S. dos; Bolfarini, C.; Botta, W.J.; Kiminami, C.S.; Afonso, C.R.M., E-mail: guimaraes.andreh@gmail.com [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil)

2014-07-01

Iron-based amorphous alloys show outstanding characteristics such as high hardness and wear resistance, with microstructure partially amorphous, making them favorable to spray forming process (SF), which has cooling rates between 10{sup 3}-10{sup 5} K/s. Thus, this work aims to use the SF in one of the alloy cast iron present in this project, being chosen the alloy with a better set of results, through the performed characterizations. The alloys studied in this project were: (Fe{sub 65}Cr{sub 17}Mo{sub 2}C{sub 14}Si{sub 1}Cu{sub 1}){sub 100-x}B{sub x} (x = 5, 8 and 12% at) and (Fe{sub 65}Cr{sub 17}Mo{sub 2}C{sub 14}Si{sub 1}Cu{sub 1}){sub 88}Nb{sub 4}B{sub 8} (at.%), being all processed through Discovery® Plasma and 'melt- spinning' and characterized using: TEM, SEM, DSC, XRD and microhardness test. The cast iron alloy selected were (Fe{sub 65}Cr{sub 17}Mo{sub 2}C{sub 14}Si{sub 1}Cu{sub 1}){sub 88}Nb{sub 4}B+8, getting by the spray forming process, deposit and overspray powder. With them, were realized almost the same characterizations, except for the TEM. The results showed 1044±102 (HV1) in Vickers microhardness and nanocrystalline overspray powder from 20-45 μm to > 180 μm. (author)

Some continual integrals from gaussian forms

International Nuclear Information System (INIS)

Mazmanishvili, A.S.

1985-01-01

The result summary of continual integration of gaussian functional type is given. The summary contains 124 continual integrals which are the mathematical expectation of the corresponding gaussian form by the continuum of random trajectories of four types: real-valued Ornstein-Uhlenbeck process, Wiener process, complex-valued Ornstein-Uhlenbeck process and the stochastic harmonic one. The summary includes both the known continual integrals and the unpublished before integrals. Mathematical results of the continual integration carried in the work may be applied in the problem of the theory of stochastic process, approaching to the finding of mean from gaussian forms by measures generated by the pointed stochastic processes

Production of ceramic formed parts by means of plasma spraying

International Nuclear Information System (INIS)

Kirner, K.

1989-01-01

Open and closed pipes and tubes, nozzles and crucibles, conical parts and other molded articles of ceramic materials such as aluminium oxide, magnesium-aluminium spinel, zirconium oxide, zirconium silicate and special ceramics can be fabricated by spray application to a core which is afterwards removed. Because at the same time these are mainly high temperature materials and high temperature application areas, plasma spraying is preferred. The process and examples of application are described, the advantages and disadvantages are pointed out. (orig.) [de

Plasma spray formed near-net-shape MoSi2-Si3N4 bulk nanocomposites-structure property evaluation

International Nuclear Information System (INIS)

Hong, S.J.; Viswanathan, V.; Rea, K.; Patil, S.; Deshpande, S.; Georgieva, P.; McKechnie, T.; Seal, S.

2005-01-01

This article, for the first time, presents the challenges toward the successful consolidation of near-net-shape bulk MoSi 2 -Si 3 N 4 -SiC nanocomposite using plasma spray forming. A detailed characterization of the spray formed bulk nanocomponent has been performed using optical microscopy (OM), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and Vickers hardness testing. Vickers hardness (900 Hv) and fracture toughness (∼>5 MPa m 1/2 ) of the nanocomposite showed a little deviation from the expected, which might be due to the difference in the particle (Si 3 N 4 ) size and their distribution in the MoSi 2 matrix as a function of component thickness. Relatively higher hardness is attributed to the retention of the nanostructure in the composite. In addition, the as fabricated bulk nanocomposite showed enhanced oxidation resistance

Plasma Sprayed Hydroxyapatite Coatings: Influence of Spraying Power on Microstructure

International Nuclear Information System (INIS)

Mohd, S. M.; Abd, M. Z.; Abd, A. N.

2010-01-01

The plasma sprayed hydroxyapatite (HA) coatings are used on metallic implants to enhance the bonding between the implant and bone in human body. The coating process was implemented at different spraying power for each spraying condition. The coatings formed from a rapid solidification of molten and partly molten particles that impact on the surface of substrate at high velocity and high temperature. The study was concentrated on different spraying power that is between 23 to 31 kW. The effect of different power on the coatings microstructure was investigated using scanning electron microscope (SEM) and phase composition was evaluated using X-ray diffraction (XRD) analysis. The coatings surface morphology showed distribution of molten, partially melted particles and some micro-cracks. The produced coatings were found to be porous as observed from the cross-sectional morphology. The coatings XRD results indicated the presence of crystalline phase of HA and each of the patterns was similar to the initial powder. Regardless of different spraying power, all the coatings were having similar XRD patterns.

Influence of spray forming process parameters on the microstructure and porosity of Mg{sub 2}Si rich aluminum alloys

Energy Technology Data Exchange (ETDEWEB)

Stelling, O.; Hehl, A. von [Foundation Institute for Material Science, Bremen (Germany); Uhlenwinkel, V. [University of Bremen, FB4 FG01 Department Process and Chemcial Engineering, Bremen (Germany); Krug, P. [PEAK Werkstoff GmbH, Velbert (Germany); Ellendt, N.

2010-07-15

Due to high cooling rates spray forming is an appropriate process to produce aluminum alloys with a high content of Mg{sub 2}Si. Compared to common casting processes, a fine microstructure can be achieved yielding in improved mechanical properties. In this work, billets were spray formed from the two alloys AlMg15Si8Cu2 (22 mass-% Mg{sub 2}Si) and AlMg20.5Si11Cu2 (30 mass-% Mg{sub 2}Si) under different spraying conditions. The analysis of the microstructure showed that the size of Mg{sub 2}Si dispersoids is very sensitive to process parameters. Besides the well known thermal effects of melt superheat (carried out from -40 K to +170 K) and GMR (varied from 2.0 to 6.3) a strong influence of the scanning frequency of the atomizer nozzle (7 Hz and 15 Hz) could be observed. Similar effects could be found for the occurrence of porosity. A new parameter, the enthalpy flow to gas flow ratio (EGR), was defined from these two parameters of which correlations of Mg{sub 2}Si dispersoid size and amount of porosity were found. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

High resolution visualization and analysis of nasal spray drug delivery.

Science.gov (United States)

Inthavong, Kiao; Fung, Man Chiu; Tong, Xuwen; Yang, William; Tu, Jiyuan

2014-08-01

Effective nasal drug delivery of new-generation systemic drugs requires efficient devices that can achieve targeted drug delivery. It has been established that droplet size, spray plume, and droplet velocity are major contributors to drug deposition. Continual effort is needed to better understand and characterise the physical mechanisms underpinning droplet formation from nasal spray devices. High speed laser photography combined with an in-house designed automated actuation system, and a highly precise traversing unit, measurements and images magnified in small field-of-view regions within the spray was performed. The qualitative results showed a swirling liquid sheet at the near-nozzle region as the liquid is discharged before ligaments of fluid are separated off the liquid sheet. Droplets are formed and continue to deform as they travel downstream at velocities of up to 20 m/s. Increase in actuation pressure produces more rapid atomization and discharge time where finer droplets are produced. The results suggest that device designs should consider reducing droplet inertia to penetrate the nasal valve region, but find a way to deposit in the main nasal passage and not escape through to the lungs.

Spray rolling aluminum alloy strip

Energy Technology Data Exchange (ETDEWEB)

McHugh, Kevin M.; Delplanque, J.-P.; Johnson, S.B.; Lavernia, E.J.; Zhou, Y.; Lin, Y

2004-10-10

Spray rolling combines spray forming with twin-roll casting to process metal flat products. It consists of atomizing molten metal with a high velocity inert gas, cooling the resultant droplets in flight and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets teams with conductive cooling at the rolls to rapidly remove the alloy's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly solidified product. While similar in some ways to twin-roll casting, spray rolling has the advantage of being able to process alloys with broad freezing ranges at high production rates. This paper describes the process and summarizes microstructure and tensile properties of spray-rolled 2124 and 7050 aluminum alloy strips. A Lagrangian/Eulerian poly-dispersed spray flight and deposition model is described that provides some insight into the development of the spray rolling process. This spray model follows droplets during flight toward the rolls, through impact and spreading, and includes oxide film formation and breakup when relevant.

Review of Thermal Spray Coating Applications in the Steel Industry: Part 2—Zinc Pot Hardware in the Continuous Galvanizing Line

Science.gov (United States)

Matthews, S.; James, B.

2010-12-01

This two-part article series reviews the application of thermal spray coating technology in the production of steel and steel sheet products. Part 2 of this article series is dedicated to coating solutions in the continuous galvanizing line. The corrosion mechanisms of Fe- and Co-based bulk materials are briefly reviewed as a basis for the development of thermal spray coating solutions. WC-Co thermal spray coatings are commonly applied to low Al-content galvanizing hardware due to their superior corrosion resistance compared to Fe and Co alloys. The effect of phase degradation, carbon content, and WC grain size are discussed. At high Al concentrations, the properties of WC-Co coatings degrade significantly, leading to the application of oxide-based coatings and corrosion-resistant boride containing coatings. The latest results of testing are summarized, highlighting the critical coating parameters.

CONCHAS-SPRAY, Reactive Flows with Fuel Sprays

International Nuclear Information System (INIS)

Cloutman, L.D.; Dukowicz, J.K.; Ramshaw, J.D.; Amsden, A.A.

2001-01-01

Description of program or function: CONCHAS-SPRAY solves the equations of transient, multicomponent, chemically reactive fluid dynamics, together with those for the dynamics of an evaporating liquid spray. The program was developed with applications to internal combustion engines in mind. The formulation is spatially two-dimensional, and encompasses both planar and axisymmetric geometries. In the latter case, the flow is permitted to swirl about the axis of symmetry. CONCHAS-SPRAY is a time-marching, finite- difference program that uses a partially implicit numerical scheme. Spatial differences are formed with respect to a generalized two- dimensional mesh of arbitrary quadrilaterals whose corner locations are specified functions of time. This feature allows a Lagrangian, Eulerian, or mixed description, and is particularly useful for representing curved or moving boundary surfaces. Arbitrary numbers of species and chemical reactions are allowed. The latter are subdivided into kinetic and equilibrium reactions, which are treated by different algorithms. A turbulent law-of-the-wall boundary layer option is provided. CONCHAS-SPRAY calls a number of LANL system subroutines to display graphic or numerical information on microfiche. These routines are not included, but are described in the reference report. Several routines called from LINPACK and SLATEC1.0 are included

Micrometeorological measurements during the Blackmo 88 spray trials

Science.gov (United States)

D. E. Anderson; D. R. Miller; Y. S. Wang; W. E. Yendol; M. L. McManus

1991-01-01

Instrumentation was arrayed on a 120 foot tower to detail the local atmospheric conditions during the Blackmo 88 spray experiment. Measurements were continuous for 30 minute periods encompassing each spray pass.

1994 Thermal spray industrial applications: Proceedings

International Nuclear Information System (INIS)

Berndt, C.C.; Sampath, S.

1994-01-01

The 7th National Thermal Spray Conference met on June 20--24, 1994, in Boston, Massachusetts. The conference was sponsored by the Thermal Spray Division of ASM International and co-sponsored by the American Welding Society, Deutscher Verband fur Schweisstechnik e.V., High Temperature Society of Japan, International Thermal Spray Association, and Japanese Thermal Spraying Society. The conference covered applications for automobiles, aerospace, petrochemicals, power generation, and biomedical needs. Materials included metals, ceramics, and composites with a broad range of process developments and diagnostics. Other sections included modeling and systems control; spray forming and reactive spraying; post treatment; process, structure and property relationships; mechanical properties; and testing, characterization and wear. One hundred and seventeen papers have been processed separately for inclusion on the data base

Near-net-shape 95W-3.5Ni-1.5Fe thin-walled products produced by plasma spray forming

International Nuclear Information System (INIS)

Wang, Y.M.; Xiong, X.; Min, X.B.; Xie, L.; Zheng, F.

2010-01-01

Tungsten heavy alloy 95W-3.5Ni-1.5Fe (in wt.%) refractory metallic thin-walled products (diameter ≤100 mm, length ≤150 mm and wall thickness ≤5 mm) were produced using plasma spray forming (PSF) covered in argon atmosphere at a pressure of 1.01 x 10 5 Pa followed by vacuum liquid phase sintering at 1465, 1485 and 1500 deg. C for 90 min, respectively. A lamellar structure consisting of vertical columnar grains and some fine particles was found in PSF deposits. Relative density of the deposits was about 87.70% with poor mechanical property. Upon vacuum liquid phase sintering, their density and property have been improved significantly. The microstructures of PSF deposits before and after vacuum sintering were found to consist with tungsten and (Ni, Fe)-rich phase. Volume fraction of (Ni, Fe)-rich phase was decreased due to vaporization that occurred in plasma spraying and vacuum liquid phase sintering. Their fracture surfaces were dominated by intergranular rupture. The lamellar structure remained in the deposits during early stages of sintering (solid state sintering and initial of liquid phase sintering). Particle rearrangement and rapid densification of the deposits did not occur until the surface of tungsten particles being modified and changed into spheroids by solution and precipitation. In the end, the PSF deposits have been transformed from lamellar structure into two phase composites with dispersed spheroidal tungsten grains embedded in a continuous network of (Ni, Fe)-rich phase.

High level waste forms: glass marbles and thermal spray coatings

International Nuclear Information System (INIS)

Treat, R.L.; Oma, K.H.; Slate, S.C.

1982-01-01

A process that converts high-level waste to glass marbles and then coats the marbles has been developed at Pacific Northwest Laboratory (PNL) under sponsorship of the US Department of Energy. The process consists of a joule-heated glass melter, a marble-making device based on a patent issued to Corning Glass Works, and a coating system that includes a plasma spray coater and a marble tumbler. The process was developed under the Alternative Waste Forms Program which strived to improve upon monolithic glass for immobilizing high-level wastes. Coated glass marbles were found to be more leach-resistant, and the marbles, before coating were found to be very homogeneous, highly impact resistant, and conductive to encapsulation in a metal matric for improved heat transfer and containment. Marbles are also ideally suited for quality assurance and recycling. However, the marble process is more complex, and marbles require a larger number of canisters for waste containment and have a higher surface area than do glass monoliths

Bioinspired hybrid materials from spray-formed ceramic templates.

Science.gov (United States)

Dwivedi, Gopal; Flynn, Katherine; Resnick, Michael; Sampath, Sanjay; Gouldstone, Andrew

2015-05-20

Thermally sprayed ceramics, when infiltrated with polymer, exhibit synergistic increases in strength and toughness. The structure of such composites-a dense, brick-mortar arrangement-is strikingly similar to that of nacre, as are the mechanisms underlying the robust mechanical behavior. This industrial-scale process thus presents an exciting tool for bio-mimetic exploration. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modelling the influence of the gas to melt ratio on the fraction solid of the surface in spray formed billets

DEFF Research Database (Denmark)

Hattel, Jesper Henri; Pryds, Nini

2006-01-01

the atomisation stage taking thermal coupling into consideration and the deposition of the droplets at the surface of the billet taking geometrical aspects such as shading into account. The coupling between these two models is accomplished by ensuring that the total droplet size distribution of the spray......In this paper, the relationship between the Gas to Melt Ratio (GMR) and the solid fraction of an evolving billet surface is investigated numerically. The basis for the analysis is a recently developed integrated procedure for modelling the entire spray forming process. This model includes...... is the summation of “local” droplet size distributions along the r-axis of the spray cone. The criterion for a successful process has been a predefined process window characterised by a desired solid fraction range at a certain distance from the atomizer. Inside this process window, the gas and melt flows have...

Influence of powder and spray parameters on erosion and corrosion properties of HVOF sprayed WC-Co-Cr coatings

Energy Technology Data Exchange (ETDEWEB)

Berget, John

1998-07-01

Thermal spraying is a generic term including various processes used to deposit coatings on surfaces. The coating material is in the form of powder or a wire and is melted or softened by means of a heat source. A gas stream accelerates the material towards a prepared surface and deposits it there to form the coating. Examples of components being maintained by application of thermal spray coatings are gate valves and ball valves for the offshore industry and turbine blades in power generations installations. Recent investigation has shown that the commonly used coating material WC-Co is not corrosion resistant. But it can be improved by the addition of Cr. The main objective of this thesis is to study the influence of spray process control variables and powder characteristics on the erosion and erosion-corrosion properties of the coatings. Spray process variables investigated include energy input, powder feed rate and spray distance. Powder characteristics studied are average size of the WC particles, relative proportions of Co and Cr in the metal phase and powder grain size distribution.

High-power electronics thermal management with intermittent multijet sprays

International Nuclear Information System (INIS)

Panão, Miguel R.O.; Correia, André M.; Moreira, António L.N.

2012-01-01

Thermal management plays a crucial role in the development of high-power electronics devices, e.g. in electric vehicles. The greatest energy demands occur during power peaks, implying dynamic thermal losses within the vehicle’s driving cycle. Therefore, the need for devising intelligent thermal management systems able to efficiently respond to these power peaks has become a technological challenge. Experiments have been performed with methanol in order to quantify the maximum heat flux removed by a multijet spray to keep the 4 cm 2 surface temperature stabilized and below the threshold of 125 °C. A multijet atomization strategy consists in producing a spray through the multiple and simultaneous impact of N j cylindrical jets. Moreover, the spray intermittency is expressed through the duty cycle (DC), which depends on the frequency and duration of injection. Results evidence that: i) a shorter time between consecutive injection cycles enables a better distribution of the mass flow rate, resulting in larger heat transfer coefficient values, as well as higher cooling efficiencies; ii) compared with continuous sprays, the analysis evidences that an intermittent spray allows benefiting more from phase-change convection. Moreover, the mass flux is mainly affecting heat transfer rather than differences induced in the spray structure by using different multijet configurations. - Highlights: ► Intermittent spray cooling (ISC) is advantageous for intelligent thermal management. ► Distributing the mass flow rate through ISC improves heat transfer. ► Multijet sprays with increasing number of jets have higher heat transfer rates. ► ISC with multijet sprays benefit more from phase-change than continuous sprays.

Structure of Non-evaporating diesel sprays

International Nuclear Information System (INIS)

Mirza, M.R.; Baluch, A.H.; Tahir, Z.R.

2008-01-01

Need is always felt of some rational experimental information on fuel spray jet formation, its development and dispersion in the combustion chamber of an internal combustion engine. The latest study uses computational fluid dynamics for the modeling of engine flows. The original experimental work of the present author on non-evaporating sprays produced by a single-hole orifice type nozzle using a distribution type commercial fuel injection pump forms the basis to derive correlations for penetration rates, break up times and lengths of non-evaporating diesel sprays. The correlations derived can be used to do CFD modeling of sprays under variable conditions of injector nozzle hole diameter, fuel injection pressure and combustion chamber pressure. (author)

Characterization of alumina scales formed during isothermal and cyclic oxidation of plasma-sprayed TBC systems at 1150 C

International Nuclear Information System (INIS)

Haynes, J.A.; Ferber, M.K.; Porter, W.D.; Rigney, E.D.

1999-01-01

The isothermal- and cyclic-oxidation behavior of thermal barrier coating (TBC) systems consisting of vacuum plasma-sprayed (VPS) Ni-22Cr-10Al/Y (wt%) bond coatings and air plasma-sprayed (APS) Y 2 O 3 -stabilized ZrO 2 (YSZ) top coatings (on single-crystal superalloys) was investigated. The microstructures, flaw contents, and fracture behavior of the Al 2 O 3 scales formed during oxidation testing at 1150 C were characterized (by analysis of coating and scale fracture surfaces and metallographic cross sections). Significant localized fracture and buckling of the Al 2 O 3 scales that formed along the bond-coat--top-coat interfaces were observed after cyclic oxidation of TBCs. However, substantial amounts of localized scale damage did not induce rapid TBC failure. Decohesion of the columnar alumina scales on the rough bond-coat surfaces occurred by both internal Al 2 O 3 fracture (parallel to the metal surface) and oxide-metal delamination. There were microstructural indications of Al 2 O 3 scale crack healing by sintering into planar arrays of voids. Alumina scales that formed on convex NiCrAlY surfaces (with radii of 50 microm or less) after cyclic oxidation, whereas scales formed by isothermal oxidation contained few visible voids. Accelerated void growth in Al 2 O 3 scales on the irregular NiCrAlY surfaces appeared to be creep-related and was attributed to the synergistic effects of geometric and thermal stresses

An assessment of thermal spray coating technologies for high temperature corrosion protection

International Nuclear Information System (INIS)

Heath, G.R.; Heimgartner, P.; Gustafsson, S.; Irons, G.; Miller, R.

1997-01-01

The use of thermally sprayed coatings in combating high temperature corrosion continues to grow in the major industries of chemical, waste incineration, power generation and pulp and paper. This has been driven partially by the development of corrosion resistant alloys, improved knowledge and quality in the thermal spray industry and continued innovation in thermal spray equipment. There exists today an extensive range of thermal spray process options, often with the same alloy solution. In demanding corrosion applications it is not sufficient to just specify alloy and coating method. For the production of reliable coatings the whole coating production envelope needs to be considered, including alloy selection, spray parameters, surface preparation, base metal properties, heat input etc. Combustion, arc-wire, plasma, HVOF and spray+fuse techniques are reviewed and compared in terms of their strengths and limitations to provide cost-effective solutions for high temperature corrosion protection. Arc wire spraying, HP/HVOF and spray+fuse are emerging as the most promising techniques to optimise both coating properties and economic/practical aspects. (orig.)

Head spray nozzle in reactor pressure vessel

International Nuclear Information System (INIS)

Hatano, Shun-ichi.

1990-01-01

In a reactor pressure vessel of a BWR type reactor, a head spray nozzle is used for cooling the head of the pressure vessel and, in view of the thermal stresses, it is desirable that cooling is applied as uniformly as possible. A conventional head spray is constituted by combining full cone type nozzles. Since the sprayed water is flown down upon water spraying and the sprayed water in the vertical direction is overlapped, the flow rate distribution has a high sharpness to form a shape as having a maximum value near the center and it is difficult to obtain a uniform flow rate distribution in the circumferential direction. Then, in the present invention, flat nozzles each having a spray water cross section of laterally long shape, having less sharpness in the circumferential distribution upon spraying water to the inner wall of the pressure vessel and having a wide angle of water spray are combined, to make the flow rate distribution of spray water uniform in the inner wall of the pressure vessel. Accordingly, the pressure vessel can be cooled uniformly and thermal stresses upon cooling can be decreased. (N.H.)

Thermal Spray Coating of Tungsten for Tokamak Device

International Nuclear Information System (INIS)

Jiang Xianliang; Gitzhofer, F; Boulos, M I

2006-01-01

Thermal spray, such as direct current (d.c.) plasma spray or radio frequency induced plasma spray, was used to deposit tungsten coatings on the copper electrodes of a tokamak device. The tungsten coating on the outer surface of one copper electrode was formed directly through d.c. plasma spraying of fine tungsten powder. The tungsten coating/lining on the inner surface of another copper electrode could be formed indirectly through induced plasma spraying of coarse tungsten powder. Scanning electron microscopy (SEM) was used to examine the cross section and the interface of the tungsten coating. Energy Dispersive Analysis of X-ray (EDAX) was used to analyze the metallic elements attached to a separated interface. The influence of the particle size of the tungsten powder on the density, cracking behavior and adhesion of the coating is discussed. It is found that the coarse tungsten powder with the particle size of 45 ∼ 75 μm can be melted and the coating can be formed only by using induced plasma. The coating deposited from the coarse powder has much higher cohesive strength, adhesive strength and crack resistance than the coating made from the fine powder with a particle size of 5 μm

Spray drying of beryllium oxide powder

International Nuclear Information System (INIS)

Sepulveda, J.L.; Kahler, D.A.

1991-01-01

Forming of beryllia ceramics through dry pressing requires the agglomeration of the powder through spray drying. To produce high quality fired ceramics it is necessary to disperse/grind the primary powder prior to binder addition. Size reduction of the powder is accomplished using an aqueous system in Vibro-Energy mills (VEM) charged with beryllia media to minimize contamination. Two VEM mills of different size were used to characterize the grinding operation. Details of the grinding kinetics are described within the context of the Macroscopic Population Balance Model approach. Spray drying of the ceramic slurry was accomplished with both a centrifugal atomizer and a two fluid nozzle atomizer. Two different spray dryers were used. Important operating parameters affecting the size distribution of the spray dried powder are discussed

Spray pyrolysis process for preparing superconductive films

International Nuclear Information System (INIS)

Hsu, H.M.; Yee, I.Y.

1991-01-01

This paper describes a spray pyrolysis method for preparing thin superconductive film. It comprises: preparing a spray pyrolysis solution comprising Bi,Sr,Ca and Cu metals in a solvent; heating a substrate to a first temperature; spraying the solution onto the heated substrate to form a film thereon; heating the film and substrate to a second temperature of about 700 degrees-825 degrees C, the second temperature being higher than the first temperature; heating the film and substrate to a third temperature of about 870 degrees-890 degrees C to melt the film; once the film and substrate reach the third temperature, further heat treating the film and substrate; cooling the film and substrate to ambient temperature. This patent also describes a spray pyrolysis method for preparing thin superconductive films. It comprises: preparing a spray pyrolysis solution comprising Bi, Ca and Cu metals and fluxing agent in a solvent; heating a substrate to a first temperature; spraying the solution onto the heated substrate to form a film thereon; heating the film and substrate to a second temperature about 700 degrees-825 degrees C, the second temperature being higher than the first temperature; heating the film and substrate at a third temperature about 840 degrees-860 degrees C; and cooling the film and substrate to ambient temperature

Bulk synthesis by spray forming of Al–Cu–Fe and Al–Cu–Fe–Sn alloys containing a quasicrystalline phase

International Nuclear Information System (INIS)

Srivastava, V.C.; Huttunen-Saarivirta, E.; Cui, C.; Uhlenwinkel, V.; Schulz, A.; Mukhopadhyay, N.K.

2014-01-01

Highlights: • 40 kg Bulk material spray formed based on Al–Cu–Fe and Al–Cu–Fe + Sn. • Deposited Al–Cu–Fe alloy showed single phase bulk quasicrystals(QC). • DSC, XRD and microscopic analyses were done to ascertain the QC nature. • Sn does not help in single phase quasicrystal formation in the deposit. • The possible structural evolution mechanisms have been discussed in detail. - Abstract: In this study, Al–Cu–Fe alloys without and with the addition of Sn and containing a quasicrystalline phase were spray deposited. The spray-deposited bulk materials were characterized in terms of microstructure and hardness. The results showed that the Al 62.5 Cu 25 Fe 12.5 alloy contains the icosahedral quasicrystalline phase (i-phase) along with the minor λ-Al 13 Fe 4 phase, whereas the Al 62.5 Cu 25 Fe 12.5 + Sn alloy contains five phases: the major i-phase and the crystalline phases of Sn, θ-Al 2 Cu, λ-Al 13 Fe 4 and β-AlFe(Cu) phases. These results have been corroborated by X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM) and differential scanning calorimetry (DSC). The hardness value of the Al–Cu–Fe alloy reached 10.5 GPa at 50 g load and then decreased steadily with increase in the applied load, while that for Al–Cu–Fe–Sn alloy it was originally somewhat lower, then decreased dramatically with slight increase in the applied load but stayed constant with further load increase. The hardness indentations in Al–Cu–Fe alloy introduced cracking in the material, whereas in the case of Al–Cu–Fe–Sn alloy the Sn-rich areas inhibited the crack growth. The present study provides an insight into the mechanism of phase and microstructural evolutions during spray forming of the studied alloys. Furthermore, the role of Sn in terms of microstructure and properties is highlighted

Molybdenum plasma spray powder, process for producing said powder, and coating made therefrom

International Nuclear Information System (INIS)

Lafferty, W.D.; Cheney, R.F.; Pierce, R.H.

1979-01-01

Plasma spray powders of molybdenum particles containing 0.5 to 15 weight percent oxygen and obtained by reacting molybdenum particles with oxygen or oxides in a plasma, form plasma spray coatings exhibiting hardness comparable to flame sprayed coatings formed from molybdenum wire and plasma coatings of molybdenum powders. Such oxygen rich molybdenum powders may be used to form wear resistant coatings, such as for piston rings. (author)

Antibacterial drugs in the form of sprays for the topical treatment of pyodermas and dermatoses complicated with a secondary infection

Directory of Open Access Journals (Sweden)

YE. V. Matushevskaya

2014-01-01

Full Text Available The article covers issues related to the application of topical antibacterial drugs for the treatment of pyodermic skin diseases. The author describes mechanisms of action and advantages of the topical form of antibiotics and GCS for the topical treatment of pyodermas. The article substantiates indications for the administration of topical GCS drugs in a combination with antibacterial drugs. The efficacy and safety of antibacterial and combination topical drugs such as Neomycin, Oxycort and Polcortolon TC in the form sprays for the treatment of pyodermas and complicated forms of chronic dermatosis.

Spray drying for processing of nanomaterials

International Nuclear Information System (INIS)

Lindeloev, Jesper Saederup; Wahlberg, Michael

2009-01-01

Consolidation of nano-particles into micron-sized granules reduces the potential risks associated with handling nano-powders in dry form. Spray drying is a one step granulation technique which can be designed for safe production of free flowing low dusty granules from suspensions of nano-particles. Spray dried granules are well suited for subsequent processing into final products where the superior properties given by the nano-particles are retained. A spray drier with bag filters inside the drying chamber and recycling of drying gas combined with containment valves are proposed as a safe process for granulation of potential hazardous nano-particles.

Cold spraying of aluminum bronze on profiled submillimeter cermet structures formed by laser cladding

Science.gov (United States)

Ryashin, N. S.; Malikov, A. G.; Shikalov, V. S.; Gulyaev, I. P.; Kuchumov, B. M.; Klinkov, S. V.; Kosarev, V. F.; Orishich, A. M.

2017-10-01

The paper presents results of the cold spraying of aluminum bronze coatings on substrates profiled with WC/Ni tracks obtained by laser cladding. Reinforcing cermet frames shaped as grids with varied mesh sizes were clad on stainless steel substrates using a CO2 laser machine "Siberia" (ITAM SB RAS, Russia). As a result, surfaces/substrates with heterogeneous shape, composition, and mechanical properties were obtained. Aluminum bronze coatings were deposited from 5lF-NS powder (Oerlikon Metco, Switzerland) on those substrates using cold spraying equipment (ITAM SB RAS). Data of profiling, microstructure diagnostics, EDS analysis, and mechanical tests of obtained composites is reported. Surface relief of the sprayed coatings dependence on substrate structure has been demonstrated.

Factors affecting the development of sprays produced by multihole injectors for direct-injection engine applications

OpenAIRE

Van Romunde, R. Z.

2011-01-01

The spray form development from a state of the art multi-hole injector for gasoline direct injection internal combustion engines is examined to attempt to determine the thermo-fluid dynamics affecting the spray development. The current state of knowledge regarding spray break-up and the interactivity of the factors on spray form are detailed. The spray under investigation was injected into purposely designed quiescent chambers to decouple the effects of the fluid mechanics on s...

77 FR 3598 - Ophthalmic and Topical Dosage Form New Animal Drugs; Gentamicin and Betamethasone Spray

Science.gov (United States)

2012-01-25

... veterinary prescription use of gentamicin sulfate and betamethasone valerate topical spray in dogs. DATES... Veterinary Medicine (HFV-170), Food and Drug Administration, 7500 Standish Pl., Rockville, MD 20855, (240... prescription use of Gentamicin Topical Spray (gentamicin sulfate and betamethasone valerate) in dogs. Sparhawk...

Analysis of processes in DC arc plasma torches for spraying that use air as plasma forming gas

International Nuclear Information System (INIS)

Frolov, V; Ivanov, D; Toropchin, A

2014-01-01

Developed in Saint Petersburg State Polytechnical University technological processes of air-plasma spraying of wear-resistant, regenerating, hardening and decorative coatings used in number of industrial areas are described. The article contains examples of applications of air plasma spraying of coatings as well as results of mathematical modelling of processes in air plasma torches for spraying

Microstructure evolution and mechanical properties of T15 high speed steel prepared by twin-atomiser spray forming and thermo-mechanical processing

International Nuclear Information System (INIS)

Zhang, Guoqing; Yuan, Hua; Jiao, Dongling; Li, Zhou; Zhang, Yong; Liu, Zhongwu

2012-01-01

Spray formed T15 high speed steel (HSS) billets were deposited using a state-of-the-art twin-atomiser spray forming facility. The effects of post thermo-mechanical processing (hot isostatic pressing and hot forging) and heat treatment on the microstructure and mechanical properties were investigated. As-deposited billet has a density over 99.3% of the theoretical value and no measurable macro-segregation was observed. The microstructure consists of the equiaxed grains with mean size of ∼18 μm and MC- and M 6 C-type carbides non-uniformly distributed inside the grains and along the grain boundaries. After optimal thermo-mechanical processing and heat treatment, the microstructure was composed of equiaxed fine tempered martensites, and refined M 6 C and MC spherical carbides particles uniformly distributed along the grain boundaries and inside the grains. The hardness reached HRC68 after thermo-mechanical processing, and the corresponding impact toughness and bending strength reached 27 J/cm 2 and 4600 MPa respectively. Although HIP cannot increase the bending strength significantly, it can effectively improve the impact toughness through refining and globurizing carbides.

Biofouling of Cr-Nickel Spray Coated Films on Steel Surfaces

International Nuclear Information System (INIS)

Yoshida, Kento; Kanematsu, Hideyuki; Kuroda, Daisuke; Ikigai, Hajime; Kogo, Takeshi; Yokoyama, Seiji

2012-01-01

Nowadays, corrosion of metals brings us serious economic loss and it often reaches several percentage of GNP. Particularly the marine corrosion was serious and the counter measure was very hard to be established, since the number of factors is huge and complicated. One of the complicated factors in marine corrosion is biofouling. Biofouling was classified into two main categories, microfouling and macrofouling. The former is composed of biofilm formation mainly. Marine bacteria are attached to material surfaces, seeking for nutrition in oligotrophic environment and they excrete polysaccharide to form biofilm on metal surfaces. Then larger living matters are attached on the biofilms to develop biofouling on metal surfaces, which often lead loss and failures of metals in marine environments. From the viewpoint of corrosion protection and maintenance of marine structures, biofouling should be mitigated as much as possible. In this study, we applied spray coating to steels and investigated if chromium-nickel spray coating could mitigate the biofouling, being compared with the conventional aluminium-zinc spray coating in marine environments. The specimens used for this investigation are aluminium, zinc, aluminium-zinc, stacked chromium/nickel and those films were formed on carbon steel (JIS SS400). And the pores formed by spray coating were sealed by a commercial reagent for some specimens. All of those specimens were immersed into sea water located at Marina Kawage (854-3, Chisato, Tsu, Mie Prefecture) in Ise Bay for two weeks. The depth of the specimen was two meter from sea water surface and the distance was always kept constant, since they were suspended from the floating pier. The temperature in sea water changed from 10 to 15 degrees Celsius during the immersion test. The biofouling behavior was investigated by low vacuum SEM (Hitachi Miniscope TM1000) and X-ray fluorescent analysis. When the spray coated specimens with and without sealing agents were compared

Inhibition of Recrystallization of Amorphous Lactose in Nanocomposites Formed by Spray-Drying.

Science.gov (United States)

Hellrup, Joel; Alderborn, Göran; Mahlin, Denny

2015-11-01

This study aims at investigating the recrystallization of amorphous lactose in nanocomposites. In particular, the focus is on the influence of the nano- to micrometer length scale nanofiller arrangement on the amorphous to crystalline transition. Further, the relative significance of formulation composition and manufacturing process parameters for the properties of the nanocomposite was investigated. Nanocomposites of amorphous lactose and fumed silica were produced by co-spray-drying. Solid-state transformation of the lactose was studied at 43%, 84%, and 94% relative humidity using X-ray powder diffraction and microcalorimetry. Design of experiments was used to analyze spray-drying process parameters and nanocomposite composition as factors influencing the time to 50% recrystallization. The spray-drying process parameters showed no significant influence. However, the recrystallization of the lactose in the nanocomposites was affected by the composition (fraction silica). The recrystallization rate constant decreased as a function of silica content. The lowered recrystallization rate of the lactose in the nanocomposites could be explained by three mechanisms: (1) separation of the amorphous lactose into discrete compartments on a micrometer length scale (compartmentalization), (2) lowered molecular mobility caused by molecular interactions between the lactose molecules and the surface of the silica (rigidification), and/or (3) intraparticle confinement of the amorphous lactose. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Low pressure plasma spray deposition of W-Ni-Fe alloy

International Nuclear Information System (INIS)

Mutasim, Z.Z.; Smith, R.W.

1991-01-01

The production of net shape refractory metal structural preforms are increasing in importance in chemical processing, defense and aerospace applications. Conventional methods become limited for refractory metal processing due to the high melting temperatures and fabrication difficulties. Plasma spray forming, a high temperature process, has been shown to be capable of refractory metal powder consolidation in net shape products. The research reported here has evaluated this method for the deposition of heavy tungsten alloys. Plasma Melted Rapidly Solidified (PMRS) W 8%Ni-2%Fe refractory metal powders were spray formed using vacuum plasma spray (VPS) process and produced 99% dense, fine grain and homogeneous microstructures. In this paper plasma operating parameters (plasma arc gas type and flowrate plasma gun nozzle size and spray distance) were studied and their effects on deposit's density and microstructure are reported

Confinement of Amorphous Lactose in Pores Formed Upon Co-Spray Drying With Nanoparticles.

Science.gov (United States)

Hellrup, Joel; Mahlin, Denny

2017-01-01

This study aims at investigating factors influencing humidity-induced recrystallization of amorphous lactose, produced by co-spray drying with particles of cellulose nanocrystals or sodium montmorillonite. In particular, the focus is on how the nanoparticle shape and surface properties influence the nanometer to micrometer length scale nanofiller arrangement in the nanocomposites and how the arrangements influence the mechanisms involved in the inhibition of the amorphous to crystalline transition. The nanocomposites were produced by co-spray drying. Solid-state transformations were analyzed at 60%-94% relative humidity using X-ray powder diffraction, microcalorimetry, and light microscopy. The recrystallization rate constant for the lactose/cellulose nanocrystals and lactose/sodium montmorillonite nanocomposites was lowered at nanofiller contents higher than 60% and was stable for months at 80% nanofiller. The most likely explanation to these results is spontaneous formations of mesoporous particle networks that the lactose is confined upon co-spray drying at high filler content. Compartmentalization and rigidification of the amorphous lactose proved to be less important mechanisms involved in the stabilization of lactose in the nanocomposites. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Visible Photodetectors Based on Organic-Inorganic Hybrids Using Electrostatic Spraying Technology

Directory of Open Access Journals (Sweden)

Liang-Wen Ji

2013-12-01

Full Text Available This paper discusses an organic-inorganic hybrid white photodetector with the structure of ITO /AZO/ZnO NWs:P3HT: PCBM/PEDOT: PSS/Al produced with an electrostatic spraying method. The method of production was as follows: First, different spraying methods (continuous spraying, discontinuous spraying and different spraying times were tested before the final electrostatic spraying. Then, different annealing times (10 min and 20 min were tested to anneal the coated film. Lastly, we investigated the photoelectric properties, including transparency analysis of the film surface topography through XRD, OM, FE-SEM, AFM and UV-VIS. The results showed that the detector with discontinuous spraying and 20 mins annealing had a photocurrent of approx. 22.1×10-4A, dark current (drain current of approx. 1.94×10-7A, and a ratio of photocurrent to dark current of approximately 1.14×104, which produced optimal photoelectric characteristics.

Process for forming exoergic structures with the use of a plasma

Science.gov (United States)

Kelly, M.D.

1987-05-29

A method of forming exoergic structures, as well as exoergic structures produced by the method, is provided. The method comprises the steps of passing a plasma-forming gas through a plasma spray gun, forming a plasma spray, introducing exoergic material into the plasma spray and directing the plasma spray toward a substrate, and allowing the exoergic material to become molten in the plasma spray and to thereafter impinge on the substrate to form a solid mass of exoergic material, the shape of which corresponds to the shape of the substrate.

Microstructural characteristics of spray formed and heat treated Al–(Y, La)–Ni–Co system

International Nuclear Information System (INIS)

Srivastava, V.C.; Surreddi, K.B.; Scudino, S.; Schowalter, M.; Uhlenwinkel, V.; Schulz, A.; Eckert, J.; Rosenauer, A.; Zoch, H.-W.

2013-01-01

Highlights: •Al–(La, Y)–Ni–Co based alloys are spray formed to thickness 10–12 mm. •XRD and DSC confirms the presence of large fraction of amorphous phase. •Optical, SEM and TEM studies corroborated the observations made. Mechanism of microstructural evolution brought out. •Heat treatment of spray deposited materials showed increased hardness which decreased at high temperature annealing. •La containing system showed better thermal stability than that without La. -- Abstract: Recent studies on the synthesis of bulk Al–RE (Rare Earth)-TM (Transition Metal) based materials, from melt spun ribbons and gas atomized powders, have shown that partially amorphous or nano-crystalline structures lead to a high specific strength. In the present study, therefore, spray atomization and deposition process has been used to produce plates of Al 85 Y 8 Ni 5 Co 2 (deposit D1) and Al 83 Y 5 La 5 Ni 5 Co 2 (deposit D2) systems so as to synthesize bulk deposit of nano-crystalline and/or partially amorphous materials in a single step. The rapid solidification and high undercooling of droplets during atomization and the chilling effect on undercooled liquid upon deposition give rise to the above microstructural features. The microstructural features of deposits as well as overspray powders were studied using optical, scanning and transmission electron microscope. The alloys invariably showed a large fraction of nano-crystalline structure and amorphous features, characterized by featureless regions at optical resolution, along with distribution of primary equilibrium phases. The differential scanning calorimetric (DSC) analysis of the deposits showed similar crystallization features as observed during crystallization of fully amorphous melt spun ribbons of respective compositions. The transmission electron microscopy of deposit D1 showed the presence of 50–100 nm size fcc-Al precipitates in an amorphous matrix decorated with 5–20 nm fcc-Al crystallites. The

Modification of the solid-state nature of sulfathiazole and sulfathiazole sodium by spray drying.

Science.gov (United States)

Bianco, Stefano; Caron, Vincent; Tajber, Lidia; Corrigan, Owen I; Nolan, Lorraine; Hu, Yun; Healy, Anne Marie

2012-06-01

Solid-state characterisation of a drug following pharmaceutical processing and upon storage is fundamental to successful dosage form development. The aim of the study was to investigate the effects of using different solvents, feed concentrations and spray drier configuration on the solid-state nature of the highly polymorphic model drug, sulfathiazole (ST) and its sodium salt (STNa). The drugs were spray-dried from ethanol, acetone and mixtures of these organic solvents with water. Additionally, STNa was spray-dried from pure water. The physicochemical properties including the physical stability of the spray-dried powders were compared to the unprocessed materials. Spray drying of ST from either acetonic or ethanolic solutions with the spray drier operating in a closed cycle mode yielded crystalline powders. In contrast, the powders obtained from ethanolic solutions with the spray drier operating in an open cycle mode were amorphous. Amorphous ST crystallised to pure form I at ≤35 % relative humidity (RH) or to polymorphic mixtures at higher RH values. The usual crystal habit of form I is needle-like, but spherical particles of this polymorph were generated by spray drying. STNa solutions resulted in an amorphous material upon processing, regardless of the solvent and the spray drier configuration employed. Moisture induced crystallisation of amorphous STNa to a sesquihydrate, whilst crystallisation upon heating gave rise to a new anhydrous polymorph. This study indicated that control of processing and storage parameters can be exploited to produce drugs with a specific/desired solid-state nature.

Current implications of past DDT indoor spraying in Oman.

Science.gov (United States)

Booij, Petra; Holoubek, Ivan; Klánová, Jana; Kohoutek, Jiří; Dvorská, Alice; Magulová, Katarína; Al-Zadjali, Said; Čupr, Pavel

2016-04-15

In Oman, DDT was sprayed indoors during an intensive malaria eradication program between 1976 and 1992. DDT can remain for years after spraying and is associated with potential health risk. This raises the concern for human exposure in areas where DDT was used for indoor spraying. Twelve houses in three regions with a different history of DDT indoor spraying were chosen for a sampling campaign in 2005 to determine p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and p,p'-dichlorodiphenyldichloroethane (p,p'-DDD) levels in indoor air, dust, and outdoor soil. Although DDT was only sprayed indoor, p,p'-DDT, p,p'-DDE and p,p'-DDD were also found in outdoor soil. The results indicate that release and exposure continue for years after cessation of spraying. The predicted cancer risk based on concentrations determined in 2005, indicate that there was still a significant cancer risk up to 13 to 16years after indoor DDT spraying. A novel approach, based on region-specific half-lives, was used to predict concentrations in 2015 and showed that more than 21years after spraying, cancer risk for exposure to indoor air, dust, and outdoor soil are acceptable in Oman for adults and young children. The model can be used for other locations and countries to predict prospective exposure of contaminants based on indoor experimental measurements and knowledge about the spraying time-schedule to extrapolate region-specific half-lives and predict effects on the human population years after spraying. Copyright © 2015 Elsevier B.V. All rights reserved.

Nano spray drying for encapsulation of pharmaceuticals.

Science.gov (United States)

Arpagaus, Cordin; Collenberg, Andreas; Rütti, David; Assadpour, Elham; Jafari, Seid Mahdi

2018-05-17

Many pharmaceuticals such as pills, capsules, or tablets are prepared in a dried and powdered form. In this field, spray drying plays a critical role to convert liquid pharmaceutical formulations into powders. In addition, in many cases it is necessary to encapsulate bioactive drugs into wall materials to protect them against harsh process and environmental conditions, as well as to deliver the drug to the right place and at the correct time within the body. Thus, spray drying is a common process used for encapsulation of pharmaceuticals. In view of the rapid progress of nanoencapsulation techniques in pharmaceutics, nano spray drying is used to improve drug formulation and delivery. The nano spray dryer developed in the recent years provides ultrafine powders at nanoscale and high product yields. In this paper, after explaining the concept of nano spray drying and understanding the key elements of the equipment, the influence of the process parameters on the final powders properties, like particle size, morphology, encapsulation efficiency, drug loading and release, will be discussed. Then, numerous application examples are reviewed for nano spray drying and encapsulation of various drugs in the early stages of product development along with a brief overview of the obtained results and characterization techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

Applications of thermal spraying for automotive parts. Jidosha ni okeru yosha no tekiyo

Energy Technology Data Exchange (ETDEWEB)

Mori, K [Toyota Motor Co. Ltd., Aichi (Japan)

1992-10-31

Application of thermal spraying for automotive parts is described. Outlines of the spraying types that are materialized recently, like 'gel-double spraying of turbo-compressor housing part' and 'iron alloy spraying to outer portion of valve lifter made with Al alloy', are introduced. Gel-double spraying technology is widely used in the jet engine of aeroplane, however its use in automotive turbo was difficult from the reason like quality assurance relating to continuous production of automotives. As a result of the research and development based on the above reasons, a low speed torque is confirmed by the formation of gel-double spray layer. Spraying to the outer part of the valve lifter made from Al alloy is cited as the best example of thermal spraying. Relation between flying speed of spraying particles and degree of flattening, etc., relating to the conformity of adhesion power of coated layer, is explained. Further research topics are given as; improvement of spraying efficiency, improvement of resistance of spraying equipments, unification of equipments standards, quantification of spray coatings, design of spray materials, etc. 9 refs., 8 figs., 1 tab.

High quality ceramic coatings sprayed by high efficiency hypersonic plasma spraying gun

International Nuclear Information System (INIS)

Zhu Sheng; Xu Binshi; Yao JiuKun

2005-01-01

This paper introduced the structure of the high efficiency hypersonic plasma spraying gun and the effects of hypersonic plasma jet on the sprayed particles. The optimised spraying process parameters for several ceramic powders such as Al 2 O 3 , Cr 2 O 3 , ZrO 2 , Cr 3 C 2 and Co-WC were listed. The properties and microstructure of the sprayed ceramic coatings were investigated. Nano Al 2 O 3 -TiO 2 ceramic coating sprayed by using the high efficiency hypersonic plasma spraying was also studied. Compared with the conventional air plasma spraying, high efficiency hypersonic plasma spraying improves greatly the ceramic coatings quality but at low cost. (orig.)

THE INTERACTION OF A COLD ATOMISED SPRAY WITH A CIRCULAR CYLINDER

Directory of Open Access Journals (Sweden)

A. AROUSSI

2010-09-01

Full Text Available The development of non-intrusive diagnostic techniques has significantly increased with the introduction of lasers. Laser based anemometry, such as Laser Doppler (LDA, Phase Doppler (PDA, and Particle Image Velocimetery (PIV can provide an accurate description of flows without interference. This study determines experimentally the fluid motion resulting from the interaction of a liquid spray with a circular cylinder. Two experimental settings were examined: the first is a discharging spray into free air and the second is a spray impinging on a circular cylinder placed 25 cylinder diameters downstream of the nozzle. These sprays were quantified using PIV. A non-intrusive droplet sizing technique was used to characterise the spray. This has shown that, within the spray, the average droplet diameter increases when the circular cylinder is introduced and so does the frequency of occurrence of these large droplets. In the wake behind the cylinder, the smaller droplets were quickly entrained and recirculated, while the larger droplets continued in the general direction of the spray cone.

Effect of spray angle and spray volume on deposition of a medium droplet spray with air support in ivy pot plants.

Science.gov (United States)

Foqué, Dieter; Pieters, Jan G; Nuyttens, David

2014-03-01

Spray boom systems, an alternative to the predominantly-used spray guns, have the potential to considerably improve crop protection management in glasshouses. Based on earlier experiments, the further optimization of the deposits of a medium spray quality extended range flat fan nozzle type using easy adjustable spray boom settings was examined. Using mineral chelate tracers and water sensitive papers, the spray results were monitored at three plant levels, on the upper side and the underside of the leaves, and on some off-target collectors. In addition, the deposition datasets of all tree experiments were compared. The data showed that the most efficient spray distribution with the medium spray quality flat fan nozzles was found with a 30° forward angled spray combined with air support and an application rate of 1000 L ha(-1) . This technique resulted in a more uniform deposition in the dense canopy and increased spray deposition on the lower side of the leaves compared with the a standard spray boom application. Applying 1000 L ha(-1) in two subsequent runs instead of one did not seem to show any added value. Spray deposition can be improved hugely simply by changing some spray boom settings like nozzle type, angling the spray, using air support and adjusting the spray volume to the crop. © 2013 Society of Chemical Industry.

Determination of parameters for successful spray coating of silicon microneedle arrays.

Science.gov (United States)

McGrath, Marie G; Vrdoljak, Anto; O'Mahony, Conor; Oliveira, Jorge C; Moore, Anne C; Crean, Abina M

2011-08-30

Coated microneedle patches have demonstrated potential for effective, minimally invasive, drug and vaccine delivery. To facilitate cost-effective, industrial-scale production of coated microneedle patches, a continuous coating method which utilises conventional pharmaceutical processes is an attractive prospect. Here, the potential of spray-coating silicon microneedle patches using a conventional film-coating process was evaluated and the key process parameters which impact on coating coalescence and weight were identified by employing a fractional factorial design to coat flat silicon patches. Processing parameters analysed included concentration of coating material, liquid input rate, duration of spraying, atomisation air pressure, gun-to-surface distance and air cap setting. Two film-coating materials were investigated; hydroxypropylmethylcellulose (HPMC) and carboxymethylcellulose (CMC). HPMC readily formed a film-coat on silicon when suitable spray coating parameter settings were determined. CMC films required the inclusion of a surfactant (1%, w/w Tween 80) to facilitate coalescence of the sprayed droplets on the silicon surface. Spray coating parameters identified by experimental design, successfully coated 280μm silicon microneedle arrays, producing an intact film-coat, which follows the contours of the microneedle array without occlusion of the microneedle shape. This study demonstrates a novel method of coating microneedle arrays with biocompatible polymers using a conventional film-coating process. It is the first study to indicate the thickness and roughness of coatings applied to microneedle arrays. The study also highlights the importance of identifying suitable processing parameters when film coating substrates of micron dimensions. The ability of a fractional factorial design to identify these critical parameters is also demonstrated. The polymer coatings applied in this study can potentially be drug loaded for intradermal drug and vaccine delivery

Optical fuel spray measurements

Energy Technology Data Exchange (ETDEWEB)

Hillamo, H.

2011-07-01

Diesel fuel sprays, including fuel/air mixing and the physics of two-phase jet formation, are discussed in the thesis. The fuel/air mixing strongly affects emissions formation in spray combustion processes where the local combustion conditions dictate the emission formation. This study comprises optical measurements both in pressurized spray test rigs and in a running engine.The studied fuel injection was arranged with a common rail injection system and the injectors were operated with a solenoid-based injection valve. Both marine and heavy-duty diesel engine injectors were used in the study. Optical fuel spray measurements were carried out with a laser-based double-framing camera system. This kind of equipments is usually used for flow field measurements with Particle Image Velocimetry technique (PIV) as well as for backlight imaging. Fundamental fuel spray properties and spray formation were studied in spray test rigs. These measurements involved studies of mixing, atomization, and the flow field. Test rig measurements were used to study the effect of individual injection parameters and component designs. Measurements of the fuel spray flow field, spray penetration, spray tip velocity, spray angle, spray structure, droplet accumulation, and droplet size estimates are shown. Measurement campaign in a running optically accessible large-bore medium-speed engine was also carried out. The results from engine tests were compared with equivalent test rig measurements, as well as computational results, to evaluate the level of understanding of sprays. It was shown that transient spray has an acceleration and a deceleration phase. Successive flow field measurements (PIV) in optically dense diesel spray resulted in local and average velocity data of diesel sprays. Processing fuel spray generates a flow field to surrounding gas and entrainment of surrounding gas into fuel jet was also seen at the sides of the spray. Laser sheet imaging revealed the inner structure of diesel

No Heat Spray Drying Technology

Energy Technology Data Exchange (ETDEWEB)

Beetz, Charles [ZoomEssence, Inc., Hebron, KY (United States)

2016-06-15

No Heat Spray Drying Technology. ZoomEssence has developed our Zooming™ spray drying technology that atomizes liquids to powders at ambient temperature. The process of drying a liquid into a powder form has been traditionally achieved by mixing a heated gas with an atomized (sprayed) fluid within a vessel (drying chamber) causing the solvent to evaporate. The predominant spray drying process in use today employs air heated up to 400° Fahrenheit to dry an atomized liquid into a powder. Exposing sensitive, volatile liquid ingredients to high temperature causes molecular degradation that negatively impacts solubility, stability and profile of the powder. In short, heat is detrimental to many liquid ingredients. The completed award focused on several areas in order to advance the prototype dryer to a commercial scale integrated pilot system. Prior to the award, ZoomEssence had developed a prototype ‘no-heat’ dryer that firmly established the feasibility of the Zooming™ process. The award focused on three primary areas to improve the technology: (1) improved ability to formulate emulsions for specific flavor groups and improved understanding of the relationship of emulsion properties to final dry particle properties, (2) a new production atomizer, and (3) a dryer controls system.

Spray characteristics and spray cooling heat transfer in the non-boiling regime

International Nuclear Information System (INIS)

Cheng, Wen-Long; Han, Feng-Yun; Liu, Qi-Nie; Fan, Han-Lin

2011-01-01

Spray cooling is an effective method for dissipating high heat fluxes in the field of electronics thermal control. In this study, experiments were performed with distilled water as a test liquid to study the spray cooling heat transfer in non-boiling regime. A Phase Doppler Anemometry (PDA) was used to study the spray characteristics. The effects of spray flow rate, spray height, and inlet temperature on spray cooling heat transfer were investigated. It was found that the parameters affect heat transfer of spray cooling in non-boiling regime by the spray characteristics and working fluid thermophysical properties. Then the corresponding droplet axial velocity and Sauter mean diameter (SMD) were successfully correlated with mean absolute error of 15%, which were based upon the orifice diameter, the Weber and Reynolds numbers of the orifice flow prior to liquid breakup, dimensionless spray height and spray cross-section radius. The heat transfer in non-boiling regime was correlated with a mean absolute error of 7%, which was mainly associated with the working fluid thermophysical properties, the Weber and Reynolds numbers hitting the heating surface, dimensionless heating surface temperature and diameter. -- Highlights: → The spray flow rate, spray height, and inlet temperature affect heat transfer of spray cooling in non-boiling regime by the spray characteristics and the working fluid thermophysical properties. → Then the corresponding droplet axial velocity and Sauer mean diameter (SMD) were successfully correlated with mean absolute error of 15%. → The heat transfer in non-boiling regime was correlated with a mean absolute error of 7%.

Spray deposition and spray drift in orchard spraying by multiple row sprayers

NARCIS (Netherlands)

Wenneker, M.; Zande, van de J.C.; Michielsen, J.G.P.; Stallinga, H.; Velde, van P.

2016-01-01

The evaluation of the latest data on spray drift in orchard spraying in the Netherlands, and measurements of surface water quality parameters show that the current legislation and measures are insufficient to protect the surface water. To meet the national and European objectives regarding surface

Microstructure formation and corrosion behaviour in HVOF-sprayed Inconel 625 coatings

International Nuclear Information System (INIS)

Zhang, D.; Harris, S.J.; McCartney, D.G.

2003-01-01

The nickel-based alloy Inconel 625 was thermally sprayed by two different variants of the high velocity oxy-fuel process. In this study, coatings deposited by a liquid-fuelled gun were compared with those produced by a gas-fuelled system; in general, the former generates higher particle velocities but lower particle temperatures. Investigations into the microstructural evolution of the coatings, using scanning electron microscopy and X-ray diffraction, are presented along with results on their aqueous corrosion behaviour, obtained from salt spray and potentiodynamic tests. It is inferred from coating microstructures that, during spraying, powder particles generally comprised three separate zones as follows: fully melted regions; partially melted zones; and an unmelted core. However, the relative proportions formed in an individual powder particle depended on its size, trajectory through the gun, the gas dynamics (velocity/temperature) of the thermal spray gun and the type of gun employed. Cr 2 O 3 was the principal oxide phase formed during spraying and the quantity appeared to be directly related to the degree to which particles were melted. The salt spray test provides a sensitive means of determining the presence of interconnected porosity in coatings and those produced with the liquid-fuelled gun exhibited reduced interconnected porosity and increased corrosion resistance compared with deposits obtained from the gas-fuelled system. In addition, potentiodynamic tests revealed that passive current densities are 10-20 times lower in liquid-fuel coatings than in those sprayed with the gas-fuelled gun

Spray From a Rolling Tire: Mechanics of Droplet Formation

Science.gov (United States)

Plocher, Dennis; Browand, Fred

2010-11-01

The spray pattern immediately behind a single-groove tire rolling on a wet surface is produced in the laboratory using a specially designed tire spray simulator. The spray development is examined using high speed video. Water from the groove forms a liquid sheet as the tire-tread lifts away from the surface. The sheet is not of uniform thickness, but it remains attached to the tread. The thinner portions of the sheet become even thinner as the tire rotates, and eventually break to produce holes near the tire surface. The holes grow as the sheet margins surrounding the holes retract into the thicker portions of the sheet which become roughly cylindrical "ligaments" aligned at right angles to the direction of spray motion. The ligaments break into large droplets via a Rayleigh instability. The smallest droplets form when the margins of two holes collide. As Weber number, We = ρU^2w/2σ , based on tire groove half width, w/2, varies by a factor of 25, the sheet-ligament structure persists, but ligaments become less organized, and more small droplets appear in the pattern.

MODEL REPRESENTATION OF THE SPRAY DRYING PROCESS OF THE DISTILLERY STILLAGE FILTRATE BASED ON NAVIERSTOKES EQUATIONS

Directory of Open Access Journals (Sweden)

A. A. Shevtsov

2015-01-01

Full Text Available Spray drying of solutions and suspensions is among the most common methods of producing a wide range of powdered products in chemical, food and pharmaceutical industries. For the drying of heat-sensitive materials, which is fully applicable to the distillery stillage filtrate continuous-flow type of contact of drying agent and the solution droplets is examined. Two-phase simulation method of computational hydrodynamics in a stationary state for studying the process of drying of the distillery stillage filtrate in the pilot spray dryer under the following assumptions was used. The components form an ideal mixture, the properties of which are calculated directly from the properties of the components and their proportions. The droplets were presented in spherical form. The density and specific heat of the solution and the coefficient of vapors diffusion in the gas phase remained unchanged. To solve the heat exchange equations between the drying agent and the drops by the finite volume method the software package ANSYS CFX was used. The bind between the two phases was established by Navier-Stokes equations. The continuous phase (droplets of the distillery stillage filtrate was described by the k-ε turbulence model. The results obtained showed that the interaction of "drop-wall" causes a significant change of velocity, temperature and humidity both of a drying agent and the product particles. The behavior of the particles by spraying, collision with walls and deposition of the finished product allowed to determine the dependence of physical parameters of the drying process, of the geometric dimensions of the dryer. Comparison of simulation results with experimental data showed satisfactory convergence of the results: for the temperature of the powder 10% its humidity of 12% and temperature of the spent drying agent at the outlet from the drier of 13%. The possibility of using the model in the spray dryers designing, and control of the drying process

Effect of spray application technique on spray deposition in greenhouse strawberries and tomatoes.

Science.gov (United States)

Braekman, Pascal; Foque, Dieter; Messens, Winy; Van Labeke, Marie-Christine; Pieters, Jan G; Nuyttens, David

2010-02-01

Increasingly, Flemish greenhouse growers are using spray booms instead of spray guns to apply plant protection products. Although the advantages of spray booms are well known, growers still have many questions concerning nozzle choice and settings. Spray deposition using a vertical spray boom in tomatoes and strawberries was compared with reference spray equipment. Five different settings of nozzle type, size and pressure were tested with the spray boom. In general, the standard vertical spray boom performed better than the reference spray equipment in strawberries (spray gun) and in tomatoes (air-assisted sprayer). Nozzle type and settings significantly affected spray deposition and crop penetration. Highest overall deposits in strawberries were achieved using air-inclusion or extended-range nozzles. In tomatoes, the extended-range nozzles and the twin air-inclusion nozzles performed best. Using smaller-size extended-range nozzles above the recommended pressure range resulted in lower deposits, especially inside the crop canopy. The use of a vertical spray boom is a promising technique for applying plant protection products in a safe and efficient way in tomatoes and strawberries, and nozzle choice and setting should be carefully considered.

Indoor spray measurement of spray drift potential using a spray drift test bench : effect of drift-reducing nozzle types, spray boom height, nozzle spacing and forward speed

NARCIS (Netherlands)

Moreno Ruiz, J.R.

2014-01-01

In a series of indoor experiments spray drift potential was assessed when spraying over a spray drift testbench with two different driving speeds, 2m/s and 4m/s, two different spray boom heights, 30 cm and 50 cm, and two different nozzle spacing, 25 cm and 50 cm, for six different nozzle types. The

Spray drying of bead resins: feasibility tests

International Nuclear Information System (INIS)

Gay, R.L.; Grantham, L.F.; Jones, L.J.

1984-01-01

Rockwell International has developed a volume reduction system for low-level reactor wastes based on drying the wastes in a heated-air spray dryer. The drying of slurries of sodium sulfate, boric acid, and powdered ion exchange resins was demonstrated in previous tests. The drying of bead ion exchange resins can be especially difficult due to the relatively large size of bead resins (about 500 to 800 microns) and their natural affinity for water. This water becomes part of the pore structure of the resins and normally comprises 50 t 60 wt % of the resin weight. A 76-cm-diameter spray dryer was used for feasibility tests of spray drying of cation and anion bead resins. These resins were fed to the dryer in the as-received form (similar to dewatered resins) and as slurries. A dry, free-flowing product was produced in all the tests. The volume of the spray-dried product was one-half to one-third the volume of the as-received material. An economic analysis was made of the potential cost savings that can be achieved using the Rockwel spray dryer system. In-plant costs, transportation costs, and burial costs of spray-dried resins were compared to similar costs for disposal of dewatered resins. A typical utility producing 170 m 3 (6,000 ft 3 ) per year of dewatered resins can save $600,000 to $700,000 per year using this volume reduction system

Microstructure and mechanical properties of spray deposited hypoeutectic Al-Si alloy

International Nuclear Information System (INIS)

Ferrarini, C.F.; Bolfarini, C.; Kiminami, C.S.; Botta F, W.J.

2004-01-01

The microstructure and the tensile properties of an Al-8.9 wt.% Si-3.2 wt.% Cu-0.9 wt.% Fe-0.8% Zn alloy processed by spray forming was investigated. The alloy was gas atomized with argon and deposited onto a copper substrate. The microstructure was evaluated by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Small faceted dispersoids observed surrounding equiaxial α-Al matrix were identified by SEM-EDS as silicon particles. Sand cast samples with the same composition showed a columnar dendritic α-Al matrix, Al-Si eutectic, polyhedric α-AlFeSi and needle-like β-AlFeSi intermetallics. In the spray formed material the formation of the Al-Si eutetic was suppressed, and the formation of the α-AlFeSi and β-AlFeSi intermetallics was strongly reduced. The fine and homogeneous microstructure showed an aluminium matrix with grain size ranging from 30 to 40 μm, and particle size of the silicon dispersoids having a mean size of 12 μm. Room temperature tensile tests of the spray formed alloy showed relative increasing of strength and elongation when compared with the values observed for the conventionally cast counterparts. These results can be ascribed to the refined microstructure and the scarce presence of intermetallics of the spray formed material

Effect of layer thickness on the properties of nickel thermal sprayed steel

Energy Technology Data Exchange (ETDEWEB)

Nurisna, Zuhri, E-mail: zuhri-nurisna@yahoo.co.id; Triyono,, E-mail: triyonomesin@uns.ac.id; Muhayat, Nurul, E-mail: nurulmuhayat@staff.uns.ac.id; Wijayanta, Agung Tri, E-mail: agungtw@uns.ac.id [Department of Mechanical Engineering, Sebelas Maret University, Jl. Jr. Sutami 36 A, Surakarta (Indonesia)

2016-03-29

Thermal arc spray nickel coating is widely used for decorative and functional applications, by improving corrosion resistance, wear resistance, heat resistence or by modifying other properties of the coated materials. There are several properties have been studied. Layer thickness of nickel thermal sprayed steel may be make harder the substrate surface. In this study, the effect of layer thickness of nickel thermal sprayed steel has been investigated. The rectangular substrate specimens were coated by Ni–5 wt.% Al using wire arc spray method. The thickness of coating layers were in range from 0.4 to 1.0 mm. Different thickness of coating layers were conducted to investigate their effect on hardness and morphology. The coating layer was examined by using microvickers and scanning electron microscope with EDX attachment. Generally, the hardness at the interface increased with increasing thickness of coating layers for all specimens due to higher heat input during spraying process. Morphology analysis result that during spraying process aluminum would react with surrounding oxygen and form aluminum oxide at outer surface of splat. Moreover, porosity was formed in coating layers. However, presence porosity is not related to thickness of coating material. The thicker coating layer resulted highesr of hardness and bond strength.

Spray Drying of High Sugar Content Foods: Improving of Product Yield and Powder Properties

Directory of Open Access Journals (Sweden)

Mehmet Koç

2016-05-01

Full Text Available Spray drying is the most preferred drying method to produce powdered food in the food industry and it is also widely used to convert sugar-rich liquid foods to a powder form. During and/or after spray drying process of sugar-rich products, undesirable situation was appeared such as stickiness, high moisture affinity (hygroscopicity and low solubility due to low molecular weight monosaccharides that found naturally in the structure. The basis of these problems was formed by low glass transition temperature of sugar-rich products. This review gives information about the difficulties in drying of sugar-rich products via spray dryer, actions need to be taken against these difficulties and drying of sugar-rich honey and fruit juices with spray drying method.

Spray cooling

International Nuclear Information System (INIS)

Rollin, Philippe.

1975-01-01

Spray cooling - using water spraying in air - is surveyed as a possible system for make-up (peak clipping in open circuit) or major cooling (in closed circuit) of the cooling water of the condensers in thermal power plants. Indications are given on the experiments made in France and the systems recently developed in USA, questions relating to performance, cost and environmental effects of spray devices are then dealt with [fr

Advances in Thermal Spray Deposition of Billets for Particle Reinforced Light Metals

International Nuclear Information System (INIS)

Wenzelburger, Martin; Zimmermann, Christian; Gadow, Rainer

2007-01-01

Forming of light-metals in semi-solid state offers some advantages like low process temperatures, improved mould durability, good flow behavior and fine, globular microstructure of the final material. By the introduction of ceramic particles, increased elastic modulus and yield strength as well as wear resistance and creep behavior can be obtained. By semi-solid forging or semi-solid casting, particle reinforced metals (PRM) can be produced with improved matrix microstructure and beneficial forming process parameters compared to conventional MMC manufacturing techniques. The production of this kind of light metal matrix composites requires the supply of dense semi-finished parts with well defined volume fractions of homogeneously distributed particulate reinforcement. A manufacturing method for cylindrical light metal billets is described that applies thermal spraying as a build-up process for simultaneous deposition of matrix and reinforcement phase with cored wires as spraying material. Thermal spraying leads to small grain sizes and prevents dendrite formation. However, long process cycle times lead to billet heating and recrystallization of the matrix microstructure. In order to preserve small grain sizes that enable semi-solid forming, the thermal spraying process was analyzed by in-flight particle analysis and thermography. As a consequence, the deposition process was optimized by adaptation of the thermal spraying parameters and by application of additional cooling, leading to lower billet temperatures and finer PRM billet microstructure

NACOM - a code for sodium spray fire analysis

International Nuclear Information System (INIS)

Rao, P.M.; Kannan, S.E.

2002-01-01

Full text: In liquid metal fast breeder reactors (LMFBR), leakage of sodium can result in a spray fire. Because of higher burning rates in droplet form combustion of sodium in spray fire, thermal consequences are more severe than that in a sodium pool fire. The code NACOM was developed for the analysis of sodium spray fires in LMFBRs facilities. The code uses the validated model for estimating the falling droplet burning rates in pre-ignition and vapour phase combustion stages. It uses a distribution system to generate the droplet groups of different diameters that represent the spray. The code requires about 20 input parameters like sodium leak rates, sodium temperature, initial cell conditions like oxygen concentration, temperature and dimensions. NACOM is a validated code based on experiments with sodium inventory up to 650 kg in 0 to 21 % O 2 atmospheres. The paper brings out the salient features of the code along with the sensitivity analysis of the main input parameters like spray volume mean diameter, oxygen concentration etc. based on the results obtained. The limitations of the code and the confidence margins applicable to results obtained are also brought out

Spray boom for selectively spraying a herbicidal composition onto dicots

DEFF Research Database (Denmark)

2012-01-01

There is provided a method and spray boom for discriminating cereal crop (monocot) and weeds (dicots). The spray boom includes means for digitally recording an image of a selected area to be treated by a nozzle on the spray boom, whereby a plant material is identified based on a segmentation proc...

Spray forming of Cu–11.85Al–3.2Ni–3Mn (wt%) shape memory alloy

Energy Technology Data Exchange (ETDEWEB)

Cava, Régis D., E-mail: regis_cava@hotmail.com [Department of Materials Engineering, Federal University of São Carlos, São Carlos (Brazil); Bolfarini, Claudemiro; Kiminami, Cláudio S. [Department of Materials Engineering, Federal University of São Carlos, São Carlos (Brazil); Mazzer, Eric M. [Postgraduate Program in Materials Science and Engineering, Federal University of São Carlos (Brazil); Botta Filho, Walter J. [Department of Materials Engineering, Federal University of São Carlos, São Carlos (Brazil); Gargarella, Piter; Eckert, Jürger [IFW Dresden, Institute for Complex Materials, Dresden (Germany)

2014-12-05

Highlights: • We characterized a Cu-based shape memory alloy produced by spray forming. • The deposit presented equiaxial grains and monoclinic martensite β′ microstructure. • The deposit’s shape memory properties varied as a function of the cooling rates. • The results opened a new window in the manufacture of Cu shape memory materials. - Abstract: Cu-based shape memory alloys (SMA) in the range of Cu–(11.8–13.5)Al–(3.2–4)Ni–(2–3)Mn (wt%) exhibit high thermal and electrical conductivity, combine good mechanical properties with a pronounced shape memory effect, and are low cost (Dutkiewicz et al., 1999). Their processing requires high cooling rates to reduce grain size, prevent decomposition of the ß phase into equilibrium phases, and induce martensite transformation. In this investigation, Cu–11.85Al–3.2Ni–3Mn (wt%) shape memory alloy was processed by spray forming, a rapid solidification technique that involves cooling rates of 10{sup 1} to 10{sup 4} K/s, to determine the potential of producing deposits with adequate microstructure, homogeneity and porosity for the manufacture of SMA near net shape parts. To this end, 5.2 kg of alloy with nominal composition was atomized with nitrogen gas under a pressure of 0.5 MPa and a gas–metal ratio (GMR) of 1.93. The atomized material was deposited at 60 rpm on a rotating steel substrate positioned 350 mm below the gas nozzle. The microstructure of the deposit was characterized by optical and scanning electron microscopy, X-ray diffraction and differential scanning calorimetry. The deposit with an effective diameter of 240 mm and 75 mm height presented equiaxial grains with a martensite microstructure. Grain sizes varied from 25 μm in the lower region (contact with the steel substrate) to 160 μm in the upper region of the deposit. Measurements of the reverse martensite transformation temperature of the deposit in different regions revealed its strong influence on the grain size.

Electrical properties of pressure quenched silicon by thermal spraying

International Nuclear Information System (INIS)

Tan, S.Y.; Gambino, R.J.; Sampath, S.; Herman, H.

2007-01-01

High velocity thermal spray deposition of polycrystalline silicon film onto single crystal substrates, yields metastable high pressure forms of silicon in nanocrystalline form within the deposit. The phases observed in the deposit include hexagonal diamond-Si, R-8, BC-8 and Si-IX. The peculiar attribute of this transformation is that it occurs only on orientation silicon substrate. The silicon deposits containing the high pressure phases display a substantially higher electrical conductivity. The resistivity profile of the silicon deposit containing shock induced metastable silicon phases identified by X-ray diffraction patterns. The density of the pressure induced polymorphic silicon is higher at deposit/substrate interface. A modified two-layer model is presented to explain the resistivity of the deposit impacted by the pressure induced polymorphic silicon generated by the thermal spraying process. The pressure quenched silicon deposits on the p - silicon substrate, with or without metastable phases, display the barrier potential of about 0.72 eV. The measured hall mobility value of pressure quenched silicon deposits is in the range of polycrystalline silicon. The significance of this work lies in the fact that the versatility of thermal spray may enable applications of these high pressure forms of silicon

Reduction of spray pressure leads to less emission and better deposition of spray liquid at high-volume spraying in greenhouse tomato

NARCIS (Netherlands)

Os, van E.A.; Michielsen, J.M.G.P.; Corver, F.J.M.; Berg, van den J.V.; Bruins, M.A.; Porskamp, H.A.J.; Zande, van de J.C.

2005-01-01

In an experimental greenhouse, growing a tomato crop, it was investigated if a reduction in spray pressure could improve the spray result, while, simultaneously, emission to the ground could be reduced. Spray deposition on the leaves and the emission to the ground was evaluated at different spray

Effects of nozzle type and spray angle on spray deposition in ivy pot plants.

Science.gov (United States)

Foqué, Dieter; Nuyttens, David

2011-02-01

Fewer plant protection products are now authorised for use in ornamental growings. Frequent spraying with the same product or a suboptimal technique can lead to resistance in pests and diseases. Better application techniques could improve the sustainable use of the plant protection products still available. Spray boom systems--instead of the still predominantly used spray guns--might improve crop protection management in greenhouses considerably. The effect of nozzle type, spray pressure and spray angle on spray deposition and coverage in ivy pot plants was studied, with a focus on crop penetration and spraying the bottom side of the leaves in this dense crop. The experiments showed a significant and important effect of collector position on deposition and coverage in the plant. Although spray deposition and coverage on the bottom side of the leaves are generally low, they could be improved 3.0-4.9-fold using the appropriate application technique. When using a spray boom in a dense crop, the nozzle choice, spray pressure and spray angle should be well considered. The hollow-cone, the air-inclusion flat-fan and the standard flat-fan nozzle with an inclined spray angle performed best because of the effect of swirling droplets, droplets with a high momentum and droplet direction respectively. Copyright © 2010 Society of Chemical Industry.

Continuous internal channels formed in aluminum fusion welds

Science.gov (United States)

Gault, J.; Sabo, W.

1967-01-01

Process produces continuous internal channel systems on a repeatable basis in 2014-T6 aluminum. Standard machining forms the initial channel, which is filled with tungsten carbide powder. TIG machine fusion welding completes formation of the channel. Chem-mill techniques enlarge it to the desired size.

Processamento de achocolatado de cupuaçu por spray-dryer Cupuassu chocolate drink powder processed by spray-dryer

Directory of Open Access Journals (Sweden)

Suzana Caetano da Silva Lannes

2003-03-01

Full Text Available O achocolatado de cupuaçu é uma mistura do pó de cupuaçu, açúcar, aroma e outros ingredientes constantes da formulação. Este produto formulado foi processado por spray-dryer, gerando um produto seco, pulverizado e instantaneizado. O achocolatado acrescido de água (concentrado passa pelo spray-dryer formando glóbulos de pequeno diâmetro que são arrastados por uma corrente de ar quente. A rápida evaporação de líquido permite manter baixa a temperatura do ar na secagem, não afetando o produto. O pó de cupuaçu não dispersa prontamente em água devido ao seu conteúdo de óleo. Conseqüentemente, necessita-se de uma forma desengordurada para se obter instantaneização. A secagem por spray-dryer reúne as melhores condições de rendimento técnico em comparação com outros processos. Obtiveram rendimentos de processo acima de 20% e a instantaneização completa do produto.Cupuassu chocolate drink powder is a mixture of cupuassu powder, sugar, flavour and other ingredients of formulation. The product was processed by spray-dryer, leading a dry, pulverized and instantised product. The chocolate drink powder with water (concentrated pass through spray-dryer forming small diameter globules that are arrested by a hot air stream. The rapid evaporation allows keeping low temperature at drying air, and no affecting the product. The process is a set of better conditions of technique and economical efficiency in comparison to other process. Cupuassu powder does not disperse readily in water owing to its oil content. Consequently, a form of cocoa with the oil removed is needed to produce an acceptably instant drink. The results obtained were satisfactory, due to the complete instantisation of the product after processing.

Experimental and numerical analysis of the cooling performance of water spraying systems during a fire.

Directory of Open Access Journals (Sweden)

YaoHan Chen

Full Text Available The water spray systems are effective protection systems in the confined or unconfined spaces to avoid the damage to building structures since the high temperature when fires occur. NFPA 15 and 502 have suggested respectively that the factories or vehicle tunnels install water spray systems to protect the machinery and structures. This study discussed the cooling effect of water spray systems in experimental and numerical analyses. The actual combustion of woods were compared with the numerical simulations. The results showed that although the flame continued, the cooling effects by water spraying process within 120 seconds were obvious. The results also indicated that the simulation results of the fifth version Fire Dynamics Simulator (FDS overestimated the space temperature before water spraying in the case of the same water spray system.

Standard practice for modified salt spray (fog) testing

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 This practice covers and sets forth conditions for five modifications in salt spray (fog) testing for specification purposes. These are in chronological order of their development: 1.1.1 Annex A1, acetic acid-salt spray test, continuous. 1.1.2 Annex A2, cyclic acidified salt spray test. 1.1.3 Annex A3, seawater acidified test, cyclic (SWAAT). 1.1.4 Annex A4, SO2 salt spray test, cyclic. 1.1.5 Annex A5, dilute electrolyte cyclic fog dry test. 1.2 This practice does not prescribe the type of modification, test specimen or exposure periods to be used for a specific product, nor the interpretation to be given to the results. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to consult and establish appropriate safety and health practices and determine the applicabilit...

Radiolysis of spray solutions

International Nuclear Information System (INIS)

Habersbergerova, A.; Janovsky, I.

1985-01-01

The factors were studied affecting thiosulfate radiolysis in the so-called spray solution for nuclear power plant containments. The reaction mechanism of primary radiolytic reactions leading to thiosulfate decomposition was studied using pulse radiolysis. Also measured was hydrazine loss in the irradiation of the bubbling solution intended for the capture of volatile chemical forms of radioiodine. Pulse radiolysis was used to study the kinetics of hydrazine reaction with elemental iodine. (author)

Method and closing pores in a thermally sprayed doped lanthanum chromite interconnection layer

Science.gov (United States)

Singh, Prabhakar; Ruka, Roswell J.

1995-01-01

A dense, substantially gas-tight electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an air electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element or elements selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by thermal spraying doped LaCrO.sub.3 particles, either by plasma arc spraying or flame spraying; (C) depositing a mixture of CaO and Cr.sub.2 O.sub.3 on the surface of the thermally sprayed layer; and (D) heating the doped LaCrO.sub.3 layer coated with CaO and Cr.sub.2 O.sub.3 surface deposit at from about 1000.degree. C. to 1200.degree. C. to substantially close the pores, at least at a surface, of the thermally sprayed doped LaCrO.sub.3 layer. The result is a dense, substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the nonselected portion of the air electrode. A fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell, for example for generation of electrical power.

Measurements and predictions for nonevaporating sprays in a quiescent environment

Science.gov (United States)

Solomon, A. S. P.; Shuen, J.-S.; Faeth, G. M.; Zhang, Q.-F.

1983-01-01

Yule et al. (1982) have conducted a study of vaporizing sprays with the aid of laser techniques. The present investigation has the objective to supplement the measurements performed by Yule et al., by considering the limiting case of a spray in a stagnant environment. Mean and fluctuating velocities of the continuous phase are measured by means of laser Doppler anemometry (LDA) techniques, while Fraunhofer diffraction and slide impaction methods are employed to determine drop sizes. Liquid fluxes in the spray are found by making use of an isokinetic sampling probe. The obtained data are used as a basis for the evaluation of three models of the process, including a locally homogeneous flow (LHF) model, a deterministic separated flow (DSF) model, and a stochastic separated flow (SSF) model. It is found that the LHF and DSF models do not provide very satisfactory predictions for the test sprays, while the SSF model does provide reasonably good predictions of the observed structure.

Evaluation of sprayed hypochlorous acid solutions for their virucidal activity against avian influenza virus through in vitro experiments

Science.gov (United States)

HAKIM, Hakimullah; THAMMAKARN, Chanathip; SUGURO, Atsushi; ISHIDA, Yuki; KAWAMURA, Akinobu; TAMURA, Miho; SATOH, Keisuke; TSUJIMURA, Misato; HASEGAWA, Tomomi; TAKEHARA, Kazuaki

2014-01-01

Hypochlorous acid (HOCl) solutions were evaluated for their virucidal ability against a low pathogenic avian influenza virus (AIV), H7N1. HOCl solutions containing 50, 100 and 200 ppm chlorine (pH 6) or their sprayed solutions (harvested in dishes placed at 1 or 30 cm distance between the spray nozzle and dish) were mixed with the virus with or without organic materials (5% fetal bovine serum: FBS). Under plain diluent conditions (without FBS), harvested solutions of HOCl after spraying could decrease the AIV titer by more than 1,000 times, to an undetectable level (< 2.5 log10TCID50/ml) within 5 sec, with the exception of the 50 ppm solution harvested after spraying at the distance of 30 cm. Under the dirty conditions (in the presence of 5% FBS), they lost their virucidal activity. When HOCl solutions were sprayed directly on the virus on rayon sheets for 10 sec, the solutions of 100 and 200 ppm could inactivate AIV immediately after spraying, while 50 ppm solution required at least 3 min of contact time. In the indirect spray form, after 10 sec of spraying, the lids of the dishes were opened to expose the virus on rayon sheets to HOCl. In this form, the 200 ppm solution inactivated AIV within 10 min of contact, while 50 and 100 ppm could not inactivate it. These data suggest that HOCl can be used in spray form to inactivate AIV at the farm level. PMID:25421399

Evaluation of sprayed hypochlorous acid solutions for their virucidal activity against avian influenza virus through in vitro experiments.

Science.gov (United States)

Hakim, Hakimullah; Thammakarn, Chanathip; Suguro, Atsushi; Ishida, Yuki; Kawamura, Akinobu; Tamura, Miho; Satoh, Keisuke; Tsujimura, Misato; Hasegawa, Tomomi; Takehara, Kazuaki

2015-02-01

Hypochlorous acid (HOCl) solutions were evaluated for their virucidal ability against a low pathogenic avian influenza virus (AIV), H7N1. HOCl solutions containing 50, 100 and 200 ppm chlorine (pH 6) or their sprayed solutions (harvested in dishes placed at 1 or 30 cm distance between the spray nozzle and dish) were mixed with the virus with or without organic materials (5% fetal bovine serum: FBS). Under plain diluent conditions (without FBS), harvested solutions of HOCl after spraying could decrease the AIV titer by more than 1,000 times, to an undetectable level (< 2.5 log10TCID50/ml) within 5 sec, with the exception of the 50 ppm solution harvested after spraying at the distance of 30 cm. Under the dirty conditions (in the presence of 5% FBS), they lost their virucidal activity. When HOCl solutions were sprayed directly on the virus on rayon sheets for 10 sec, the solutions of 100 and 200 ppm could inactivate AIV immediately after spraying, while 50 ppm solution required at least 3 min of contact time. In the indirect spray form, after 10 sec of spraying, the lids of the dishes were opened to expose the virus on rayon sheets to HOCl. In this form, the 200 ppm solution inactivated AIV within 10 min of contact, while 50 and 100 ppm could not inactivate it. These data suggest that HOCl can be used in spray form to inactivate AIV at the farm level.

Fabrication of Semiconducting Methylammonium Lead Halide Perovskite Particles by Spray Technology

Science.gov (United States)

Ahmadian-Yazdi, Mohammad-Reza; Eslamian, Morteza

2018-01-01

In this "nano idea" paper, three concepts for the preparation of methylammonium lead halide perovskite particles are proposed, discussed, and tested. The first idea is based on the wet chemistry preparation of the perovskite particles, through the addition of the perovskite precursor solution to an anti-solvent to facilitate the precipitation of the perovskite particles in the solution. The second idea is based on the milling of a blend of the perovskite precursors in the dry form, in order to allow for the conversion of the precursors to the perovskite particles. The third idea is based on the atomization of the perovskite solution by a spray nozzle, introducing the spray droplets into a hot wall reactor, so as to prepare perovskite particles, using the droplet-to-particle spray approach (spray pyrolysis). Preliminary results show that the spray technology is the most successful method for the preparation of impurity-free perovskite particles and perovskite paste to deposit perovskite thin films. As a proof of concept, a perovskite solar cell with the paste prepared by the sprayed perovskite powder was successfully fabricated.

Fabrication of Semiconducting Methylammonium Lead Halide Perovskite Particles by Spray Technology.

Science.gov (United States)

Ahmadian-Yazdi, Mohammad-Reza; Eslamian, Morteza

2018-01-10

In this "nano idea" paper, three concepts for the preparation of methylammonium lead halide perovskite particles are proposed, discussed, and tested. The first idea is based on the wet chemistry preparation of the perovskite particles, through the addition of the perovskite precursor solution to an anti-solvent to facilitate the precipitation of the perovskite particles in the solution. The second idea is based on the milling of a blend of the perovskite precursors in the dry form, in order to allow for the conversion of the precursors to the perovskite particles. The third idea is based on the atomization of the perovskite solution by a spray nozzle, introducing the spray droplets into a hot wall reactor, so as to prepare perovskite particles, using the droplet-to-particle spray approach (spray pyrolysis). Preliminary results show that the spray technology is the most successful method for the preparation of impurity-free perovskite particles and perovskite paste to deposit perovskite thin films. As a proof of concept, a perovskite solar cell with the paste prepared by the sprayed perovskite powder was successfully fabricated.

Machinability of Al 6061 Deposited with Cold Spray Additive Manufacturing

Science.gov (United States)

Aldwell, Barry; Kelly, Elaine; Wall, Ronan; Amaldi, Andrea; O'Donnell, Garret E.; Lupoi, Rocco

2017-10-01

Additive manufacturing techniques such as cold spray are translating from research laboratories into more mainstream high-end production systems. Similar to many additive processes, finishing still depends on removal processes. This research presents the results from investigations into aspects of the machinability of aluminum 6061 tubes manufactured with cold spray. Through the analysis of cutting forces and observations on chip formation and surface morphology, the effect of cutting speed, feed rate, and heat treatment was quantified, for both cold-sprayed and bulk aluminum 6061. High-speed video of chip formation shows changes in chip form for varying material and heat treatment, which is supported by the force data and quantitative imaging of the machined surface. The results shown in this paper demonstrate that parameters involved in cold spray directly impact on machinability and therefore have implications for machining parameters and strategy.

Linear Stability Analysis of Laminar Premixed Fuel-Rich Double-Spray Flames

Directory of Open Access Journals (Sweden)

Noam Weinberg

2014-03-01

Full Text Available This paper considers the stability of a double-spray premixed flame formed when both fuel and oxidizer are initially present in the form of sprays of evaporating liquid droplets. To simplify the inherent complexity that characterizes the analytic solution of multi-phase combustion processes, the analysis is restricted to fuel-rich laminar premixed double-spray flames, and assumes a single-step global chemical reaction mechanism. Steady-state solutions are obtained and the sensitivity of the flame temperature and the flame propagating velocity to the initial liquid fuel and/or oxidizer loads are established. The stability analysis revealed an increased proneness to cellular instability induced by the presence of the two sprays, and for the fuel-rich case considered here the influence of the liquid oxidizer was found to be more pronounced than that of the liquid fuel. Similar effects were noted for the neutral pulsating stability boundaries. The impact of unequal latent heats of vaporization is also investigated and found to be in keeping with the destabilizing influence of heat loss due to droplet evaporation. It should be noted that as far as the authors are aware no experimental evidence is available for (at least validation of the predictions. However, they do concur in a general and reasonable fashion with independent experimental evidence in the literature of the behavior of single fuel spray laminar premixed flames.

Effect of the borax mass and pre-spray medium temperature on droplet size and velocity vector distributions of intermittently sprayed starchy solutions.

Science.gov (United States)

Naz, Muhammad Yasin; Sulaiman, Shaharin Anwar; Ariwahjoedi, Bambang

2015-02-07

Spray coating technology has demonstrated great potential in the slow release fertilizers industry. The better understanding of the key spray parameters benefits both the environment and low cost coating processes. The use of starch based materials to coat the slow release fertilizers is a new development. However, the hydraulic spray jet breakup of the non-Newtonian starchy solutions is a complex phenomenon and very little known. The aim of this research was to study the axial and radial distributions of the Sauter Mean Diameter (SMD) and velocity vectors in pulsing spray patterns of native and modified tapioca starch solutions. To meet the objective, high speed imaging and Phase Doppler Anemometry (PDA) techniques were employed to characterize the four compositions of the starch-urea-borax complex namely S0, S1, S2 and S3. The unheated solutions exhibited very high viscosities ranging from 2035 to 3030 cP. No jet breakup was seen at any stage of the nozzle operation at an injection pressure of 1-5 bar. However, at 80 °C temperature and 5 bar pressure, the viscosity was reduced to 455 to 638 cP and dense spray patterns emerged from the nozzle obscuring the PDA signals. The axial size distribution revealed a significant decrease in SMD along the spray centreline. The smallest axial SMD (51 to 79 μm) was noticed in S0 spray followed by S1, S2 and S3. Unlikely, the radial SMD in S0 spray did not vary significantly at any stage of the spray injection. This trend was attributed to the continuous growth of the surface wave instabilities on the native starch sheet. However, SMD obtained with S1, S2 and S3 varied appreciably along the radial direction. The mean velocity vector profiles followed the non-Gaussian distribution. The constant vector distributions were seen in the near nozzle regions, where the spray was in the phase of development. In far regions, the velocity vectors were poly-dispersed and a series of ups and downs were seen in the respective radial

U.S. Air Forces Aerial Spray Mission: Should the Department of Defense Continue to Operate this Weapon of Mass Dispersion

Science.gov (United States)

2015-12-01

or should it be outsourced to commercial sources. This research investigates the many advantages and disadvantages of the military aerial spray...Aerial Spraying for Mosquito Control for Fort Bend County – Technical Specifications Compliance , 12 June 2014. Federal Aviation Administration, Air

Structure of steam water mixture spray

International Nuclear Information System (INIS)

Mitsuhashi, Yuki; Mizutani, Hiroya; Sanada, Toshiyuki; Saito, Takayuki

2008-01-01

The flow structure of steam and water mixture spray is studied both numerically and experimentally. The velocity and pressure profiles of the single phase flow are calculated using numerical methods. Using calculated flow fields, the droplet behavior is predicted by the one-way interaction model. This numerical analysis clarifies that the droplets are still accelerated after they are sprayed from the nozzle. In the experiments, the spray of the mixture is observed by using ultra high-speed video camera, and the velocity field is measured by using PIV technique. Along with this PIV velocity field measurement, the velocities and diameters of droplets are measured by phase Doppler anemometry. Furthermore, mixing process of steam and water, and atomization process of liquid film are observed through the transparent nozzle. The high-speed photography observation reveals that the flow inside the nozzle forms the annular flow and the most of the liquid film is atomized at the nozzle outlet. Finally, the optimum method of processing mixture of steam and water is proposed. (author)

Coated particle waste form development

International Nuclear Information System (INIS)

Oma, K.H.; Buckwalter, C.Q.; Chick, L.A.

1981-12-01

Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes

Radio frequency induction plasma spraying of molybdenum

International Nuclear Information System (INIS)

Jiang Xianliang

2003-01-01

Radio frequency (RF) induction plasma was used to make free-standing deposition of molybdenum (Mo). The phenomena of particle melting, flattening, and stacking were investigated. The effect of process parameters such as plasma power, chamber pressure, and spray distance on the phenomena mentioned above was studied. Scanning electron microscopy (SEM) was used to analyze the plasma-processed powder, splats formed, and deposits obtained. Experimental results show that less Mo particles are spheroidized when compared to the number of spheroidized tungsten (W) particles at the same powder feed rate under the same plasma spray condition. Molten Mo particles can be sufficiently flattened on substrate. The influence of the process parameters on the flattening behavior is not significant. Mo deposit is not as dense as W deposit, due to the splash and low impact of molten Mo particles. Oxidation of the Mo powder with a large particle size is not evident under the low pressure plasma spray

D. C. plasma-sprayed coatings of nano-structured alumina-titania-silica

CERN Document Server

Jiang Xian Liang

2002-01-01

nano-crystalline powders of omega(Al sub 2 O sub 3) = 95%, omega(TiO sub 2) = 3%, and omega(SiO sub 2) = 2%, were reprocessed into agglomerated particles for plasma spraying, by using consecutive steps of ball milling, slurry forming, spray drying, and heat treatment. D.C. plasma was used to spray the agglomerated nano-crystalline powders, and resultant coatings were deposited on the substrate of stainless steel. Scanning electron microscopy (SEM) was used to examine the morphology of the agglomerated powders and the cross section of the alumina-titania-silica coatings. Experimental results show that the agglomerated nano-crystalline particles are spherical, with a size from (10-90) mu m. The flow ability of the nano-crystalline powders is greatly improved after the reprocessing. The coatings deposited by the plasma spraying are mainly of nano-structure. Unlike conventional plasma-sprayed coatings, no laminar layer could be found in the nano-structured coatings. Although the nano-structured coatings have a lo...

Understanding plasma spraying process and characteristics of DC-arc plasma gun (PJ-100

Directory of Open Access Journals (Sweden)

Jovana Ružić

2012-12-01

Full Text Available The thermal spray processes are a group of coating processes used to apply metallic or non-metallic coatings. In these processes energy sources are used to heat the coating material (in the form of powder, wire, or rod form to a molten or semi-molten state and accelerated towards a prepared surface by either carrier gases or atomization jets. In plasma spraying process, the spraying material is generally in the form of powder and requires a carrier gas to feed the powder into the plasma jet, which is passing between the hot cathode and the cylindrical nozzle-shaped anode. The design of DC plasma gun (PJ - 100 is designed and manufactured in Serbia. Plasma spaying process, the powder injection with the heat, momentum and mass transfers between particles and plasma jet, and the latest developments related to the production of DC plasma gun are described in this article.

Some Material Characteristics of Cold-Sprayed Structures

Directory of Open Access Journals (Sweden)

Victor K. Champagne

2007-01-01

Full Text Available The deposition and consolidation of metal powders by means of cold spray are methods whereby powder particles are accelerated to high velocity through entrainment in a gas undergoing expansion in a rocket nozzle and are subsequently impacted upon a surface. The impacted powder particles form a consolidated structure which can be several centimeters thick. The characteristics of this structure depend on the initial characteristics of the metal powder and upon impact velocity. The influence of impact velocity on strain hardening and porosity are examined. A materials model is proposed for these phenomena, and model calculation is compared with experiment for the cold spraying of aluminum.

Metastable phases in yttrium oxide plasma spray deposits and their effect on coating properties

International Nuclear Information System (INIS)

Gourlaouen, V.; Schnedecker, G.; Boncoeur, M.; Lejus, A.M.; Collongues, R.

1993-01-01

Yttrium oxide coatings were obtained by plasma spray. Structural investigations on these deposits show that, due to the drastic conditions of this technique, a minor monoclinic B phase is formed in the neighborhood of the major cubic C form. The authors discuss here the influence of different plasma spray parameters on the amount of the B phase formed. They describe also the main properties of Y 2 O 3 B and C phases in these deposits such as structural characteristics, thermal stability and mechanical behavior

Study on spraying water soluble resin to reduce pollution for Fukushima daiichi NPP accident

International Nuclear Information System (INIS)

Zhang Qiong; Guo Ruiping; Zhang Chunming; Han Fujuan; Hua Jie; Zhang Jiankui

2012-01-01

After Fukushima nuclear accident, Tokyo electric power company used the method of spraying water soluble resin synthesis at the scene of the accident, to restrain and control the spread of the radioactive dust, by forming consolidation layer in pollution area surface. This paper briefly introduced the accident, motivation of spraying water soluble resin, spraying range and implementation process. According to the relevant report on Fukushima nuclear accident, the effect of spraying water soluble resin for reducing pollution was analyzed. The mechanism of reducing pollution for water soluble resin and the application prospect were discussed. Spraying water soluble resin for fixing radioactive dust has reasonable reducing pollution effect. It is worth to use as reference and study in China. (authors)

Encapsulation of lycopene using spray-drying and molecular inclusion processes

Directory of Open Access Journals (Sweden)

Itaciara Larroza Nunes

2007-09-01

Full Text Available This study aimed to obtain encapsulated lycopene in a powder form, using either spray-drying or molecular inclusion with beta -cyclodextrin ( beta -CD followed by freeze-drying. The encapsulation efficiency using spray-drying ranged from 94 to 96%, with an average yield of 51%, with microcapsules showing superficial indentations and lack of cracks and breakages. Lycopene- beta -CD complexes were only formed at a molar ratio of 1:4, and irregular structures of different sizes that eventually formed aggregates, similar to those of beta -CD, were observed after freeze-drying. About 50% of the initial lycopene did not form complexes with beta -CD. Lycopene purity increased from 96.4 to 98.1% after spray-drying, whereas lycopene purity decreased from 97.7 to 91.3% after complex formation and freeze-drying. Both the drying processes yielded pale-pink, dry, free-flowing powders.Técnicas de encapsulamento, como "spray-drying" e formação de complexos por inclusão com ciclodextrinas, vêm sendo avaliadas para viabilizar a adição de carotenóides em sistemas hidrofílicos e aumentar a sua estabilidade durante o processamento e estocagem. Portanto, o objetivo do presente trabalho foi obter licopeno encapsulado na forma de pó, utilizando processos de "spray-drying" ou de inclusão molecular com beta -ciclodextrina (CD seguido de liofilização. A eficiência do encapsulamento utilizando "spray-drying" variou de 94 a 96% e o rendimento médio foi de 51%, com as microcápsulas apresentando indentações superficiais, porém sem falhas ou aberturas na superfície. A formação de complexo licopeno- beta -CD ocorreu apenas quando utilizada razão molar de 1:4, e estruturas irregulares de diferentes tamanhos que eventualmente formaram agregados, similares às da beta -CD, foram observadas após liofilização. O licopeno não complexado neste processo ficou em torno de 50%. A pureza do licopeno (% área do all-trans-licopeno aumentou de 96,4 para 98,1% ap

Production of cocrystals in an excipient matrix by spray drying.

Science.gov (United States)

Walsh, David; Serrano, Dolores R; Worku, Zelalem Ayenew; Norris, Brid A; Healy, Anne Marie

2018-01-30

Spray drying is a well-established scale-up technique for the production of cocrystals. However, to the best of our knowledge, the effect of introducing a third component into the feed solution during the spray drying process has never been investigated. Cocrystal formation in the presence of a third component by a one-step spray drying process has the potential to reduce the number of unit operations which are required to produce a final pharmaceutical product (e.g. by eliminating blending with excipient). Sulfadimidine (SDM), a poorly water soluble active pharmaceutical ingredient (API), and 4-aminosalicylic acid (4ASA), a hydrophilic molecule, were used as model drug and coformer respectively to form cocrystals by spray drying in the presence of a third component (excipient). The solubility of the cocrystal in the excipient was measured using a thermal analysis approach. Trends in measured solubility were in agreement with those determined by calculated Hansen Solubility Parameter (HSP) values. The ratio of cocrystal components to excipient was altered and cocrystal formation at different weight ratios was assessed. Cocrystal integrity was preserved when the cocrystal components were immiscible with the excipient, based on the difference in Hansen Solubility Parameters (HSP). For immiscible systems (difference in HSP > 9.6 MPa 0.5 ), cocrystal formation occurred even when the proportion of excipient was high (90% w/w). When the excipient was partly miscible with the cocrystal components, cocrystal formation was observed post spray drying, but crystalline API and coformer were also recovered in the processed powder. An amorphous dispersion was formed when the excipient was miscible with the cocrystal components even when the proportion of excipient used as low (10% w/w excipient). For selected spray dried cocrystal-excipient systems an improvement in tableting characteristics was observed, relative to equivalent physical mixtures. Copyright © 2017 Elsevier

Structure Analysis Of Corrosion Resistant Thermal Sprayed Coatings On Low Alloy Steels

Science.gov (United States)

Chaliampalias, D.; Vourlias, G.; Pistofidis, N.; Pavlidou, E.; Stergiou, A.; Stergioudis, G.; Polychroniadis, E. K.

2007-04-01

Metallic coatings have been proved to reduce the rate of corrosion of steel in various atmospheres. In this work the structure of Al, Cu-Al and Zn thermal sprayed coatings is examined. The as formed coatings are extremely rough, and they are composed of several phases which increase corrosion resistance as it was determined Salt Spray Chamber tests.

Pharmaceutical spray drying: solid-dose process technology platform for the 21st century.

Science.gov (United States)

Snyder, Herman E

2012-07-01

Requirement for precise control of solid-dosage particle properties created with a scalable process technology are continuing to expand in the pharmaceutical industry. Alternate methods of drug delivery, limited active drug substance solubility and the need to improve drug product stability under room-temperature conditions are some of the pharmaceutical applications that can benefit from spray-drying technology. Used widely for decades in other industries with production rates up to several tons per hour, pharmaceutical uses for spray drying are expanding beyond excipient production and solvent removal from crystalline material. Creation of active pharmaceutical-ingredient particles with combinations of unique target properties are now more common. This review of spray-drying technology fundamentals provides a brief perspective on the internal process 'mechanics', which combine with both the liquid and solid properties of a formulation to enable high-throughput, continuous manufacturing of precision powder properties.

Macro controlling of copper oxide deposition processes and spray mode by using home-made fully computerized spray pyrolysis system

Science.gov (United States)

Essa, Mohammed Sh.; Chiad, Bahaa T.; Shafeeq, Omer Sh.

2017-09-01

Thin Films of Copper Oxide (CuO) absorption layer have been deposited using home-made Fully Computerized Spray Pyrolysis Deposition system FCSPD on glass substrates, at the nozzle to substrate distance equal to 20,35 cm, and computerized spray mode (continues spray, macro-control spray). The substrate temperature has been kept at 450 °c with the optional user can enter temperature tolerance values ± 5 °C. Also that fixed molar concentration of 0.1 M, and 2D platform speed or deposition platform speed of 4mm/s. more than 1000 instruction program code, and specific design of graphical user interface GUI to fully control the deposition process and real-time monitoring and controlling the deposition temperature at every 200 ms. The changing in the temperature has been recorded during deposition processes, in addition to all deposition parameters. The films have been characterized to evaluate the thermal distribution over the X, Y movable hot plate, the structure and optical energy gap, thermal and temperature distribution exhibited a good and uniform distribution over 20 cm2 hot plate area, X-ray diffraction (XRD) measurement revealed that the films are polycrystalline in nature and can be assigned to monoclinic CuO structure. Optical band gap varies from 1.5-1.66 eV depending on deposition parameter.

Reactor container spray device

International Nuclear Information System (INIS)

Yanai, Ryoichi.

1980-01-01

Purpose: To enable decrease in the heat and the concentration of radioactive iodine released from the reactor vessel into the reactor container in the spray device of BWR type reactors. Constitution: A plurality of water receiving trays are disposed below the spray nozzle in the dry well and communicated to a pressure suppression chamber by way of drain pipeways passing through a diaphragm floor. When the recycling system is ruptured and coolants in the reactor vessel and radioactive iodine in the reactor core are released into the dry well, spray water is discharged from the spray nozzle to eliminate the heat and the radioactive iodine in the dry well. In this case, the receiving trays collect the portions of spray water whose absorption power for the heat and radioactive iodine is nearly saturated and falls them into the pool water of the pressure suppression chamber. Consequently, other portions of the spray water that still possess absorption power can be jetted with no hindrance, to increase the efficiency for the removal of the heat and iodine of the spray droplets. (Horiuchi, T.)

Slurry spray distribution within a simulated laboratory scale spray dryer

International Nuclear Information System (INIS)

Bertone, P.C.

1979-01-01

It was found that the distribution of liquid striking the sides of a simulated room temperature spray dryer was not significantly altered by the choice of nozles, nor by a variation in nozzle operating conditions. Instead, it was found to be a function of the spray dryer's configuration. A cocurrent flow of air down the drying cylinder, not possible with PNL's closed top, favorably altered the spray distribution by both decreasing the amount of liquid striking the interior of the cylinder from 72 to 26% of the feed supplied, and by shifting the zone of maximum impact from 1.0 to 1.7 feet from the nozzle. These findings led to the redesign of the laboratory scale spray dryer to be tested at the Savannah River Plant. The diameter of the drying chamber was increased from 5 to 8 inches, and a cocurrent flow of air was established with a closed recycle. Finally, this investigation suggested a drying scheme which offers all the advantages of spray drying without many of its limitations

Surface modeling of workpiece and tool trajectory planning for spray painting robot.

Directory of Open Access Journals (Sweden)

Yang Tang

Full Text Available Automated tool trajectory planning for spray-painting robots is still a challenging problem, especially for a large free-form surface. A grid approximation of a free-form surface is adopted in CAD modeling in this paper. A free-form surface model is approximated by a set of flat patches. We describe here an efficient and flexible tool trajectory optimization scheme using T-Bézier curves calculated in a new way from trigonometrical bases. The distance between the spray gun and the free-form surface along the normal vector is varied. Automotive body parts, which are large free-form surfaces, are used to test the scheme. The experimental results show that the trajectory planning algorithm achieves satisfactory performance. This algorithm can also be extended to other applications.

An in vitro Method for Predicting Inhalation Toxicity of Impregnation Spray Products

DEFF Research Database (Denmark)

Sørli, Jorid B.; Hansen, Jitka S.; Nørgaard, Asger Wisti

2015-01-01

Impregnation spray products are used for making surfaces water and dirt repellent. The products are composed of one or more active film-forming components dissolved or suspended in an appropriate solvent mixture. Exposure to impregnation spray products may cause respiratory distress and new cases...

Some features of spray breakup in effervescent atomizers

Energy Technology Data Exchange (ETDEWEB)

Gadgil, Hrishikesh P.; Raghunandan, B.N. [Indian Institute of Science, Department of Aerospace Engineering, Bangalore (India)

2011-02-15

The near orifice spray breakup at low GLR (gas to liquid ratio by mass) values in an effervescent atomizer is studied experimentally using water as a simulant and air as atomizing gas. From the visualizations, the near orifice spray structures are classified into three modes: discrete bubble explosions, continuous bubble explosions and annular conical spray. The breakup of the spray is quantified in terms of the mean bubble bursting distance from the orifice. The parametric study indicates that the mean bubble bursting distance mainly depends on airflow rate, jet diameter and mixture velocity. It is also observed that the jet diameter has a dominant effect on the bubble bursting distance when compared to mixture velocity at a given airflow rate. The mean bubble bursting distance is shown to be governed by a nondimensional two-phase flow number consisting of all the aforementioned parameters. The location of bubble bursting is found to be highly unsteady spatially, which is influenced by flow dynamics inside the injector. It is proposed that this unsteadiness in jet breakup length is a consequence of varying degree of bubble expansion caused due to the intermittent occurrence of single phase and two-phase flow inside the orifice. (orig.)

Transported PDF Modeling of Ethanol Spray in Hot-Diluted Coflow Flame

OpenAIRE

Ma, L.; Naud, B.; Roekaerts, D.J.E.M.

2015-01-01

This paper presents a numerical modeling study of one ethanol spray flame from the Delft Spray-in-Hot-Coflow (DSHC) database, which has been used to study Moderate or Intense Low-oxygen Dilution (MILD) combustion of liquid fuels (Correia Rodrigues et al. Combust. Flame 162(3), 759–773, 2015). A “Lagrangian-Lagrangian” approach is adopted where both the joint velocity-scalar Probability Density Function (PDF) for the continuous phase and the joint PDF of droplet properties are modeled and solv...

Microstructure evolution during spray rolling and heat treatment of 2124 Al

Energy Technology Data Exchange (ETDEWEB)

McHugh, K.M. [Industrial Technology Department, Idaho National Laboratory, Idaho Falls, ID 83415-2050 (United States)], E-mail: kevin.mchugh@inl.gov; Lin, Y.; Zhou, Y.; Johnson, S.B.; Delplanque, J.-P.; Lavernia, E.J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States)

2008-03-25

Spray rolling is a strip-casting technology that combines elements of spray forming and twin-roll casting. It consists of atomizing molten metal with a high velocity inert gas, quenching the resultant droplets in flight, and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets and conduction heat transfer at the rolls rapidly remove the metal's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly-solidified strip. Spray rolling operates at a higher solidification rate than conventional twin-roll casting and is able to process a broader range of alloys at high production rates. A laboratory-scale strip caster was constructed and used to evaluate the interplay of processing parameters and strip quality for strips up to 200 mm wide and 1.6-6.4 mm thick. This paper examines microstructure evolution during spray rolling and explores how gas-to-metal mass flow ratio influences the microstructure and mechanical properties of spray-rolled 2124 Al. The influences of solution heat treatment and cold rolling on grain structure and constituent particle spheroidization are also examined.

Numerical modelling of fuel sprays

Energy Technology Data Exchange (ETDEWEB)

Bergstroem, C.

1999-06-01

The way the fuel is introduced into the combustion chamber is one of the most important parameters for the power output and the generation of emissions in the combustion of liquid fuels. The interaction between the turbulent gas flow field and the liquid fuel droplets, the vaporisation of them and the mixing of the gaseous fuel with the ambient air that are vital parameters in the combustion process. The use of numerical calculations is an important tool to better understand these complex interacting phenomena. This thesis reports on the numerical modelling of fuel sprays in non-reacting cases using an own developed spray module. The spray module uses the stochastic parcel method to represent the spray. The module was made in such manner that it could by coupled with different gas flow solver. Results obtained from four different gas flow solvers are presented in the thesis, including the use of two different kinds of turbulence models. In the first part the spray module is coupled with a k-{eta} based 2-D cylindrical gas flow solver. A thorough sensitivity analysis was performed on the spray and gas flow solver parameters, such as grid size dependence and sensitivity to initial values of k-{eta}. The results of the spray module were also compared to results from other spray codes, e.g. the well known KIVA code. In the second part of this thesis the spray was injected into a turbulent and fully developed crossflow studied. The spray module was attached to a LES (Large Eddy Simulation) based flow solvers enabling the study of the complex structures and time dependent phenomena involved in spray in crossflows. It was found that the spray performs an oscillatory motion and that the Strouhal number in the wake was about 0.1. Different spray breakup models were evaluated by comparing with experimental results 66 refs, 56 figs

Drop formation of black liquor spraying; Mustalipeaen pisaroituminen

Energy Technology Data Exchange (ETDEWEB)

Fogelholm, C J; Kankkunen, A; Nieminen, K; Laine, J; Miikkulainen, P [Helsinki Univ. of Technology, Otaniemi (Finland): Lab. of Energy Technology and Environmental Protection

1997-10-01

Black liquor is a spent liquor of the pulp and paper industry. It is burned in kraft recovery boilers for chemical and energy recovery. The high dry solids content and viscosity of black liquor require a high spraying temperature. This affects the performance of the boiler. Kraft recovery boiler deposit formation, emissions and chemical recovery are strongly affected by the drop size and the velocity of the black liquor spray formed by a splashplate nozzle. The sheet breakup mechanism is studied with a system based on a video and image-analysis. The drop size of mill-scale nozzles was measured also with an image-analysis-system. Measurements were carried out in a spray test chamber. The sheet breakup mechanism and drop size tests were carried out both below and over the boiling point of black liquor. Special attention was paid to the effect of flashing on drop formation. Temperature increase normally decreases drop size. In the temperature where the wavy-sheet disintegration changes to perforated-sheet disintegration the drop size increases. Spray velocity rises when the temperature is increased above the boiling point. (orig.)

Thermal Arc Spray Overview

Science.gov (United States)

Hafiz Abd Malek, Muhamad; Hayati Saad, Nor; Kiyai Abas, Sunhaji; Mohd Shah, Noriyati

2013-06-01

Usage of protective coating for corrosion protection was on highly demand during the past decade; and thermal spray coating played a major part during that time. In recent years, the thermal arc spray coating becomes a popular coating. Many big players in oil and gas such as PETRONAS, EXXON MOBIL and SHELL in Malaysia tend to use the coating on steel structure as a corrosion protection. Further developments in coating processes, the devices, and raw materials have led to expansion of functional coatings and applications scope from conventional coating to specialized industries. It is widely used because of its ability to withstand high process temperature, offer advantages in efficiency, lower cost and acts as a corrosion protection. Previous research also indicated that the thermal arc spray offers better coating properties compared to other methods of spray. This paper reviews some critical area of thermal spray coating by discussing the process/parameter of thermal arc spray technology and quality control of coating. Coating performance against corrosion, wear and special characteristic of coating are also described. The field application of arc spray technology are demonstrated and reviewed.

Thermal Arc Spray Overview

International Nuclear Information System (INIS)

Malek, Muhamad Hafiz Abd; Saad, Nor Hayati; Abas, Sunhaji Kiyai; Shah, Noriyati Mohd

2013-01-01

Usage of protective coating for corrosion protection was on highly demand during the past decade; and thermal spray coating played a major part during that time. In recent years, the thermal arc spray coating becomes a popular coating. Many big players in oil and gas such as PETRONAS, EXXON MOBIL and SHELL in Malaysia tend to use the coating on steel structure as a corrosion protection. Further developments in coating processes, the devices, and raw materials have led to expansion of functional coatings and applications scope from conventional coating to specialized industries. It is widely used because of its ability to withstand high process temperature, offer advantages in efficiency, lower cost and acts as a corrosion protection. Previous research also indicated that the thermal arc spray offers better coating properties compared to other methods of spray. This paper reviews some critical area of thermal spray coating by discussing the process/parameter of thermal arc spray technology and quality control of coating. Coating performance against corrosion, wear and special characteristic of coating are also described. The field application of arc spray technology are demonstrated and reviewed.

Systematic Investigation on the Influence of Spray Parameters on the Mechanical Properties of Atmospheric Plasma-Sprayed YSZ Coatings

Science.gov (United States)

Mutter, Markus; Mauer, Georg; Mücke, Robert; Guillon, Olivier; Vaßen, Robert

2018-04-01

In the atmospheric plasma spray (APS) process, micro-sized ceramic powder is injected into a thermal plasma where it is rapidly heated and propelled toward the substrate. The coating formation is characterized by the subsequent impingement of a large number of more or less molten particles forming the so-called splats and eventually the coating. In this study, a systematic investigation on the influence of selected spray parameters on the coating microstructure and the coating properties was conducted. The investigation thereby comprised the coating porosity, the elastic modulus, and the residual stress evolution within the coating. The melting status of the particles at the impingement on the substrate in combination with the substrate surface condition is crucial for the coating formation. Single splats were collected on mirror-polished substrates for selected spray conditions and evaluated by identifying different types of splats (ideal, distorted, weakly bonded, and partially molten) and their relative fractions. In a previous study, these splat types were evaluated in terms of their effect on the above-mentioned coating properties. The particle melting status, which serves as a measure for the particle spreading behavior, was determined by in-flight particle temperature measurements and correlated to the coating properties. It was found that the gun power and the spray distance have a strong effect on the investigated coating properties, whereas the feed rate and the cooling show minor influence.

In Situ Acoustic Monitoring of Thermal Spray Process Using High-Frequency Impulse Measurements

Science.gov (United States)

Tillmann, Wolfgang; Walther, Frank; Luo, Weifeng; Haack, Matthias; Nellesen, Jens; Knyazeva, Marina

2018-01-01

In order to guarantee their protective function, thermal spray coatings must be free from cracks, which expose the substrate surface to, e.g., corrosive media. Cracks in thermal spray coatings are usually formed because of tensile residual stresses. Most commonly, the crack occurrence is determined after the thermal spraying process by examination of metallographic cross sections of the coating. Recent efforts focus on in situ monitoring of crack formation by means of acoustic emission analysis. However, the acoustic signals related to crack propagation can be absorbed by the noise of the thermal spraying process. In this work, a high-frequency impulse measurement technique was applied to separate different acoustic sources by visualizing the characteristic signal of crack formation via quasi-real-time Fourier analysis. The investigations were carried out on a twin wire arc spraying process, utilizing FeCrBSi as a coating material. The impact of the process parameters on the acoustic emission spectrum was studied. Acoustic emission analysis enables to obtain global and integral information on the formed cracks. The coating morphology and coating defects were inspected using light microscopy on metallographic cross sections. Additionally, the resulting crack patterns were imaged in 3D by means of x-ray microtomography.

The Report of Suicide by Ingestion of Lidocaine Topical Spray

Directory of Open Access Journals (Sweden)

Hossein Hassanian-Moghaddam

2014-09-01

Full Text Available Background: Lidocaine is a local anesthetic and antiarrhythmic agent. There are reports on accidental and intentional cases of poisoning following injection of lidocaine while rare are the fatal cases realized after oral ingestion of lidocaine. Suicidal poisoning with lidocaine pharmaceutical formulations is rare since no pharmaceutical dosage forms for oral use are available except gels and sprays used as local anesthetics in dentistry. Cases: Three cases of suicidal poisoning by ingestion of the content of lidocaine topical spray are reported in the present study. The cases developed episodes of seizure requiring diazepam and other therapeutic modalities upon admission. Eventually, one of the cases expired. Conclusion: To the best of our knowledge, this study is the first reported case of suicidal poisoning after ingestion of this formulation which highlights the fact that lidocaine topical spray formulation may be used for committing suicide. Ingestion of lidocaine present in topical spray can induce varying levels of toxicity that can even be fatal.

Influence of Solvent Composition on the Performance of Spray-Dried Co-Amorphous Formulations

DEFF Research Database (Denmark)

Mishra, Jaya; Rades, Thomas; Löbmann, Korbinian

2018-01-01

Ball-milling is usually used to prepare co-amorphous drug–amino acid (AA) mixtures. In this study, co-amorphous drug–AA mixtures were produced using spray-drying, a scalable industrially preferred preparation method. The influence of the solvent type and solvent composition was investigated....... Mixtures of indomethacin (IND) and each of the three AAs arginine, histidine, and lysine were ball-milled and spray-dried at a 1:1 molar ratio, respectively. Spray-drying was performed at different solvent ratios in (a) ethanol and water mixtures and (b) acetone and water mixtures. Different ratios...... that using spray-drying as a preparation method, all IND–AA mixtures could be successfully converted into the respective co-amorphous forms, irrespective of the type of solvent used, but depending on the solvent mixture ratios. Both ball-milled and spray-dried co-amorphous samples showed an enhanced...

Micro-structural investigations of spray hydrolyzed TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Lakhotiya, H. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Centre for Converging Technologies, University of Rajasthan, Jaipur (India); Singh, Ripandeep; Bahadur, J. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Sen, D., E-mail: debasis@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Das, Avik; Mazumder, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Paul, B. [Materials Processing Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Sastry, P.U. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Lemmel, H. [Atominstitut, Vienna University of Technology, 1020 Vienna (Austria); Institut Laue-Langevin, 38000 Grenoble (France)

2014-01-25

Highlights: • Titania microstructure formation by spray hydrolysis. • Morphological transition during spray hydrolysis process. • Hollow microspheres and fractal like grains depending on precursor concentration. • Use of scattering and microscopy techniques in probing mesoscopic structures. • A plausible mechanism regarding the morphological transition is also introduced. -- Abstract: Hydrolysis across tiny spray droplet allows a facile one step synthesis of interesting sub-micrometric structures owing to the large available surface area unlike bulk hydrolysis. In the present work, it has been demonstrated that titania precursor concentration plays a significant role in effecting morphological transformation during spray hydrolysis. While hollow microspheres are formed primarily at low precursor concentration, fractal like grains, having two levels of hierarchy, result at high precursor concentration. Mesoscopic structure of these spray hydrolyzed grains has been investigated by ultra small-angle neutron scattering, small-angle X-ray scattering and scanning electron microscopy. Thermal evolution of initial amorphous phase of titania into crystalline rutile phase, through intermediate anatase and brookite phases, is followed by high temperature X-ray diffraction. A plausible mechanism has been elucidated for the observed morphological transition with variation of precursor concentration.

A critical review on the spray drying of fruit extract: effect of additives on physicochemical properties.

Science.gov (United States)

Krishnaiah, Duduku; Nithyanandam, Rajesh; Sarbatly, Rosalam

2014-01-01

Spray drying accomplishes drying while particles are suspended in the air and is one method in the family of suspended particle processing systems, along with fluid-bed drying, flash drying, spray granulation, spray agglomeration, spray reaction, spray cooling, and spray absorption. This drying process is unique because it involves both particle formation and drying. The present paper reviews spray drying of fruit extracts, such as acai, acerola pomace, gac, mango, orange, cactus pear, opuntia stricta fruit, watermelon, and durian, and the effects of additives on physicochemical properties such as antioxidant activity, total carotenoid content, lycopene and β-carotene content, hygroscopy, moisture content, volatile retention, stickiness, color, solubility, glass transition temperature, bulk density, rehydration, caking, appearance under electron microscopy, and X-ray powder diffraction. The literature clearly demonstrates that the effect of additives and encapsulation play a vital role in determining the physicochemical properties of fruit extract powder. The technical difficulties in spray drying of fruit extracts can be overcome by modifying the spray dryer design. It also reveals that spray drying is a novel technology for converting fruit extract into powder form.

D. C. plasma-sprayed coatings of nano-structured alumina-titania-silica

International Nuclear Information System (INIS)

Jiang Xianliang

2002-01-01

nano-crystalline powders of ω(Al 2 O 3 ) = 95%, ω(TiO 2 ) = 3%, and ω(SiO 2 ) = 2%, were reprocessed into agglomerated particles for plasma spraying, by using consecutive steps of ball milling, slurry forming, spray drying, and heat treatment. D.C. plasma was used to spray the agglomerated nano-crystalline powders, and resultant coatings were deposited on the substrate of stainless steel. Scanning electron microscopy (SEM) was used to examine the morphology of the agglomerated powders and the cross section of the alumina-titania-silica coatings. Experimental results show that the agglomerated nano-crystalline particles are spherical, with a size from (10-90) μm. The flow ability of the nano-crystalline powders is greatly improved after the reprocessing. The coatings deposited by the plasma spraying are mainly of nano-structure. Unlike conventional plasma-sprayed coatings, no laminar layer could be found in the nano-structured coatings. Although the nano-structured coatings have a lower microhardness than conventional microstructured coatings, the toughness of the nano-structured ceramic coatings is significantly improved

Hair spray poisoning

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/002705.htm Hair spray poisoning To use the sharing features on this page, please enable JavaScript. Hair spray poisoning occurs when someone breathes in (inhales) ...

Preparation of nanoscale pulmonary drug delivery formulations by spray drying

DEFF Research Database (Denmark)

Bohr, Adam; Ruge, Christian A; Beck-Broichsitter, Moritz

2014-01-01

and can offer controlled drug release. There are numerous methods for producing therapeutic nanoparticles, each with their own advantages and suitable application. Liquid atomization techniques such as spray drying can produce nanoparticle formulations in a dry powder form suitable for pulmonary...... administration in a direct one-step process. This chapter describes the different state-of-the-art techniques used to prepare drug nanoparticles (with special emphasize on spray drying techniques) and the strategies for administering such unique formulations to the pulmonary environment....

Evaluation of effervescent atomizer internal design on the spray unsteadiness using a phase/Doppler particle analyzer

Energy Technology Data Exchange (ETDEWEB)

Liu, Meng; Duan, YuFeng; Zhang, TieNan [School of Energy and Environment, Southeast University, Sipailou 2, Nanjing 210096 (China)

2010-09-15

The purpose of this research was to investigate the dependence of effervescent spray unsteadiness on operational conditions and atomizer internal design by the ideal spray theory of Edwards and Marx. The convergent-divergent effervescent atomizer spraying water with air as atomizing medium in the ''outside-in'' gas injection was used in this study. Results demonstrated that droplet formation process at various air to liquid ratio (ALR) led to the spray unsteadiness and all droplet size classes exhibited unsteadiness behavior in spray. The spray unsteadiness reduced quickly at ALR of 3% and decreased moderately at ALR of other values as the axial distance increased. When the axial distance was 200 mm, the spray unsteadiness reduced dramatically with the increase in radial distance, but lower spray unsteadiness at the center of spray and higher spray unsteadiness at the edge of spray were shown as the axial distance increased. The spray unsteadiness at the center region of spray increased with the injection pressure. Low spray unsteadiness and good atomization performance can be obtained when the diameter of incline aeration holes increased at ALR of 10%. Although short mixing chamber with large discharge orifice diameter for convergent-divergent effervescent atomizer produced good atomization, the center region of spay showed high spray unsteadiness and maybe formed the droplet clustering. (author)

Ceramic plasma-sprayed coating of melting crucibles for casting metal fuel slugs

International Nuclear Information System (INIS)

Kim, Ki Hwan; Lee, Chong Tak; Lee, Chan Bock; Fielding, R.S.; Kennedy, J.R.

2013-01-01

Thermal cycling and melt reaction studies of ceramic coatings plasma-sprayed on Nb substrates were carried out to evaluate the performance of barrier coatings for metallic fuel casting applications. Thermal cycling tests of the ceramic plasma-sprayed coatings to 1450 °C showed that HfN, TiC, ZrC, and Y 2 O 3 coating had good cycling characteristics with few interconnected cracks even after 20 cycles. Interaction studies by 1550 °C melt dipping tests of the plasma-sprayed coatings also indicated that HfN and Y 2 O 3 do not form significant reaction layer between U–20 wt.% Zr melt and the coating layer. Plasma-sprayed Y 2 O 3 coating exhibited the most promising characteristics among HfN, TiC, ZrC, and Y 2 O 3 coating

Thermal spray coatings replace hard chrome

International Nuclear Information System (INIS)

Schroeder, M.; Unger, R.

1997-01-01

Hard chrome plating provides good wear and erosion resistance, as well as good corrosion protection and fine surface finishes. Until a few years ago, it could also be applied at a reasonable cost. However, because of the many environmental and financial sanctions that have been imposed on the process over the past several years, cost has been on a consistent upward trend, and is projected to continue to escalate. Therefore, it is very important to find a coating or a process that offers the same characteristics as hard chrome plating, but without the consequent risks. This article lists the benefits and limitations of hard chrome plating, and describes the performance of two thermal spray coatings (tungsten carbide and chromium carbide) that compared favorably with hard chrome plating in a series of tests. It also lists three criteria to determine whether plasma spray or hard chrome plating should be selected

Graph Quasicontinuous Functions and Densely Continuous Forms

Directory of Open Access Journals (Sweden)

Lubica Hola

2017-07-01

Full Text Available Let $X, Y$ be topological spaces. A function $f: X \\to Y$ is said to be graph quasicontinuous if there is a quasicontinuous function $g: X \\to Y$ with the graph of $g$ contained in the closure of the graph of $f$. There is a close relation between the notions of graph quasicontinuous functions and minimal usco maps as well as the notions of graph quasicontinuous functions and densely continuous forms. Every function with values in a compact Hausdorff space is graph quasicontinuous; more generally every locally compact function is graph quasicontinuous.

Influences of spray parameters on the structure and corrosion resistance of stainless steel layers coated on carbon steel by plasma spray treatment

International Nuclear Information System (INIS)

Yeom, Kyong An; Lee, Sang Dong; Kwon, Hyuk Sang; Shur, Dong Soo; Kim, Joung Soo

1996-01-01

Stainless steel powders were sprayed on the grit-blasted SM45C carbon steel substrates using a plasma spray method. The influences of the spray parameters on the structure and corrosion resistance of the layers coated on the carbon steel were investigated. Corrosion behavior of the layers were analyzed by the anodic polarization tests in deaerated 0.1 M NaCl + 0.01 M NaOH solution at 80 deg C. The surface roughness and porosity were observed to decrease with decreasing the particle size. The surface hardness of the coating was always higher than that of the matrix, SM45C, implying that the higher resistance of the coating to erosion-corrosion than that of matrix, and increased as the spray power and the spray distance increase. Stainless steel coats showed more corrosion resistance than the carbon steel did, due to their passivity. The corrosion resistance of the coats, however, were inferior to that of the bulk stainless steels due to the inherent defects formed in the coats. The defects such as rough surface and pores provided the occluded sites favorable for the initiation of localized corrosion, resulting in the conclusion that finer the powder is, higher the corrosion resistance is. And the Cr oxides formation resulting in Cr depletion around the oxides reduced the corrosion resistance of the coats. (author)

A review of various nozzle range of wire arc spray on FeCrBMnSi metal coating

Science.gov (United States)

Purwaningsih, Hariyati; Rochiem, Rochman; Suchaimi, Muhammad; Jatimurti, Wikan; Wibisono, Alvian Toto; Kurniawan, Budi Agung

2018-04-01

Low Temperature Hot Corrosion (LTHC) is type of hot corrosion which occurred on 700-800°C and usually on turbine blades. So, as a result the material of turbine blades is crack and degredation of rotation efficiency. Hot corrosion protection with the use of barrier that separate substrate and environment is one of using metal surface coating, wire arc spray method. This study has a purpose to analyze the effect of nozzle distance and gas pressure on FeCrBMnSi coating process using wire arc spray method on thermal resistance. The parameter of nozzle distance and gas pressure are used, resulted the best parameter on distance 400 mm and gas pressure 3 bar which has the bond strength of 12,58 MPa with porosity percentage of 5,93% and roughness values of 16,36 µm. While the examination of thermal cycle which by heating and cooling continuously, on the coating surface is formed oxide compound (Fe3O4) which cause formed crack propagation and delamination. Beside that hardness of coating surface is increase which caused by precipitate boride (Fe9B)0,2

Remotely controlled spray gun

Science.gov (United States)

Cunningham, William C. (Inventor)

1987-01-01

A remotely controlled spray gun is described in which a nozzle and orifice plate are held in precise axial alignment by an alignment member, which in turn is held in alignment with the general outlet of the spray gun by insert. By this arrangement, the precise repeatability of spray patterns is insured.

Experimental Studies of Spray Deposition on a Flat Surface in a Vacuum Environment

Science.gov (United States)

Golliher, Eric L.; Yao, S. C.

2015-01-01

Cooling of spacecraft components in the space environment is an on-going research effort. The electronics used in modern spacecraft are always changing and the heat flux is increasing. New, one-of-a-kind missions require new approaches to thermal control. In this research, under vacuum conditions, a pulsed water spray impinged on a small disc, while a high speed data acquisition system recorded the temperature histories of this copper disc. The water droplets froze quickly and accumulated on the disc as the spray continued. After the spray stopped, the frozen water that remained on the disc then sublimated into the vacuum environment and cooled the disc. This paper examines two important aspects of this process: 1) the difference in spray start up and shutdown in a vacuum environment versus in a standard atmospheric pressure environment, and 2) the water utilization efficiency in a vacuum environment due to the effects of drop trajectories and drop bouncing on the surface. Both phenomena play a role during spray cooling in a vacuum. This knowledge should help spacecraft designers plan for spray cooling as an option to cool spacecraft electronics, human metabolic generated heat, and heat from other sources.

Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying

Directory of Open Access Journals (Sweden)

Goedele Craye

2015-12-01

Full Text Available In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS as a solubilizer, was explored as a production method for co-amorphous simvastatin–lysine (SVS-LYS at 1:1 molar mixtures, which previously have been observed to form a co-amorphous mixture upon ball milling. In addition, a spray-dried formulation of SVS without LYS was prepared. Energy-dispersive X-ray spectroscopy (EDS revealed that SLS coated the SVS and SVS-LYS particles upon spray drying. X-ray powder diffraction (XRPD and differential scanning calorimetry (DSC showed that in the spray-dried formulations the remaining crystallinity originated from SLS only. The best dissolution properties and a “spring and parachute” effect were found for SVS spray-dried from a 5% SLS solution without LYS. Despite the presence of at least partially crystalline SLS in the mixtures, all the studied formulations were able to significantly extend the stability of amorphous SVS compared to previous co-amorphous formulations of SVS. The best stability (at least 12 months in dry conditions was observed when SLS was spray-dried with SVS (and LYS. In conclusion, spray drying of SVS and LYS from aqueous surfactant solutions was able to produce formulations with improved physical stability for amorphous SVS.

Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying.

Science.gov (United States)

Craye, Goedele; Löbmann, Korbinian; Grohganz, Holger; Rades, Thomas; Laitinen, Riikka

2015-12-03

In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS) as a solubilizer, was explored as a production method for co-amorphous simvastatin-lysine (SVS-LYS) at 1:1 molar mixtures, which previously have been observed to form a co-amorphous mixture upon ball milling. In addition, a spray-dried formulation of SVS without LYS was prepared. Energy-dispersive X-ray spectroscopy (EDS) revealed that SLS coated the SVS and SVS-LYS particles upon spray drying. X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) showed that in the spray-dried formulations the remaining crystallinity originated from SLS only. The best dissolution properties and a "spring and parachute" effect were found for SVS spray-dried from a 5% SLS solution without LYS. Despite the presence of at least partially crystalline SLS in the mixtures, all the studied formulations were able to significantly extend the stability of amorphous SVS compared to previous co-amorphous formulations of SVS. The best stability (at least 12 months in dry conditions) was observed when SLS was spray-dried with SVS (and LYS). In conclusion, spray drying of SVS and LYS from aqueous surfactant solutions was able to produce formulations with improved physical stability for amorphous SVS.

Spray Drying of High Sugar Content Foods: Improving of Product Yield and Powder Properties

OpenAIRE

Mehmet Koç; Figen Kaymak-Ertekin

2016-01-01

Spray drying is the most preferred drying method to produce powdered food in the food industry and it is also widely used to convert sugar-rich liquid foods to a powder form. During and/or after spray drying process of sugar-rich products, undesirable situation was appeared such as stickiness, high moisture affinity (hygroscopicity) and low solubility due to low molecular weight monosaccharides that found naturally in the structure. The basis of these problems was formed by low glass transiti...

Comparision on dynamic behavior of diesel spray and rapeseed oil spray in diesel engine

Science.gov (United States)

Sapit, Azwan; Azahari Razali, Mohd; Faisal Hushim, Mohd; Jaat, Norrizam; Nizam Mohammad, Akmal; Khalid, Amir

2017-04-01

Fuel-air mixing is important process in diesel combustion. It significantly affects the combustion and emission of diesel engine. Biomass fuel has high viscosity and high distillation temperature and may negatively affect the fuel-air mixing process. Thus, study on the spray development and atomization of this type of fuel is important. This study investigates the atomization characteristics and droplet dynamic behaviors of diesel engine spray fuelled by rapeseed oil (RO) and comparison to diesel fuel (GO). Optical observation of RO spray was carried out using shadowgraph photography technique. Single nano-spark photography technique was used to study the characteristics of the spray while dual nano-spark shadowgraph technique was used to study the spray droplet behavior. Using in-house image processing algorithm, the images were processed and the boundary condition of each spray was also studied. The results show that RO has very poor atomization due to the high viscosity nature of the fuel when compared to GO. This is in agreement with the results from spray droplet dynamic behavior studies that shows due to the high viscosity, the RO spray droplets are large in size and travel downward, with very little influence of entrainment effect due to its large kinematic energy.

Experiments on aerosol removal by high-pressure water spray

Energy Technology Data Exchange (ETDEWEB)

Corno, Ada del, E-mail: delcorno@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Morandi, Sonia, E-mail: morandi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Parozzi, Flavio, E-mail: parozzi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Araneo, Lucio, E-mail: lucio.araneo@polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy); CNR-IENI, via Cozzi 53, I-20125 Milano (Italy); Casella, Francesco, E-mail: francesco2.casella@mail.polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy)

2017-01-15

Highlights: • Experimental research to measure the efficiency of high-pressure sprays in capturing aerosols if applied to a filtered containment venting system in case of severe accident. • Cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m{sup 3}. • Carried out in a chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls equipped with a high pressure water spray with single nozzle. • Respect to low-pressure sprays, removal efficiency turned out significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure sprays system. - Abstract: An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m{sup 3}. The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was

Experiments on aerosol removal by high-pressure water spray

International Nuclear Information System (INIS)

Corno, Ada del; Morandi, Sonia; Parozzi, Flavio; Araneo, Lucio; Casella, Francesco

2017-01-01

Highlights: • Experimental research to measure the efficiency of high-pressure sprays in capturing aerosols if applied to a filtered containment venting system in case of severe accident. • Cloud of monodispersed SiO_2 particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m"3. • Carried out in a chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls equipped with a high pressure water spray with single nozzle. • Respect to low-pressure sprays, removal efficiency turned out significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure sprays system. - Abstract: An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO_2 particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m"3. The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was detected with 1 �

Solid-state, triboelectrostatic and dissolution characteristics of spray-dried piroxicam-glucosamine solid dispersions.

Science.gov (United States)

Adebisi, Adeola O; Kaialy, Waseem; Hussain, Tariq; Al-Hamidi, Hiba; Nokhodchi, Ali; Conway, Barbara R; Asare-Addo, Kofi

2016-10-01

This work explores the use of both spray drying and d-glucosamine HCl (GLU) as a hydrophilic carrier to improve the dissolution rate of piroxicam (PXM) whilst investigating the electrostatic charges associated with the spray drying process. Spray dried PXM:GLU solid dispersions were prepared and characterised (XRPD, DSC, SEM). Dissolution and triboelectric charging were also conducted. The results showed that the spray dried PXM alone, without GLU produced some PXM form II (DSC results) with no enhancement in solubility relative to that of the parent PXM. XRPD results also showed the spray drying process to decrease the crystallinity of GLU and solid dispersions produced. The presence of GLU improved the dissolution rate of PXM. Spray dried PXM: GLU at a ratio of 2:1 had the most improved dissolution. The spray drying process generally yielded PXM-GLU spherical particles of around 2.5μm which may have contributed to the improved dissolution. PXM showed a higher tendency for charging in comparison to the carrier GLU (-3.8 versus 0.5nC/g for untreated material and -7.5 versus 3.1nC/g for spray dried materials). Spray dried PXM and spray dried GLU demonstrated higher charge densities than untreated PXM and untreated GLU, respectively. Regardless of PXM:GLU ratio, all spray dried PXM:GLU solid dispersions showed a negligible charge density (net-CMR: 0.1-0.3nC/g). Spray drying of PXM:GLU solid dispersions can be used to produce formulation powders with practically no charge and thereby improving handling as well as dissolution behaviour of PXM. Copyright © 2016 Elsevier B.V. All rights reserved.

Study of fuel spray characteristics for premixed lean diesel combustion; Kihaku yokongo diesel kikan ni okeru nenryo funmu keisei ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Sasaki, S.; Miyamoto, T.; Harada, A.; Akagawa, H.; Tsujimura, K. [New ACE Institute Co. Ltd., Tokyo (Japan)

1998-05-01

A study is being made on premixed lean diesel combustion (PREDIC) by means of early fuel injection in diesel engines. The PREDIC makes it possible to largely reduce NOx emission, but has such problems as ignition control and increase in THC and CO generation. In order to clarify the relationship between fuel spray characteristics in the PREDIC and properties of gas mixture and exhausts, the present study has investigated spread and internal structure of the spray by means of spray observation experiment using a pintle swirl nozzle. Based on the result therefrom, simulations were used to investigate effects of spatial dispersion characteristics of the spray on properties of the gas mixture and exhausts before ignition. The pintle swirl nozzle forms conical spray having an air layer inside the spray, where penetration is suppressed even under low atmospheric pressure. By forming hollow spray or solid spray in the conical spray, a possibility was indicated that equivalent ratio distribution of the gas mixture can be controlled and NO emission may be reduced. 8 refs., 12 figs., 1 tab.

Thermal spray for commercial shipbuilding

Science.gov (United States)

Rogers, F. S.

1997-09-01

Thermal spraying of steel with aluminum to protect it from corrosion is a technology that has been proven to work in the marine environment. The thermal spray coating system includes a paint sealer that is applied over the thermally sprayed aluminum. This extends the service life of the coating and provides color to the end product. The thermal spray system protects steel both through the principle of isolation (as in painting) and galvanizing. With this dual protection mechanism, steel is protected from corrosion even when the coating is damaged. The thermal- sprayed aluminum coating system has proved the most cost- effective corrosion protection system for the marine environment. Until recently, however, the initial cost of application has limited its use for general application. Arc spray technology has reduced the application cost of thermal spraying of aluminum to below that of painting. Commercial shipbuilders could use this technology to enhance their market position in the marine industry.

Structure and property evaluation of a vacuum plasma sprayed nanostructured tungsten-hafnium carbide bulk composite

NARCIS (Netherlands)

Rea, K. E.; Viswanathan, V.; Kruize, A.; De Hosson, J. Th. M.; O'Dell, S.; McKechnie, T.; Rajagopalan, S.; Vaidyanathan, R.; Seal, S.; O’Dell, S.

2008-01-01

Vacuum plasma spray (VPS) forming of tungsten-based metal matrix nanocomposites (MMCs) has shown to be a cost effective and time saving method for the formation of bulk monolithic nanostructured then no-mechanical components. Spray drying of powder feedstock appears to have a significant effect on

Correlation of microstructure and wear resistance of molybdenum blend coatings fabricated by atmospheric plasma spraying

International Nuclear Information System (INIS)

Hwang, Byoungchul; Lee, Sunghak; Ahn, Jeehoon

2004-01-01

The correlation of microstructure and wear resistance of various molybdenum blend coatings applicable to automotive parts was investigated in this study. Five types of spray powders, one of which was pure molybdenum powder and the others were blends of brass, bronze, and aluminum alloy powders with molybdenum powder, were deposited on a low-carbon steel substrate by atmospheric plasma spraying (APS). Microstructural analysis of the coatings showed that they consisted of a curved lamellar structure formed by elongated splats, with hard phases that formed during spraying being homogeneously distributed in the molybdenum matrix. The wear test results revealed that the blend coatings showed better wear resistance than the pure molybdenum coating because they contained a number of hard phases. In particular, the molybdenum coating blended with bronze and aluminum alloy powders and the counterpart material showed an excellent wear resistance due to the presence of hard phases, such as CuAl 2 and Cu 9 Al 4 . In order to improve overall wear properties for the coating and the counterpart material, appropriate spray powders should be blended with molybdenum powders to form hard phases in the coatings

Optimization of Arc-Sprayed Ni-Cr-Ti Coatings for High Temperature Corrosion Applications

Science.gov (United States)

Matthews, S.; Schweizer, M.

2013-04-01

High Cr content Ni-Cr-Ti arc-spray coatings have proven successful in resisting the high temperature sulfidizing conditions found in black liquor recovery boilers in the pulp and paper industry. The corrosion resistance of the coatings is dependent upon the coating composition, to form chromium sulfides and oxides to seal the coating, and on the coating microstructure. Selection of the arc-spray parameters influences the size, temperature and velocity of the molten droplets generated during spraying, which in turn dictates the coating composition and formation of the critical coating microstructural features—splat size, porosity and oxide content. Hence it is critical to optimize the arc-spray parameters in order to maximize the corrosion resistance of the coating. In this work the effect of key spray parameters (current, voltage, spray distance and gas atomizing pressure) on the coating splat thickness, porosity content, oxide content, microhardness, thickness, and surface profile were investigated using a full factorial design of experiment. Based on these results a set of oxidized, porous and optimized coatings were prepared and characterized in detail for follow-up corrosion testing.

Detailed assessment of diesel spray atomization models using visible and X-ray extinction measurements

Energy Technology Data Exchange (ETDEWEB)

Magnotti, G.M.; Genzale, C.L. (GIT)

2017-12-01

The physical mechanisms characterizing the breakup of a diesel spray into droplets are still unknown. This gap in knowledge has largely been due to the challenges of directly imaging this process or quantitatively measuring the outcomes of spray breakup, such as droplet size. Recent x-ray measurements by Argonne National Laboratory, utilized in this work, provide needed information about the spatial evolution of droplet sizes in selected regions of the spray under a range of injection pressures (50–150 MPa) and ambient densities (7.6–22.8 kg/m3) relevant for diesel operating conditions. Ultra-small angle x-ray scattering (USAXS) measurements performed at the Advanced Photon Source are presented, which quantify Sauter mean diameters (SMD) within optically thick regions of the spray that are inaccessible by conventional droplet sizing measurement techniques, namely in the near-nozzle region, along the spray centerline, and within the core of the spray. To quantify droplet sizes along the periphery of the spray, a complementary technique is proposed and introduced, which leverages the ratio of path-integrated x-ray and visible laser extinction (SAMR) measurements to quantify SMD. The SAMR and USAXS measurements are then utilized to evaluate current spray models used for engine computational fluid dynamic (CFD) simulations. We explore the ability of a carefully calibrated spray model, premised on aerodynamic wave growth theory, to capture the experimentally observed trends of SMD throughout the spray. The spray structure is best predicted with an aerodynamic primary and secondary breakup process that is represented with a slower time constant and larger formed droplet size than conventionally recommended for diesel spray models. Additionally, spray model predictions suggest that droplet collisions may not influence the resultant droplet size distribution along the spray centerline in downstream regions of the spray.

Electrostatically atomised hydrocarbon sprays

Energy Technology Data Exchange (ETDEWEB)

Yule, A.J.; Shrimpton, J.S.; Watkins, A.P.; Balachandran, W.; Hu, D. [UMIST, Manchester (United Kingdom). Thermofluids Division, Dept. of Mechanical Engineering

1995-07-01

A burner using an electrostatic method to produce and control a fuel spray is investigated for non-burning sprays. The burner has a charge injection nozzle and the liquid flow rate and charge injection rate are varied using hydrocarbon liquids of differing viscosities, surface tensions and electrical conductivities (kerosene, white spirit and diesel oil). Droplet size distributions are measured and it is shown how the dropsize, spray pattern, breakup mechanism and breakup length depend on the above variables, and in particular on the specific charge achieved in the spray. The data are valuable for validating two computer models under development. One predicts the electric field and flow field inside the nozzle as a function of emitter potential, geometry and flow rate. The other predicts the effect of charge on spray dispersion, with a view to optimizing spray combustion. It is shown that electrostatic disruptive forces can be used to atomize oils at flow rates commensurate with practical combustion systems and that the charge injection technique is particularly suitable for highly resistive liquids. Possible limitations requiring further research include the need to control the wide spray angle, which may provide fuel-air mixtures too lean near the nozzle, and the need to design for maximum charge injection rate, which is thought to be limited by corona breakdown in the gas near the nozzle orifice. 30 refs., 15 figs., 1 tab.

On the mechanism of extractive electrospray ionization (EESI) in the dual-spray configuration.

Science.gov (United States)

Wang, Rui; Gröhn, Arto Juhani; Zhu, Liang; Dietiker, Rolf; Wegner, Karsten; Günther, Detlef; Zenobi, Renato

2012-03-01

Dual-spray extractive electrospray ionization (EESI) mass spectrometry as a versatile analytical technique has attracted much interest due to its advantages over conventional electrospray ionization (ESI). The crucial difference between EESI and ESI is that in the EESI process, the analytes are introduced in nebulized form via a neutral spray and ionized by collisions with the charged droplets from an ESI source formed by spraying pure solvent. However, the mechanism of the droplet-droplet interactions in the EESI process is still not well understood. For example, it is unclear which type of droplet-droplet interaction is dominant: bounce, coalescence, disruption, or fragmentation? In this work, droplet-droplet interaction was investigated in detail based on a theoretical model. Phase Doppler anemometry (PDA) was employed to investigate the droplet behavior in the EESI plume and provide the experimental data (droplet size and velocity) necessary for theoretical analysis. Furthermore, numerical simulations were performed to clarify the influence of the sheath gas flow on the EESI process. No coalescence between the droplets in the ESI spray and the droplets in the sample spray was observed using various geometries and sample flow rates. Theoretical analysis, together with the PDA results, suggests that droplet fragmentation may be the dominant type of droplet-droplet interaction in the EESI. The interaction time between the ESI droplet and the sample droplet was estimated to be <5 μs. This work gives a clear picture of droplet-droplet interactions in the dual-spray EESI process and detailed information for the optimization of this method for future applications that require higher sensitivity.

Influence of spray parameters on the microstructure and mechanical properties of gas-tunnel plasma sprayed hydroxyapatite coatings

International Nuclear Information System (INIS)

Morks, M.F.; Kobayashi, Akira

2007-01-01

For biomedical applications, hydroxyapatite (HA) coatings were deposited on 304 stainless steel substrate by using a gas tunnel type plasma spraying process. The influences of spraying distances and plasma arc currents on the microstructure, hardness and adhesion properties of HA coatings were investigated. Microstructure observation by SEM showed that HA coatings sprayed at low plasma power have a porous structure and poor hardness. HA coatings sprayed at high plasma power and short spraying distance are characterized by good adhesion and low porosity with dense structure. Hardness increased for HA coatings sprayed at shorter spraying distance and higher plasma power, mainly due to the formation of dense coatings

Particle size distribution of aerosols sprayed from household hand-pump sprays containing fluorine-based and silicone-based compounds.

Science.gov (United States)

Kawakami, Tsuyoshi; Isama, Kazuo; Ikarashi, Yoshiaki

2015-01-01

Japan has published safety guideline on waterproof aerosol sprays. Furthermore, the Aerosol Industry Association of Japan has adopted voluntary regulations on waterproof aerosol sprays. Aerosol particles of diameter less than 10 µm are considered as "fine particles". In order to avoid acute lung injury, this size fraction should account for less than 0.6% of the sprayed aerosol particles. In contrast, the particle size distribution of aerosols released by hand-pump sprays containing fluorine-based or silicone-based compounds have not been investigated in Japan. Thus, the present study investigated the aerosol particle size distribution of 16 household hand-pump sprays. In 4 samples, the ratio of fine particles in aerosols exceeded 0.6%. This study confirmed that several hand-pump sprays available in the Japanese market can spray fine particles. Since the hand-pump sprays use water as a solvent and their ingredients may be more hydrophilic than those of aerosol sprays, the concepts related to the safety of aerosol-sprays do not apply to the hand pump sprays. Therefore, it may be required for the hand-pump spray to develop a suitable method for evaluating the toxicity and to establish the safety guideline.

Optimal control of nonlinear continuous-time systems in strict-feedback form.

Science.gov (United States)

Zargarzadeh, Hassan; Dierks, Travis; Jagannathan, Sarangapani

2015-10-01

This paper proposes a novel optimal tracking control scheme for nonlinear continuous-time systems in strict-feedback form with uncertain dynamics. The optimal tracking problem is transformed into an equivalent optimal regulation problem through a feedforward adaptive control input that is generated by modifying the standard backstepping technique. Subsequently, a neural network-based optimal control scheme is introduced to estimate the cost, or value function, over an infinite horizon for the resulting nonlinear continuous-time systems in affine form when the internal dynamics are unknown. The estimated cost function is then used to obtain the optimal feedback control input; therefore, the overall optimal control input for the nonlinear continuous-time system in strict-feedback form includes the feedforward plus the optimal feedback terms. It is shown that the estimated cost function minimizes the Hamilton-Jacobi-Bellman estimation error in a forward-in-time manner without using any value or policy iterations. Finally, optimal output feedback control is introduced through the design of a suitable observer. Lyapunov theory is utilized to show the overall stability of the proposed schemes without requiring an initial admissible controller. Simulation examples are provided to validate the theoretical results.

Spray Formation of Herschel-Bulkley Fluids using Impinging Jets

Science.gov (United States)

Rodrigues, Neil; Gao, Jian; Chen, Jun; Sojka, Paul E.

2015-11-01

The impinging jet spray formation of two non-Newtonian, shear-thinning, Herschel-Bulkley fluids was investigated in this work. The water-based gelled solutions used were 1.0 wt.-% agar and 1.0 wt.-% kappa carrageenan. A rotational rheometer and a capillary viscometer were used to measure the strain-rate dependency of viscosity and the Herschel-Bulkley Extended (HBE) rheological model was used to characterize the shear-thinning behavior. A generalized HBE jet Reynolds number Rej , gen - HBE was used as the primary parameter to characterize the spray formation. A like-on-like impinging jet doublet was used to produce atomization. Shadowgraphs were captured in the plane of the sheet formed by the two jets using a CCD camera with an Nd:YAG laser beam providing the back-illumination. Typical behavior for impinging jet atomization using Newtonian liquids was not generally observed due to the non-Newtonian, viscous properties of the agar and kappa carrageenan gels. Instead various spray patterns were observed depending on Rej , gen - HBE. Spray characteristics of maximum instability wavelength and sheet breakup length were extracted from the shadowgraphs. Multi-University Research Initiative Grant Number W911NF-08-1-0171.

Direct spraying method for fabrication of paper-based microfluidic devices

International Nuclear Information System (INIS)

Liu, Ning; An, Hong-Jie; Lew, Wen Siang; Xu, Jing; Phan, Dinh-Tuan; Hashimoto, Michinao

2017-01-01

Direct spraying of hydrophobic materials is an affordable, easy-to-use and equipment-free method for fabrication of flexible microsensors, albeit not yet widely adopted. To explore its application potential, in this paper, we propose and demonstrate two novel hybrid methods to fabricate paper-based components. Firstly, through combing direct spraying with Parafilm embedding, a leak-free paper-based sample preconcentrator for fluorescence sensing was fabricated. The leak-free device worked on the principle of ion concentration polarization (ICP) effect, and achieved enhancement of fluorescent tracer by 220 folds on a paper substrate. Secondly, by using the sprayed hydrophobic patterns, paper-based microsized supercapacitors (mSCs) were fabricated. Vacuum filtration was used to deposit multi-wall carbon nanotubes (MWCNT)-dispersed solution on a porous substrate to form electrodes. A volumetric capacitance of 42.5 mF cm −3 at a current density of 2 mA cm −3 was obtained on the paper-based mSC. Our demonstrations have shown the versatility of direct spraying for the fabrication of integrative paper-based microfluidic devices. (paper)

Synthesis and Deposition of TiC-Fe Coatings by Oxygen-acetylene Flame Spraying

Institute of Scientific and Technical Information of China (English)

无

2003-01-01

A simpler and more convenient method for producing wear-resistant, TiC-reinforced coatings were investigated in this study. It consists of the simultaneous synthesis and deposition of TiC-Fe materials by oxyacetylene flame spraying.Solid reagents bound together to form a single particle are injected into the flame stream where an in-situ reaction occurs. The reaction products are propelled onto a substrate to form a coating. Microstructural analyses reveal that TiC and Fe are the dominant phases in the coatings. The reaction between Ti and C happens step by step along with the reactive spray powder flight, and TiC-Fe materials were mainly synthesized where the spray distance is 125～170 mm. The TiC-Fe coatings are composed of alternate TiC-rich and TiC-poor lamellae with different microhardness of 11.9～13.7 and 3.0～6.0 Gpa, respectively. Submicron and round TiC particles are dispersed within a ductile metal matrix. The peculiar microstructure is thought to be responsible for its good wear resistance, which is better nearly five times than WC-reinforced cermet coatings obtained by traditional oxyacetylene flame spray.

Wear and microstructural characteristics of spray atomized zircon sand reinforced LM13 alloy

Energy Technology Data Exchange (ETDEWEB)

Kaur, K.; Pandey, O.P. [School of Physics and Materials Science, Thapar University Patiala, Punjab (India)

2010-07-15

The requirement of the high performance light weight materials demands the development of varieties of materials within the economical range to get it commercialized. Light weight aluminium alloys are used in several structural applications like automotive, aerospace, defense industry and other fields of engineering. The ceramic particle reinforced aluminium metal matrix composites (AMCs) have emerged as a suitable candidate for commercial applications. A variety of processing routes have been adopted to manufacture AMCs. In the present work LM13 alloy reinforced with zircon sand is formed via spray forming. During experimentation a self prepared convergent-divergent nozzle is used for inert gas atomization of the melt which is subsequently deposited on copper substrate placed vertically below the atomizer. The zircon sand particles are injected in the atomization zone by external injectors aligned perpendicular to the gas atomization axis. Zircon sand has been found to have new promising economical commercial candidate due to its easy availability and good mechanical properties like high hardness, high modulus of elasticity and good thermal stability. The microhardness of cast alloy and spray formed composite shows that the spray formed zircon sand reinforced composite has higher hardness. Also the lower wear rate has been observed in case of the zircon sand reinforced AMC as compared to LM13 alloy. This behaviour is further analyzed in light of microstructural features of the spray deposited composite using optical and scanning electron microscope (SEM). A comparative study of this material (LM13/Zircon sand) with the parent alloy (LM13) is presented in this work. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Using complexation for the microencapsulation of nisin in biopolymer matrices by spray-drying.

Science.gov (United States)

Ben Amara, Chedia; Kim, Lanhee; Oulahal, Nadia; Degraeve, Pascal; Gharsallaoui, Adem

2017-12-01

The aim of this study is to investigate the potential of complexation to encapsulate nisin (5g/L concentration) using spray-drying technique and to evaluate how complexation with pectin or alginate (2g/L concentration) can preserve nisin structure and antimicrobial activity. Spray-drying of nisin-low methoxyl pectin or nisin-alginate electrostatic complexes has led to the microencapsulation of the peptide in different networks that were highly influenced by the polysaccharide type. Turbidity and particle size measurements indicated that while spray-drying promoted the aggregation of nisin-pectin complexes, it favored the dissociation of nisin-alginate aggregates to form individual complexes. Structural changes of nisin induced by complexation with pectin or alginate and spray-drying were studied by using UV-Vis absorption and fluorescence spectroscopy. The results showed that complexation with pectin or alginate preserved nisin structure as well as its antimicrobial activity during spray-drying. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cotton harvest at 40% versus 75% boll-splitting on yield and economic return under standard and proactive boll weevil (Coleoptera: Curculionidae) spray regimes.

Science.gov (United States)

Showler, A T; Robinson, J R C

2008-10-01

The standard practice of two or three preemptive insecticide applications at the start of pinhead (1-2-mm-diameter) squaring followed by threshold-triggered (when 10% of randomly selected squares have oviposition punctures) insecticide applications for boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), control does not provide reliable protection of cotton, Gossypium hirsutum L., lint production. This study, conducted during 2004 and 2005, showed that three to six fewer spray applications in a "proactive" approach, in which spraying began at the start of large (5.5-8-mm-diameter) square formation and continued at approximately 7-d intervals while large squares were abundant, resulted in fewer infested squares and 1.4- to 1.7-fold more lint than the standard treatment. Fewer sprays and increased yield made proactive spraying significantly more profitable than the standard approach, which resulted in relatively low or negative economic returns. Harvest at 75% boll-split in the proactive spray regime of 2005 resulted in four-fold greater economic return than cotton harvested at 40% boll-split because of improved protection of large squares and the elimination of late-season sprays inherent to standard spray regime despite the cost of an extra irrigation in the 75% boll-split treatments. The earlier, 40% harvest trigger does not avoid high late-season boll weevil pressure, which exerts less impact on bolls, the predominant form of fruiting body at that time, than on squares. Proactive spraying and harvest timing are based on an important relationship between nutrition, boll weevil reproduction, and economic inputs; therefore, the tactic of combining proaction with harvest at 75% boll-split is applicable where boll weevils are problematic regardless of climate or region, or whether an eradication program is ongoing.

Spatio-temporal droplet size statistics in developing spray of starchy solution

Science.gov (United States)

Naz, Muhammad Yasin; Sulaiman, Shaharin Anwar; Ariwahjoedi, Bambang

2015-07-01

In the given research, the spray jet breakup of a modified starch solution was studied as a function of jet injection time and nozzle orifice diameter. The starch-urea-borax solution was prepared and tested with three axisymmetric full cone nozzles at service temperature of 80°C and the injection pressure of 5 bar. It is worth mentioning that no jet breakup was seen below these temperature and pressure values. The imaging studies on the time based spray evolution revealed monotonic increase in both; spray cone angle and tip penetration with an increase in injection time form 0-300 mm. Hereinafter, both parameters exhibited constants value over injection time. Phase Doppler Anemometry (PDA) measurements of the droplet size revealed significant decrease in the Sauter Mean Diameter (SMD) along the spray centerline. However, a steady decrease in SMD was seen towards the spray boundary. For fixed injection time of 300 ms, the overall SMD was decreased from 112 to 71 µm at 60 mm downstream, from 102 to 64 µm at 100 mm downstream and from 85 to 61 µm at 140 mm downstream with an increase in orifice diameter from 1.19 to 1.59 mm.

An experimental methodology to quantify the spray cooling event at intermittent spray impact

International Nuclear Information System (INIS)

Moreira, Antonio L.N.; Carvalho, Joao; Panao, Miguel R.O.

2007-01-01

The present paper describes an experimental methodology devised to study spray cooling with multiple-intermittent sprays as those found in fuel injection systems of spark-ignition and diesel engines, or in dermatologic surgery applications. The spray characteristics and the surface thermal behaviour are measured by combining a two-component phase-Doppler anemometer with fast response surface thermocouples. The hardware allows simultaneous acquisition of Doppler and thermocouple signals which are processed in Matlab to estimate the time-varying heat flux and fluid-dynamic characteristics of the spray during impact. The time resolution of the acquisition system is limited by the data rate of validation of the phase-Doppler anemometer, but it has been shown to be accurate for the characterization of spray-cooling processes with short spurt durations for which the transient period of spray injection plays an important role. The measurements are processed in terms of the instantaneous heat fluxes, from which phase-average values of the boiling curves are obtained. Two of the characteristic parameters used in the thermal analysis of stationary spray cooling events, the critical heat flux (CHF) and Leidenfrost phenomenon, are then inferred in terms of operating conditions of the multiple-intermittent injections, such as the frequency, duration and pressure of injection. An integral method is suggested to describe the overall process of heat transfer, which accounts for the fluid-dynamic heterogeneities induced by multiple and successive droplet interactions within the area of spray impact. The method considers overall boiling curves dependant on the injection conditions and provides an empirical tool to characterize the heat transfer processes on the impact of multiple-intermittent sprays. The methodology is tested in a preliminary study of the effect of injection conditions on the heat removed by a fuel spray striking the back surface of the intake valve as in spark

Online characterization of nano-aerosols released by commercial spray products using SMPS–ICPMS coupling

Energy Technology Data Exchange (ETDEWEB)

Losert, Sabrina; Hess, Adrian [Empa Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Analytical Chemistry (Switzerland); Ilari, Gabriele [Empa Swiss Federal Laboratories for Materials Science and Technology, Electron Microscopy Center (Switzerland); Goetz, Natalie von, E-mail: natalie.von.goetz@chem.ethz.ch; Hungerbuehler, Konrad [ETH Zürich Swiss Federal Institute of Technology Zürich, Institute for Chemical and Bioengineering (Switzerland)

2015-07-15

Nanoparticle-containing sprays are a critical class of consumer products, since human exposure may occur by inhalation of nanoparticles (NP) in the generated aerosols. In this work, the suspension and the released aerosol of six different commercially available consumer spray products were analyzed. Next to a broad spectrum of analytical methods for the characterization of the suspension, a standardized setup for the analysis of aerosol has been used. In addition, a new online coupling technique (SMPS–ICPMS) for the simultaneous analysis of particle size and elemental composition of aerosol particles has been applied. Results obtained with this new method were confirmed by other well-established techniques. Comparison of particles in the original suspensions and in the generated aerosol showed that during spraying single particles of size less than 20 nm had been formed, even though in none of the suspensions particles of size less than 280 nm were present (Aerosol size range scanned: 7–300 nm). Both pump sprays and propellant gas sprays were analyzed and both released particles in the nm size range. Also, both water-based and organic solvent-based sprays released NP. However, a trend was observed that spraying an aqueous suspension contained in a pump spray dispenser after drying resulted in bigger agglomerates than spraying organic suspensions in propellant gas dispensers.

Modifications Of A Commercial Spray Gun

Science.gov (United States)

Allen, Peter B.

1993-01-01

Commercial spray gun modified to increase spray rate and make sprayed coats more nearly uniform. Consists of gun head and pneumatic actuator. Actuator opens valves for two chemical components, called "A" and "B," that react to produce foam. Components flow through orifices, into mixing chamber in head. Mixture then flows through control orifice to spray tip. New spray tip tapered to reduce area available for accumulation of foam and makes tip easier to clean.

Efficacy of lignocaine in gel and spray form during buccal infiltration anesthesia in children: a randomized clinical trial.

Science.gov (United States)

Sharma, Anshul; Suprabha, B S; Shenoy, Ramya; Rao, Arathi

2014-11-01

To compare the efficacy of 15% lignocaine spray and 8% lignocaine gel as a topical anesthetic, in reducing pain, during buccal infiltration in children. Forty-two patients aged between 7 and 12 years requiring restorative procedures/extraction/pulp therapy of primary/ permanent teeth in the maxillary arch, under buccal infiltration anesthesia were selected for the study. The participants were randomly allocated into 2 groups of 21 each. In group A, 8% lignocaine gel and in group B, 15% lignocaine spray was applied prior to buccal infiltration. Pain was assessed using Wong-Baker faces pain rating scale (WBFPRS) and faces legs activity cry and consolability (FLACC) painscale. Pearson's chi-square test revealed that there was no significant difference in the FLACC scores of the two groups (p = 0.54). Independent t-test demonstrated that there was no significant difference in Wong-Bakers faces pain score between the two agents (p = 0.07). There is no significant difference in the efficacy of 15% lignocaine spray and 8% lignocaine gel as a topical anesthetic in controlling pain during buccal infiltration anesthesia, in children.

Deposition of Coating to Protect Waste Water Reservoir in Acidic Solution by Arc Thermal Spray Process

Directory of Open Access Journals (Sweden)

Han-Seung Lee

2018-01-01

Full Text Available The corrosion characteristics of 304 stainless steel (SS and titanium (Ti coatings deposited by the arc thermal spray process in pH 4 solution were assessed. The Ti-sprayed coating exhibits uniform, less porous, and adherent coating morphology compared to the SS-sprayed coating. The electrochemical study, that is, electrochemical impedance spectroscopy (EIS, revealed that as exposure periods to solution were increased, the polarization resistance (Rp decreased and the charge transfer resistance (Rct increased owing to corrosion of the metallic surface and simultaneously at the same time the deposition of oxide films/corrosion on the SS-sprayed surface, while Ti coating transformed unstable oxides into the stable phase. Potentiodynamic studies confirmed that both sprayed coatings exhibited passive tendency attributed due to the deposition of corrosion products on SS samples, whereas the Ti-sprayed sample formed passive oxide films. The Ti coating reduced the corrosion rate by more than six times compared to the SS coating after 312 h of exposure to sulfuric acid- (H2SO4- contaminated water solution, that is, pH 4. Scanning electron microscope (SEM results confirmed the uniform and globular morphology of the passive film on the Ti coating resulting in reduced corrosion. On the other hand, the corrosion products formed on SS-sprayed coating exhibit micropores with a net-like microstructure. X-ray diffraction (XRD revealed the presence of the composite oxide film on Ti-sprayed samples and lepidocrocite (γ-FeOOH on the SS-coated surface. The transformation of TiO and Ti3O into TiO2 (rutile and anatase and Ti3O5 after 312 h of exposure to H2SO4 acid reveals the improved corrosion resistance properties of Ti-sprayed coating.

Characterization of Sodium Spray Aerosols

Energy Technology Data Exchange (ETDEWEB)

Nelson, C. T.; Koontz, R. L.; Silberberg, M. [Atomics International, North American Rockwell Corporation, Canoga Park, CA (United States)

1968-12-15

The consequences of pool and spray fires require evaluation in the safety analysis of liquid metal-cooled fast breeder reactors. Sodium spray fires are characterized by high temperature and pressure, produced during the rapid combustion of sodium in air. Following the initial energy release, some fraction of the reaction products are available as aerosols which follow the normal laws of agglomeration, growth, settling, and plating. An experimental study is underway at Atomics International to study the characteristics of high concentration sprays of liquid sodium in reduced oxygen atmospheres and in air. The experiments are conducted in a 31.5 ft{sup 3} (2 ft diam. by 10 ft high) vessel, certified for a pressure of 100 lb/in{sup 2} (gauge). The spray injection apparatus consists of a heated sodium supply pot and a spray nozzle through which liquid sodium is driven by nitrogen pressure. Spray rate and droplet size can be varied by the injection velocity (nozzle size, nitrogen pressure, and sodium temperature). Aerosols produced in 0, 4, and 10 vol. % oxygen environments have been studied. The concentration and particle size distribution of the material remaining in the air after the spray injection and reaction period are measured. Fallout rates are found to be proportional to the concentration of aerosol which remains airborne following the spray period. (author)

Modeling of droplet dynamic and thermal behaviour during spray ...

Indian Academy of Sciences (India)

Modeling Studies Volume 26 Issue 3 April 2003 pp 355-364 ... Mathematical modeling of supersonic gas atomization for spray forming has been investigated. ... Department of Mechanical Engineering, M.S. Ramaiah Institute of Technology, Bangalore 560 054, India; Department of Mechanical Engineering, University ...

Powder compression mechanics of spray-dried lactose nanocomposites.

Science.gov (United States)

Hellrup, Joel; Nordström, Josefina; Mahlin, Denny

2017-02-25

The aim of this study was to investigate the structural impact of the nanofiller incorporation on the powder compression mechanics of spray-dried lactose. The lactose was co-spray-dried with three different nanofillers, that is, cellulose nanocrystals, sodium montmorillonite and fumed silica, which led to lower micron-sized nanocomposite particles with varying structure and morphology. The powder compression mechanics of the nanocomposites and physical mixtures of the neat spray-dried components were evaluated by a rational evaluation method with compression analysis as a tool, using the Kawakita equation and the Shapiro-Konopicky-Heckel equation. Particle rearrangement dominated the initial compression profiles due to the small particle size of the materials. The strong contribution of particle rearrangement in the materials with fumed silica continued throughout the whole compression profile, which prohibited an in-depth material characterization. However, the lactose/cellulose nanocrystals and the lactose/sodium montmorillonite nanocomposites demonstrated high yield pressure compared with the physical mixtures indicating increased particle hardness upon composite formation. This increase has likely to do with a reinforcement of the nanocomposite particles by skeleton formation of the nanoparticles. In summary, the rational evaluation of mechanical properties done by applying powder compression analysis proved to be a valuable tool for mechanical evaluation for this type of spray-dried composite materials, unless they demonstrate particle rearrangement throughout the whole compression profile. Copyright © 2016 Elsevier B.V. All rights reserved.

A spray flamelet/progress variable approach combined with a transported joint PDF model for turbulent spray flames

Science.gov (United States)

Hu, Yong; Olguin, Hernan; Gutheil, Eva

2017-05-01

A spray flamelet/progress variable approach is developed for use in spray combustion with partly pre-vaporised liquid fuel, where a laminar spray flamelet library accounts for evaporation within the laminar flame structures. For this purpose, the standard spray flamelet formulation for pure evaporating liquid fuel and oxidiser is extended by a chemical reaction progress variable in both the turbulent spray flame model and the laminar spray flame structures, in order to account for the effect of pre-vaporised liquid fuel for instance through use of a pilot flame. This new approach is combined with a transported joint probability density function (PDF) method for the simulation of a turbulent piloted ethanol/air spray flame, and the extension requires the formulation of a joint three-variate PDF depending on the gas phase mixture fraction, the chemical reaction progress variable, and gas enthalpy. The molecular mixing is modelled with the extended interaction-by-exchange-with-the-mean (IEM) model, where source terms account for spray evaporation and heat exchange due to evaporation as well as the chemical reaction rate for the chemical reaction progress variable. This is the first formulation using a spray flamelet model considering both evaporation and partly pre-vaporised liquid fuel within the laminar spray flamelets. Results with this new formulation show good agreement with the experimental data provided by A.R. Masri, Sydney, Australia. The analysis of the Lagrangian statistics of the gas temperature and the OH mass fraction indicates that partially premixed combustion prevails near the nozzle exit of the spray, whereas further downstream, the non-premixed flame is promoted towards the inner rich-side of the spray jet since the pilot flame heats up the premixed inner spray zone. In summary, the simulation with the new formulation considering the reaction progress variable shows good performance, greatly improving the standard formulation, and it provides new

Chemistry and tensile properties of a recycled AA7050 via spray forming and ECAP/E

Directory of Open Access Journals (Sweden)

Alexandre Hyodo

2012-10-01

Full Text Available The aim of this work is to evaluate the conjugation of advanced processing techniques, such as spray forming, extrusion and ECAP as a processing route for reuse of machining chips generated during aircrafts manufacturing parts from AA7050-T7451 raw material plates supplied according to AMS 4050H¹. In this way, the sprayforming process was used for remelting, and billet production, followed by extrusion and ECAP. At the end of the process, an artificial aging according to AMS 2772E ² was conducted. An assessment of chemical composition, microstructure, and mechanical properties evolution throughout the process were performed. The results have showed that this proposed route may be used as a potential technological route for secondary aluminum source. For extrusion route for overaged condition, 144 MPa yield strength and 14% of elongation was attained. Beside this, at this stage of work, was verified that the hot extrusion process is more effective for reduction of porosity and microstructure development than ECAP, but on the other hand this one has reduced porosity dispersion significantly for the extrusion parameters adopted. The adopted homogenization schedule, followed by artificial aging after has resulted in excessive grain growth.

Pharmaceutical Particle Engineering via Spray Drying

Science.gov (United States)

2007-01-01

This review covers recent developments in the area of particle engineering via spray drying. The last decade has seen a shift from empirical formulation efforts to an engineering approach based on a better understanding of particle formation in the spray drying process. Microparticles with nanoscale substructures can now be designed and their functionality has contributed significantly to stability and efficacy of the particulate dosage form. The review provides concepts and a theoretical framework for particle design calculations. It reviews experimental research into parameters that influence particle formation. A classification based on dimensionless numbers is presented that can be used to estimate how excipient properties in combination with process parameters influence the morphology of the engineered particles. A wide range of pharmaceutical application examples—low density particles, composite particles, microencapsulation, and glass stabilization—is discussed, with specific emphasis on the underlying particle formation mechanisms and design concepts. PMID:18040761

Spray Drying as a Processing Technique for Syndiotactic Polystyrene to Powder Form for Part Manufacturing Through Selective Laser Sintering

Science.gov (United States)

Mys, N.; Verberckmoes, A.; Cardon, L.

2017-03-01

Selective laser sintering (SLS) is a rapidly expanding field of the three-dimensional printing concept. One stumbling block in the evolution of the technique is the limited range of materials available for processing with SLS making the application window small. This article aims at identifying syndiotactic polystyrene (sPS) as a promising material. sPS pellets were processed into powder form with a lab-scale spray dryer with vibrating nozzle. This technique is the focus of this scope as it almost eliminates the agglomeration phenomenon often encountered with the use of solution-based processing techniques. Microspheres obtained were characterized in shape and size by scanning electron microscopy and evaluation of the particle size distribution. The effect the processing technique imparts on the intrinsic properties of the material was examined by differential scanning calorimetry analysis.

Dynamics of flare sprays

International Nuclear Information System (INIS)

Tandberg-Hanssen, E.; Hansen, R.T.

1980-01-01

During solar cycle No. 20 new insight into the flare-spray phenomenon has been attained due to several innovations in solar optical-observing techniques (higher spatial resolution cinema-photography, tunable pass-band filters, multi-slit spectroscopy and extended angular field coronographs). From combined analysis of 13 well-observed sprays which occured between 1969-1974 we conclude that (i) the spray material originates from a preexisting active region filament which undergoes increased absorption some tens of minutes prior to the abrupt chromospheric brightening at the 'flare-start', and (ii) the spray material is confined within a steadily expanding, loop-shaped (presumably magnetically controlled) envelope with part of the material draining back down along one or both legs of the loop. (orig.)

Absorption/desorption in sprays

International Nuclear Information System (INIS)

Naimpally, A.

1987-01-01

This survey paper shall seek to present the present state of knowledge concerning absorption and desorption in spray chambers. The first part of the paper presents the theories and formulas for the atomization and break-up of sprays in nozzles. Formulas for the average (sauter-mean) diameters are then presented. For the case of absorption processes, the formulas for the dimensionless mass transfer coefficients is in drops. The total; mass transfer is the total of the transfer in individual drops. For the case of desorption of sparingly soluble gases from liquids in a spray chamber, the mass transfer occurs in the spray just at the point of break-up of the jet. Formulas for the desorption of gases are presented

Evaluation of sub-zero and residence times after continuous versus multiple intermittent cryogen spray cooling exposure on human skin phantom

OpenAIRE

Ramirez-San-Juan, JC; Tuqan, AT; Kelly, KM; Nelson, JS; Aguilar, G

2004-01-01

Cryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during various laser dermatologic surgeries. However, as the application of single or multiple cryogen spurts becomes available on some commercial lasers devices, it is necessary to determine the optimal CSC parameters for different laser surgeries. The objective of this study was to measure the time the sprayed surface of a human skin phantom (HSP) remains below water freezing temperature 0°C, referred to as subzero...

Non-spherical particle formation induced by repulsive hydration forces during spray drying

Energy Technology Data Exchange (ETDEWEB)

Suh, Yong Jae; Lee, Jin-Woo; Chang, Hankwon; Jang, Hee-Dong, E-mail: hdjang@kigam.re.kr; Cho, Kuk, E-mail: kukcho@pusan.ac.kr [Korea Institute of Geoscience and Mineral Resources (Korea, Republic of)

2013-09-15

Non-spherical particles were produced during a spray-drying process, but the exact mechanism of their formation was unknown. The non-spherical particles form when the strength of the colloidal droplets is exceeded by external stress stemming from drag in the velocity gradient. Here, we show that repulsive hydration forces reduce the mechanical strength of the droplets; this is critical to the formation of non-spherical particles. Toroidal or ellipsoidal particles were prepared from low-concentration hydrophilic SiO{sub 2}, TiO{sub 2}, and CuO colloidal solutions, but not from hydrophobic ZnO colloidal solutions. The surface properties of the solid particulates are crucial for the morphology of particles formed during spray drying.

Non-spherical particle formation induced by repulsive hydration forces during spray drying

International Nuclear Information System (INIS)

Suh, Yong Jae; Lee, Jin-Woo; Chang, Hankwon; Jang, Hee-Dong; Cho, Kuk

2013-01-01

Non-spherical particles were produced during a spray-drying process, but the exact mechanism of their formation was unknown. The non-spherical particles form when the strength of the colloidal droplets is exceeded by external stress stemming from drag in the velocity gradient. Here, we show that repulsive hydration forces reduce the mechanical strength of the droplets; this is critical to the formation of non-spherical particles. Toroidal or ellipsoidal particles were prepared from low-concentration hydrophilic SiO 2 , TiO 2 , and CuO colloidal solutions, but not from hydrophobic ZnO colloidal solutions. The surface properties of the solid particulates are crucial for the morphology of particles formed during spray drying

Study on fuel particle motion of a diesel spray; Diesel funmu ryushi no kyodo ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, N. [Isuzu Motors Ltd., Tokyo (Japan); Tsujimura, K.

1998-08-25

This study was performed to clarify the mechanism of mixture formation at peripheral area of diesel spray with PIV technique. Two dimensional cross-sectional photographs of diesel spray were taken with double pulse laser sheet. Local fuel spray particles were analyzed with an auto-correlation method and velocity vector and vorticity of the fuel spray particle were obtained. The vortex number increased and vorticity scale became smaller and its value grew higher with both smaller injection nozzle diameter and higher fuel injection velocity. With this injection condition, the mixing of fuel spray with ambient gas seems to be improved and the turbulence is expected to increase in the regions of higher vortex number, higher vorticity and smaller vorticity scale. Based on above results, the branch-like structure of diesel fuel spray was considered to be caused by vortices which formed in the shear layer between the spray and the ambient gas. 14 refs., 18 figs., 1 tab.

Development of spraying methods for high density bentonite barriers. Part 3. Field investigation of spraying methods

International Nuclear Information System (INIS)

Tanaka, Toshiyuki; Nakajima, Makoto; Kobayashi, Ichizo; Toida, Masaru; Fukuda, Katsumi; Sato, Tatsuro; Nonaka, Katsumi; Gozu, Keisuke

2007-01-01

The authors have developed a new method of constructing high density bentonite barriers by means of a wet spraying method. Using this method, backfill material can be placed in narrow upper and side parts in a low-level radioactive waste disposal facility. Using a new supplying machine for bentonite, spraying tests were conducted to investigate the conditions during construction. On the basis of the test results, the various parameters for the spraying method were investigated. The test results are summarized as follows: 1. The new machine supplied about twice the weight of material supplied by a screw conveyor. A dry density of spraying bentonite 0.05 Mg/m 3 higher than that of a screw conveyor with the same water content could be achieved. 2. The dry density of sprayed bentonite at a boundary with concrete was the same as that at the center of the cross section. 3. The variation in densities of bentonite sprayed in the vertical downward and horizontal directions was small. Also, density reduction due to rebound during spraying was not seen. 4. Bentonite controlled by water content could be sprayed smoothly in the horizontal direction by a small machine. Also rebound could be collected by a machine conveying air. (author)

Plasma sprayed samarium--cobalt permanent magnets

International Nuclear Information System (INIS)

Willson, M.C.; Janowiecki, R.J.

1975-01-01

Samarium--cobalt permanent magnets were fabricated by arc plasma spraying. This process involves the injection of relatively coarse powder particles into a high-temperature gas for melting and spraying onto a substrate. The technique is being investigated as an economical method for fabricating cobalt--rare earth magnets for advanced traveling wave tubes and cross-field amplifiers. Plasma spraying permits deposition of material at high rates over large areas with optional direct bonding to the substrate, and offers the ability to fabricate magnets in a variety of shapes and sizes. Isotropic magnets were produced with high coercivity and good reproducibility in magnetic properties. Post-spray thermal treatments were used to enhance the magnetic properties of sprayed deposits. Samarium--cobalt magnets, sprayed from samarium-rich powder and subjected to post-spray heat treatment, displayed energy products in excess of 9 million gauss-oersteds and coercive forces of approximately 6000 oersteds. Bar magnet arrays were constructed by depositing magnets on ceramic substrates. (auth)

Plasma sprayed samarium--cobalt permanent magnets

International Nuclear Information System (INIS)

Willson, M.C.; Janowiecki, R.J.

1975-01-01

Samarium--Co permanent magnets were fabricated by arc plasma spraying. This process involves the injection of relatively coarse powder particles into a high temperature gas for melting and spraying onto a substrate. The technique is being investigated as an economical method for fabricating Co--rare earth magnets for advanced traveling wave tubes and cross-field amplifiers. Plasma spraying permits deposition of material at high rates over large areas with optional direct bonding to the substrate, and offers the ability to fabricate magnets in a variety of shapes and sizes. Isotropic magnets were produced with high coercivity and good reproducibility in magnetic properties. Post-spray thermal treatments were used to enhance the magnetic properties of sprayed deposits. Samarium--Co magnets, sprayed from Sm-rich powder and subjected to post-spray heat treatment, displayed energy products in excess of 9 million G-Oe and coercive forces of approximately 6000 Oe. Bar magnet arrays were constructed by depositing magnets on ceramic substrates

Simultaneous Polymerization and Polypeptide Particle Production via Reactive Spray-Drying.

Science.gov (United States)

Glavas, Lidija; Odelius, Karin; Albertsson, Ann-Christine

2016-09-12

A method for producing polypeptide particles via in situ polymerization of N-carboxyanhydrides during spray-drying has been developed. This method was enabled by the development of a fast and robust synthetic pathway to polypeptides using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as an initiator for the ring-opening polymerization of N-carboxyanhydrides. The polymerizations finished within 5 s and proved to be very tolerant toward impurities such as amino acid salts and water. The formed particles were prepared by mixing the monomer, N-carboxyanhydride of l-glutamic acid benzyl ester (NCAGlu) and the initiator (DBU) during the atomization process in the spray-dryer and were spherical with a size of ∼1 μm. This method combines two steps; making it a straightforward process that facilitates the production of polypeptide particles. Hence, it furthers the use of spray-drying and polypeptide particles in the pharmaceutical industry.

Applicability of fan spray nozzles to stripping insoluble gases from viscous liquids

International Nuclear Information System (INIS)

Tseng, H.H.; Johnson, E.F.

1983-08-01

Fan spray nozzle stripping appears to be a practical technique for separating dilute volatile solutes from nonvolatile solvents. In particular this technique can be used to strip molecular tritium and tritium fluoride at extremely small concentration (in the parts per million range) from molten salts used as blanket materials in a fusion reactor. Under adjusted operating conditions of the fan spray as it leaves the nozzle, a high percentage of the theoretically maximum achievable stripping would take place from the expanding sheet of the fan spray as it leaves the nozzle and before it breaks up. Although the only available experimental data are for aqueous solutions, a new theoretical analysis of the fan spray sheet demonstrates the applicability of this technique to nonaqueous liquids. The equation derived from this analysis relates the theoretically achievable mass transfer efficiency to the properties of the liquid flowing through the fan spray nozzle and to the operating conditions of the nozzle. Any fluid with viscosity higher than or equal to that of water would be expected to follow this equation as long as a fan-shaped sheet is formed under the operating conditions of the nozzle

Spray Drift Reduction Evaluations of Spray Nozzles Using a Standardized Testing Protocol

Science.gov (United States)

2010-07-01

Drop Size Characteristics in a Spray Using Optical Nonimaging Light-Scattering Instruments,” Annual Book of ASTM Standards, Vol. 14-02, ASTM...Test Method for Determining Liquid Drop Size Characteristics in a Spray Using Optical Non- imaging Light-Scattering Instruments 22. AGDISP Model

Advanced Diagnostics for High Pressure Spray Combustion.

Energy Technology Data Exchange (ETDEWEB)

Skeen, Scott A.; Manin, Julien Luc; Pickett, Lyle M.

2014-06-01

The development of accurate predictive engine simulations requires experimental data to both inform and validate the models, but very limited information is presently available about the chemical structure of high pressure spray flames under engine- relevant conditions. Probing such flames for chemical information using non- intrusive optical methods or intrusive sampling techniques, however, is challenging because of the physical and optical harshness of the environment. This work details two new diagnostics that have been developed and deployed to obtain quantitative species concentrations and soot volume fractions from a high-pressure combusting spray. A high-speed, high-pressure sampling system was developed to extract gaseous species (including soot precursor species) from within the flame for offline analysis by time-of-flight mass spectrometry. A high-speed multi-wavelength optical extinction diagnostic was also developed to quantify transient and quasi-steady soot processes. High-pressure sampling and offline characterization of gas-phase species formed following the pre-burn event was accomplished as well as characterization of gas-phase species present in the lift-off region of a high-pressure n-dodecane spray flame. For the initial samples discussed in this work several species were identified, including polycyclic aromatic hydrocarbons (PAH); however, quantitative mole fractions were not determined. Nevertheless, the diagnostic developed here does have this capability. Quantitative, time-resolved measurements of soot extinction were also accomplished and the novel use of multiple incident wavelengths proved valuable toward characterizing changes in soot optical properties within different regions of the spray flame.

Microstructure and mechanical properties of spray-deposited Mg-12.55Al-3.33Zn-0.58Ca-1Nd alloy

International Nuclear Information System (INIS)

Bai Pucun; Dong Taishang; Hou Xiaohu; Zhao Chunwang; Xing Yongming

2010-01-01

A Mg-Al-Zn-Ca-Nd magnesium alloy was prepared by spray forming technology, and the spray-deposited alloy was subsequently hot-extruded with a reduction rate of 16:1 at 623 K. The mechanical properties of the extruded alloy were investigated, and the result shows that the spray-formed Mg alloy offers superior tensile strength with poor ductility. The morphologies, fracture characteristic and chemical compositions of the extruded alloy were then explored by scanning electron microscopy with energy dispersive spectrometer. Furthermore, microstructure of the extruded alloy was examined by X-ray diffractometry and transmission electron microscopy. The results indicate that the microstructure of the spray-deposited magnesium alloy consists of α-Mg and Al 2 Ca phases, and the Al 2 Ca compound is distributed along the grain boundaries of the primary α-Mg. Moreover, twin substructure is found to exist in microstructure of the Al 2 Ca phase, rare earth Nd in the Al 2 Ca phase in the form of solid solution.

Effects of spray axis incident angle on heat transfer performance of rhombus-pitch shell-and-tube interior spray evaporator

International Nuclear Information System (INIS)

Lin, Ru-Li; Chang, Tong-Bou; Liang, Chih-Chang

2012-01-01

An interior spray method is proposed for enhancing the heat transfer performance of a compact rhombus-pitch shell-and-tube spray evaporator. The experimental results show that the shell-side heat transfer coefficient obtained using the proposed spray method is significantly higher than that achieved in a conventional flooded-type evaporator. Four different spray axis incident angles (0 .deg., 45 .deg., 60 .deg. and 75 .deg.) are tested in order to investigate the effect of the spray inclination angle on the heat transfer performance of the spray evaporator system. It is shown that the optimal heat transfer performance is obtained using a spray axis incident angle of 60 .deg.

A study on the macroscopic spray behavior and atomization characteristics of biodiesel and dimethyl ether sprays under increased ambient pressure

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyung Jun; Park, Su Han [Graduate School of Hanyang University, 17 Haengdang-dong, Seoungdong-gu, Seoul 133-791 (Korea); Lee, Chang Sik [Department of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea)

2010-03-15

The aim of this work is to investigate the spray behaviors of biodiesel and dimethyl ether (DME) fuels using image processing and atomization performance analysis of the two fuel sprays injected through a common-rail injection system under various ambient pressure conditions in a high pressure chamber. In order to observe the biodiesel and DME fuel spray behaviors under various ambient pressures, the spray images were analyzed at various times after the start of energization using a visualization system consisting of a high speed camera and two metal halide light sources. In addition, a high pressure chamber that can withstand a pressure of 4 MPa was used for adjusting the ambient pressure. From the spray images, spray characteristics such as the spray tip penetration, cone angle, area, and contour plot at various light intensity levels were analyzed using image conversion processing. Also, the local Sauter mean diameters (SMD) were measured at various axial/radial distances from the nozzle tip by a droplet measuring system to compare the atomization performances of the biodiesel and DME sprays. The results showed that the ambient pressure had a significant effect on the spray characteristics of the fuels at the various experimental conditions. The spray tip penetration and spray area decreased as the ambient pressure increased. The contour plot of the biodiesel and DME sprays showed a high light intensity level in the center regions of the sprays. In addition, it was revealed that the atomization performance of the biodiesel spray was inferior to that of the DME spray at the same injection and ambient conditions. (author)

Fixed automated spray technology.

Science.gov (United States)

2011-04-19

This research project evaluated the construction and performance of Boschungs Fixed Automated : Spray Technology (FAST) system. The FAST system automatically sprays de-icing material on : the bridge when icing conditions are about to occur. The FA...

Continuous powder feeding for pharmaceutical solid dosage form manufacture: a short review.

Science.gov (United States)

Blackshields, Caroline A; Crean, Abina M

2018-07-01

There has been a noticeable shift from pharmaceutical batch processing towards a more continuous mode of manufacture for solid oral dosage forms. Continuous solid oral dose processes would not be possible in the absence of a highly accurate feeding system. The performance of feeders defines the content of formulations and is therefore a critical operation in continuous manufacturing of solid dosage forms. It was the purpose of this review to review the role of the initial powder feeding step in a continuous manufacturing process. Different feeding mechanisms are discussed with a particular emphasis on screw controlled loss in weight (LIW) feeding. The importance of understanding the physical properties of the raw materials and its impact on the feeding process is reviewed. Prior knowledge of materials provides an initial indication of how the powders will behave through processing and facilitates in the selection of the most suitable (i) feeder (capacity), (ii) feeding mechanism, and (iii) in the case of screw feeder - screw type. The studies identified in this review focus on the impact of material on powder feeding performance.

Industrial application of model predictive control to a milk powder spray drying plant

DEFF Research Database (Denmark)

Petersen, Lars Norbert; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

2016-01-01

In this paper, we present our first results from an industrial application of model predictive control (MPC) with real-time steady-state target optimization (RTO) for control of an industrial spray dryer that produces enriched milk powder. The MPC algorithm is based on a continuous-time transfer...... provides significantly better control of the residual moisture content, increases the throughput and decreases the energy consumption compared to conventional PI-control. The MPC operates the spray dryer closer to the residual moisture constraint of the powder product. Thus, the same amount of feed...

LSPRAY-IV: A Lagrangian Spray Module

Science.gov (United States)

Raju, M. S.

2012-01-01

LSPRAY-IV is a Lagrangian spray solver developed for application with parallel computing and unstructured grids. It is designed to be massively parallel and could easily be coupled with any existing gas-phase flow and/or Monte Carlo Probability Density Function (PDF) solvers. The solver accommodates the use of an unstructured mesh with mixed elements of either triangular, quadrilateral, and/or tetrahedral type for the gas flow grid representation. It is mainly designed to predict the flow, thermal and transport properties of a rapidly vaporizing spray. Some important research areas covered as a part of the code development are: (1) the extension of combined CFD/scalar-Monte- Carlo-PDF method to spray modeling, (2) the multi-component liquid spray modeling, and (3) the assessment of various atomization models used in spray calculations. The current version contains the extension to the modeling of superheated sprays. The manual provides the user with an understanding of various models involved in the spray formulation, its code structure and solution algorithm, and various other issues related to parallelization and its coupling with other solvers.

Droplets and sprays

CERN Document Server

Sazhin, Sergei

2014-01-01

Providing a clear and systematic description of droplets and spray dynamic models, this book maximises reader insight into the underlying physics of the processes involved, outlines the development of new physical and mathematical models, and broadens understanding of interactions between the complex physical processes which take place in sprays. Complementing approaches based on the direct application of computational fluid dynamics (CFD), Droplets and Sprays treats both theoretical and practical aspects of internal combustion engine process such as the direct injection of liquid fuel, subcritical heating and evaporation. Includes case studies that illustrate the approaches relevance to automotive applications,  it is also anticipated that the described models can find use in other areas such as in medicine and environmental science.

Microstructure and mechanical properties of plasma sprayed HA/YSZ/Ti-6Al-4V composite coatings.

Science.gov (United States)

Khor, K A; Gu, Y W; Pan, D; Cheang, P

2004-08-01

Plasma sprayed hydroxyapatite (HA) coatings on titanium alloy substrate have been used extensively due to their excellent biocompatibility and osteoconductivity. However, the erratic bond strength between HA and Ti alloy has raised concern over the long-term reliability of the implant. In this paper, HA/yttria stabilized zirconia (YSZ)/Ti-6Al-4V composite coatings that possess superior mechanical properties to conventional plasma sprayed HA coatings were developed. Ti-6Al-4V powders coated with fine YSZ and HA particles were prepared through a unique ceramic slurry mixing method. The so-formed composite powder was employed as feedstock for plasma spraying of the HA/YSZ/Ti-6Al-4V coatings. The influence of net plasma energy, plasma spray standoff distance, and post-spray heat treatment on microstructure, phase composition and mechanical properties were investigated. Results showed that coatings prepared with the optimum plasma sprayed condition showed a well-defined splat structure. HA/YSZ/Ti-6Al-4V solid solution was formed during plasma spraying which was beneficial for the improvement of mechanical properties. There was no evidence of Ti oxidation from the successful processing of YSZ and HA coated Ti-6Al-4V composite powders. Small amount of CaO apart from HA, ZrO(2) and Ti was present in the composite coatings. The microhardness, Young's modulus, fracture toughness, and bond strength increased significantly with the addition of YSZ. Post-spray heat treatment at 600 degrees C and 700 degrees C for up to 12h was found to further improve the mechanical properties of coatings. After the post-spray heat treatment, 17.6% increment in Young's modulus (E) and 16.3% increment in Vicker's hardness were achieved. The strengthening mechanisms of HA/YSZ/Ti-6Al-4V composite coatings were related to the dispersion strengthening by homogeneous distribution of YSZ particles in the matrix, the good mechanical properties of Ti-6Al-4V and the formation of solid solution among HA

Visualization research on spray atomization, evaporation and combustion processes of ethanol–diesel blend under LTC conditions

International Nuclear Information System (INIS)

Huang, Sheng; Deng, Peng; Huang, Ronghua; Wang, Zhaowen; Ma, Yinjie; Dai, Hui

2015-01-01

Highlights: • Spray combustion of E20 diesel in LTC condition shows a U-shape flame structure. • The chasing behavior of fuel spray exists near the spray axis. • Fuel ignition doesn’t initiate at the spray tip but in peripheral regions behind it. • An improper chamber structure may lead to a long post-combustion duration. - Abstract: Utilization of ethanol in diesel engines has been widely studied by means of engine experiments and emission detection. However, pertinent studies on the spray combustion process of ethanol–diesel blends are scarce. In order to verify the effect of ethanol in modern diesel engines, an experiment is conducted to visualize the spray combustion process of ethanol–diesel blend under LTC conditions. Stages including atomization, evaporation and combustion, are investigated individually to realize synergistic analysis. Meanwhile, considering the long time scale of combustion after fuel injection finishes, characteristics during and after injection period are both targeted in this paper. Moreover, measurement of macroscopic characteristics, such as spray tip penetration, spray spreading cone angle and flame lift off length, provides a quantitative profile of the spray structure. Results show that, evaporation, different from atomization, has little influence on spray penetration, but promotes the spray spreading angle and spray projected area. So does combustion, which enlarges the spray projected area further. Ignition takes place on the periphery behind the spray tip, then quickly extends to the whole head of the spray and forms a U-shape diffusion structure. After the injection period, the residual spray tail develops into wavelike structures due to absence of subsequent entrainment force. Also, the penetration speed falls greatly to an extent much slower than flame propagation, which frees the flame from the lift-off effect. Subsequently, the flame propagates upstream towards the nozzle orifice. After consumed all fuel in

Plasma-sprayed titanium coating to polyetheretherketone improves the bone-implant interface.

Science.gov (United States)

Walsh, William R; Bertollo, Nicky; Christou, Chrisopher; Schaffner, Dominik; Mobbs, Ralph J

2015-05-01

Rapid and stable fixation at the bone-implant interface would be regarded as one of the primary goals to achieve clinical efficacy, regardless of the surgical site. Although mechanical and physical properties of polyetheretherketone (PEEK) provide advantages for implant devices, the hydrophobic nature and the lack of direct bone contact remains a limitation. To examine the effects of a plasma-sprayed titanium coated PEEK on the mechanical and histologic properties at the bone-implant interface. A preclinical laboratory study. Polyetheretherketone and plasma-sprayed titanium coated PEEK implants (Ti-bond; Spinal Elements, Carlsbad, CA, USA) were placed in a line-to-line manner in cortical bone and in a press-fit manner in cancellous bone of adult sheep using an established ovine model. Shear strength was assessed in the cortical sites at 4 and 12 weeks, whereas histology was performed in cortical and cancellous sites at both time points. The titanium coating dramatically improved the shear strength at the bone-implant interface at 4 weeks and continued to improve with time compared with PEEK. Direct bone ongrowth in cancellous and cortical sites can be achieved using a plasma-sprayed titanium coating on PEEK. Direct bone to implant bonding can be achieved on PEEK in spite of its hydrophobic nature using a plasma-sprayed titanium coating. The plasma-sprayed titanium coating improved mechanical properties in the cortical sites and the histology in cortical and cancellous sites. Copyright © 2015 Elsevier Inc. All rights reserved.

Thermal failure of nanostructured thermal barrier coatings with cold sprayed nanostructured NiCrAlY bond coat

Energy Technology Data Exchange (ETDEWEB)

Zhang, Q.; Li, Y.; Zhang, S.L.; Wang, X.R.; Yang, G.J.; Li, C.X.; Li, C.J. [Xi' an Jiaotong Univ., Xi' an (China)

2008-07-01

Nanostructured YSZ is expected to exhibit a high strain tolerability due to its low Young's modulus and consequently high durability. In this study, a porous YSZ as the thermal barrier coating was deposited by plasma spraying using an agglomerated nanostructured YSZ powder on a Ni-based superalloy Inconel 738 substrate with a cold-sprayed nanostructured NiCrAlY as the bond coat. The heat treatment in Ar atmosphere was applied to the cold-sprayed bond coat before deposition of YSZ. The isothermal oxidation and thermal cycling tests were applied to examine failure modes of plasma-sprayed nanostructured YSZ. The results showed that YSZ coating was deposited by partially melted YSZ particles. The nonmelted fraction of spray particles retains the porous nanostructure of the starting powder into the deposit. YSZ coating exhibits a bimodal microstructure consisting of nanosized particles retained from the powder and micro-columnar grains formed through the solidification of the melted fraction in spray particles. The oxidation of the bond coat occurs during the heat treatment in Ar atmosphere. The uniform oxide at the interface between the bond coat and YSZ can be formed during isothermal test. The cracks were observed at the interface between TGO/BC or TGO/YSZ after thermal cyclic test. However, the failure of TBCs mainly occurred through spalling of YSZ within YSZ coating. The failure characteristics of plasma-sprayed nanostructured YSZ are discussed based on the coating microstructure and formation of TGO on the bond coat surface. (orig.)

Immunological and physical evaluation of the multistage tuberculosis subunit vaccine candidate H56/CAF01 formulated as a spray-dried powder

DEFF Research Database (Denmark)

Thakur, Aneesh; Ingvarsson, Pall Thor; Schmidt, Signe Tandrup

2018-01-01

Liquid vaccine dosage forms have limited stability and require refrigeration during their manufacture, distribution and storage. In contrast, solid vaccine dosage forms, produced by for example spray drying, offer improved storage stability and reduced dependence on cold-chain facilities. This is......Liquid vaccine dosage forms have limited stability and require refrigeration during their manufacture, distribution and storage. In contrast, solid vaccine dosage forms, produced by for example spray drying, offer improved storage stability and reduced dependence on cold-chain facilities...

PIV measurement of internal structure of diesel fuel spray

Energy Technology Data Exchange (ETDEWEB)

Cao, Z M [Ecotechnology System Lab., Yokohama National Univ. (Japan); Nishino, K [Div. of Artificial Environment and Systems, Yokohama National Univ. (Japan); Mizuno, S [Yokohama National Univ. (Japan); Torii, K [Dept. of Mechanical Engineering and Materials Science, Yokohama National Univ. (Japan)

2000-12-01

This paper reports particle image velocimetry (PIV) measurements of diesel fuel spray injected from a single-hole nozzle at injection pressures ranging from 30 to 70 MPa, which are comparable to partial-load operating conditions of commercial diesel engines. The fuel is injected into a non-combusting environment pressurized up to 2.0 MPa. A laser-induced fluorescent (LIF) technique is utilized to visualize internal structures of fuel sprays formed by densely-distributing droplets. A specially designed synchronization system is developed to acquire double-frame spray images at an arbitrary time delay after injection. A direct cross-correlation PIV technique is applied to measure instantaneous droplet velocity distribution. Unique large-scale structures in droplet concentration, called 'branch-like structures' by Azetsu et al. (1990), are observed and shown to be associated with active vortical motions, which appear to be responsible for the mixing between droplets and the surrounding gas. It is found that the droplets tend to move out of the vortical structures and accumulate in the regions of low vorticity. Some other interesting features concerning droplet velocity fields are also presented. (orig.)

Diesel spray characterization; Dieselmoottorin polttoainesuihkujen ominaisuudet

Energy Technology Data Exchange (ETDEWEB)

Pitkaenen, J.; Turunen, R.; Paloposki, T.; Rantanen, P.; Virolainen, T. [Helsinki Univ. of Technology, Otaniemi (Finland). Internal Combustion Engine Lab.

1997-10-01

Fuel injection of diesel engines will be studied using large-scale models of fuel injectors. The advantage of large-scale models is that the measurement of large-scale diesel sprays will be easier than the measurement of actual sprays. The objective is to study the break-up mechanism of diesel sprays and to measure drop size distributions in the inner part of the spray. The results will be used in the development of diesel engines and diesel fuels. (orig.)

Multiple-Nozzle Spray Head Applies Foam Insulation

Science.gov (United States)

Walls, Joe T.

1993-01-01

Spray head equipped with four-nozzle turret mixes two reactive components of polyurethane and polyisocyanurate foam insulating material and sprays reacting mixture onto surface to be insulated. If nozzle in use becomes clogged, fresh one automatically rotated into position, with minimal interruption of spraying process. Incorporates features recirculating and controlling pressures of reactive components to maintain quality of foam by ensuring proper blend at outset. Also used to spray protective coats on or in ships, aircraft, and pipelines. Sprays such reactive adhesives as epoxy/polyurethane mixtures. Components of spray contain solid-particle fillers for strength, fire retardance, toughness, resistance to abrasion, or radar absorption.

Water spray interaction with air-steam mixtures under containment spray conditions: experimental study in the TOSQAN facility

Energy Technology Data Exchange (ETDEWEB)

Porcheron, E.; Lemaitre, P.; Malet, J.; Nuboer, A.; Brun, P.; Bouilloux, L.; Vendel, J. [Institut de Radioprotection et de Surete Nucleaire (IRSN), Direction de la Surete des Usines, des laboratoires, des transports et des dechets, Saclay, BP 68 - 91192 Gif-sur-Yvette cedex (France)

2005-07-01

Full text of publication follows: During the course of an hypothetical severe accident in a Pressurized Water Reactor (PWR), hydrogen can be produced by the reactor core oxidation and distributed into the reactor containment according to convection flows and steam wall condensation. In order to assess the risk of detonation generated by a high local hydrogen concentration, hydrogen distribution in the containment has to be known. The TOSQAN experimental program has been created to simulate typical accidental thermal hydraulic flow conditions in the reactor containment. The present work is devoted to study the interaction of a water spray injection used as a mitigation mean in order to reduce containment pressure and to produce a mixing of air, steam and hydrogen induced by spray entrainment and condensation on droplet. In order to have a better understanding of physical phenomena, we need to make a detailed characterization of the spray and the gas. The TOSQAN facility that is highly instrumented with non-intrusive diagnostics consists in a closed cylindrical vessel (7 m{sup 3} volume, 4 m high, 1.5 m i.d.) into which steam is injected. Water droplets size is measured in the vessel by the Interferometric Laser Imaging for Droplet Sizing technique. Droplet velocity is obtained by Particle Image Velocimetry and Laser Doppler Velocimetry, and droplet temperature is measured by global rainbow refractometry. Gas concentration measurements are performed by Spontaneous Raman Scattering. The walls of the vessel are thermostatically controlled by heated oil circulation. Inner spray system that is located on the top of the enclosure on the vertical axis, is composed of a single nozzle producing a full cone water spray. Spray test scenario consists of water spray injection in TOSQAN that is first pressurized with a steam injection (steam injection is stopped before spray injection). Water spray falling into the sump is removed to avoid accumulation and evaporation

Gas entrainment by one single French PWR spray, SARNET-2 spray benchmark

Energy Technology Data Exchange (ETDEWEB)

Malet, J., E-mail: jeanne.malet@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, Saclay (France); Mimouni, S., E-mail: stephane.mimouni@edf.fr [Electricité de France, EDF MF2E, Chatou (France); Manzini, G., E-mail: giovanni.manzini@rse-web.it [RSE, Milano (Italy); Xiao, J., E-mail: jianjun.xiao@kit.edu [IKET, KIT, Karlsruhe (Germany); Vyskocil, L., E-mail: vyl@ujv.cz [UJV Rez (Czech Republic); Siccama, N.B., E-mail: siccama@nrg.eu [NRG, Safety and Power (Netherlands); Huhtanen, R., E-mail: risto.huhtanen@vtt.fi [VTT, PO Box 1000, FI-02044 VTT (Finland)

2015-02-15

Highlights: • This paper presents a benchmark performed in the frame of the SARNET-2 EU project. • It concerns momentum transfer between a PWR spray and the surrounding gas. • The entrained gas velocities can vary up to 100% from one code to another. • Simplified boundary conditions for sprays are generally used by the code users. • It is shown how these simplified conditions impact the gas entrainment. - Abstract: This paper presents a benchmark performed in the frame of the SARNET-2 EU project, dealing with momentum transfer between a real-scale PWR spray and the surrounding gas. It presents a description of the IRSN tests on the CALIST facility, the participating codes (8 contributions), code-experiment and code-to-code comparisons. It is found that droplet velocities are almost well calculated one meter below the spray nozzle, even if the spread of the spray is not recovered and the values of the entrained gas velocity vary up to 100% from one code to another. Concerning sensitivity analysis, several ‘simplifications’ have been made by the contributors, especially based on the boundary conditions applied at the location where droplets are injected. It is shown here that such simplifications influence droplet and entrained gas characteristics. The next step will be to translate these conclusions in terms of variables representative of interesting parameters for nuclear safety.

Gas entrainment by one single French PWR spray, SARNET-2 spray benchmark

International Nuclear Information System (INIS)

Malet, J.; Mimouni, S.; Manzini, G.; Xiao, J.; Vyskocil, L.; Siccama, N.B.; Huhtanen, R.

2015-01-01

Highlights: • This paper presents a benchmark performed in the frame of the SARNET-2 EU project. • It concerns momentum transfer between a PWR spray and the surrounding gas. • The entrained gas velocities can vary up to 100% from one code to another. • Simplified boundary conditions for sprays are generally used by the code users. • It is shown how these simplified conditions impact the gas entrainment. - Abstract: This paper presents a benchmark performed in the frame of the SARNET-2 EU project, dealing with momentum transfer between a real-scale PWR spray and the surrounding gas. It presents a description of the IRSN tests on the CALIST facility, the participating codes (8 contributions), code-experiment and code-to-code comparisons. It is found that droplet velocities are almost well calculated one meter below the spray nozzle, even if the spread of the spray is not recovered and the values of the entrained gas velocity vary up to 100% from one code to another. Concerning sensitivity analysis, several ‘simplifications’ have been made by the contributors, especially based on the boundary conditions applied at the location where droplets are injected. It is shown here that such simplifications influence droplet and entrained gas characteristics. The next step will be to translate these conclusions in terms of variables representative of interesting parameters for nuclear safety

14 CFR 23.239 - Spray characteristics.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Spray characteristics. 23.239 Section 23.239 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Handling Characteristics § 23.239 Spray characteristics. Spray may not dangerously obscure the vision of...

14 CFR 29.239 - Spray characteristics.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Spray characteristics. 29.239 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Ground and Water Handling Characteristics § 29.239 Spray characteristics. If certification for water operation is requested, no spray characteristics...

14 CFR 27.239 - Spray characteristics.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Spray characteristics. 27.239 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Ground and Water Handling Characteristics § 27.239 Spray characteristics. If certification for water operation is requested, no spray characteristics...

Ionization Suppression and Recovery in Direct Biofluid Analysis Using Paper Spray Mass Spectrometry

Science.gov (United States)

Vega, Carolina; Spence, Corina; Zhang, Chengsen; Bills, Brandon J.; Manicke, Nicholas E.

2016-04-01

Paper spray mass spectrometry is a method for the direct analysis of biofluid samples in which extraction of analytes from dried biofluid spots and electrospray ionization occur from the paper on which the dried sample is stored. We examined matrix effects in the analysis of small molecule drugs from urine, plasma, and whole blood. The general method was to spike stable isotope labeled analogs of each analyte into the spray solvent, while the analyte itself was in the dried biofluid. Intensity of the labeled analog is proportional to ionization efficiency, whereas the ratio of the analyte intensity to the labeled analog in the spray solvent is proportional to recovery. Ion suppression and recovery were found to be compound- and matrix-dependent. Highest levels of ion suppression were obtained for poor ionizers (e.g., analytes lacking basic aliphatic amine groups) in urine and approached -90%. Ion suppression was much lower or even absent for good ionizers (analytes with aliphatic amines) in dried blood spots. Recovery was generally highest in urine and lowest in blood. We also examined the effect of two experimental parameters on ion suppression and recovery: the spray solvent and the sample position (how far away from the paper tip the dried sample was spotted). Finally, the change in ion suppression and analyte elution as a function of time was examined by carrying out a paper spray analysis of dried plasma spots for 5 min by continually replenishing the spray solvent.

Immediate effect of benzalkonium chloride in decongestant nasal spray on the human nasal mucosal temperature.

Science.gov (United States)

Lindemann, J; Leiacker, R; Wiesmiller, K; Rettinger, G; Keck, T

2004-08-01

Benzalkonium chloride is a preservative commonly used in nasal decongestant sprays. It has been suggested that benzalkonium chloride may be harmful to the nasal mucosa. Decongestion with the vasoconstrictor xylometazoline containing benzalkonium chloride has been shown to cause a significant reduction of the nasal mucosal temperature. The purpose of the present study was to determine the short-term influence of xylometazoline nasal spray with and without benzalkonium chloride on the nasal mucosal temperature. Healthy volunteers (30) were included in the study. Fifteen volunteers received xylometazoline nasal spray (1.0 mg/mL) containing benzalkonium chloride (0.1 mg/mL) and 15 age-matched subjects, received xylometazoline nasal spray without benzalkonium chloride. Using a miniaturized thermocouple the septal mucosal temperature was continuously measured at defined intranasal detection sites before and after application of the nasal spray. The mucosal temperature values did not significantly differ between the group receiving xylometazoline containing benzalkonium chloride and the group receiving xylometazoline spray without benzalkonium chloride before and after decongestion (P > 0.05). In both study groups septal mucosal temperatures significantly decreased after decongestion (P reduction of the nasal mucosal blood flow following vasoconstriction. This study indicates that benzalkonium chloride itself does not seem to influence nasal blood flow and nasal mucosal temperature in topical nasal decongestants.

A comparison of biological effect and spray liquid distribution and deposition for different spray application techniques in different crops

OpenAIRE

Larsolle, Anders; Wretblad, Per; Westberg, Carl

2002-01-01

The objective of this study was to compare a selection of spray application techniques with different application volumes, with respect to the spray liquid distribution on flat surfaces, the deposition in fully developed crops and the biological effect. The spray application techniques in this study were conventional spray technique with three different nozzles: Teelet XR, Lechler ID and Lurmark DriftBeta, and also AirTec, Danfoil, Hardi Twin, Kyndestoit and Släpduk. The dynamic spray liquid ...

Transient analysis of intermittent multijet sprays

Energy Technology Data Exchange (ETDEWEB)

Panao, Miguel R.O.; Moreira, Antonio Luis N. [Universidade Tecnica de Lisboa, IN, Center for Innovation, Technology and Policy Research, Instituto Superior Tecnico, Lisboa (Portugal); Durao, Diamantino G. [Universidade Lusiada, Lisboa (Portugal)

2012-07-15

This paper analyzes the transient characteristics of intermittent sprays produced by the single-point impact of multiple cylindrical jets. The aim is to perform a transient analysis of the intermittent atomization process to study the effect of varying the number of impinging jets in the hydrodynamic mechanisms of droplet formation. The results evidence that hydrodynamic mechanisms underlying the physics of ligament fragmentation in 2-impinging jets sprays also apply to sprays produced with more than 2 jets during the main period of injection. Ligaments detaching from the liquid sheet, as well as from its bounding rim, have been identified and associated with distinct droplet clusters, which become more evident as the number of impinging jets increases. Droplets produced by detached ligaments constitute the main spray, and their axial velocity becomes more uniformly distributed with 4-impinging jets because of a delayed ligament fragmentation. Multijet spray dispersion patterns are geometric depending on the number of impinging jets. Finally, an analysis on the Weber number of droplets suggests that multijet sprays are more likely to deposit on interposed surfaces, thus becoming a promising and competitive atomization solution for improving spray cooling. (orig.)

Mechanical and Microstructural Behavior of Cold-Sprayed Titanium- and Nickel-Based Coatings

Science.gov (United States)

Cavaliere, P.; Silvello, A.

2015-12-01

Cold spraying is a coating technology that can deposit materials with unique properties. The coating forms through intensive plastic deformation of particles impacting on a substrate at temperature well below the melting point of the sprayed material. Recently, various studies have been published regarding the microstructural and mechanical evolution of metal-matrix composite coatings produced by cold spraying. Herein, we describe the principal results of the available literature in the field of cold-sprayed composites. It is shown that more research is required to solve various questions in this field, for example, the different deformation modes of the material exhibited for various processing conditions, the reinforcing percentage of different material combinations, and the mechanical properties resulting from these complex systems. In the present study, this issue is approached and described for cold-sprayed Ni- and Ti-based composites. Materials were produced with varying ceramic phase (BN and TiAl3) fraction. The variation of the grain size, adhesion strength, porosity, and hardness of the deposits as a function of the ceramic phase fraction and processing parameters (impacting particle speed) is described. The interaction mechanisms between the cold-sprayed particles and the metal matrix during the coating process are presented and described. The results demonstrate a beneficial effect on grain size and porosity with increasing reinforcing phase percentage, as well as narrow processing parameter ranges to achieve the optimal properties with respect to the pure parent materials.

Time variation in the reaction-zone structure of two-phase spray detonations.

Science.gov (United States)

Pierce, T. H.; Nicholls, J. A.

1973-01-01

A detailed theoretical analysis of the time-varying detonation structure in a monodisperse spray is presented. The theory identifies experimentally observed reaction-zone overpressures as deriving from blast waves formed therein by the explosive ignition of the spray droplets, and follows in time the motion, change in strength, and interactions of these blast waves with one another, and with the leading shock. The results are compared with experimental data by modeling the motion of a finite-size circular pressure transducer through the theoretical data field in an x-t space.

Mechanism of Action of Lung Damage Caused by a Nanofilm Spray Product

DEFF Research Database (Denmark)

Larsen, Søren T.; Dallot, Constantin; Larsen, Susan W

2014-01-01

and identification of toxicological targets are important to perform rational and cost-effective toxicological studies. Thus, because the pulmonary surfactant system appears to be an important toxicological target for waterproofing spray products, study of surfactant inhibition could be included in toxicological...... during respiration. The active film-forming component used in the present spray product is also found in several other products on the market. Hence, it may be expected that these products may have a toxicity similar to the waterproofing product studied here. Elucidation of the toxicological mechanism...

Effectiveness of containment sprays in containment management

International Nuclear Information System (INIS)

Nourbakhsh, H.P.; Perez, S.E.; Lehner, J.R.

1993-05-01

A limited study has been performed assessing the effectiveness of containment sprays-to mitigate particular challenges which may occur during a severe accident. Certain aspects of three specific topics related to using sprays under severe accident conditions were investigated. The first was the effectiveness of sprays connected to an alternate water supple and pumping source because the actual containment spray pumps are inoperable. This situation could occur during a station blackout. The second topic concerned the adverse as well as beneficial effects of using containment sprays during severe accident scenario where the containment atmosphere contains substantial quantities of hydrogen along with steam. The third topic was the feasibility of using containment sprays to moderate the consequences of DCH

Characteristics of spray flames and the effect of group combustion on the morphology of flame-made nanoparticles

Science.gov (United States)

Eslamian, Morteza; Heine, Martin C.

2008-01-01

Characteristics of burning and non-burning sprays generated by a coaxial air-assist nozzle, previously used for the synthesis of ceramic nanoparticles by flame spray pyrolysis (FSP), are studied using phase Doppler anemometry. Also, the effect of droplet interaction on the overall combustion behavior of the spray (group combustion) and, consequently, on the characteristics of flame-made ceramic particles is investigated. A physical model is proposed which correlates the formation of inhomogeneous mixtures of micron-sized hollow particles and solid nanoparticles to the combustion mode: the precursor droplets which entirely evaporate in the hot flame are responsible for the formation of nanoparticles. The vapor species react, forming intermediate and product molecules and clusters that quickly grow to nanosized ceramic particles. On the other hand, under certain conditions, a small number of the droplets, particularly with large initial sizes, escape from the spray boundaries and become extinguished, producing large hollow ceramic particles. It is also possible that some of the large droplets, which lie within the spray core, do not entirely evaporate. These surviving droplets then form large particles which are usually hollow but can collapse to solid particles at sufficiently high temperatures. Also, a criterion for the formation of homogeneous ceramic nanoparticles is presented.

Characteristics of spray flames and the effect of group combustion on the morphology of flame-made nanoparticles

International Nuclear Information System (INIS)

Eslamian, Morteza; Heine, Martin C

2008-01-01

Characteristics of burning and non-burning sprays generated by a coaxial air-assist nozzle, previously used for the synthesis of ceramic nanoparticles by flame spray pyrolysis (FSP), are studied using phase Doppler anemometry. Also, the effect of droplet interaction on the overall combustion behavior of the spray (group combustion) and, consequently, on the characteristics of flame-made ceramic particles is investigated. A physical model is proposed which correlates the formation of inhomogeneous mixtures of micron-sized hollow particles and solid nanoparticles to the combustion mode: the precursor droplets which entirely evaporate in the hot flame are responsible for the formation of nanoparticles. The vapor species react, forming intermediate and product molecules and clusters that quickly grow to nanosized ceramic particles. On the other hand, under certain conditions, a small number of the droplets, particularly with large initial sizes, escape from the spray boundaries and become extinguished, producing large hollow ceramic particles. It is also possible that some of the large droplets, which lie within the spray core, do not entirely evaporate. These surviving droplets then form large particles which are usually hollow but can collapse to solid particles at sufficiently high temperatures. Also, a criterion for the formation of homogeneous ceramic nanoparticles is presented

Methods of studying aging and stabilization of spray-congealed solid dispersions with carnauba wax. 1. Microcalorimetric investigation.

Science.gov (United States)

Emås, M; Nyqvist, H

2000-03-20

Rapidly cooled materials are often unstable as a result of changes in their physical properties due to imperfect crystallization. In the process of spray-congealing, melted material is atomized into droplets which very quickly solidify. This increases the possibility of the material crystallizing in different metastable forms. In this study it is shown that isothermal microcalorimetry can be used to observe the change in the thermodynamic state of spray-congealed carnauba wax during storage. In order to accelerate the thermodynamic change in the spray-congealed wax, three annealing procedures have been developed and compared using isothermal microcalorimetry. By means of annealing, a spray-congealed product closer to a thermodynamically stable state has been achieved.

Preparation of cellulose based microspheres by combining spray coagulating with spray drying.

Science.gov (United States)

Wang, Qiao; Fu, Aiping; Li, Hongliang; Liu, Jingquan; Guo, Peizhi; Zhao, Xiu Song; Xia, Lin Hua

2014-10-13

Porous microspheres of regenerated cellulose with size in range of 1-2 μm and composite microspheres of chitosan coated cellulose with size of 1-3 μm were obtained through a two-step spray-assisted approach. The spray coagulating process must combine with a spray drying step to guarantee the formation of stable microspheres of cellulose. This approach exhibits the following two main virtues. First, the preparation was performed using aqueous solution of cellulose as precursor in the absence of organic solvent and surfactant; Second, neither crosslinking agent nor separated crosslinking process was required for formation of stable microspheres. Moreover, the spray drying step also provided us with the chance to encapsulate guests into the resultant cellulose microspheres. The potential application of the cellulose microspheres acting as drug delivery vector has been studied in two PBS (phosphate-buffered saline) solution with pH values at 4.0 and 7.4 to mimic the environments of stomach and intestine, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of non-invasive trunk sprays and trunk-injected emamectic benzoate

Science.gov (United States)

Deborah G. McCullough; D.L. Cappaert; T.M. Poland; A.C. Anulewicz; P. Lewis; J. Molongoski

2008-01-01

In 2007, we continued to evaluate two neo-nicotinoid insecticides, imidacloprid and dinotefuron, applied as non-invasive trunk sprays to control emerald ash borer (EAB), Agrilus planipennis Fairmaire. Neo-nicotinoid products are widely used to protect landscape ash trees because they are relatively safe for humans and non-target species. These...

Characterization of sprayed CuInS2 films by XRD and Raman spectroscopy measurements

International Nuclear Information System (INIS)

Lee, Dong-Yeup; Kim, JunHo

2010-01-01

We studied CuInS 2 (CIS) film growth using two deposition methods, which were high electrostatic field assisted ultrasonic spray (HEFAUS) deposition and sulfurization of Cu-In metallic film. The sprayed-films were grown with chalcopyrite ordering and Cu-Au ordering mixed. In order to obtain higher quality CIS films, post-sulfurization was carried out for sprayed-films. The post-sulfurization induced improvement of crystallinity and enhancement of chalcopyrite ordering. However, it was observed that Cu-Au ordering still coexisted in the CIS film after post-sulfurization. With the same sulfurization condition, sulfurization was done to transform Cu-In metallic film into CIS film. The sulfurized metallic film was turned out to be formed as CIS film with higher crystallinity and better chalcopyrite ordering than sulfurized sprayed-films. All fabricated films were characterized by X-ray diffraction, Raman scattering, scanning electron microscope and energy dispersive X-ray analysis measurements.

Supplementary Microstructural Features Induced During Laser Surface Melting of Thermally Sprayed Inconel 625 Coatings

Science.gov (United States)

Ahmed, Nauman; Voisey, K. T.; McCartney, D. G.

2014-02-01

Laser surface melting of thermally sprayed coatings has the potential to enhance their corrosion properties by incorporating favorable microstructural changes. Besides homogenizing the as-sprayed structure, laser melting may induce certain microstructural modifications (i.e., supplementary features) in addition to those that directly improve the corrosion performance. Such features, being a direct result of the laser treatment process, are described in this paper which is part of a broader study in which high velocity oxy-fuel sprayed Inconel 625 coatings on mild-steel substrates were treated with a diode laser and the modified microstructure characterized using optical and scanning electron microscopy and x-ray diffraction. The laser treated coating features several different zones, including a region with a microstructure in which there is a continuous columnar dendritic structure through a network of retained oxide stringers.

Electro-spray deposition of a mesoporous TiO2 charge collection layer: toward large scale and continuous production of high efficiency perovskite solar cells.

Science.gov (United States)

Kim, Min-cheol; Kim, Byeong Jo; Yoon, Jungjin; Lee, Jin-wook; Suh, Dongchul; Park, Nam-gyu; Choi, Mansoo; Jung, Hyun Suk

2015-12-28

The spin-coating method, which is widely used for thin film device fabrication, is incapable of large-area deposition or being performed continuously. In perovskite hybrid solar cells using CH(3)NH(3)PbI(3) (MAPbI(3)), large-area deposition is essential for their potential use in mass production. Prior to replacing all the spin-coating process for fabrication of perovskite solar cells, herein, a mesoporous TiO(2) electron-collection layer is fabricated by using the electro-spray deposition (ESD) system. Moreover, impedance spectroscopy and transient photocurrent and photovoltage measurements reveal that the electro-sprayed mesoscopic TiO(2) film facilitates charge collection from the perovskite. The series resistance of the perovskite solar cell is also reduced owing to the highly porous nature of, and the low density of point defects in, the film. An optimized power conversion efficiency of 15.11% is achieved under an illumination of 1 sun; this efficiency is higher than that (13.67%) of the perovskite solar cell with the conventional spin-coated TiO(2) films. Furthermore, the large-area coating capability of the ESD process is verified through the coating of uniform 10 × 10 cm(2) TiO(2) films. This study clearly shows that ESD constitutes therefore a viable alternative for the fabrication of high-throughput, large-area perovskite solar cells.

Influence of Solvent Composition on the Performance of Spray-Dried Co-Amorphous Formulations

Directory of Open Access Journals (Sweden)

Jaya Mishra

2018-04-01

Full Text Available Ball-milling is usually used to prepare co-amorphous drug–amino acid (AA mixtures. In this study, co-amorphous drug–AA mixtures were produced using spray-drying, a scalable industrially preferred preparation method. The influence of the solvent type and solvent composition was investigated. Mixtures of indomethacin (IND and each of the three AAs arginine, histidine, and lysine were ball-milled and spray-dried at a 1:1 molar ratio, respectively. Spray-drying was performed at different solvent ratios in (a ethanol and water mixtures and (b acetone and water mixtures. Different ratios of these solvents were chosen to study the effect of solvent mixtures on co-amorphous formulation. Residual crystallinity, thermal properties, salt/partial salt formation, and powder dissolution profiles of the IND–AA mixtures were investigated and compared to pure crystalline and amorphous IND. It was found that using spray-drying as a preparation method, all IND–AA mixtures could be successfully converted into the respective co-amorphous forms, irrespective of the type of solvent used, but depending on the solvent mixture ratios. Both ball-milled and spray-dried co-amorphous samples showed an enhanced dissolution rate and maintained supersaturation compared to the crystalline and amorphous IND itself. The spray-dried samples resulting in co-amorphous samples were stable for at least seven months of storage.

Optical monitoring systems for thermal spray processes: droplets behavior and substrate pre-treatments

Science.gov (United States)

Kawaguchi, Y.; Kobayashi, N.; Yamagata, Y.; Miyazaki, F.; Yamasaki, M.; Tanaka, J.; Muraoka, K.

2017-11-01

Thermal spray is a technique to form molten droplets using either plasma- or combustion-heating, which impinge upon substrates to form coating layers for various purposes, such as anti-corrosion and anti-wear layers. Although it is an established technique having a history of more than a century, operations of spray guns together with preparing suitable substrate surfaces for obtaining good coating layers still rely on experienced technicians. Because of the necessity of meeting more and more stringent requirements for coating quality and cost from customers, there has been a strong need to try to monitor spray processes, so as to obtain the best possible spray coating layers. The basic requirements for such monitoring systems are *reasonably cheap, *easy operation for laypersons, *easy access to targets to be investigated, and *an in-situ capability. The purpose of the present work is to provide suitable optical monitoring systems for (1) droplets behavior and (2) substrate pre-treatments. For the former (1), the first result was already presented at the 17th laser-aided plasma diagnostics meeting (LAPD17) in 2015 in Sapporo, and the results of its subsequent applications into real spray environments are shown in this article in order to validate the previous proposal. Topic (2) is new in the research program, and the proof-of-principle experiment for the proposed method yielded a favorable result. Based on this positive result, an overall strategy is being planned to fulfill the final objective of the optical monitoring of substrate pre-treatments. Details of these two programs (1) and (2) together with the present status are described.

Engineering spray-dried rosemary extracts with improved physicomechanical properties: a design of experiments issue

Directory of Open Access Journals (Sweden)

Luiza T. Chaul

Full Text Available ABSTRACT A 33 Box–Behnken design and Response Surface Methodology were performed to evaluate the influence of extract feed rate, drying air inlet temperature and spray nozzle airflow rate on the process yield, stability parameters (moisture content and water activity and on several physicomechanical properties of spray-dried rosemary extracts. Powder yield ranged from 17.1 to 74.96%. The spray-dried rosemary extracts showed moisture content and water activity below 5% and 0.5%, respectively, which indicate their chemical and microbiological stabilities. Even without using drying aids, some sets of experimental conditions rendered dried products with suitable flowability and compressibility characteristics for direct preparation of solid dosage forms. Analysis of variance and Response Surface Methodology proved that studied factors significantly affected most of the spray-dried rosemary extract quality indicators at different levels. The main processing parameter affecting the spray-dried rosemary extract characteristics was inlet temperature. The best combination of parameters used to obtain a reasonable yield of stable dry rosemary extracts with adequate technological properties for pharmaceutical purpose involves an extract feed rate of 2 ml/min, 80 °C inlet temperature and 40 l/min SA. The design of experiments approach is an interesting strategy for engineering spray-dried rosemary extracts with improved characteristics for pharmaceutical industrial purpose.

Endospore production allows using spray-drying as a possible formulation system of the biocontrol agent Bacillus subtilis CPA-8.

Science.gov (United States)

Yánez-Mendizabal, V; Viñas, I; Usall, J; Cañamás, T; Teixidó, N

2012-04-01

The role of endospore production by Bacillus subtilis CPA-8 on survival during spray-drying was investigated by comparison with a non-spore-forming biocontrol agent Pantoea agglomerans CPA-2. Endospore formation promoted heat resistance in CPA-8 depending on growth time (72 h cultures were more resistant than 24 h ones). The survival of CPA-8 and CPA-2 after spray-drying was determined after being grown in optimised media for 24 and 72 h. Spray-dried 72 h CPA-8 had the best survival (32%), while CPA-2 viability was less than 2%. CPA-8 survival directly related with its ability to produce endospores. Spray-dried CPA-8 reduced Monilinia fructicola conidia germination similarly to fresh cells, demonstrating that spray-drying did not adversely affect biocontrol efficacy. Endospore production thus improves CPA-8 resistance to spray-drying. These results can provide a reliable basis for optimising of the spray-drying formulation process for CPA-8 and other microorganisms.

An evaluation of the electric arc spray and (HPPS) processes for the manufacturing of high power plasma spraying MCrAIY coatings

Science.gov (United States)

Sacriste, D.; Goubot, N.; Dhers, J.; Ducos, M.; Vardelle, A.

2001-06-01

The high power plasma torch (PlazJet) can be used to spray refractory ceramics with high spray rates and deposition efficiency. It can provide dense and hard coating with high bond strengths. When manufacturing thermal barrier coatings, the PlazJet gun is well adapted to spraying the ceramic top coat but not the MCrAIY materials that are used as bond coat. Arc spraying can compete with plasma spraying for metallic coatings since cored wires can be used to spray alloys and composites. In addition, the high production rate of arc spraying enables a significant decrease in coating cost. This paper discusses the performances of the PlazJet gun, and a twin-wire are spray system, and compares the properties and cost of MCrAIY coatings made with these two processes. For arc spraying, the use of air or nitrogen as atomizing gas is also investigated.

A numerical simulation of wheel spray for simplified vehicle model based on discrete phase method

Directory of Open Access Journals (Sweden)

Xingjun Hu

2015-07-01

Full Text Available Road spray greatly affects vehicle body soiling and driving safety. The study of road spray has attracted increasing attention. In this article, computational fluid dynamics software with widely used finite volume method code was employed to investigate the numerical simulation of spray induced by a simplified wheel model and a modified square-back model proposed by the Motor Industry Research Association. Shear stress transport k-omega turbulence model, discrete phase model, and Eulerian wall-film model were selected. In the simulation process, the phenomenon of breakup and coalescence of drops were considered, and the continuous and discrete phases were treated as two-way coupled in momentum and turbulent motion. The relationship between the vehicle external flow structure and body soiling was also discussed.

Effects of nasal drug delivery device and its orientation on sprayed particle deposition in a realistic human nasal cavity.

Science.gov (United States)

Tong, Xuwen; Dong, Jingliang; Shang, Yidan; Inthavong, Kiao; Tu, Jiyuan

2016-10-01

In this study, the effects of nasal drug delivery device and the spray nozzle orientation on sprayed droplets deposition in a realistic human nasal cavity were numerically studied. Prior to performing the numerical investigation, an in-house designed automated actuation system representing mean adults actuation force was developed to produce realistic spray plume. Then, the spray plume development was filmed by high speed photography system, and spray characteristics such as spray cone angle, break-up length, and average droplet velocity were obtained through off-line image analysis. Continuing studies utilizing those experimental data as boundary conditions were applied in the following numerical spray simulations using a commercially available nasal spray device, which was inserted into a realistic adult nasal passage with external facial features. Through varying the particle releasing direction, the deposition fractions of selected particle sizes on the main nasal passage for targeted drug delivery were compared. The results demonstrated that the middle spray direction showed superior spray efficiency compared with upper or lower directions, and the 10µm agents were the most suitable particle size as the majority of sprayed agents can be delivered to the targeted area, the main passage. This study elaborates a comprehensive approach to better understand nasal spray mechanism and evaluate its performance for existing nasal delivery practices. Results of this study can assist the pharmaceutical industry to improve the current design of nasal drug delivery device and ultimately benefit more patients through optimized medications delivery. Copyright © 2016 Elsevier Ltd. All rights reserved.

ROTARY SPRAY DUSTER

Directory of Open Access Journals (Sweden)

E. S. Nechaeva

2013-01-01

Full Text Available Results of researches of hydraulic resistance, ablation of splashes and efficiency of dedusting in the rotor spray dust collector are given. Influence of frequency of rotation of the spray, the specified speed of gas and diameter of spattering holes on hydraulic resistance, size ablation of splashes and efficiency of a dedusting the device by diameter 0,25 m is investigated. As model liquid water is used. Results of mathematical processing are presented.

The influence of spill-line geometry on a spray generated by a pressure-swirl atomizer

Directory of Open Access Journals (Sweden)

Malý Milan

2016-01-01

Full Text Available An experimental investigation of characteristics of spray generated by a pressure-swirl atomizer (spill-return type was performed using shadowgraphy and Phase-Doppler Anemometry (PDA. Several different geometries of the spill-return orifice were tested in terms of a spray stability and quality on a cold test bench. PDA measurement yields a drop-size distribution and velocity data while the shadowgraphy unveils a break-up process in detail. Performed measurements reveal significant differences in spray characteristics as well as differences in spray stability. The results suggest that the air core, formed inside the swirl chamber, passes through the spill orifice, which causes instability of the inner flow. These instabilities lead to a chaotic state of sheet breakup resulting in shortening of breakup distance. Obtained findings are used to propose possible changes in the atomizer design for improvement of its performance.

The influence of spill-line geometry on a spray generated by a pressure-swirl atomizer

Science.gov (United States)

Malý, Milan; Janáčková, Lada; Jedelský, Jan; Jícha, Miroslav

2016-03-01

An experimental investigation of characteristics of spray generated by a pressure-swirl atomizer (spill-return type) was performed using shadowgraphy and Phase-Doppler Anemometry (PDA). Several different geometries of the spill-return orifice were tested in terms of a spray stability and quality on a cold test bench. PDA measurement yields a drop-size distribution and velocity data while the shadowgraphy unveils a break-up process in detail. Performed measurements reveal significant differences in spray characteristics as well as differences in spray stability. The results suggest that the air core, formed inside the swirl chamber, passes through the spill orifice, which causes instability of the inner flow. These instabilities lead to a chaotic state of sheet breakup resulting in shortening of breakup distance. Obtained findings are used to propose possible changes in the atomizer design for improvement of its performance.

Microscopic Examination of Cold Spray Cermet Sn+In2O3 Coatings for Sputtering Target Materials.

Science.gov (United States)

Winnicki, M; Baszczuk, A; Rutkowska-Gorczyca, M; Jasiorski, M; Małachowska, A; Posadowski, W; Znamirowski, Z; Ambroziak, A

2017-01-01

Low-pressure cold spraying is a newly developed technology with high application potential. The aim of this study was to investigate potential application of this technique for producing a new type of transparent conductive oxide films target. Cold spraying technique allows the manufacture of target directly on the backing plate; therefore the proposed sputtering target has a form of Sn+In 2 O 3 coating sprayed onto copper substrate. The microstructure and properties of the feedstock powder prepared using three various methods as well as the deposited ones by low-pressure cold spraying coatings were evaluated, compared, and analysed. Produced cermet Sn+In 2 O 3 targets were employed in first magnetron sputtering process to deposit preliminary, thin, transparent conducting oxide films onto the glass substrates. The resistivity of obtained preliminary films was measured and allows believing that fabrication of TCO (transparent conducting oxide) films using targets produced by cold spraying is possible in the future, after optimization of the deposition conditions.

Microscopic Examination of Cold Spray Cermet Sn+In2O3 Coatings for Sputtering Target Materials

Directory of Open Access Journals (Sweden)

M. Winnicki

2017-01-01

Full Text Available Low-pressure cold spraying is a newly developed technology with high application potential. The aim of this study was to investigate potential application of this technique for producing a new type of transparent conductive oxide films target. Cold spraying technique allows the manufacture of target directly on the backing plate; therefore the proposed sputtering target has a form of Sn+In2O3 coating sprayed onto copper substrate. The microstructure and properties of the feedstock powder prepared using three various methods as well as the deposited ones by low-pressure cold spraying coatings were evaluated, compared, and analysed. Produced cermet Sn+In2O3 targets were employed in first magnetron sputtering process to deposit preliminary, thin, transparent conducting oxide films onto the glass substrates. The resistivity of obtained preliminary films was measured and allows believing that fabrication of TCO (transparent conducting oxide films using targets produced by cold spraying is possible in the future, after optimization of the deposition conditions.

On the modeling of fuel sprays

Energy Technology Data Exchange (ETDEWEB)

Bergstroem, Christer

1997-12-01

This report concerns on the modelling of fuel sprays in a non-combustible case using an own developed fuel spray code module. The spray code is made as an independent module to simplify the use of different gas flow solvers together with the spray module. This enables the possibility to use different turbulence models. In the report two turbulence models has been used, the standard k-{epsilon} and the LES (Large Eddy Simulation) model. The report presents results obtained from a sensitivity study of both numerical and physical parameters on an evaporating spray under diesel like conditions (light duty diesel engine) with the spray code module attached to a cylindrical gas phase flow solver. The results from the sensitivity analysis showed that these effects were not so pronounced as has been reported. It was suggested that this was due to the `easy` nature of the investigated case, where the flow field could be sufficiently resolved without violating the droplet void fraction criteria and break-up, collision and combustion that may increase the grid spacing sensitivity were not modelled. An investigation was performed to valuate the feasibility of using LES as turbulence model. Calculations of the initial phase of a developing jet were made and it was found that in the initial phase of the spray and the flow structure were similar to that of a spatially developing jet flow, which is in agreement with experimental observations. Results from LES calculations on a developing spray jet was also compared with k-{epsilon} based ones. This result showed that the spray-LES approach captured the transition from a laminar to a turbulent flow field with an increase in turbulent kinetic energy k along the injection direction 45 refs, 37 figs, 2 tabs

Stochastic model of the near-to-injector spray formation assisted by a high-speed coaxial gas jet

Energy Technology Data Exchange (ETDEWEB)

Gorokhovski, M [Laboratoire de Mecanique des Fluides et d' Acoustique, CNRS-Ecole Centrale de Lyon-INSA Lyon-Universite Claude Bernard Lyon 1, 36 Avenue Guy de Collongue, 69131 Ecully Cedex (France); Jouanguy, J [Laboratoire de Mecanique de Lille, Ecole Centrale de Lille, Blvd Paul Langevin, 59655 Villeneuve d' Ascq Cedex (France); Chtab-Desportes, A [CD-adapco, 31 rue Delizy 93698 Pantin Cedex (France)], E-mail: mikhael.gorokhovski@ec-lyon.fr

2009-06-01

The stochastic model of spray formation in the vicinity of the air-blast atomizer has been described and assessed by comparison with measurements. In this model, the 3D configuration of a continuous liquid core is simulated by spatial trajectories of specifically introduced stochastic particles. The stochastic process is based on the assumption that due to a high Weber number, the exiting continuous liquid jet is depleted in the framework of statistical universalities of a cascade fragmentation under scaling symmetry. The parameters of the stochastic process have been determined according to observations from Lasheras's, Hopfinger's and Villermaux's scientific groups. The spray formation model, based on the computation of spatial distribution of the probability of finding the non-fragmented liquid jet in the near-to-injector region, is combined with the large-eddy simulation (LES) in the coaxial gas jet. Comparison with measurements reported in the literature for different values of the gas-to-liquid dynamic pressure ratio showed that the model predicts correctly the distribution of liquid in the close-to-injector region, the mean length of the liquid core, the spray angle and the typical size of droplets in the far field of spray.

Radio-frequency plasma spraying of ceramics

International Nuclear Information System (INIS)

Okada, T.; Hamatani, H.; Yoshida, T.

1989-01-01

This study was aimed at developing a novel spraying process using a radio-frequency (rf) plasma. Experiments of Al 2 O 3 and ZrO 2 - 8 wt% Y 2 O 3 spraying showed that the initial powder size was the most important parameter for depositing dense coatings. The optimum powder sizes of Al 2 O 3 and ZrO 2 - 8 wt% Y 2 O 3 were considered to be around 100 and 80 μm, respectively. The use of such large-size powders compared with those used by conventional dc plasma spraying made it possible to deposit adherent ceramics coatings of 150 to 300 μm on as-rolled SS304 substrates. It was also shown that low particle velocity of about 10 m/s, which is peculiar to rf plasma spraying, was sufficient for particle deformation, though it imposed a severe limitation on the substrate position. These experimental results prove that rf plasma spraying is an effective process and a strong candidate to open new fields of spraying applications

Direct morphological comparison of vacuum plasma sprayed and detonation gun sprayed hydroxyapatite coatings for orthopaedic applications.

Science.gov (United States)

Gledhill, H C; Turner, I G; Doyle, C

1999-02-01

Hydroxyapatite coatings on titanium substrates were produced using two thermal spray techniques vacuum plasma spraying and detonation gun spraying. X-ray diffraction was used to compare crystallinity and residual stresses in the coatings. Porosity was measured using optical microscopy in conjunction with an image analysis system. Scanning electron microscopy and surface roughness measurements were used to characterise the surface morphologies of the coatings. The vacuum plasma sprayed coatings were found to have a lower residual stress, a higher crystallinity and a higher level of porosity than the detonation gun coatings. It is concluded that consideration needs to be given to the significance of such variations within the clinical context.

Large Eddy Simulation of the spray formation in confinements

International Nuclear Information System (INIS)

Lampa, A.; Fritsching, U.

2013-01-01

Highlights: • Process stability of confined spray processes is affected by the geometric design of the spray confinement. • LES simulations of confined spray flow have been performed successfully. • Clustering processes of droplets is predicted in simulations and validated with experiments. • Criteria for specific coherent gas flow patterns and droplet clustering behaviour are found. -- Abstract: The particle and powder properties produced within spray drying processes are influenced by various unsteady transport phenomena in the dispersed multiphase spray flow in a confined spray chamber. In this context differently scaled spray structures in a confined spray environment have been analyzed in experiments and numerical simulations. The experimental investigations have been carried out with Particle-Image-Velocimetry to determine the velocity of the gas and the discrete phase. Large-Eddy-Simulations have been set up to predict the transient behaviour of the spray process and have given more insight into the sensitivity of the spray flow structures in dependency from the spray chamber design

In Vitro Assessment of Spray Deposition Patterns in a Pediatric (12 Year-Old) Nasal Cavity Model.

Science.gov (United States)

Sawant, Namita; Donovan, Maureen D

2018-03-26

Nasal sprays available for the treatment of cold and allergy symptoms currently use identical formulations and devices for adults as well as for children. Due to the obvious differences between the nasal airway dimensions of a child and those of an adult, the performance of nasal sprays in children was evaluated. Deposition patterns of nasal sprays administered to children were tested using a nasal cast based on MRI images obtained from a 12 year old child's nasal cavity. Test formulations emitting a range of spray patterns were investigated by actuating the device into the pediatric nasal cast under controlled conditions. The results showed that the nasal sprays impacted in the anterior region of the 12 year old child's nasal cavity, and only limited spray entered the turbinate region - the effect site for most topical drugs and the primary absorptive region for systemically absorbed drugs. Differences in deposition patterns following the administration of nasal sprays to adults and children may lead to differences in efficacy between these populations. Greater anterior deposition in children may result in decreased effectiveness, greater anterior dosage form loss, and the increased potential for patient non-compliance.

An electrothermal chemical technology for thermal spray coatings

International Nuclear Information System (INIS)

Wald, S.; Appelbaum, G.; Alimi, R.; Rabani, L.; Zoler, D.; Zhitomirsky, V.; Factor, M.; Roman, I.

1998-01-01

A new spray technology for producing hard-coatings, has been developed at the SOREQ Nuclear Research Center. The concept is based on the extensive experience accumulated at SOREQ in the course of the development of Electrothermal (ET), Electrothermal-Chemical (ETC) and Solid-Propellant Electrothermal-Chemical (SPETC) guns(r). High quality coatings may be obtained by thermal spraying powder particles onto a variety of substrates. Mature state-of-the-art technologies such as plasma spray, high velocity oxy fuel (HVOF) and detonation gun (D-Gun) are widely used for many applications. As each method has its own drawbacks there is a need for a combination of several parameters which cannot be achieved by any existing individual commercial technology. The method presented is oriented toward a high-quality, multi-step, high-throughput, easily programmable continuous coating process and relatively inexpensive technology. The combustion products of a solid or liquid propellant accelerate the powder particles of the coating material. A pulsed-plasma jet, provided by a confined capillary discharge, ignites the propellant and controls the combustion process. The powder particles are accelerated to velocities over 1000 m/s. Due to the very high carrier gas density, high velocity, high throughput and high powder consumption efficiency are obtained. The plasma jet enables control of the gas temperature and consequently influences the powder temperature

A comparative study between hot-melt extrusion and spray-drying for the manufacture of anti-hypertension compatible monolithic fixed-dose combination products.

Science.gov (United States)

Kelleher, J F; Gilvary, G C; Madi, A M; Jones, D S; Li, S; Tian, Y; Almajaan, A; Senta-Loys, Z; Andrews, G P; Healy, A M

2018-07-10

The purpose of this work was to investigate the application of different advanced continuous processing techniques (hot melt extrusion and spray drying) to the production of fixed-dose combination (FDC) monolithic systems comprising of hydrochlorothiazide and ramipril for the treatment of hypertension. Identical FDC formulations were manufactured by the two different methods and were characterised using powder X-ray diffraction (PXRD) and modulated differential scanning calorimetry (mDSC). Drug dissolution rates were investigated using a Wood's apparatus, while physical stability was assessed on storage under controlled temperature and humidity conditions. Interestingly both drugs were transformed into their amorphous forms when spray dried, however, hydrochlorothiazide was determined, by PXRD, to be partially crystalline when hot melt extruded with either polymer carrier (Kollidon® VA 64 or Soluplus®). Hot melt extrusion was found to result in significant degradation of ramipril, however, this could be mitigated by the inclusion of the plasticizer, polyethylene glycol 3350, in the formulation and appropriate adjustment of processing temperature. The results of intrinsic dissolution rate studies showed that hot-melt extruded samples were found to release both drugs faster than identical formulations produced via spray drying. However, the differences were attributable to the surface roughness of the compressed discs in the Wood's apparatus, rather than solid state differences between samples. After a 60-day stability study spray dried samples exhibited a greater physical stability than the equivalent hot melt extruded samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Experimental characterization of gasoline sprays under highly evaporating conditions

Science.gov (United States)

Khan, Muhammad Mahabat; Sheikh, Nadeem Ahmed; Khalid, Azfar; Lughmani, Waqas Akbar

2018-05-01

An experimental investigation of multistream gasoline sprays under highly evaporating conditions is carried out in this paper. Temperature increase of fuel and low engine pressure could lead to flash boiling. The spray shape is normally modified significantly under flash boiling conditions. The spray plumes expansion along with reduction in the axial momentum causes the jets to merge and creates a low-pressure area below the injector's nozzle. These effects initiate the collapse of spray cone and lead to the formation of a single jet plume or a big cluster like structure. The collapsing sprays reduces exposed surface and therefore they last longer and subsequently penetrate more. Spray plume momentum increase, jet plume reduction and spray target widening could delay or prevent the closure condition and limit the penetration (delayed formation of the cluster promotes evaporation). These spray characteristics are investigated experimentally using shadowgraphy, for five and six hole injectors, under various boundary conditions. Six hole injectors produce more collapsing sprays in comparison to five hole injector due to enhanced jet to jet interactions. The spray collapse tendency reduces with increase in injection pressure due high axial momentum of spray plumes. The spray evaporation rates of five hole injector are observed to be higher than six hole injectors. Larger spray cone angles of the six hole injectors promote less penetrating and less collapsing sprays.

Plasma spraying of hard magnetic coatings based on Sm-Co alloys

International Nuclear Information System (INIS)

KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" data-affiliation=" (Siberian State Aerospace University named after Academician M.F. Reshetnev 31 KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" >Saunin, V N; KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" data-affiliation=" (Siberian State Aerospace University named after Academician M.F. Reshetnev 31 KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" >Telegin, S V

2015-01-01

Our research is focused on the formation of hard magnetic coatings by plasma spraying an arc-melted Sm-Co powder. We have studied basic magnetic characteristics depending on the components ratio in the alloy. A sample with a 40 wt.% Sm coating exhibits the highest coercive force (63 kOe) as compared to near-to-zero coercive force in the starting powder. X-ray structure analysis of the starting alloy and the coating reveals that the amount of SmCo 5 phase in the sprayed coating increases occupying up to 2/3 of the sample. We have also studied temperature dependence of the coating and have been able to obtain plasma sprayed permanent magnets operating within the temperature range from -100 to +500 °C. The technique used does not involve any additional thermal treatment and allows a coating to be formed right on the magnetic conductor surface irrespective of the conductor geometry

Effectiveness of cleaning-disinfection wipes and sprays against multidrug-resistant outbreak strains.

Science.gov (United States)

Kenters, Nikki; Huijskens, Elisabeth G W; de Wit, Sophie C J; van Rosmalen, Joost; Voss, Andreas

2017-08-01

Hospital rooms play an important role in the transmission of several health care-associated pathogens. During the last few years, a number of innovative cleaning-disinfecting products have been brought to market. In this study, commercially available products combining cleaning and disinfection were compared, using 2 different application methods. The aim was to determine which product was most effective in simultaneous cleaning and disinfection of surfaces. Seven cleaning-disinfecting wipes and sprays based on different active ingredients were tested for their efficacy in removal of microbial burden and proteins. Efficacy was tested with known Dutch outbreak strains: vancomycin-resistant enterococci (VRE), Klebsiella pneumoniae OXA-48, or Acinetobacter baumannii. For all bacteria, ready-to-use cleaning-disinfecting products reduced the microbial count with a log 10 reduction >5 with a 5-minute exposure time, with the exception of a spray based on hydrogen peroxide. Omitting the aforementioned hydrogen peroxide spray, there were no significant differences between use of a wipe or spray in bacterial load reduction. Using adenosine triphosphate (ATP) measurements, a significant difference in log 10 relative light units (RLU) reduction between various bacteria (P ≤ .001) was observed. In general, a >5 log 10 reduction of colony forming units (CFU) for tested wipes and sprays was obtained for all tested bacteria strains, with exception of hydrogen peroxide spray and VRE. Although ATP may show a difference between pre- and postcleaning, RLU reduction does not correlate with actual CFU reductions. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Study of Multi-Function Micro-Plasma Spraying Technology

International Nuclear Information System (INIS)

Wang Liuying; Wang Hangong; Hua Shaochun; Cao Xiaoping

2007-01-01

A multi-functional micro-arc plasma spraying system was developed according to aerodynamics and plasma spray theory. The soft switch IGBT (Insulated Gate Bipolar Transistor) invert technique, micro-computer control technique, convergent-divergent nozzle structure and axial powder feeding techniques have been adopted in the design of the micro-arc plasma spraying system. It is not only characterized by a small volume, a light weight, highly accurate control, high deposition efficiency and high reliability, but also has multi-functions in plasma spraying, welding and quenching. The experimental results showed that the system can produce a supersonic flame at a low power, spray Al 2 O 3 particles at an average speed up to 430 m/s, and make nanostructured AT13 coatings with an average bonding strength of 42.7 MPa. Compared to conventional 9M plasma spraying with a higher power, the coatings with almost the same properties as those by conventional plasma spray can be deposited by multi-functional micro-arc plasma spraying with a lower power plasma arc due to an improved power supply design, spray gun structure and powder feeding method. Moreover, this system is suitable for working with thin parts and undertaking on site repairs, and as a result, the application of plasma spraying will be greatly extended

Study on Spray Characteristics and Spray Droplets Dynamic Behavior of Diesel Engine Fueled by Rapeseed Oil

Directory of Open Access Journals (Sweden)

Sapit Azwan

2014-07-01

Full Text Available Fuel-air mixing is important process in diesel combustion. It directly affects the combustion and emission of diesel engine. Biomass fuel needs great help to atomize because the fuel has high viscosity and high distillation temperature. This study investigates the atomization characteristics and droplet dynamic behaviors of diesel engine spray fueled by rapeseed oil (RO. Optical observation of RO spray was carried out using shadowgraph photography technique. Single nano-spark photography technique was used to study the characteristics of the rapeseed oil spray while dual nano-spark shadowgraph technique was used to study the spray droplet behavior. The results show that RO has very poor atomization due to the high viscosity nature of the fuel. This is in agreement with the results from spray droplet dynamic behavior studies that shows due to the high viscosity, the droplets are large in size and travel downward, with very little influence of entrainment effect due to its large kinematic energy.

Nanostructure of plasma-sprayed hydroxyapatite coating

International Nuclear Information System (INIS)

Suvorova, E.I.; Klechkovskaya, V.V.; Bobrovsky, V.V.; Khamchukov, Yu.D.; Klubovich, V.V.

2003-01-01

Calcium phosphate coatings were studied by high-resolution transmission microscopy, microdiffraction, and X-ray energy-dispersive spectroscopy. Coatings were prepared by spraying hydroxyapatite targets onto copper, nickel, and chromium substrates and onto NaCl and BaF 2 single crystals in an argon plasma at a gas pressure of ∼1 Pa; the sputter power was about 200 W; and the RF-generator frequency was 13.56 MHz. Under the conditions used, thin layers of nanocrystalline hydroxyapatite were formed regardless of the nature of the substrate

Seawater spray injury to Quercus acutissima leaves: crystal deposition, stomatal clogging, and chloroplast degeneration.

Science.gov (United States)

Kim, Ki Woo; Koo, Kyosang; Kim, Pan-Gi

2011-05-01

Effects of seawater spray on leaf structure were investigated in Quercus acutissima by electron microscopy and X-ray microanalysis. Two-year-old seedlings of Q. acutissima were sprayed with seawater and kept in a greenhouse maintained at 25°C. The most recognizable symptoms of seawater-sprayed seedlings included leaf necrosis, crystal deposition, stomatal clogging, and chloroplast degeneration. Field emission scanning electron microscopy revealed that the leaf surface was covered with additional layers of remnants of seawater spray. Composed of sodium and chloride, cube-shaped crystals (halite) were prevalently found on trichomes and epidermis, and formed aggregates. Meanwhile, wedge-shaped crystals were deposited on epidermis and consisted of calcium and sulfur. As a result of stomatal clogging by crystal deposition on the abaxial surface, it was conceivable that plant respiration became severely hampered. Transmission electron microscopy showed degenerated cytoplasm of seawater-sprayed leaves. It was common to observe severe plasmolysis and disrupted chloroplasts with a reduced number of thylakoids in grana. These results indicate that foliar applications of seawater were sufficient to induce necrosis of Q. acutissima seedlings as an abiotic disturbance factor. Copyright © 2010 Wiley-Liss, Inc.

Numerical investigation of spray combustion in jet mixing type combustor for low NOx emission

International Nuclear Information System (INIS)

Watanabe, Hirotatsu; Suwa, Yoshikazu; Matsushita, Yohsuke; Morozumi, Yoshio; Aoki, Hideyuki; Tanno, Shoji; Miura, Takatoshi

2008-01-01

The present paper describes a numerical investigation of spray combustion in a jet mixing type combustor. In this combustor, kerosene spray was injected with a pressure atomizer, and high speed combustion air was introduced towards the spray flow through some inlet air nozzles to improve mixing of the spray and the air. In the numerical simulation, the conservative equations of mass, momentum and energy in the turbulent flow field were solved in conjunction with the k-ε two equation turbulence model. The effects of the diameter and the number of air inlet nozzles on the combustion behavior and NO emission were numerically investigated. When the diameter of the inlet air nozzle decreased from 8 to 4 mm, the calculated NO mole fraction in the exhaust gas was drastically decreased by about 80%. An increase in the inlet velocity resulted in improvement of the mixing of the spray and the air, and hence, the high temperature region where thermal NO was formed became narrow. As a result, the exhaust NO mole fraction decreased. Furthermore, a decrease in exhaust NO mole fraction was explained by a decrease in the residence time in the high temperature region above 1800 K

Low-cost plasmonic solar cells prepared by chemical spray pyrolysis

Directory of Open Access Journals (Sweden)

Erki Kärber

2014-12-01

Full Text Available Solar cells consisting of an extremely thin In2S3/CuInS2 buffer/absorber layer uniformly covering planar ZnO were prepared entirely by chemical spray pyrolysis. Au nanoparticles (Au-NPs were formed via thermal decomposition of a gold(III chloride trihydrate (HAuCl4·3H2O precursor by spraying 2 mmol/L of the aqueous precursor solution onto a substrate held at 260 °C. Current–voltage scans and external quantum efficiency spectra were used to evaluate the solar cell performance. This work investigates the effect of the location of the Au-NP layer deposition (front side vs rear side in the solar cell and the effect of varying the volume (2.5–10 mL of the sprayed Au precursor solution. A 63% increase (from 4.6 to 7.5 mA/cm2 of the short-circuit current density was observed when 2.5 mL of the precursor solution was deposited onto the rear side of the solar cell.

Characteristics of combustion flame sprayed nickel aluminum using a Coanda Assisted Spray Manipulation collar for off-normal deposits

Science.gov (United States)

Archibald, Reid S.

A novel flame spray collar called the Coanda Assisted Spray Manipulation collar (CSM) has been tested for use on the Sulzer Metco 5P II combustion flame spray gun. A comparison study of the stock nozzle and the CSM has been performed by evaluating the porosity, surface roughness, microhardness, tensile strength and microscopy of normal and off-normal sprayed NiAl deposits. The use of the CSM collar resulted in the need to position the sprayed coupons closer to the gun, which in turn affected the particle impact energy and particle temperatures of the NiAl powder. For the CSM, porosities had a larger scatterband, surface roughness was comparably the same, microhardness was lower, and tensile strength was higher. The microscopy analysis revealed a greater presence of unmelted particles and steeper intersplat boundaries for the CSM. For both processes, the porosity and surface roughness increased and the microhardness decreased as the spray angle decreased.

Formation of hydrotalcite coating on the aluminum alloy 6060 in spray system

DEFF Research Database (Denmark)

Zhou, Lingli; Friis, Henrik; Roefzaad, Melanie

2016-01-01

Coatings with the composition of Li-Al-NO3 hydrotalcite were formed on the Al alloy 6060 using a spray system. The coatings consist of crystals with a typical hydrotalcite structure. Dense, uniform and blade-like flakes cover completely the surface of the Al substrate. The coatings display a multi......-layer structure with average thickness of ∼1000 nm. The hydrotalcite-coated samples performed better than those without coatings in salt-spray and filiform-corrosion tests, and further treatment involving sealing with a Mg acetate solution and dipping in a H2O2 + Ce-based solution improved the corrosion...

Evaluation of cross-linked chitosan microparticles containing acyclovir obtained by spray-drying

International Nuclear Information System (INIS)

Stulzer, Hellen Karine; Tagliari, Monika Piazzon; Parize, Alexandre Luis; Silva, Marcos Antonio Segatto; Laranjeira, Mauro Cesar Marghetti

2009-01-01

The aim of this study was to obtain microparticles containing acyclovir (ACV) and chitosan cross-linked with tripolyphosphate using the spray-drying technique. The resultant system was evaluated through loading efficiency, differential scanning calorimetry (DSC), thermogravimetric analysis (TG), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), in vitro release and stability studies. The results obtained indicated that the polymer/ACV ratio influenced the final properties of the microparticles, with higher ratios giving the best encapsulation efficiency, dissolution profiles and stability. The DSC and XRPD analyses indicated that the ACV was transformed into amorphous form during the spray-drying process

High temperature oxidation and corrosion in marine environments of thermal spray deposited coatings

International Nuclear Information System (INIS)

Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Stergioudis, G.; Skolianos, S.; Chrissafis, K.

2008-01-01

Flame spraying is a widely used technique for depositing a great variety of materials in order to enforce the mechanical or the anticorrosion characteristics of the substrate. Its high rate application is due to the rapidity of the process, its effectiveness and its low cost. In this work, flame-sprayed Al coatings are deposited on low carbon steels in order to enhance their anticorrosion performance. The main adhesion mechanism of the coating is mechanical anchorage, which can provide the necessary protection to steel used in several industrial and constructive applications. To evaluate the corrosion resistance of the coating, the as-coated samples are subjected in a salt spray chamber and in elevated temperature environments. The examination and characterization of the corroded samples is done by scanning electron microscopy and X-ray diffraction analysis. The as-formed coatings are extremely rough and have a lamellic homogeneous morphology. It is also found that Al coatings provide better protection in marine atmospheres, while at elevated temperatures a thick oxide layer is formed, which can delaminate after long oxidation periods due to its low adherence to the underlying coating, thus eliminating the substrate protection

Planar measurements of spray-induced wall cooling using phosphor thermometry

Science.gov (United States)

Dragomirov, Plamen; Mendieta, Aldo; Abram, Christopher; Fond, Benoît; Beyrau, Frank

2018-03-01

The wall cooling induced by spray impingement is investigated using phosphor thermometry. Thin coatings of zinc oxide (ZnO) phosphor were applied with a transparent chemical binder onto a steel surface. Instantaneous spatially resolved temperatures were determined using the spectral intensity ratio method directly after the injection of UV-grade hexane onto the surface using a commercial gasoline injector. The investigations showed that 2D temperature measurements with high spatial and shot-to-shot precision of, respectively, 0.5 and 0.6 K can be achieved, allowing the accurate resolution of the cooling induced by the spray. The presence of a liquid film over the phosphor coating during measurements showed no noticeable influence on the measured temperatures. However, in some cases a change in the intensity ratio at the spray impingement area, in the form of a permanent "stain", could be observed after multiple injections. The formation of this stain was less likely with increasing annealing time of the coating as well as lower plate operating temperatures during the injection experiments. Finally, the experimental results indicate a noticeable influence of the thickness of the phosphor coating on the measured spray-induced wall cooling history. Hence, for quantitative analysis, a compromise between coating thickness and measurement accuracy needs to be considered for similar applications where the heat transfer rates are very high.

Glass Forming Ability of Amorphous Drugs Investigated by Continuous Cooling and Isothermal Transformation.

Science.gov (United States)

Blaabjerg, Lasse I; Lindenberg, Eleanor; Löbmann, Korbinian; Grohganz, Holger; Rades, Thomas

2016-09-06

The aim of this study was to investigate the glass forming ability of 12 different drugs by the determination of continuous cooling and isothermal transformation diagrams in order to elucidate if an inherent differentiation between the drugs with respect to their the glass forming ability can be made. Continuous-cooling-transformation (CCT) and time-temperature-transformation (TTT) diagrams of the drugs were developed in order to predict the critical cooling rate necessary to convert the drug from the melt into an amorphous form. While TTT diagrams overestimated the actual critical cooling rate, they allowed an inherent differentiation of glass forming ability for the investigated drugs into drugs that are extremely difficult to amorphize (>750 °C/min), drugs that require modest cooling rates (>10 °C/min), and drugs that can be made amorphous even at very slow cooling rates (>2 °C/min). Thus, the glass forming ability can be predicted by the use of TTT diagrams. In contrast to TTT diagrams, CCT diagrams may not be suitable for small organic molecules due to poor separation of exothermic events, which makes it difficult to determine the zone of recrystallization. In conclusion, this study shows that glass forming ability of drugs can be predicted by TTT diagrams.

Preparation and characterization of spray-dried co-amorphous drug-amino acid salts

DEFF Research Database (Denmark)

Jensen, Katrine Birgitte Tarp; Blaabjerg, Lasse Ingerslev; Lenz, Elisabeth

2016-01-01

scale. In this study, spray-drying was investigated as a scale up preparation method for co-amorphous indomethacin (IND)-amino acid mixtures. In addition, the physico-chemical properties of the different co-amorphous systems were investigated with respect to the amino acids' ability towards co...... dissolution behaviour, and physical stability at various storage conditions, were examined. KEY FINDINGS: Results showed that IND could be converted into an amorphous form in combination with the amino acids arginine (ARG), histidine (HIS) and lysine (LYS) by spray-drying. Solid state characterization...... mixtures were physically stable (>10 months) at room temperature and 40°C under dry conditions. Intrinsic dissolution of the co-amorphous mixtures showed an improved dissolution behaviour under intestinal pH conditions for IND-ARG compared with the crystalline and amorphous forms of the drug. On the other...

Development of process data capturing, analysis and controlling for thermal spray techniques - SprayTracker

Science.gov (United States)

Kelber, C.; Marke, S.; Trommler, U.; Rupprecht, C.; Weis, S.

2017-03-01

Thermal spraying processes are becoming increasingly important in high-technology areas, such as automotive engineering and medical technology. The method offers the advantage of a local layer application with different materials and high deposition rates. Challenges in the application of thermal spraying result from the complex interaction of different influencing variables, which can be attributed to the properties of different materials, operating equipment supply, electrical parameters, flow mechanics, plasma physics and automation. In addition, spraying systems are subject to constant wear. Due to the process specification and the high demands on the produced coatings, innovative quality assurance tools are necessary. A central aspect, which has not yet been considered, is the data management in relation to the present measured variables, in particular the spraying system, the handling system, working safety devices and additional measuring sensors. Both the recording of all process-characterizing variables, their linking and evaluation as well as the use of the data for the active process control presuppose a novel, innovative control system (hardware and software) that was to be developed within the scope of the research project. In addition, new measurement methods and sensors are to be developed and qualified in order to improve the process reliability of thermal spraying.

Fundamental Study on the Effect of Spray Parameters on Characteristics of P3HT:PCBM Active Layers Made by Spray Coating

Directory of Open Access Journals (Sweden)

Yu Xie

2015-08-01

Full Text Available This paper is an attempt to elucidate the effects of the important spray characteristics on the surface morphology and light absorbance of spray-on P3HT:PCBM thin-films, used as an active layer in polymer solar cells (PSCs. Spray coating or deposition is a viable scalable technique for the large-scale, fast, and low-cost fabrication of solution-processed solar cells, and has been widely used for device fabrication, although the fundamental understanding of the underlying and controlling parameters, such as spray characteristics, droplet dynamics, and surface wettability, is still limited, making the results on device fabrication not reproducible and unreliable. In this paper, following the conventional PSC architecture, a PEDOT:PSS layer is first spin-coated on glass substrates, followed by the deposition of P3HT:PCBM using an automatic ultrasonic spray coating system, with a movable nozzle tip, to mimic an industrial manufacturing process. To gain insight, the effects of the spray carrier air pressure, the number of spray passes, the precursor flow rate, and precursor concentration are studied on the surface topography and light absorbance spectra of the spray-on films. Among the results, it is found that despite the high roughness of spray-on films, the light absorbance of the film is satisfactory. It is also found that the absorbance of spray-on films is a linear function of the number of spray passes or deposition layers, based on which an effective film thickness is defined for rough spray-on films. The effective thickness of a rough spray-on P3HT:PCBM film was found to be one-quarter of that of a flat film predicted by a simple mass balance.

Influence of nature of the substrate in the deposition of yttria-stabilized zirconia by spray pyrolysis

International Nuclear Information System (INIS)

Halmenschlager, C.M.; Malfatti, C.F.; Bergmann, C.P.; Neagu, R.

2012-01-01

Spray pyrolysis technique consist in spraying a precursor solution on a heated substrate. In the last few decades this process has attracted much attention because of its versatility. Controlling the parameters is possible to produce dense or porous film. Spray pyrolysis has been applied to obtain several materials such as electrodes or electrolytes for SOFC, semiconductors, materials for solar cells and so on. However, some behaviors such as Leidenfrost effect have been poorly considered and it may affect the coating quality. This work aims to evaluate the influence of the substrate and how Leidenfrost effect affects the coating by spray pyrolysis. To achieve this goal yttria-stabilized zirconia solutions made with different solvents were deposited on different substrates at different temperatures. These coatings were characterized by X-ray diffraction and scanning electron microscopy. The results show that there is a limit temperature which is related to properties of the solvent and the surface of the substrates where films are continuous. (author)

Fine Sprays for Disinfection within Healthcare

Directory of Open Access Journals (Sweden)

G Nasr

2016-09-01

Full Text Available Problems exist worldwide with Hospital Acquired Infections (HAI's. The Spray Research Group (SRG have been working with relevant industries in developing a product which can provide a delivery system for treatment chemicals for surfaces, including the design and testing of a novel Spill-Return Atomiser (SRA for this purpose. A comprehensive description of this atomiser has already been given. This paper reports on a new application of this atomiser and discusses the problem of spray coating for disinfection that has been considered very little in previous work. The related spray coating performance tests in developing the product are thus provided. The experimental work includes determining the required spray duration and the coverage area produced by different sprays, including the analysis of the effects of atomiser positions, configurations, and the required number of atomisers. Comparison is made with the efficacy of an ultrasonic gas atomiser that is currently used for this purpose. The investigation has found that the utilisation of fine sprays (10μm>D32>25μm at high liquid pressure (<12MPa and low flow rates (<0.3 l/min is suitable for surface disinfection in healthcare applications (i.e. MRSA, VRSA etc.

Microcontainers as an oral delivery system for spray dried cubosomes containing ovalbumin

DEFF Research Database (Denmark)

Nielsen, Line Hagner; Rades, Thomas; Boyd, Ben

2017-01-01

The purpose of this study was to prepare cubosomes encapsulating the model antigen ovalbumin (OVA) via spray drying, and to characterise such cubosomes with a view for their potential application in oral vaccine delivery. Furthermore the cubosome formulation was loaded into polymeric...... microcontainers intended as an oral drug delivery system. The cubosomes consisted of commercial glyceryl monooleate, Dimodan®, containing OVA and were surrounded with a dextran shell prepared by spray drying. Cryo-TEM was used to confirm that cubosomes were formed after hydration of the spray dried precursor...... the cubosomes and microcontainers occurred at pH 6.8, releasing 44.1±5.6% of the OVA in 96h. Small-angle X-ray scattering (SAXS) revealed that the 'dry' particles possessed an internal ordered lipid structure (lamellar and inverse micellar phase) by virtue of a small amount of residual water, and after...

Synthesis of Macroporous Silica Particles by Continuous Generation of Droplets for Insulating Materials.

Science.gov (United States)

Cho, Young-Sang; Lee, Dokyoung

2018-09-01

We report on the synthesis of porous silica particles by self-assembly routes in a continuous manner for application to thermal insulators. A continuous process was employed to produce tiny droplets containing precursor materials such as silica and organic templates for self-organization to fabricate particles with well defined pores. A rotating cylinder system or a spray drying process was adopted to form emulsions or aerosol droplets as micro-reactors for self-assembly, and the physical properties including the thermal conductivity of the resulting porous particles were compared between the two methods. The porous particles could be coated as a thick film by solution dripping, and the fluorination treatment using a silane coupling agent was performed to produce superhydrophobic surfaces of insulating layers by a lotus effect.

Post-heat treatment of arc-sprayed coating prepared by the wires combination of Mg-cathode and Al-anode to form protective intermetallic layers

International Nuclear Information System (INIS)

Xu Rongzheng; Song Gang

2011-01-01

A Mg-Al intermetallic compounds coating was prepared on the surface of Mg-steel lap joint by arc-sprayed Al-Mg composite coating (Mg-cathode and Al-anode) and its post-heat treatment (PHT). The effect of PHT temperature on the phase transition, microstructure and mechanical properties of the coating was investigated by X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscopy, optical microscope and microhardness test. The result shows that the intermetallic compounds layer that is mainly composed of Al 3 Mg 2 and Mg 17 Al 12 is formed by the self-diffusion reaction of Mg and Al splats in the coating after PHT for 4 h at 430 deg. C.

LETTER TO THE EDITOR: Green emission and bandgap narrowing due to two-photon excitation in thin film CdS formed by spray pyrolysis

Science.gov (United States)

Ullrich, B.; Schroeder, R.

2001-08-01

Thin (10 µm) film CdS on Pyrex® formed by spray pyrolysis is excited below the gap at 804 nm with 200 fs laser pulses at room temperature. Excitation intensities up to 250 GW cm-2 evoke green bandgap emission due to two-photon transitions. This two-photon photoluminescence does not show a red emission contribution in contrast to the single-photon excited emission, which is dominated by broad emission in the red spectral range. It is demonstrated that two-photon excitation causes photo-induced bandgap narrowing due to Debye screening. At 250 GW cm-2 bandgap narrowing of 47 meV is observed, which corresponds to an excited electron density of 1.6×1018 cm-3.

Biomechanical and histologic evaluation of two application forms of surgical glue for mesh fixation to the abdominal wall.

Science.gov (United States)

Ortillés, Á; Pascual, G; Peña, E; Rodríguez, M; Pérez-Köhler, B; Mesa-Ciller, C; Calvo, B; Bellón, J M

2017-11-01

The use of an adhesive for mesh fixation in hernia repair reduces chronic pain and minimizes tissue damage in the patient. This study was designed to assess the adhesive properties of a medium-chain (n-butyl) cyanoacrylate glue applied as drops or as a spray in a biomechanical and histologic study. Both forms of glue application were compared to the use of simple-loose or continuous-running polypropylene sutures for mesh fixation. Eighteen adult New Zealand White rabbits were used. For mechanical tests in an ex vivo and in vivo study, patches of polypropylene mesh were fixed to an excised fragment of healthy abdominal tissue or used to repair a partial abdominal wall defect in the rabbit respectively. Depending on the fixation method used, four groups of 12 implants each or 10 implants each respectively for the ex vivo and in vivo studies were established: Glue-Drops, Glue-Spray, Suture-Simple and Suture-Continuous. Biomechanical resistance in the ex vivo implants was tested five minutes after mesh fixation. In vivo implants for biomechanical and histologic assessment were collected at 14 days postimplant. In the ex vivo study, the continuous suture implants showed the highest failure sample tension, while the implants fixed with glue showed lower failure sample tension values. However, the simple and continuous suture implants returned the highest stretch values. In the in vivo implants, failure sample tension values were similar among groups while the implants fixed with a continuous running suture had the higher stretch values, and the glue-fixed implants the lower stretch values. All meshes showed good tissue integration within the host tissue regardless of the fixation method used. Our histologic study revealed the generation of a denser, more mature repair tissue when the cyanoacrylate glue was applied as a spray rather than as drops. Copyright © 2017 Elsevier Ltd. All rights reserved.

Water spray interaction with air-steam mixtures under containment spray conditions: comparison of heat and mass transfer modelling with the TOSQAN spray tests

International Nuclear Information System (INIS)

Malet, J.; Lemaitre, P.; Porcheron, E.; Vendel, J.

2005-01-01

Full text of publication follows: During the course of a hypothetical severe accident in a Pressurized Water Reactor (PWR), hydrogen can be produced by the reactor core oxidation and distributed into the reactor containment according to convection flows and water steam wall condensation. In order to mitigate the risk of detonation generated by a high local hydrogen concentration, spray systems are used in the containment. The TOSQAN programme has been created to simulate separate-effect tests representative of typical accidental thermal-hydraulic flow conditions in the reactor containment. The present work concerns the interaction of a water spray, used at the top of the containment in order to reduce the steam partial pressure, with air-steam mixtures. The main phenomena occurring when water spray is used are the mixing induced by spray entrainment and the condensation on droplets. In order to improve the latter phenomena, different levels of modelling can be used. The objective of this paper is to analyze experimental results obtained for water spray interaction with air-steam mixtures using different heat and mass transfer modelling. For this purpose, two modelling issues have been used: the first one is devoted for the determination of the gas thermodynamical properties, and the second one concerns the droplets characterization. In the first one, the gas thermodynamical analysis is performed using depressurization, gas temperature variation and humidity decrease during the spray injection. In this modelling, heat and mass transfer between the spray and the surrounding gas is treated in a global way by energy balance between the total amount of water and the gas. In the second one, droplets characterization is obtained by means of droplet size, temperature and velocities evolutions. In this modelling, the spray is considered as a single droplet falling with an initial velocity. Droplet interactions are neglected. Assessment of these two modelling is performed

Fluctuations of a spray generated by an airblast atomizer

Energy Technology Data Exchange (ETDEWEB)

Batarseh, Feras Z.; Gnirss, Markus; Roisman, Ilia V.; Tropea, Cameron [Technische Universitaet Darmstadt (Germany). Chair of Fluid Mechanics and Aerodynamics

2009-06-15

This paper is devoted to the study of the aerodynamic instability of the spray generated by an airblast atomizer. As a result of this instability the spray shape and its velocity fluctuate with a certain frequency, which depends on the operational parameters of the atomizer. The effect of three parameters, namely; chamber pressure, liquid phase flow rate and the gas phase flow rate on the spray fluctuating frequency are investigated. The velocity vector of the drops in the spray and the arrival times to the detection volume are measured using the laser Doppler instrument. The slotting technique is applied to the data of axial velocity and arrival times of the drops in order to estimate the dominating spray frequencies. Additionally, the shape of the spray has been observed using the high-speed video system. The frequencies of the shape fluctuations are estimated using proper orthogonal decomposition of the time-resolved images of the spray. We show that the frequencies of the spray velocity and those exhibited by spray shape coincide over a wide range of spray parameters. Finally, a simple scaling for the spray frequency is proposed and validated by the experimental data. (orig.)

Characterization of viscous biofuel sprays using digital imaging in the near field region

International Nuclear Information System (INIS)

Sallevelt, J.L.H.P.; Pozarlik, A.K.; Brem, G.

2015-01-01

Highlights: • Biodiesel, vegetable oil and glycerin sprays have been studied using PDIA. • The study is focused on the effect of fuel viscosity on the spray characteristics. • Viscosity has a strong effect on the breakup length in pressure-swirl atomization. • The results are compared to combustion experiments with a micro gas turbine. • The penetration depth of ligaments can be a critical factor in burning viscous fuel. - Abstract: The atomization of biodiesel, vegetable oil and glycerin has been studied in an atmospheric spray rig by using digital imaging (PDIA). Images of the spray were captured in the near field, just 18 mm downstream of the atomizer, and processed to automatically determine the size of both ligaments and droplets. The effect of the spray structure in this region is of major interest for the combustion of biofuels in gas turbines. The sprays were produced by a pressure-swirl atomizer that originates from the multifuel micro gas turbine (MMGT) setup. Various injection conditions have been tested to investigate the influence of viscosity on the spray characteristics and to assess the overall performance of the atomizer. The spray measurements have been compared to combustion experiments with biodiesel and vegetable oil in the micro gas turbine at similar injection conditions. The results show that the primary breakup process rapidly deteriorates when the viscosity is increased. A higher viscosity increases the breakup length, which becomes visible at the measurement location in the form of ligaments. This effect leads to an unacceptable spray quality once the viscosity slightly exceeds the typical range for conventional gas turbine fuels. The SMD in the investigated spray region was not significantly affected by viscosity, but mainly influenced by injection pressure. The data furthermore indicate an increase in SMD with surface tension. It was found that the penetration depth of ligaments can have major impact on the combustion process

Spatial and temporal distribution of airborne Bacillus thuringiensis var. kurstaki during an aerial spray program for gypsy moth eradication.

Science.gov (United States)

Teschke, K; Chow, Y; Bartlett, K; Ross, A; van Netten, C

2001-01-01

We measured airborne exposures to the biological insecticide Bacillus thuringiensis var. kurstaki (Btk) during an aerial spray program to eradicate gypsy moths on the west coast of Canada. We aimed to determine whether staying indoors during spraying reduced exposures, to determine the rate of temporal decay of airborne concentrations, and to determine whether drift occurred outside the spray zone. During spraying, the average culturable airborne Btk concentration measured outdoors within the spray zone was 739 colony-forming units (CFU)/m3 of air. Outdoor air concentrations decreased over time, quickly in an initial phase with a half time of 3.3 hr, and then more slowly over the following 9 days, with an overall half-time of about 2.4 days. Inside residences during spraying, average concentrations were initially 2-5 times lower than outdoors, but at 5-6 hr after spraying began, indoor concentrations exceeded those outdoors, with an average of 244 CFU/m3 vs. 77 CFU/m3 outdoors, suggesting that the initial benefits of remaining indoors during spraying may not persist as outside air moves indoors with normal daily activities. There was drift of culturable Btk throughout a 125- to 1,000-meter band outside the spray zone where measurements were made, a consequence of the fine aerosol sizes that remained airborne (count median diameters of 4.3 to 7.2 microm). Btk concentrations outside the spray zone were related to wind speed and direction, but not to distance from the spray zone.

Simultaneous effects of water spray and crosswind on performance of natural draft dry cooling tower

Directory of Open Access Journals (Sweden)

Ahmadikia Hossein

2013-01-01

Full Text Available To investigate the effect of water spray and crosswind on the effectiveness of the natural draft dry cooling tower (NDDCT, a three-dimensional model has been developed. Efficiency of NDDCT is improved by water spray system at the cooling tower entrance for high ambient temperature condition with and without crosswind. The natural and forced heat convection flow inside and around the NDDCT is simulated numerically by solving the full Navier-Stokes equations in both air and water droplet phases. Comparison of the numerical results with one-dimensional analytical model and the experimental data illustrates a well-predicted heat transfer rate in the cooling tower. Applying water spray system on the cooling tower radiators enhances the cooling tower efficiency at both no wind and windy conditions. For all values of water spraying rate, NDDCTs operate most effectively at the crosswind velocity of 3m/s and as the wind speed continues to rise to more than 3 m/s up to 12 m/s, the tower efficiency will decrease by approximately 18%, based on no-wind condition. The heat transfer rate of radiator at wind velocity 10 m/s is 11.5% lower than that of the no wind condition. This value is 7.5% for water spray rate of 50kg/s.

Spray casting project final report

International Nuclear Information System (INIS)

Churnetski, S.R.; Thompson, J.E.

1996-08-01

Lockheed Martin Energy Systems, Inc. (Energy Systems), along with other participating organizations, has been exploring the feasibility of spray casting depleted uranium (DU) to near-net shape as a waste minimization effort. Although this technology would be useful in a variety of applications where DU was the material of choice, this effort was aimed primarily at gamma-shielding components for use in storage and transportation canisters for high-level radioactive waste, particularly in the Multipurpose Canister (MPC) application. In addition to the waste-minimization benefits, spray casting would simplify the manufacturing process by allowing the shielding components for MPC to be produced as a single component, as opposed to multiple components with many fabrication and assembly steps. In earlier experiments, surrogate materials were used to simulate the properties (specifically reactivity and density) of DU. Based on the positive results from those studies, the project participants decided that further evaluation of the issues and concerns that would accompany spraying DU was warranted. That evaluation occupied substantially all of Fiscal Year 1995, yielding conceptual designs for both an intermediate facility and a production facility and their associated engineering estimates. An intermediate facility was included in this study to allow further technology development in spraying DU. Although spraying DU to near-net shape seems to be feasible, a number of technical, engineering, and safety issues would need to be evaluated before proceeding with a production facility. This report is intended to document the results from the spray-casting project and to provide information needed by anyone interested in proceeding to the next step

Continuously renewed wall for a thermonuclear reactor

International Nuclear Information System (INIS)

Livshits, A.I.; Pustovojt, YU.M.; Samartsev, A.A.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Atomnoj Ehnergii)

1982-01-01

The possibility of creating a continuously renewed first wall of a thermonuclear reactor is experimentally investigated. The following variants of the wall are considered: the wall is double, its part turned to plasma is made of comparatively thin material. The external part separated from it by a small gap appears to be protected from interaction with plasma and performs structural functions. The gap contains the mixture of light helium and hydrogen and carbon-containing gas. The light gas transfers heat from internal part of the wall to the external part. Carbon-containing gas provides continuous renewal of carbon coating of the operating surface. The experiment is performed with palladium membrane 20 μm thick. Carbon is introduced into the membrane by benzol pyrolysis on one of the surfaces at the membrane temperature of 900 K. Carbon removal from the operating side of the wall due to its spraying by fast particles is modelled by chemical itching with oxygen given to the operating membrane wall. Observation of the carbon release on the operating surface is performed mass-spectrometrically according to the observation over O 2 transformation into CO and CO 2 . It is shown that in cases of benzol pressure of 5x10 -7 torr, carbon current on the opposite surface is not less than 3x10 12 atoms/sm 2 s and corresponds to the expected wall spraying rate in CF thermonuclear reactors. It is also shown that under definite conditions the formation and maintaining of a through protective carbon coating in the form of a monolayer or volumetric phase is possible

Thermally sprayed coatings: Aluminum on lead

International Nuclear Information System (INIS)

Usmani, S.; Czajkowski, C.J.; Zatorski, R.

1999-01-01

An experimental program to determine the feasibility of thermally spraying aluminum on a lead substrate was initiated in support of the accelerator production of tritium (APT) Project for the US Department of Energy. The program consisted of two distinct parts: (1) the characterization of the thermally sprayed coatings, including microhardness testing, effects of heating, and microstructure and porosity determinations, and (2) effects of mercury doping and heat treatments on the thermally sprayed composite. The project determined that aluminum could successfully be thermally sprayed onto the lead. The coatings had a dense microstructure, with a Vicker's Pyramid Hardness (VPH) of about 60, and a maximum porosity (found in strips on the samples) of 12%

Analysis of fuel spray characteristics for premixed lean diesel combustion; Kihaku yokongo diesel kikan ni okeru nenryo funmu kaiseki

Energy Technology Data Exchange (ETDEWEB)

Sasaki, S; Harada, a; Miyamoto, T; Akagawa, H; Tsujimura, K

1997-10-01

Premixed lean diesel combustion (PREDIC) makes it possible to achieve low NOx emission. It is an important factor to make the homogeneous spray formation for PREDIC. In this paper presents I the effect of the spray dispersion on emission characteristic were analyzed with the spray observation and engine test. Pintle type nozzle, which has different feature from orifice type nozzle, are used to form the hollow cone spray. As a result, the pintle type nozzle having grooves to generate the swirl flow, makes the reduced penetration in comparison with the hole nozzle under low ambient gas pressure. And it could improve THC, CO emissions at low NOx emission condition. 7 refs., 12 figs., 1 tab.

The erosion performance of cold spray deposited metal matrix composite coatings with subsequent friction stir processing

Energy Technology Data Exchange (ETDEWEB)

Peat, Tom, E-mail: tompeat12@gmail.com [Department of Mechanical & Aerospace Engineering, University of Strathclyde, James Weir Building, 75 Montrose Street, Glasgow G1 1XJ (United Kingdom); Galloway, Alexander; Toumpis, Athanasios [Department of Mechanical & Aerospace Engineering, University of Strathclyde, James Weir Building, 75 Montrose Street, Glasgow G1 1XJ (United Kingdom); McNutt, Philip [TWI Ltd., Granta Park, Cambridge CB21 6AL (United Kingdom); Iqbal, Naveed [TWI Technology Centre, Wallis Way, Catcliff, Rotherham, S60 5TZ (United Kingdom)

2017-02-28

Highlights: • WC-CoCr, Cr{sub 3}C{sub 2}-NiCr and Al{sub 2}O{sub 3} coatings were cold spray deposited on AA5083 and friction stir processed. • The SprayStirred WC-CoCr demonstrated a hardness increase of 100% over the cold sprayed coating. • As-deposited and SprayStirred coatings were examined under slurry erosion test conditions. • Mass and volume loss was measured following 20-min exposure to the slurry. • The WC-CoCr and Al2O3 demonstrated a reduction in volume loss of approx. 40% over the cold sprayed coating. - Abstract: This study forms an initial investigation into the development of SprayStir, an innovative processing technique for generating erosion resistant surface layers on a chosen substrate material. Tungsten carbide – cobalt chromium, chromium carbide – nickel chromium and aluminium oxide coatings were successfully cold spray deposited on AA5083 grade aluminium. In order to improve the deposition efficiency of the cold spray process, coatings were co-deposited with powdered AA5083 using a twin powder feed system that resulted in thick (>300 μm) composite coatings. The deposited coatings were subsequently friction stir processed to embed the particles in the substrate in order to generate a metal matrix composite (MMC) surface layer. The primary aim of this investigation was to examine the erosion performance of the SprayStirred surfaces and demonstrate the benefits of this novel process as a surface engineering technique. Volumetric analysis of the SprayStirred surfaces highlighted a drop of approx. 40% in the level of material loss when compared with the cold spray deposited coating prior to friction stir processing. Micro-hardness testing revealed that in the case of WC-CoCr reinforced coating, the hardness of the SprayStirred material exhibits an increase of approx. 540% over the unaltered substrate and 120% over the as-deposited composite coating. Microstructural examination demonstrated that the increase in the hardness of the

DEVELOPMENT OF WEAR RESISTANT COATINGS FORMED BY PLASMA SPRAYING OF ALLOY Ni–Fe–Cr–Si–B–C SYSTEM REINFORCED WITH CERAMICS Al2O3

Directory of Open Access Journals (Sweden)

A. S. Kalinichenko

2016-01-01

Full Text Available . Creating a functionally oriented, including nanostructured, anti-friction materials and coatings with qualitatively new complex of service properties is an important scientific and practical problem. In particular, for the cable industry it is urgent task of ensuring the high performance properties of fast deteriorating stretching and supporting rollers. Working surfaces of these parts operate under practically dry friction conditions with constantly updated material of stretching wire. Plasma spraying is one of the widely used methods of surface engineering to create wear resistant coatings and which is characterized with process flexibility and the ability to create coatings using various materials and alloys including composite ones. The installation UPU-3D with the PP-25 plasma torch was used for plasma spraying. The thickness of the sprayed layer was 0.8–1.1 mm. As a material for the deposition of composite coatings a powder mixture of self-fluxing nickel alloy PG-HN80SR4 (system Ni–Fe–Cr–Si–B–C and a neutral oxide ceramics Al2O3 was used. The amount of ceramics varied from 15 to 33 %. This ceramic oxide was selected due to the desire to reduce coatings’ costs while providing high durability. Carried out phase and microstructural studies have shown when ceramics was added in an amount more than 20 % a formation of conglomerates formed by not melted alumina particles often was observed. These conglomerates serve as crack formation centers in the coating. The phase composition of the coatings practically does not depend on the content of ceramics compounds. Tribological tests have shown that the best results were obtained when the content of the oxide ceramic in the coating was in the range from 15 to 20 %.

Box-Behnken analysis and storage of spray-dried collagenolytic proteases from Myceliophthora thermophila submerged bioprocess.

Science.gov (United States)

Hamin Neto, Youssef Ali Abou; Coitinho, Luciana Barbosa; de Freitas, Luis Alexandre Pedro; Cabral, Hamilton

2017-05-28

Enzymes do not have long-term storage stability in soluble forms, thus drying methods could minimize the loss of enzymatic activity, the spray dryer removes water under high temperatures and little time. The aims of this study were to improve the stability of enzymatic extract from Myceliophthora thermophila for potential applications in industry and to evaluate the best conditions to remove the water by spray drying technique. The parameters were tested according to Box-Behnken and evaluated by analysis of variance (ANOVA), all the parameters measured were found to influence the final enzyme activity and spray drying process yield ranged from 38.65 to 63.75%. Enzyme powders showed increased storage stability than extract and maintained about 100% of collagenolytic activity after 180 days of storage at 30°C. The results showed that the microbial enzymes maintained activity during the spray drying process and were stable during long-term storage; these are promising characteristics for industrial applications.

Novel Method of Aluminum to Copper Bonding by Cold Spray

Science.gov (United States)

Fu, Si-Lin; Li, Cheng-Xin; Wei, Ying-Kang; Luo, Xiao-Tao; Yang, Guan-Jun; Li, Chang-Jiu; Li, Jing-Long

2018-04-01

Cold spray bonding (CSB) has been proposed as a new method for joining aluminum and copper. At high speeds, solid Al particles impacted the groove between the two substrates to form a bond between Al and Cu. Compared to traditional welding technologies, CSB does not form distinct intermetallic compounds. Large stainless steel particles were introduced into the spray powders as in situ shot peen particles to create a dense Al deposit and to improve the bond strength of joints. It was discovered that introducing shot peen particles significantly improved the flattening ratio of the deposited Al particles. Increasing the proportion of shot peen particles from 0 to 70 vol.% decreased the porosity of the deposits from 12.4 to 0.2%, while the shear strength of joints significantly increased. The tensile test results of the Al-Cu joints demonstrated that cracks were initiated at the interface between the Al and the deposit. The average tensile strength was 71.4 MPa and could reach 81% of the tensile strength of pure Al.

Influence of gas detonation spraying conditions on the quality of Fe-Al intermetallic protective coatings

Directory of Open Access Journals (Sweden)

Senderowski C.

2007-01-01

Full Text Available The aim of this paper is to present generalized research results and analyses of the quality of coatings produced with self decomposing Fe-Al intermetallic powders deposited on 1045 steel in the gas detonation spraying (GDS. A number of GDS experiments has been carried out with significantly changed operational spraying parameters (the volume of the fuel gas, carrier gas, distance and the frequency of spraying which define the process energy level directly influencing the quality of the coating. On the basis of the initial results the choice of the process parameters has been made to obtain the most advantageous set of geometrical and physical-mechanical properties of the coating material and substrate. The quality of the coatings was considered by taking into account the grain morphology, chemical content, phase inhomogeneity, cohesive porosity, as well as adhesive porosity in the substrate coating joint. The coating roughness was also considered. It was found that all GDS coatings produced are built with lamellar splats which result from the GDS process transformed (changed plasticity and geometry powder particles forming the deposit. The result of the GDS spraying parameters optimization is the lack of signs of melting of the material (even in microareas while the geometry of the deposited grains is considerably changed. This phenomenon has been considered as a proof of high plasticity of the GDS formed Fe-Al intermetallic coatings.

An open-label extension study to investigate the long-term safety and tolerability of THC/CBD oromucosal spray and oromucosal THC spray in patients with terminal cancer-related pain refractory to strong opioid analgesics.

Science.gov (United States)

Johnson, Jeremy R; Lossignol, Dominique; Burnell-Nugent, Mary; Fallon, Marie T

2013-08-01

Chronic pain in patients with advanced cancer poses a serious clinical challenge. The Δ9-tetrahydrocannabinol (THC)/cannabidiol (CBD) oromucosal spray (U.S. Adopted Name, nabiximols; Sativex(®)) is a novel cannabinoid formulation currently undergoing investigation as an adjuvant therapy for this treatment group. This follow-up study investigated the long-term safety and tolerability of THC/CBD spray and THC spray in relieving pain in patients with advanced cancer. In total, 43 patients with cancer-related pain experiencing inadequate analgesia despite chronic opioid dosing, who had participated in a previous three-arm (THC/CBD spray, THC spray, or placebo), two-week parent randomized controlled trial, entered this open-label, multicenter, follow-up study. Patients self-titrated THC/CBD spray (n=39) or THC spray (n=4) to symptom relief or maximum dose and were regularly reviewed for safety, tolerability, and evidence of clinical benefit. The efficacy end point of change from baseline in mean Brief Pain Inventory-Short Form scores for "pain severity" and "worst pain" domains showed a decrease (i.e., improvement) at each visit in the THC/CBD spray patients. Similarly, the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30 scores showed a decrease (i.e., improvement) from baseline in the domains of insomnia, pain, and fatigue. No new safety concerns associated with the extended use of THC/CBD spray arose from this study. This study showed that the long-term use of THC/CBD spray was generally well tolerated, with no evidence of a loss of effect for the relief of cancer-related pain with long-term use. Furthermore, patients who kept using the study medication did not seek to increase their dose of this or other pain-relieving medication over time, suggesting that the adjuvant use of cannabinoids in cancer-related pain could provide useful benefit. Copyright © 2013 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc

Experimental Verification of Statistically Optimized Parameters for Low-Pressure Cold Spray Coating of Titanium

Directory of Open Access Journals (Sweden)

Damilola Isaac Adebiyi

2016-06-01

Full Text Available The cold spray coating process involves many process parameters which make the process very complex, and highly dependent and sensitive to small changes in these parameters. This results in a small operational window of the parameters. Consequently, mathematical optimization of the process parameters is key, not only to achieving deposition but also improving the coating quality. This study focuses on the mathematical identification and experimental justification of the optimum process parameters for cold spray coating of titanium alloy with silicon carbide (SiC. The continuity, momentum and the energy equations governing the flow through the low-pressure cold spray nozzle were solved by introducing a constitutive equation to close the system. This was used to calculate the critical velocity for the deposition of SiC. In order to determine the input temperature that yields the calculated velocity, the distribution of velocity, temperature, and pressure in the cold spray nozzle were analyzed, and the exit values were predicted using the meshing tool of Solidworks. Coatings fabricated using the optimized parameters and some non-optimized parameters are compared. The coating of the CFD-optimized parameters yielded lower porosity and higher hardness.

Electrostatic powder spraying process for the fabrication of stable superhydrophobic surfaces

Science.gov (United States)

Gu, Guotuan; Tian, Yuping; Li, Zhantie; Lu, Dongfang

2011-03-01

Nano-sized Al2O3 particles were modified by heptadecafluorodecyl trimethoxysilane and 2,3-epoxy propoxy propyl trimethoxysilicane to make it both hydrophobic and reactive. The reactive nano-particles were mixed with polyester resin containing curing agents and electrostatic sprayed on stainless steel substrates to obtain stable superhydrophobic coatings after curing. The water contact angle (WCA) on the hybrid coating is influenced by the content of Al2O3 particles in the coating. As the Al2O3 concentration in the coating was increased from 0% to 8%, WCA increased from 68° to 165°. Surface topography of the coatings was examined using scanning electron microscopy (SEM). Nano-particles covered on the coating surface formed continuous film with greatly enhanced roughness, which was found to be responsible for the superhydrophobicity. The method is simple and cost effective and can be used for preparing self-cleaning superhydrophobic coating on large areas.

Electrostatic powder spraying process for the fabrication of stable superhydrophobic surfaces

International Nuclear Information System (INIS)

Gu Guotuan; Tian Yuping; Li Zhantie; Lu Dongfang

2011-01-01

Nano-sized Al 2 O 3 particles were modified by heptadecafluorodecyl trimethoxysilane and 2,3-epoxy propoxy propyl trimethoxysilicane to make it both hydrophobic and reactive. The reactive nano-particles were mixed with polyester resin containing curing agents and electrostatic sprayed on stainless steel substrates to obtain stable superhydrophobic coatings after curing. The water contact angle (WCA) on the hybrid coating is influenced by the content of Al 2 O 3 particles in the coating. As the Al 2 O 3 concentration in the coating was increased from 0% to 8%, WCA increased from 68 o to 165 o . Surface topography of the coatings was examined using scanning electron microscopy (SEM). Nano-particles covered on the coating surface formed continuous film with greatly enhanced roughness, which was found to be responsible for the superhydrophobicity. The method is simple and cost effective and can be used for preparing self-cleaning superhydrophobic coating on large areas.

A new method for spray deposit assessment

Science.gov (United States)

Chester M. Himel; Leland Vaughn; Raymond P. Miskus; Arthur D. Moore

1965-01-01

Solid fluorescent particles suspended in a spray liquid are distributed in direct proportion to the size of the spray droplets. Use of solid fluorescent particles is the basis of a new method for visual recognition of the size and number of droplets impinging on target and nontarget portions of sprayed areas.

A simplified model of aerosol removal by containment sprays

Energy Technology Data Exchange (ETDEWEB)

Powers, D.A. (Sandia National Labs., Albuquerque, NM (United States)); Burson, S.B. (Nuclear Regulatory Commission, Washington, DC (United States). Div. of Safety Issue Resolution)

1993-06-01

Spray systems in nuclear reactor containments are described. The scrubbing of aerosols from containment atmospheres by spray droplets is discussed. Uncertainties are identified in the prediction of spray performance when the sprays are used as a means for decontaminating containment atmospheres. A mechanistic model based on current knowledge of the physical phenomena involved in spray performance is developed. With this model, a quantitative uncertainty analysis of spray performance is conducted using a Monte Carlo method to sample 20 uncertain quantities related to phenomena of spray droplet behavior as well as the initial and boundary conditions expected to be associated with severe reactor accidents. Results of the uncertainty analysis are used to construct simplified expressions for spray decontamination coefficients. Two variables that affect aerosol capture by water droplets are not treated as uncertain; they are (1) [open quote]Q[close quote], spray water flux into the containment, and (2) [open quote]H[close quote], the total fall distance of spray droplets. The choice of values of these variables is left to the user since they are plant and accident specific. Also, they can usually be ascertained with some degree of certainty. The spray decontamination coefficients are found to be sufficiently dependent on the extent of decontamination that the fraction of the initial aerosol remaining in the atmosphere, m[sub f], is explicitly treated in the simplified expressions. The simplified expressions for the spray decontamination coefficient are given. Parametric values for these expressions are found for median, 10 percentile, and 90 percentile values in the uncertainty distribution for the spray decontamination coefficient. Examples are given to illustrate the utility of the simplified expressions to predict spray decontamination of an aerosol-laden atmosphere.

Nitrite spray treatment to promote red color stability of vacuum packaged beef.

Science.gov (United States)

Song, Xiao; Cornforth, Daren; Whittier, Dick; Luo, Xin

2015-01-01

Sodium nitrite solutions were sprayed on select grade boneless rib (M. longissimus thoracis) and bottom round (mainly M. biceps femoris) steaks individually, to form bright red nitric oxide myoglobin (NO-Mb) in vacuum packages. Our objective was to determine the optimum level of nitrite in spray for stable raw steak redness, low or no residual nitrite, and low surface pinking (ham-like cured color) after cooking. Results showed that steaks sprayed with 100-350 ppm nitrite solutions had 3.0-3.6g weight gain and a calculated level of 1.3-5.3mg nitrite added/kg steak, but very low (color during 21 days of storage at 1°C (a*>10; chroma C*>16). Raw steak redness was less stable in round than rib. Visual scores for pinkness after cooking were low, indicating that cooked color at even the highest nitrite treatment (350 ppm) was acceptable. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of spray volume on the deposition, viability and infectivity of entomopathogenic nematodes in a foliar spray on vegetables.

Science.gov (United States)

Brusselman, Eva; Beck, Bert; Pollet, Sabien; Temmerman, Femke; Spanoghe, Pieter; Moens, Maurice; Nuyttens, David

2012-10-01

Spray volume can influence the amount of free water on the leaf surface and subsequently the ability of entomopathogenic nematodes (EPNs) to move. In this study, an investigation was made of the effect of spray volume (548, 730 and 1095 L ha(-1) ) on the deposition, viability and infectivity of EPNs against Galleria mellonella on savoy cabbage, cauliflower and leek. Increasing spray volume decreased nematode deposition on 7.1 cm2 leek leaf discs at a 15° angle with the spray nozzle. Although the number of living nematodes observed on leek after 240 min of exposure was not significantly different between the low-volume application (548 L ha(-1) ) and the high-volume application (1095 L ha(-1) ), a greater infectivity was obtained in the latter application. The higher number of droplets deposited on the leek discs in the high-volume application may have stimulated nematode movement. No significant effect of spray volume was observed on the relative deposition of Steinernema carpocapsae on the bottom side of cauliflower and savoy cabbage leaf discs. In spite of the low S. carpocapsae deposition on the bottom side of the savoy cabbage discs, high infectivity was obtained against G. mellonella. Using the lowest spray volume on savoy cabbage, infectivity decreased with increasing exposure time, while infectivity was not affected by exposure time when a spray volume of 730 L ha(-1) or more was used. Spray volume is an important application parameter, as it affects nematode infectivity. Future research should investigate the effect of spray volume in the field and its influence on the effect of adjuvants. Copyright © 2012 Society of Chemical Industry.

Influence of the process parameters on the spray pyrolysis technique, on the synthesis of gadolinium doped-ceria thin film

International Nuclear Information System (INIS)

Halmenschlager, C.M.; Neagu, R.; Rose, L.; Malfatti, C.F.; Bergmann, C.P.

2013-01-01

Graphical abstract: Gas-tight CGO made by spray pyrolysis suitable to be used as SOFC electrolyte. Display Omitted Highlights: ► Dense and crystalline CGO films deposited by spray pyrolysis on various substrates. ► Solvent did not have a strong influence on the film microstructure, defect concentration or thickness. ► The substrate did not have a strong influence on the film microstructure, defect concentration or thickness. ► Films with at least 2.5 μm of thickness presented high impermeability. ► The films obtained are suitable to use as a SOFC electrolyte. -- Abstract: This work presents the results of a process of optimization applied to gadolinia-doped ceria (Ce 0.8 Gd 0.2 O 1.9−x , or CGO) thin films, deposited by spray pyrolysis (SP). Spray pyrolysis is a high thermal deposition method that combines material deposition and heat treatment. This combination is advantageous since the post-deposition heat treatment step is not necessary. However, stresses are solidified in the coating during the deposition, which may lead to the initiation of a crack in the coating. The aim of this work was to achieve thin, dense, and continuous CGO coatings, which may be used as gas separation membranes and as a solid state electrochemical interfaces. Dense, flat, low-defect substrates such as silica slides, silicon mono crystal wafers, and porous substrates were used as substrates in this work. Cerium ammonium nitrate and gadolinium acetylacetonate were dissolved in ethanol and butyl carbitol to form a precursor solution that was sprayed on the heated substrates. Process parameters such as solvent composition, deposition rate and different heating regimes were analyzed. The microstructure was analyzed by secondary electron microscopy (SEM) and was found that thin, dense, and defect-free films could be produced on dense and porous substrates. The results obtained show that it is possible to obtain a CGO dense film deposited by spray pyrolysis. X-ray diffraction

Raman mapping of mannitol/lysozyme particles produced via spray drying and single droplet drying.

Science.gov (United States)

Pajander, Jari Pekka; Matero, Sanni; Sloth, Jakob; Wan, Feng; Rantanen, Jukka; Yang, Mingshi

2015-06-01

This study aimed to investigate the effect of a model protein on the solid state of a commonly used bulk agent in spray-dried formulations. A series of lysozyme/mannitol formulations were spray-dried using a lab-scale spray dryer. Further, the surface temperature of drying droplet/particles was monitored using the DRYING KINETICS ANALYZER™ (DKA) with controllable drying conditions mimicking the spray-drying process to estimate the drying kinetics of the lysozyme/mannitol formulations. The mannitol polymorphism and the spatial distribution of lysozyme in the particles were examined using X-ray powder diffractometry (XRPD) and Raman microscopy. Partial Least Squares Discriminant Analysis was used for analyzing the Raman microscopy data. XRPD results indicated that a mixture of β-mannitol and α-mannitol was produced in the spray-drying process which was supported by the Raman analysis, whereas Raman analysis indicated that a mixture of α-mannitol and δ-mannitol was detected in the single particles from DKA. In addition Raman mapping indicated that the presence of lysozyme seemed to favor the appearance of α-mannitol in the particles from DKA evidenced by close proximity of lysozyme and mannitol in the particles. It suggested that the presence of lysozyme tend to induce metastable solid state forms upon the drying process.

Albendazole Microparticles Prepared by Spray Drying Technique ...

African Journals Online (AJOL)

Purpose: To enhance the dissolution of albendazole (ABZ) using spray-drying technique. Method: ABZ binary mixtures with Kollicoat IR® (KL) and polyvinyl pyrrolidone (PVP) in various drug to polymer ratios (1: 1, 1: 2 and 1; 4) were prepared by spray-drying. The spray-dried particles were characterized for particle shape, ...

Asymmetrical bonding in cold spraying of dissimilar materials

Science.gov (United States)

Nikbakht, R.; Seyedein, S. H.; Kheirandish, S.; Assadi, H.; Jodoin, B.

2018-06-01

Characteristics of particle bonding, especially for dissimilar materials, remains a key question in cold spray deposition. There are limited reports in direct correlation to particle/substrate bonding and peripheral shear zones. Cold spraying experiments and numerical simulations are conducted to characterise and analyse the correlation between bonding and peripheral shear zones for asymmetric particle/substrate pairs of intermetallic-forming elements of nickel and titanium. The correlation between metallic bonding and highly strained areas is explored in view of the growth of the intermetallic phase at the particle/substrate interface during subsequent heat treatments. Characterisation of the as-sprayed samples reveal that for the Ni(particle)/Ti(substrate) pair, plastic deformation of the particle is dominating over substrate deformation. However, for the Ti(particle)/Ni(substrate) pair, it is observed that the substrate and particle deform to similar extents. Characterisation of the samples after a brief heat treatment at 700 °C indicate that intermetallic formation, and hence metallurgical bonding of the pairs is more likely to occur at the particle peripheries where the interface areas are highly strained, and rarely achieved at the particle base. Results also reveal that bonding extends from peripheries toward the central part of the interfaces with increasing the impact velocity. The kinetics of interfacial intermetallic formation at peripheral areas and its correlation to particle bonding is discussed in view of deformation-enhanced interdiffusion.

CHARACTERIZATION OF DIESEL SPRAY IMAGES USING A SHAPE PROCESSING METHODOLOGY

Directory of Open Access Journals (Sweden)

Cecile Petit

2011-05-01

Full Text Available In Diesel engines, a key element in achieving a clean and efficient combustion process is a proper fuel-air mixing, which is a consequence of the fuel spray development and fuel-air interaction inside the engine combustion chamber. The spray structure and behavior are classically described by the length (penetration and width (angle of the spray plume but these parameters do not give any clue on the geometrical injection center and on the spray symmetry. The purpose of this paper is to find out original tools to characterize the Diesel spray: the virtual spray origin is the geometrical injection center, which may (or may not coincide with the injector axis. Another interesting point is the description of the Diesel spray in terms of symmetry: the spray plume internal and external symmetry characterize the spray and the injector performance. Our approach is first to find out the virtual spray origin: after the image segmentation, the spray is coded with the Freeman code and with an original shape coding from which the moments are derived. The symmetry axes are then computed and the spray plumes are discarded (or not for the virtual spray origin computation, which is derived from a Voronoi diagram. The last step is the internal and external spray plume symmetry characterization thanks to correlation and mathematical distances.

Quality characteristic of spray-drying egg white powders.

Science.gov (United States)

Ma, Shuang; Zhao, Songning; Zhang, Yan; Yu, Yiding; Liu, Jingbo; Xu, Menglei

2013-10-01

Spray drying is a useful method for developing egg process and utilization. The objective of this study was to evaluate effects on spray drying condition of egg white. The optimized conditions were spraying flow 22 mL/min, feeding temperature 39.8 °C and inlet-air temperature 178.2 °C. Results of sulfydryl (SH) groups measurement indicated conformation structure have changed resulting in protein molecule occur S-S crosslinking phenomenon when heating. It led to free SH content decreased during spray drying process. There was almost no change of differential scanning calorimetry between fresh egg white and spray-drying egg white powder (EWP). For a given protein, the apparent SH reactivity is in turn influenced by the physico-chemical characteristics of the reactant. The phenomenon illustrated the thermal denaturation of these proteins was unrelated to their free SH contents. Color measurement was used to study browning level. EWP in optimized conditions revealed insignificant brown stain. Swelling capacity and scanning electron micrograph both proved well quality characteristic of spray-drying EWP. Results suggested spray drying under the optimized conditions present suitable and alternative method for egg processing industrial implementation. Egg food industrialization needs new drying method to extend shelf-life. The purpose of the study was to provide optimal process of healthy and nutritional instant spray-drying EWP and study quality characteristic of spray-drying EWP.

LSPRAY-V: A Lagrangian Spray Module

Science.gov (United States)

Raju, M. S.

2015-01-01

LSPRAY-V is a Lagrangian spray solver developed for application with unstructured grids and massively parallel computers. It is mainly designed to predict the flow, thermal and transport properties of a rapidly vaporizing spray encountered over a wide range of operating conditions in modern aircraft engine development. It could easily be coupled with any existing gas-phase flow and/or Monte Carlo Probability Density Function (PDF) solvers. The manual provides the user with an understanding of various models involved in the spray formulation, its code structure and solution algorithm, and various other issues related to parallelization and its coupling with other solvers. With the development of LSPRAY-V, we have advanced the state-of-the-art in spray computations in several important ways.

High-Performance Molybdenum Coating by Wire–HVOF Thermal Spray Process

Science.gov (United States)

Tailor, Satish; Modi, Ankur; Modi, S. C.

2018-04-01

Coating deposition on many industrial components with good microstructural, mechanical properties, and better wear resistance is always a challenge for the thermal spray community. A number of thermal spray methods are used to develop such promising coatings for many industrial applications, viz. arc spray, flame spray, plasma, and HVOF. All these processes have their own limitations to achieve porous free, very dense, high-performance wear-resistant coatings. In this work, an attempt has been made to overcome this limitation. Molybdenum coatings were deposited on low-carbon steel substrates using wire-high-velocity oxy-fuel (W-HVOF; WH) thermal spray system (trade name HIJET 9610®). For a comparison, Mo coatings were also fabricated by arc spray, flame spray, plasma spray, and powder-HVOF processes. As-sprayed coatings were analyzed using x-ray diffraction, scanning electron microscopy for phase, and microstructural analysis, respectively. Coating microhardness, surface roughness, and porosity were also measured. Adhesion strength and wear tests were conducted to determine the mechanical and wear properties of the as-sprayed coatings. Results show that the coatings deposited by W-HVOF have better performance in terms of microstructural, mechanical, and wear resistance properties, in comparison with available thermal spray process (flame spray and plasma spray).

Thermally sprayed prepregs for thixoforging of UD fiber reinforced light metal MMCs

Science.gov (United States)

Silber, Martin; Wenzelburger, Martin; Gadow, Rainer

2007-04-01

Low density and good mechanical properties are the basic requirements for lightweight structures in automotive and aerospace applications. With their high specific strength and strain to failure values, aluminum alloys could be used for such applications. Only the insufficient stiffness and thermal and fatigue strength prevented their usage in high-end applications. One possibility to solve this problem is to reinforce the light metal with unidirectional fibers. The UD fiber allows tailoring of the reinforcement to meet the direction of the component's load. In this study, the production of thermally sprayed prepregs for the manufacturing of continuous fiber reinforced MMC by thixoforging is analysed. The main aim is to optimize the winding procedure, which determines the fiber strand position and tension during the coating process. A method to wind and to coat the continuous fibers with an easy-to-use handling technique for the whole manufacturing process is presented. The prepregs were manufactured by producing arc wire sprayed AlSi6 coatings on fibers bundles. First results of bending experiments showed appropriate mechanical properties.

Effect of TiO2 addition on reaction between SiC and Ni in SiC-Ni cermet spray coatings. Part 2. ; Development of SiC-based cermet spray coatings. SiC-Ni yosha himakuchu no SiC-Ni kaimen hanno ni oyobosu TiO2 tenka no koka. 2. ; SiC-ki sametto yosha himaku no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Nakamura, T [Kumano Technical College, Mie (Japan); Oki, S; Goda, S [Kinki Univ., Higashi-Osaka, Osaka (Japan). Faculty of Science and Technology

1992-09-30

The depression of the reaction between SiC and Ni, by adding TiO2 powder in spraying powder which has caused uniform dispersion in spray coating and reduction of TiO2 by the reaction during spraying, was studied. The mass ratio of the mixed components has been, SiC:Ni:TiO2=3:2:1. The spray coating was examined by electron prove microanalysis as well as X-ray diffractometry, centering mainly to the SiC-metal interface reaction. The formation of Ni-Si compounds have been depressed by the addition of TiO2 to spraying powder and by using plasma gas containing H2. Reason for this has been that the TiC formed in the SiC-Ni interface has depressed the reaction at the SiC-Ni interface. Further, TiO2 is reduced during spraying, and TiC is thought to be formed by the reaction between Ti and SiC or reaction between TiO2 and SiC. 8 refs., 6 figs., 1 tab.

Characterization of the full cone pressure swirl spray nozzles for the nuclear reactor containment spray system

Energy Technology Data Exchange (ETDEWEB)

Jain, Manish [Department of Mechanical Engineering, I.I.T., Bombay, Powai, Mumbai (India); John, Benny [Nuclear Power Corporation of India Limited, Mumbai (India); Iyer, K.N. [Department of Mechanical Engineering, I.I.T., Bombay, Powai, Mumbai (India); Prabhu, S.V., E-mail: svprabhu@iitb.ac.in [Department of Mechanical Engineering, I.I.T., Bombay, Powai, Mumbai (India)

2014-07-01

Highlights: • Full cone spray pressure swirl nozzle with X-Vane is studied. • Laser illuminated imaging technique is used. • Correlations for coefficient of discharge, spray cone angle and SMD are suggested. • Droplet size and mass fraction distribution is measured. • Inviscid theory predicts the coefficient of discharge. - Abstract: The objective of the present study is to characterize a full cone pressure swirl nozzle for the Containment Spray System (CSS) of Indian Pressurized heavy Water reactors (IPHWR). The influence of Reynolds number and geometric parameters on the coefficient of discharge, spray cone angle, mass flux density distribution, droplet size distribution, Sauter mean diameter (SMD is studied for full cone pressure swirl full cone nozzles. The nozzles of orifice diameter range from 1.3 to 7.2 mm are studied. Experiments are conducted with water at room temperature as the working medium. The nozzles are operated with the pressure ranging from 1 to 8 bar. The measurements of the drop size distributions are performed with laser illuminated imaging technique. The spray cone-angle of the full cone nozzles is measured by the evaluation of images recorded with a camera using IMAGE J software. Correlations for coefficient of discharge, spray cone angle and Sauter mean diameter are suggested on the basis of the experimental results. Rosin–Rammler model and Nukiyama–Tanasawa distributions predict the mass fraction distribution reasonably well. However, the droplet size distribution is predicted by Nukiyama-Tanasawa model only.

Ultrafast X-ray Imaging of Fuel Sprays

Science.gov (United States)

Wang, Jin

2007-01-01

Detailed analysis of fuel sprays has been well recognized as an important step for optimizing the operation of internal combustion engines to improve efficiency and reduce emissions. Ultrafast radiographic and tomographic techniques have been developed for probing the fuel distribution close to the nozzles of direct-injection diesel and gasoline injectors. The measurement was made using x-ray absorption of monochromatic synchrotron-generated radiation, allowing quantitative determination of the fuel distribution in this optically impenetrable region with a time resolution on the order of 1 μs. Furthermore, an accurate 3-dimensional fuel-density distribution, in the form of fuel volume fraction, was obtained by the time-resolved computed tomography. These quantitative measurements constitute the most detailed near-nozzle study of a fuel spray to date. With high-energy and high-brilliance x-ray beams available at the Advanced Photon Source, propagation-based phase-enhanced imaging was developed as a unique metrology technique to visualize the interior of an injection nozzle through a 3-mm-thick steel with a 10-μs temporal resolution, which is virtually impossible by any other means.

Ultrafast X-ray Imaging of Fuel Sprays

International Nuclear Information System (INIS)

Wang Jin

2007-01-01

Detailed analysis of fuel sprays has been well recognized as an important step for optimizing the operation of internal combustion engines to improve efficiency and reduce emissions. Ultrafast radiographic and tomographic techniques have been developed for probing the fuel distribution close to the nozzles of direct-injection diesel and gasoline injectors. The measurement was made using x-ray absorption of monochromatic synchrotron-generated radiation, allowing quantitative determination of the fuel distribution in this optically impenetrable region with a time resolution on the order of 1 μs. Furthermore, an accurate 3-dimensional fuel-density distribution, in the form of fuel volume fraction, was obtained by the time-resolved computed tomography. These quantitative measurements constitute the most detailed near-nozzle study of a fuel spray to date. With high-energy and high-brilliance x-ray beams available at the Advanced Photon Source, propagation-based phase-enhanced imaging was developed as a unique metrology technique to visualize the interior of an injection nozzle through a 3-mm-thick steel with a 10-μs temporal resolution, which is virtually impossible by any other means

Plasma spraying process of disperse carbides for spraying and facing

International Nuclear Information System (INIS)

Blinkov, I.V.; Vishnevetskaya, I.A.; Kostyukovich, T.G.; Ostapovich, A.O.

1989-01-01

A possibility to metallize carbides in plasma of impulsing capacitor discharge is considered. Powders granulation occurs during plasma spraying process, ceramic core being completely capped. X-ray phase and chemical analyses of coatings did not show considerable changes of carbon content in carbides before and after plasma processing. This distinguishes the process of carbides metallization in impulsing plasma from the similar processing in arc and high-frequency plasma generator. Use of powder composites produced in the impulsing capacitor discharge, for plasma spraying and laser facing permits 2-3 times increasing wear resistance of the surface layer as against the coatings produced from mechanical powders mixtures

Studies on Nanocrystalline TiN Coatings Prepared by Reactive Plasma Spraying

Directory of Open Access Journals (Sweden)

Dong Yanchun

2008-01-01

Full Text Available Titanium nitride (TiN coatings with nanostructure were prepared on the surface of 45 steel (Fe-0.45%C via reactive plasma spraying (denoted as RPS Ti powders using spraying gun with self-made reactive chamber. The microstructural characterization, phases constitute, grain size, microhardness, and wear resistance of TiN coatings were systematically investigated. The grain size was obtained through calculation using the Scherrer formula and observed by TEM. The results of X-ray diffraction and electron diffraction indicated that the TiN is main phase of the TiN coating. The forming mechanism of the nano-TiN was characterized by analyzing the SEM morphologies of surface of TiN coating and TiN drops sprayed on the surface of glass, and observing the temperature and velocity of plasma jet using Spray Watch. The tribological properties of the coating under nonlubricated condition were tested and compared with those of the AISI M2 high-speed steel and Al2O3 coating. The results have shown that the RPS TiN coating presents better wear resistance than the M2 high-speed steel and Al2O3 coating under nonlubricated condition. The microhardness of the cross-section and longitudinal section of the TiN coating was tested. The highest hardness of the cross-section of TiN coating is 1735.43HV100 g.

Alignment Fixtures For Vacuum-Plasma-Spray Gun

Science.gov (United States)

Woodford, William H.; Mckechnie, Timothy N.; Power, Christopher A.; Daniel, Ronald L., Jr.

1993-01-01

Fixtures for alignment of vacuum-plasma-spray guns built. Each fixture designed to fit specific gun and holds small, battery-powered laser on centerline of gun. Laser beam projects small red dot where centerline intersects surface of workpiece to be sprayed. After laser beam positioned on surface of workpiece, fixture removed from gun and spraying proceeds.

Tungsten/copper composite deposits produced by a cold spray

International Nuclear Information System (INIS)

Kang, Hyun-Ki; Kang, Suk Bong

2003-01-01

An agglomerated tungsten/copper composite powder was both cold sprayed and plasma sprayed onto a mild steel substrate for electronic package applications. Most pores resulting from the spraying were found in the vicinity of the tungsten-rich regions of the final product. The levels of porosity varied with the amount of tungsten present. No copper oxidation was found at the cold-sprayed deposit, but relatively high copper oxidation was observed at the plasma-sprayed deposit

Epitaxial Growth and Cracking Mechanisms of Thermally Sprayed Ceramic Splats

Science.gov (United States)

Chen, Lin; Yang, Guan-jun

2018-02-01

In the present study, the epitaxial growth and cracking mechanisms of thermally sprayed ceramic splats were explored. We report, for the first time, the epitaxial growth of various splat/substrate combinations at low substrate temperatures (100 °C) and large lattice mismatch (- 11.26%). Our results suggest that thermal spray deposition was essentially a liquid-phase epitaxy, readily forming chemical bonding. The interface temperature was also estimated. The results convincingly demonstrated that atoms only need to diffuse and rearrange over a sufficiently short range during extremely rapid solidification. Concurrently, severe cracking occurred in the epitaxial splat/substrate systems, which indicated high tensile stress was produced during splat deposition. The origin of the tensile stress was attributed to the strong constraint of the locally heated substrate by its cold surroundings.

Research Into Ni-Cr-Si-B Coating Sprayed Onto Aluminium Substrate Using the Method of Plasma Spray

Directory of Open Access Journals (Sweden)

Raimonda Lukauskaitė

2013-02-01

Full Text Available The article deals with Ni base coatings deposited on aluminium substrate applying the method of plasma spray. The purpose of the conducted research is to improve the physical and mechanical properties of coatings on the surface of aluminium alloy work pieces. Spraying on aluminium alloys encounters serious problems, and therefore this work analyses the ways to make the situation more favourable. Before spraying, the surfaces of substrates were modified employing chemical and mechanical pre-treatment methods. The aim of pre-treating aluminium alloys was to remove oxide layers from the aluminium surface. Coating microstructures and porosity were characterised applying optical microscopy. Differences in the roughness of pre-treated surfaces have been determined referring to profilometry. The paper investigates the influence of the adhesion of plasma spray coatings on aluminium surface pretreatment. Microhardness technique was applied for measuring the hardness of coatings. The study also describes and compares the mechanical properties of Ni base coatings deposited on different pre-treated aluminium substrates using plasma spray.Article in Lithuanian

Research Into Ni-Cr-Si-B Coating Sprayed Onto Aluminium Substrate Using the Method of Plasma Spray

Directory of Open Access Journals (Sweden)

Raimonda Lukauskaitė

2012-12-01

Full Text Available The article deals with Ni base coatings deposited on aluminium substrate applying the method of plasma spray. The purpose of the conducted research is to improve the physical and mechanical properties of coatings on the surface of aluminium alloy work pieces. Spraying on aluminium alloys encounters serious problems, and therefore this work analyses the ways to make the situation more favourable. Before spraying, the surfaces of substrates were modified employing chemical and mechanical pre-treatment methods. The aim of pre-treating aluminium alloys was to remove oxide layers from the aluminium surface. Coating microstructures and porosity were characterised applying optical microscopy. Differences in the roughness of pre-treated surfaces have been determined referring to profilometry. The paper investigates the influence of the adhesion of plasma spray coatings on aluminium surface pretreatment. Microhardness technique was applied for measuring the hardness of coatings. The study also describes and compares the mechanical properties of Ni base coatings deposited on different pre-treated aluminium substrates using plasma spray.Article in Lithuanian

Sprayed concrete linings

Energy Technology Data Exchange (ETDEWEB)

Hindle, D.

1999-12-01

Sprayed concrete, or shotcrete, was invented in the 1920s for preserving dinosaur skeletons and was used underground initially in coalmines for the preservation and fine proofing of timber supports. Its use as a support lining in rock tunnelling was developed in the 1950s and 60s. The article surveys equipment available from major manufacturers and suppliers of concrete spraying equipment (Aliva, Cifa, GIA, Industri, Ingersoll Rand, etc.), specialist cement and additive manufacturers (Castle, Cement, Moria Carbotech). manufacturers of lattice girders and fibre reinforcement, and manufacturers of instrumentation for tunnel linings. 5 tabs., 9 photos.

Design and performance of atomizing nozzles for spray calcination of high-level wastes

International Nuclear Information System (INIS)

Miller, F.A.; Stout, L.A.

1981-05-01

A key aspect of high-level liquid-waste spray calcination is waste-feed atomization by using air atomizing nozzles. Atomization substantially increases the heat transfer area of the waste solution, which enhances rapid drying. Experience from the spray-calciner operations has demonstrated that nozzle flow conditions that produce 70-μ median-volume-diameter or smaller spray droplets are required for small-scale spray calciners (drying capacity less than 80 L/h). For large-scale calciners (drying capacity greater than 300 L/h), nozzle flow conditions that produce 100-μ median-volume-diameter or smaller spray droplets are required. Mass flow ratios of 0.2 to 0.4, depending on nozzle size, are required for proper operation of internal-mix atomizing nozzles. Both internal-mix and external-mix nozzles have been tested at PNL. Due to the lower airflow requirements and fewer large droplets produced, the internal-mix nozzle has been chosen for primary development in the spray calciner program at PNL. Several nozzle air-cap materials for internal-mix nozzles have been tested for wear resistance. Results show that nozzle air caps of stainless steel and Cer-vit (a machineable glass ceramic) are suceptible to rapid wear by abrasive slurries, whereas air caps of alumina and reaction-bonded silicon nitride show only slow wear. Longer-term testing is necessary to determine more accurately the actual frequency of nozzle replacement. Atomizing nozzle air caps of alumina are subject to fracture from thermal shock, whereas air caps of silicon nitride and Cer-vit are not. Fractured nozzles are held in place by the air-cap retaining ring and continue to atomize satisfactorily. Therefore, fractures caused by thermal shocking do not necessarily result in nozzle failure

GDI fuel sprays of light naphtha, PRF95 and gasoline using a piezoelectric injector under different ambient pressures

KAUST Repository

Wu, Zengyang; Wang, Libing; Badra, Jihad A.; Roberts, William L.; Fang, Tiegang

2018-01-01

This study investigates fuel sprays of light naphtha (LN), primary reference fuel (PRF) and gasoline under different ambient pressures with an outwardly opening piezo gasoline direct injection (GDI) fuel injector. The tested gasoline fuel (regular grade with up to 10% ethanol, E10) was obtained by mixing fuels with AKI (the average of the research octane number (RON) and the motor octane number (MON)) of 87 from three local gas stations. Primary reference fuel (PRF) is commonly used as gasoline surrogate fuel and is blended by iso-octane and n-heptane. PRF95 is the blend of 95% iso-octane and 5% n-heptane by volume. LN fuel was provided by Saudi Aramco Oil Company. Five different ambient pressure conditions varied from 1 bar to 10 bar were tested. The spray was visualized by applying a Mie-scattering technique and a high-speed camera was employed to capture the spray images. The spray structure, spray angle, spray penetration length and spray front fluctuation were analyzed and compared among three fuels. Spray images show that a clear filamentary hollow-cone spray structure is formed for all three fuels at atmospheric conditions, and toroidal recirculation vortexes are observed at the downstream spray edges. A higher ambient pressure leads to a stronger vortex located closer to the injector outlet. Generally speaking, larger spray angles are found under higher ambient pressure conditions for all three fuels. Gasoline fuel always has the largest spray angle for each ambient pressure, while PRF95 has the smallest at most time. For each fuel, the spray front penetration length and spray front penetration velocity decrease with increasing ambient pressure. LN, PRF95 and gasoline show similar penetration length and velocity under the tested conditions. A two-stage spray front fluctuation pattern is observed for all three fuels. Stage one begins from the start of the injection and ends at 450–500 μs after the start of the injection trigger (ASOIT) with a slow

GDI fuel sprays of light naphtha, PRF95 and gasoline using a piezoelectric injector under different ambient pressures

KAUST Repository

Wu, Zengyang

2018-03-20

This study investigates fuel sprays of light naphtha (LN), primary reference fuel (PRF) and gasoline under different ambient pressures with an outwardly opening piezo gasoline direct injection (GDI) fuel injector. The tested gasoline fuel (regular grade with up to 10% ethanol, E10) was obtained by mixing fuels with AKI (the average of the research octane number (RON) and the motor octane number (MON)) of 87 from three local gas stations. Primary reference fuel (PRF) is commonly used as gasoline surrogate fuel and is blended by iso-octane and n-heptane. PRF95 is the blend of 95% iso-octane and 5% n-heptane by volume. LN fuel was provided by Saudi Aramco Oil Company. Five different ambient pressure conditions varied from 1 bar to 10 bar were tested. The spray was visualized by applying a Mie-scattering technique and a high-speed camera was employed to capture the spray images. The spray structure, spray angle, spray penetration length and spray front fluctuation were analyzed and compared among three fuels. Spray images show that a clear filamentary hollow-cone spray structure is formed for all three fuels at atmospheric conditions, and toroidal recirculation vortexes are observed at the downstream spray edges. A higher ambient pressure leads to a stronger vortex located closer to the injector outlet. Generally speaking, larger spray angles are found under higher ambient pressure conditions for all three fuels. Gasoline fuel always has the largest spray angle for each ambient pressure, while PRF95 has the smallest at most time. For each fuel, the spray front penetration length and spray front penetration velocity decrease with increasing ambient pressure. LN, PRF95 and gasoline show similar penetration length and velocity under the tested conditions. A two-stage spray front fluctuation pattern is observed for all three fuels. Stage one begins from the start of the injection and ends at 450–500 μs after the start of the injection trigger (ASOIT) with a slow

Computational Analysis of Spray Jet Flames

Science.gov (United States)

Jain, Utsav

There is a boost in the utilization of renewable sources of energy but because of high energy density applications, combustion will never be obsolete. Spray combustion is a type of multiphase combustion which has tremendous engineering applications in different fields, varying from energy conversion devices to rocket propulsion system. Developing accurate computational models for turbulent spray combustion is vital for improving the design of combustors and making them energy efficient. Flamelet models have been extensively used for gas phase combustion because of their relatively low computational cost to model the turbulence-chemistry interaction using a low dimensional manifold approach. This framework is designed for gas phase non-premixed combustion and its implementation is not very straight forward for multiphase and multi-regime combustion such as spray combustion. This is because of the use of a conserved scalar and various flamelet related assumptions. Mixture fraction has been popularly employed as a conserved scalar and hence used to parameterize the characteristics of gaseous flamelets. However, for spray combustion, the mixture fraction is not monotonic and does not give a unique mapping in order to parameterize the structure of spray flames. In order to develop a flamelet type model for spray flames, a new variable called the mixing variable is introduced which acts as an ideal conserved scalar and takes into account the convection and evaporation of fuel droplets. In addition to the conserved scalar, it has been observed that though gaseous flamelets can be characterized by the conserved scalar and its dissipation, this might not be true for spray flamelets. Droplet dynamics has a significant influence on the spray flamelet and because of effects such as flame penetration of droplets and oscillation of droplets across the stagnation plane, it becomes important to accommodate their influence in the flamelet formulation. In order to recognize the

Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying

DEFF Research Database (Denmark)

Craye, Goedele; Löbmann, Korbinian; Grohganz, Holger

2015-01-01

In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS) as a solubilizer, was explored as a production method for co-amorphous simvastatin-lysine (SVS-LYS) at 1:1 molar mixtures, which previously have been observed to form a co...

Sintering of Fine Particles in Suspension Plasma Sprayed Coatings

Directory of Open Access Journals (Sweden)

Leszek Latka

2010-07-01

Full Text Available Suspension plasma spraying is a process that enables the production of finely grained nanometric or submicrometric coatings. The suspensions are formulated with the use of fine powder particles in water or alcohol with some additives. Subsequently, the suspension is injected into plasma jet and the liquid additives evaporate. The remaining fine solids are molten and subsequently agglomerate or remain solid, depending on their trajectory in the plasma jet. The coating’s microstructure results from these two groups of particles arriving on a substrate or previously deposited coating. Previous experimental studies carried out for plasma sprayed titanium oxide and hydroxyapatite coatings enabled us to observe either a finely grained microstructure or, when a different suspension injection mode was used, to distinguish two zones in the microstructure. These two zones correspond to the dense zone formed from well molten particles, and the agglomerated zone formed from fine solid particles that arrive on the substrate in a solid state. The present paper focuses on the experimental and theoretical analysis of the formation process of the agglomerated zone. The experimental section establishes the heat flux supplied to the coating during deposition. In order to achieve this, calorimetric measurements were made by applying experimental conditions simulating the real coatings’ growth. The heat flux was measured to be in the range from 0.08 to 0.5 MW/m2,depending on the experimental conditions. The theoretical section analyzes the sintering during the coating’s growth, which concerns the fine particles arriving on the substrate in the solid state. The models of volume, grain boundary and surface diffusion were analyzed and adapted to the size and chemistry of the grains, temperature and time scales corresponding to the suspension plasma spraying conditions. The model of surface diffusion was found to best describe the sintering during suspension

Study by X-ray diffraction and mechanical analysis of the residual stress generation during thermal spraying

International Nuclear Information System (INIS)

Pina, J.; Dias, A.; Lebrun, J.L.

2003-01-01

Thermally sprayed coatings are formed by the deposition of molten or partially molten particles, propelled onto a substrate where they impact, spread and solidify rapidly. Residual stresses are expected within the sprayed deposit as a consequence of the release of thermal and kinetic energies. A wide range of materials and two spraying techniques are considered in this study, namely atmospheric plasma spraying (APS) and high-velocity oxygen fuel. Stresses were determined by the X-ray diffraction (XRD) method. The results were compared with those calculated by mechanical analysis of stress relief in coatings detached from the substrate. Comparison of the results for adherent and free-standing coatings shows that the residual stress state can be resolved in terms of the components suggested by models that propose two stages of stress generation: quenching stresses and secondary-cooling stresses. The in-depth distribution of residual stresses, through the coating thickness, is discussed in terms of the nature of the coating system

Spray layer-by-layer films based on phospholipid vesicles aiming sensing application via e-tongue system

International Nuclear Information System (INIS)

Aoki, P.H.B.; Volpati, D.; Cabrera, F.C.; Trombini, V.L.; Riul, A.; Constantino, C.J.L.

2012-01-01

dipping- and spray-LbL techniques and also by Langmuir–Blodgett (LB) onto Pt interdigitated electrodes composing an array of sensing units (e-tongue) were applied in the detection of a xanthene derivate (eosin) in diluted solutions (10 −9 , 10 −7 and 10 −6 M). Despite the LB and LbL films are formed by the same materials (PAH and DPPG), it was found that their different molecular architectures play an important role on the electrical response of Pt interdigitated electrodes in impedance spectroscopy measurements. The high sensitivity reached by these sensing units was intimately related to changes in the film morphology caused by the adsorption of the eosin molecules onto the film surfaces during electrical measurements, as evidenced by micro-Raman technique. - Highlights: ► DPPG phospholipid vesicles were immobilized alternately with PAH through spray-LbL technique. ► DPPG is kept in the form of vesicles despite the pressure applied during spray deposition. ► Spray-LbL films of PAH/DPPG composed an array of sensors applied in e-tongue experiments. ► High diluted solutions of xanthene compound were detected.

Defect-Free Large-Area (25 cm2 Light Absorbing Perovskite Thin Films Made by Spray Coating

Directory of Open Access Journals (Sweden)

Mehran Habibi

2017-03-01

Full Text Available In this work, we report on reproducible fabrication of defect-free large-area mixed halide perovskite (CH3NH3PbI3−xClx thin films by scalable spray coating with the area of 25 cm2. This is essential for the commercialization of the perovskite solar cell technology. Using an automated spray coater, the film thickness and roughness were optimized by controlling the solution concentration and substrate temperature. For the first time, the surface tension, contact angle, and viscosity of mixed halide perovskite dissolved in dimethylformamide (DMF are reported as a function of the solution concentration. A low perovskite solution concentration of 10% was selected as an acceptable value to avoid crystallization dewetting. The determined optimum substrate temperature of 150 °C, followed by annealing at 100 °C render the highest perovskite precursor conversion, as well as the highest possible droplet spreading, desired to achieve a continuous thin film. The number of spray passes was also tuned to achieve a fully-covered film, for the condition of the spray nozzle used in this work. This work demonstrates that applying the optimum substrate temperature decreases the standard deviation of the film thickness and roughness, leading to an increase in the quality and reproducibility of the large-area spray-on films. The optimum perovskite solution concentration and the substrate temperature are universally applicable to other spray coating systems.

In situ spray deposition of cell-loaded, thermally and chemically gelling hydrogel coatings for tissue regeneration.

Science.gov (United States)

Pehlivaner Kara, Meryem O; Ekenseair, Adam K

2016-10-01

In this study, the efficacy of creating cellular hydrogel coatings on warm tissue surfaces through the minimally invasive, sprayable delivery of thermoresponsive liquid solutions was investigated. Poly(N-isopropylacrylamide)-based (pNiPAAm) thermogelling macromers with or without addition of crosslinking polyamidoamine (PAMAM) macromers were synthesized and used to produce in situ forming thermally and chemically gelling hydrogel systems. The effect of solution and process parameters on hydrogel physical properties and morphology was evaluated and compared to poly(ethylene glycol) and injection controls. Smooth, fast, and conformal hydrogel coatings were obtained when pNiPAAm thermogelling macromers were sprayed with high PAMAM concentration at low pressure. Cellular hydrogel coatings were further fabricated by different spraying techniques: single-stream, layer-by-layer, and dual stream methods. The impact of spray technique, solution formulation, pressure, and spray solution viscosity on the viability of fibroblast and osteoblast cells encapsulated in hydrogels was elucidated. In particular, the early formation of chemically crosslinked micronetworks during bulk liquid flow was shown to significantly affect cell viability under turbulent conditions compared to injectable controls. The results demonstrated that sprayable, in situ forming hydrogels capable of delivering cell populations in a homogeneous therapeutic coating on diseased tissue surfaces offer promise as novel therapies for applications in regenerative medicine. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2383-2393, 2016. © 2016 Wiley Periodicals, Inc.

Plasma sprayed coatings on crankshaft used steels

Science.gov (United States)

Mahu, G.; Munteanu, C.; Istrate, B.; Benchea, M.

2017-08-01

Plasma spray coatings may be an alternative to conventional heat treatment of main journals and crankpins of the crankshaft. The applications of plasma coatings are various and present multiple advantages compared to electric arc wire spraying or flame spraying. The study examines the layers sprayed with the following powders: Cr3C2- 25(Ni 20Cr), Al2O3- 13TiO2, Cr2O3-SiO2- TiO2 on the surface of steels used in the construction of a crankshaft (C45). The plasma spray coatings were made with the Spray wizard 9MCE facility at atmospheric pressure. The samples were analyzed in terms of micro and morphological using optical microscopy, scanning electron microscopy and X-ray diffraction. Wear tests on samples that have undergone simulates extreme working conditions of the crankshafts. In order to emphasize adherence to the base material sprayed layer, were carried out tests of microscratches and micro-indentation. Results have showed a relatively compact morphological aspect given by the successive coatings with splat-like specific structures. Following the microscratch analysis it can be concluded that Al2O3-13TiO2 coating has a higher purpose in terms of hardness compared to Cr3C2-(Ni 20Cr) and Cr2O3-SiO2- TiO2 powders. Thermal coatings of the deposited powders have increased the mechanical properties of the material. The results stand to confirm that plasma sprayed Al2O3-13TiO2 powder is in fact a efficient solution for preventing mechanical wear, even with a faulty lubrication system.

To spray or not to spray? Understanding participation in an indoor residual spray campaign in Arequipa, Peru.

Science.gov (United States)

Paz-Soldán, Valerie A; Bauer, Karin M; Hunter, Gabrielle C; Castillo-Neyra, Ricardo; Arriola, Vanessa D; Rivera-Lanas, Daniel; Rodriguez, Geoffrey H; Toledo Vizcarra, Amparo M; Mollesaca Riveros, Lina M; Levy, Michael Z; Buttenheim, Alison M

2018-01-01

Current low participation rates in vector control programmes in Arequipa, Peru complicate the control of Chagas disease. Using focus groups (n = 17 participants) and semi-structured interviews (n = 71) conducted in March and May 2013, respectively, we examined barriers to and motivators of household participation in an indoor residual spray (IRS) campaign that had taken place one year prior in Arequipa. The most common reported barriers to participation were inconvenient spray times due to work obligations, not considering the campaign to be necessary, concerns about secondary health impacts (e.g. allergic reactions to insecticides), and difficulties preparing the home for spraying (e.g. moving heavy furniture). There was also a low perception of risk for contracting Chagas disease that might affect participation. The main motivator to participate was to ensure personal health and well-being. Future IRS campaigns should incorporate more flexible hours, including weekends; provide appropriate educational messages to counter concerns about secondary health effects; incorporate peer educators to increase perceived risk to Chagas in community; obtain support from community members and leaders to build community trust and support for the campaign; and assist individuals in preparing their homes. Enhancing community trust in both the need for the campaign and its operations is key.

Injector spray characterization of methanol in reciprocating engines

Science.gov (United States)

Dodge, L.; Naegeli, D.

1994-06-01

This report covers a study that addressed cold-starting problems in alcohol-fueled, spark-ignition engines by using fine-spray port-fuel injectors to inject fuel directly into the cylinder. This task included development and characterization of some very fine-spray, port-fuel injectors for a methanol-fueled spark-ignition engine. After determining the spray characteristics, a computational study was performed to estimate the evaporation rate of the methanol fuel spray under cold-starting and steady-state conditions.

Development of cold sprayed Cu coating for canister

International Nuclear Information System (INIS)

Kim, Hyung Jun; Kang, Yoon Ha

2010-01-01

Cold sprayed Cu deposition was studied for the application of outer part of canister for high level nuclear waste. Five commercially available pure Cu powders were analyzed and sprayed by high pressure cold spray system. Electrochemical corrosion test using potentiostat in 3.5% NaCl solution was conducted as well as microstructural analysis including hardness and oxygen content measurements. Overall evaluation of corrosion performance of cold sprayed Cu deposition is inferior to forged and extruded Cu plates, but some of Cu depositions are comparable to Cu plates. The simulated corrosion test in 200m underground cave is still in progress. The effect of cold spray process parameters was also studied and the results show that the type of nozzle is the most important other than powder feed rate, spray distance, and scan speed. 1/10 scale miniature of canister was manufactured confirming that the production of full scale canister is possible

Spray Modeling for Outwardly-Opening Hollow-Cone Injector

KAUST Repository

Sim, Jaeheon

2016-04-05

The outwardly-opening piezoelectric injector is gaining popularity as a high efficient spray injector due to its precise control of the spray. However, few modeling studies have been reported on these promising injectors. Furthermore, traditional linear instability sheet atomization (LISA) model was originally developed for pressure swirl hollow-cone injectors with moderate spray angle and toroidal ligament breakups. Therefore, it is not appropriate for the outwardly-opening injectors having wide spray angles and string-like film structures. In this study, a new spray injection modeling was proposed for outwardly-opening hollow-cone injector. The injection velocities are computed from the given mass flow rate and injection pressure instead of ambiguous annular nozzle geometry. The modified Kelvin-Helmholtz and Rayleigh-Taylor (KH-RT) breakup model is used with adjusted initial Sauter mean diameter (SMD) for modeling breakup of string-like structure. Spray injection was modeled using a Lagrangian discrete parcel method within the framework of commercial CFD software CONVERGE, and the new model was implemented through the user-defined functions. A Siemens outwardly-opening hollow-cone spray injector was characterized and validated with existing experimental data at the injection pressure of 100 bar. It was found that the collision modeling becomes important in the current injector because of dense spray near nozzle. The injection distribution model showed insignificant effects on spray due to small initial droplets. It was demonstrated that the new model can predict the liquid penetration length and local SMD with improved accuracy for the injector under study.

Research of Plasma Spraying Process on Aluminum-Magnesium Alloy

Directory of Open Access Journals (Sweden)

Patricija Kavaliauskaitė

2016-04-01

Full Text Available The article examines plasma sprayed 95Ni-5Al coatings on alu-minum-magnesium (Mg ≈ 2,6‒3,6 % alloy substrate. Alumi-num-magnesium samples prior spraying were prepared with mechanical treatment (blasting with Al2O3. 95Ni-5Al coatings on aluminum-magnesium alloys were sprayed with different parameters of process and coating‘s thickness, porosity, micro-hardness and microstructure were evaluated. Also numerical simulations in electric and magnetic phenomena of plasma spray-ing were carried out.

A new method for thermal spraying of Zn-Al coatings

International Nuclear Information System (INIS)

Gorlach, I.A.

2009-01-01

This paper presents the development of the thermal spraying system built on the principles of the high velocity air flame (HVAF) process. HVAF sprayed coatings showed considerably higher bond strength than coatings obtained by the conventional methods, indicating the advantage of this method in areas where the adhesion strength is critically important. The highly dense structure of the coating obtained with HVAF eliminates a need for a top paint coat, which is typically applied on metal sprayed coatings to extend service life. The thermal sprayed coatings were characterized by the standard techniques, such as light microscopy, scanning electron microscopy with energy-dispersive spectroscopy, X-ray diffraction, salt spray and bond strength tests. The results show that thermal sprayed coatings have a dense structure, low presence of oxides and high resistance to corrosion. High spray rate and good coating quality make the HVAF thermal spray method a viable alternative to the conventional thermal spraying technologies, such as Wire Flame and Twin-Wire Arc.

Solidification of hesperidin nanosuspension by spray drying optimized by design of experiment (DoE).

Science.gov (United States)

Wei, Qionghua; Keck, Cornelia M; Müller, Rainer H

2018-01-01

To accelerate the determination of optimal spray drying parameters, a "Design of Experiment" (DoE) software was applied to produce well redispersible hesperidin nanocrystals. For final solid dosage forms, aqueous liquid nanosuspensions need to be solidified, whereas spray drying is a large-scale cost-effective industrial process. A nanosuspension with 18% (w/w) of hesperidin stabilized by 1% (w/w) of poloxamer 188 was produced by wet bead milling. The sizes of original and redispersed spray-dried nanosuspensions were determined by laser diffractometry (LD) and photon correlation spectroscopy (PCS) and used as effect parameters. In addition, light microscopy was performed to judge the redispersion quality. After a two-step design of MODDE 9, screening model and response surface model (RSM), the inlet temperature of spray dryer and the concentration of protectant (polyvinylpyrrolidone, PVP K25) were identified as the most important factors affecting the redispersion of nanocrystals. As predicted in the RSM modeling, when 5% (w/w) of PVP K25 was added in an 18% (w/w) of hesperidin nanosuspension, subsequently spray-dried at an inlet temperature of 100 °C, well redispersed solid nanocrystals with an average particle size of 276 nm were obtained. By the use of PVP K25, the saturation solubility of the redispersed nanocrystals in water was improved to 86.81 µg/ml, about 2.5-fold of the original nanosuspension. In addition, the dissolution velocity was accelerated. This was attributed to the additional effects of steric stabilization on the nanocrystals and solubilization by the PVP polymer from spray drying.

Ternary ceramic thermal spraying powder and method of manufacturing thermal sprayed coating using said powder

Energy Technology Data Exchange (ETDEWEB)

Vogli, Evelina; Sherman, Andrew J.; Glasgow, Curtis P.

2018-02-06

The invention describes a method for producing ternary and binary ceramic powders and their thermal spraying capable of manufacturing thermal sprayed coatings with superior properties. Powder contain at least 30% by weight ternary ceramic, at least 20% by weight binary molybdenum borides, at least one of the binary borides of Cr, Fe, Ni, W and Co and a maximum of 10% by weight of nano and submicro-sized boron nitride. The primary crystal phase of the manufactured thermal sprayed coatings from these powders is a ternary ceramic, while the secondary phases are binary ceramics. The coatings have extremely high resistance against corrosion of molten metal, extremely thermal shock resistance and superior tribological properties at low and at high temperatures.

Evaluation of mechanical properties of Aluminum-Copper cold sprayed and alloy 625 wire arc sprayed coatings

Science.gov (United States)

Bashirzadeh, Milad

This study examines microstructural-based mechanical properties of Al-Cu composite deposited by cold spraying and wire arc sprayed nickel-based alloy 625 coating using numerical modeling and experimental techniques. The microhardness and elastic modulus of samples were determined using the Knoop hardness technique. Hardness in both transverse and longitudinal directions on the sample cross-sections has been measured. An image-based finite element simulation algorithm was employed to determine the mechanical properties through an inverse analysis. In addition mechanical tests including, tensile, bending, and nano-indentation tests were performed on alloy 625 wire arc sprayed samples. Overall, results from the experimental tests are in relatively good agreement for deposited Al-Cu composites and alloy 625 coating. However, results obtained from numerical simulation are significantly higher in value than experimentally obtained results. Examination and comparison of the results are strong indications of the influence of microstructure characteristics on the mechanical properties of thermally spray deposited coatings.

Pulmonary delivery of antitubercular drugs using spray-dried lipid-polymer hybrid nanoparticles.

Science.gov (United States)

Bhardwaj, Ankur; Mehta, Shuchi; Yadav, Shailendra; Singh, Sudheer K; Grobler, Anne; Goyal, Amit Kumar; Mehta, Abhinav

2016-09-01

The present study aimed to develop lipid-polymer hybrid nanoparticles (LPNs) for the combined pulmonary delivery of isoniazid (INH) and ciprofloxacin hydrochloride (CIP HCl). Drug-loaded LPNs were prepared by the double-emulsification solvent evaporation method using the three-factor three-level Box-Behnken design. The optimized formulation had a size of 111.81 ± 1.2 nm, PDI of 0.189 ± 1.4, and PDE of 63.64 ± 2.12% for INH-loaded LPN, and a size of 172.23 ± 2.31 nm, PDI of 0.169 ± 1.23, and PDE of 68.49 ± 2.54% for CIP HCl-loaded LPN. Drug release was found to be sustained and controlled at lower pH and followed the Peppas model. The in vitro uptake study in alveolar macrophage (AM) showed that uptake of the drugs was increased significantly if administered in the form of LPN. The stability study proved the applications of adding PLGA in LPN as the polymeric core, which leads to a much more stable product as compared to other novel drug delivery systems. Spray drying was done to produce an inhalable, dry, powdered form of drug-loaded LPN. The spray-dried (SD) powder was equally capable of producing nano-aggregates having morphology, density, flowability and reconstitutibility in the range ideal for inhaled drug delivery. The nano aggregates produced by spray drying manifested their aerosolization efficiency in terms of the higher emitted dose and fine particle fraction with lower mass median aerodynamic diameter. The in vivo study using pharmacokinetic and pharmacodynamic approaches revealed that maximum internalization efficiency was achieved by delivering LPN in SD powdered forms by pulmonary route.

Fuel temperature influence on diesel sprays in inert and reacting conditions

International Nuclear Information System (INIS)

Payri, Raul; García-Oliver, Jose M.; Bardi, Michele; Manin, Julien

2012-01-01

The detailed knowledge of the evaporation–combustion process of the Diesel spray is a key factor for the development of robust injection strategies able to reduce the pollutant emissions and keep or increase the combustion efficiency. In this work several typical measurement applied to the diesel spray diagnostic (liquid length, lift-off length and ignition delay) have been employed in a novel continuous flow test chamber that allows an accurate control on a wide range of thermodynamic test conditions (up to 1000 K and 15 MPa). A step forward in the control of the test boundary conditions has been done employing a special system to study the fuel temperature effect on the evaporation and combustion of the spray. The temperature of the injector body has been controlled with a thermostatic system and the relationship between injector body and fuel temperature has been observed experimentally. Imaging diagnostics have been employed to visualize the liquid phase penetration in evaporative/inert conditions and, lift-off length and ignition delay in reactive condition. The results underline a clear influence of the injector body temperature on both conditions, evaporative and, in a lesser degree, reactive; finally the physical models found in the literature have been compared with the results obtained experimentally. - Highlights: ► The effect of the fuel temperature is substantial on liquid length (up to 15%). ► Fuel temperature has low effect but still appreciable on LOL and ignition delay. ► Theoretical one dimensional spray models are able to reproduce the experimental results with good accuracy.

SPRAY code user's report

International Nuclear Information System (INIS)

Shire, P.R.

1977-03-01

The SPRAY computer code has been developed to model the effects of postulated sodium spray release from LMFBR piping within containment chambers. The calculation method utilizes gas convection, heat transfer and droplet combustion theory to calculate the pressure and temperature effects within the enclosure. The applicable range is 0-21 mol percent oxygen and .02-.30 inch droplets with or without humidity. Droplet motion and large sodium surface area combine to produce rapid heat release and pressure rise within the enclosed volume

Hot Melt Extrusion and Spray Drying of Co-amorphous Indomethacin-Arginine With Polymers.

Science.gov (United States)

Lenz, Elisabeth; Löbmann, Korbinian; Rades, Thomas; Knop, Klaus; Kleinebudde, Peter

2017-01-01

Co-amorphous drug-amino acid systems have gained growing interest as an alternative to common amorphous formulations which contain polymers as stabilizers. Several preparation methods have recently been investigated, including vibrational ball milling on a laboratory scale or spray drying in a larger scale. In this study, the feasibility of hot melt extrusion for continuous manufacturing of co-amorphous drug-amino acid formulations was examined, challenging the fact that amino acids melt with degradation at high temperatures. Furthermore, the need for an addition of a polymer in this process was evaluated. After a polymer screening via the solvent evaporation method, co-amorphous indomethacin-arginine was prepared by a melting-solvent extrusion process without and with copovidone. The obtained products were characterized with respect to their solid-state properties, non-sink dissolution behavior, and stability. Results were compared to those of spray-dried formulations with the same compositions and to spray-dried indomethacin-copovidone. Overall, stable co-amorphous systems could be prepared by extrusion without or with copovidone, which exhibited comparable molecular interaction properties to the respective spray-dried products, while phase separation was detected by differential scanning calorimetry in several cases. The formulations containing indomethacin in combination with arginine and copovidone showed enhanced dissolution behavior over the formulations with only copovidone or arginine. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

The role of nano-particles in the field of thermal spray coating technology

Science.gov (United States)

Siegmann, Stephan; Leparoux, Marc; Rohr, Lukas

2005-06-01

Nano-particles play not only a key role in recent research fields, but also in the public discussions about health and safety in nanotechnology. Nevertheless, the worldwide activities in nano-particles research increased dramatically during the last 5 to 10 years. There are different potential routes for the future production of nano-particles at large scale. The main directions envisaged are mechanical milling, wet chemical reactions or gas phase processes. Each of the processes has its specific advantages and limitations. Mechanical milling and wet chemical reactions are typically time intensive and batch processes, whereas gas phase productions by flames or plasma can be carried out continuously. Materials of interest are mainly oxide ceramics, carbides, nitrides, and pure metals. Nano-ceramics are interesting candidates for coating technologies due to expected higher coating toughness, better thermal shock and wear resistance. Especially embedded nano-carbides and-nitrides offer homogenously distributed hard phases, which enhance coatings hardness. Thermal spraying, a nearly 100 years old and world wide established coating technology, gets new possibilities thanks to optimized, nano-sized and/or nano-structured powders. Latest coating system developments like high velocity flame spraying (HVOF), cold gas deposition or liquid suspension spraying in combination with new powder qualities may open new applications and markets. This article gives an overview on the latest activities in nano-particle research and production in special relation to thermal spray coating technology.

Cryogen spray cooling: Effects of droplet size and spray density on heat removal.

Science.gov (United States)

Pikkula, B M; Torres, J H; Tunnell, J W; Anvari, B

2001-01-01

Cryogen spray cooling (CSC) is an effective method to reduce or eliminate non-specific injury to the epidermis during laser treatment of various dermatological disorders. In previous CSC investigations, fuel injectors have been used to deliver the cryogen onto the skin surface. The objective of this study was to examine cryogen atomization and heat removal characteristics of various cryogen delivery devices. Various cryogen delivery device types including fuel injectors, atomizers, and a device currently used in clinical settings were investigated. Cryogen mass was measured at the delivery device output orifice. Cryogen droplet size profiling for various cryogen delivery devices was estimated by optically imaging the droplets in flight. Heat removal for various cryogen delivery devices was estimated over a range of spraying distances by temperature measurements in an skin phantom used in conjunction with an inverse heat conduction model. A substantial range of mass outputs were measured for the cryogen delivery devices while heat removal varied by less than a factor of two. Droplet profiling demonstrated differences in droplet size and spray density. Results of this study show that variation in heat removal by different cryogen delivery devices is modest despite the relatively large difference in cryogen mass output and droplet size. A non-linear relationship between heat removal by various devices and droplet size and spray density was observed. Copyright 2001 Wiley-Liss, Inc.

Effect of precursor concentration and spray pyrolysis temperature upon hydroxyapatite particle size and density.

Science.gov (United States)

Cho, Jung Sang; Lee, Jeong-Cheol; Rhee, Sang-Hoon

2016-02-01

In the synthesis of hydroxyapatite powders by spray pyrolysis, control of the particle size was investigated by varying the initial concentration of the precursor solution and the pyrolysis temperature. Calcium phosphate solutions (Ca/P ratio of 1.67) with a range of concentrations from 0.1 to 2.0 mol/L were prepared by dissolving calcium nitrate tetrahydrate and diammonium hydrogen phosphate in deionized water and subsequently adding nitric acid. Hydroxyapatite powders were then synthesized by spray pyrolysis at 900°C and at 1500°C, using these calcium phosphate precursor solutions, under the fixed carrier gas flow rate of 10 L/min. The particle size decreased as the precursor concentration decreased and the spray pyrolysis temperature increased. Sinterability tests conducted at 1100°C for 1 h showed that the smaller and denser the particles were, the higher the relative densities were of sintered hydroxyapatite disks formed from these particles. The practical implication of these results is that highly sinterable small and dense hydroxyapatite particles can be synthesized by means of spray pyrolysis using a low-concentration precursor solution and a high pyrolysis temperature under a fixed carrier gas flow rate. © 2015 Wiley Periodicals, Inc.

An experimental study on atomizing formation process of diesel spray

International Nuclear Information System (INIS)

Kim, Ki Bong

2000-02-01

In this study, the experiment has, been conducted to investigate the spray characteristics under the parameter of an ambient pressure with a single hole nozzle having aspect ratio(L/D) of 5 and diameter of 0.45mm. Under the condition of the injection pressure of 14Mpa, the initial disintegrating process of a diesel spray is investigated and analysized according to change of the ambient pressures, 0.1, 1, 2 and 3Mpa. The double flash method has been employed to visualize the process of the diesel sprays. The results obtained in this study are as follows: 1) After spray starts, the spray is shown as non-disturbance liquid column within about 1∼2mm from the nozzle tip, whose diameter is similar to that of a nozzle. For the same injection pressure, the increase of the ambient pressure makes the length of the non-disturbance liquid column become short. 2) Due to the surface wave, ligaments of the shape thread appear at the boundary of liquid column right after spray. The more developed wave together the progress of spray transforms ligaments into droplets that have generally the uniformed size. 3) In case spraying into chambers having different ambient pressures, 1, 2, and 3Mpa, the spray tip velocities reach up to 1.5, 1.2, and 0.6ms, respectively, and decrease with lapse of time. The spray angle keeps increasing for 0.6, 1.2, and 1.4ms after spray under the various ambient pressures, 3, 2, and 1Mpa, respectively, and begins to decrease and maintains the constant value. Therefore, the transition points appear near the point where the velocity decreases and the spray angle increases, simultaneously. The higher ambient pressure leads to fast appearance of transition under the same spray pressure. 4) The disintegrating mechanism of the liquid spray is two combined effects: a) friction forces between the surface waves generated at the surface of the liquid column and the ambient gas, b) the collisions of liquid droplets and ligaments by spray were overtaking

Modeling and simulation of milk emulsion drying in spray dryers

Directory of Open Access Journals (Sweden)

V. S. Birchal

2005-06-01

Full Text Available This work aims at modeling and simulating the drying of whole milk emulsion in spray dryers. Drops and particles make up the discrete phase and are distributed into temporal compartments following their residence time in the dryer. Air is the continuous and well-mixed phase. Mass and energy balances are developed for each phase, taking into account their interactions. Constitutive equations for describing the drop swelling and drying mechanisms as well as the heat and mass transfer between particles and hot air are proposed and analyzed. A set of algebraic-differential equations is obtained and solved by specific numerical codes. Results from experiments carried out in a pilot spray dryer are used to validate the model developed and the numerical algorithm. Comparing the simulated and experimental data, it is shown that the model predicts well the individual drop-particle history inside the dryer as well as the overall outlet air-particle temperature and humidity.

Aluminium-12wt% silicon coating prepared by thermal spraying technique: Part 1 optimization of spray condition based on a design of experiment

Directory of Open Access Journals (Sweden)

Jiansirisomboon, S.

2006-03-01

Full Text Available At present, thermal spray technology is used for maintenance parts of various machines in many industries. This technology can be used to improve the surface wear resistance. Therefore, this technology can significantly reduce cost of manufacturing. Al-12wt%Si alloy is an interesting and popular material used in the automotive industry. This research studies the suitable condition for spraying of Al-12wt%Si powder. This powder was sprayed by a flame spray technique onto low carbon steel substrates. The suitable conditions for spraying can be achieved by a design of experiment (DOE principle, which provided statistical data defined at 90% confidence. This research used control factors, which were oxygen flow rate, acetylene flow rate and spray distance. The satisfaction levels of these factors were set at 3 levels, i.e. low, medium and high, in order to determine suitable responses, which were hardness, thickness, wear rate and percentage volume fraction of porosity. It was found that the optimized condition for spraying Al-12wt%Si powder consisted of 38 ft3/hr (1.026 m3/hr of oxygen flow rate, 27 ft3/hr (0.729 m3/hr of acetylene flow rate and 58 mm of spray distance.

Plasma sprayed Nd-Fe-B permanent magnets

International Nuclear Information System (INIS)

Willson, M.; Bauser, S.; Liu, S.; Huang, M.

2003-01-01

This study demonstrated that the plasma spray deposition method is an alternative process for producing Nd-Fe-B magnets in addition to the two existing principal processes: the powder metallurgy process for producing sintered Nd-Fe-B magnets and the melt spinning process for bonded Nd-Fe-B magnets. Plasma spray is a potentially better process for producing magnetic parts with complicated shape, large area, thin thickness, small dimension, or unusual geometry. High intrinsic coercivity greater than 15 kOe was readily obtained for Nd 16 Dy 1 Fe 76 B 7 even in the as-deposited condition when the substrate was preheated. The plasma spray process contains only three steps: melting, crushing, and plasma spray, which is much simpler than the powder metallurgy and melt spinning processes. Without preheating the substrate, the coercivity was usually very low (∼0.1 kOe) in the as-deposited condition and it increased to 10 to >15 kOe after anneal. Evidence of magnetocrystalline anisotropy was observed in plasma sprayed Nd 15 Dy 1 Fe 77 B 7 magnets when the substrate was not preheated. It is believed that a crystal texture was developed during the plasma spray as a result of the existence of a temperature gradient in the solidifying melt

9 CFR 590.542 - Spray process drying operations.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Spray process drying operations. 590..., Processing, and Facility Requirements § 590.542 Spray process drying operations. (a) The drying room shall be... interrupted. (1) Spray nozzles, orifices, cores, or whizzers shall be cleaned immediately after cessation of...

Comparison of W–TiC composite coatings fabricated by atmospheric plasma spraying and supersonic atmospheric plasma spraying

International Nuclear Information System (INIS)

Hou, Qing Yu; Luo, Lai Ma; Huang, Zhen Yi; Wang, Ping; Ding, Ting Ting; Wu, Yu Cheng

2016-01-01

Highlights: • W–TiC composite coatings were fabricated by APS and SAPS technologies. • TiC had filling effect on pores and coating/fixing effect on un-melted particles. • Porosity and oxygen content in SAPS coating were lower than that in APS coating. • Thermal conductivity of SAPS coating was higher than that of APS coating. • SAPS coating has better ability to resist to elastic fracture than APS coating does. - Abstract: Tungsten coatings with 1.5 wt.% TiC (W/TiC) were fabricated by atmospheric plasma spraying (APS) and supersonic atmospheric plasma spraying (SAPS) techniques, respectively. The results showed that the typical lamellar structure of plasma spraying and columnar crystalline grains formed in the coatings. Pores located mainly at lamellar gaps in association with oxidation were also observed. TiC phase, distributed at lamellar gaps filled the gaps; and that distributed around un-melted tungsten particles and splashed debris coated the particles or debris that were linked with the TiC at lamellar gaps. The coating and linking of the retained TiC phase prevented the tungsten particles to come off from the coatings. The porosity and the oxygen content of the SAPS-W/TiC were lower than those of the APS-W/TiC coating. The mechanical response of the coatings was strongly dependent on the H/E* ratio (H and E* are the hardness and effective Young’s modulus, respectively). The SAPS-W/TiC coating with a higher H/E* ratio had a better ability to resist to elastic fracture and better fracture toughness as compared with the APS-W/TiC coating with a smaller H/E* ratio. The thermal conductivity of the SAPS-W/TiC coating was greater than that of the APS-W/TiC coating.

Droplet size effects on NO/x/ formation in a one-dimensional monodisperse spray combustion system

Science.gov (United States)

Sarv, H.; Nizami, A. A.; Cernansky, N. P.

1982-01-01

A one-dimensional monodisperse aerosol spray combustion facility is described and experimental results of post flame NO/NO(x) emissions are presented. Four different hydrocarbon fuels were studied: isopropanol, methanol, n-heptane, and n-octane. The results indicate an optimum droplet size in the range of 48-58 microns for minimizing NO/NO(x) production for all of the test fuels. This NO(x) behavior is associated with droplet interactions and the transition from diffusive type of spray burning to that of a prevaporized and premixed case. Decreasing the droplet size results in a trend of increasing droplet interactions, which suppresses temperatures and reduces NO(x). This trend continues until prevaporization effects begin to dominate and the system tends towards the premixed limit. The occurrence of the minimum NO(x) point at different droplet diameters for the different fuels appears to be governed by the extent of prevaporization of the fuel in the spray, and is consistent with theoretical calculations based on each fuel's physical properties.

An optimized formulation of a thermostable spray dried virus-like particles vaccine against human papillomavirus

Science.gov (United States)

Saboo, Sugandha; Tumban, Ebenezer; Peabody, Julianne; Wafula, Denis; Peabody, David S.; Chackerian, Bryce; Muttil, Pavan

2016-01-01

Existing vaccines against human papillomavirus (HPV) require continuous cold-chain storage. Previously, we developed a bacteriophage virus-like particle (VLP) based vaccine for Human Papillomavirus (HPV) infection, which elicits broadly neutralizing antibodies against diverse HPV types. Here, we formulated these VLPs into a thermostable dry powder using a multi-component excipient system and by optimizing the spray drying parameters using a half-factorial design approach. Dry powder VLPs were stable after spray drying and after long-term storage at elevated temperatures. Immunization of mice with a single dose of reconstituted dry powder VLPs that were stored at 37°C for more than a year elicited high anti-L2 IgG antibody titers. Spray dried thermostable, broadly protective L2 bacteriophage VLPs vaccine could be accessible to remote regions of the world (where ~84% of cervical cancer patients reside) by eliminating the cold-chain requirement during transportation and storage. PMID:27019231

Fabrication of gas turbine water-cooled composite nozzle and bucket hardware employing plasma spray process

Science.gov (United States)

Schilke, Peter W.; Muth, Myron C.; Schilling, William F.; Rairden, III, John R.

1983-01-01

In the method for fabrication of water-cooled composite nozzle and bucket hardware for high temperature gas turbines, a high thermal conductivity copper alloy is applied, employing a high velocity/low pressure (HV/LP) plasma arc spraying process, to an assembly comprising a structural framework of copper alloy or a nickel-based super alloy, or combination of the two, and overlying cooling tubes. The copper alloy is plamsa sprayed to a coating thickness sufficient to completely cover the cooling tubes, and to allow for machining back of the copper alloy to create a smooth surface having a thickness of from 0.010 inch (0.254 mm) to 0.150 inch (3.18 mm) or more. The layer of copper applied by the plasma spraying has no continuous porosity, and advantageously may readily be employed to sustain a pressure differential during hot isostatic pressing (HIP) bonding of the overall structure to enhance bonding by solid state diffusion between the component parts of the structure.

Polydisperse effects in jet spray flames

Science.gov (United States)

Weinberg, Noam; Greenberg, J. Barry

2018-01-01

A laminar jet polydisperse spray diffusion flame is analysed mathematically for the first time using an extension of classical similarity solutions for gaseous jet flames. The analysis enables a comparison to be drawn between conditions for flame stability or flame blow-out for purely gaseous flames and for spray flames. It is found that, in contrast to the Schmidt number criteria relevant to gas flames, droplet size and initial spray polydispersity play a critical role in determining potential flame scenarios. Some qualitative agreement for lift-off height is found when comparing predictions of the theory and sparse independent experimental evidence from the literature.

Spray deposition using impulse atomization technique

International Nuclear Information System (INIS)

Ellendt, N.; Schmidt, R.; Knabe, J.; Henein, H.; Uhlenwinkel, V.

2004-01-01

A novel technique, impulse atomization, has been used for spray deposition. This single fluid atomization technique leads to different spray characteristics and impact conditions of the droplets compared to gas atomization technique which is the common technique used for spray deposition. Deposition experiments with a Cu-6Sn alloy were conducted to evaluate the appropriateness of impulse atomization to produce dense material. Based on these experiments, a model has been developed to simulate the thermal history and the local solidification rates of the deposited material. A numerical study shows how different cooling conditions affect the solidification rate of the material

Spraying mode effect on droplet formation and ion chemistry in electrosprays.

Science.gov (United States)

Nemes, Peter; Marginean, Ioan; Vertes, Akos

2007-04-15

Depending on the spraying conditions and fluid properties, a variety of electrospray regimes exists. Here we explore the changes in ion production that accompany the transitions among the three axial spraying modes, the burst mode, the pulsating Taylor cone mode, and the cone-jet mode. Spray current oscillation and phase Doppler anemometry measurements, fast imaging of the electrified meniscus, and mass spectrometry are utilized to study the formation, size, velocity, and chemical composition of droplets produced in the three modes. High-speed images indicate that the primary droplets are produced by varicose waves and lateral kink instabilities on the liquid jet emerging from the Taylor cone, whereas secondary droplets are formed by fission. Dramatic changes in the droplet size distributions result from the various production and breakup mechanisms observed at different emitter voltages and liquid flow rates. We demonstrate that droplet fission can be facilitated by space charge effects along the liquid jet and in the plume. Compared to the other two regimes, a significantly enhanced signal-to-noise ratio, a lower degree of analyte oxidation, and milder fragmentation are observed for the cone-jet mode.

Containment atmosphere response to external sprays

International Nuclear Information System (INIS)

Green, J.; Almenas, K.

1995-01-01

The application of external sprays to a containment steel shell can be an effective energy removal method and has been proposed in the passive AP-600 design. Reduction of the steel shell temperature in contact with the containment atmosphere enhances both heat and mass transfer driving forces. Large scale experimental data in this area is scarce, therefore the measurements obtained from the E series tests conducted at the German HDR facility deserve special attention. These long term tests simulated various severe accident conditions, including external spraying of the hemispherical steel shell. This investigation focuses upon the integral response of the HDR containment atmosphere during spray periods and upon methods by which lumped parameter system codes, like CONTAIN, model the underlying condensation phenomena. Increases in spray water flowrates above a minimum value were ineffective at improving containment pressure reduction since the limiting resistance for energy transfer lies in the noncondensable-vapor boundary layer at the inner condensing surface. The spray created an unstable condition by cooling the upper layers of a heated atmosphere and thus inducing global natural circulation flows in the facility and subsequently, abrupt changes in lighter-than-air noncondensable (J 2 /He) concentrations. Modeling results using the CONTAIN code are outlined and code limitations are delineated

Containment atmosphere response to external sprays

Energy Technology Data Exchange (ETDEWEB)

Green, J.; Almenas, K. [Univ. of Maryland, College Park, MD (United States)

1995-09-01

The application of external sprays to a containment steel shell can be an effective energy removal method and has been proposed in the passive AP-600 design. Reduction of the steel shell temperature in contact with the containment atmosphere enhances both heat and mass transfer driving forces. Large scale experimental data in this area is scarce, therefore the measurements obtained from the E series tests conducted at the German HDR facility deserve special attention. These long term tests simulated various severe accident conditions, including external spraying of the hemispherical steel shell. This investigation focuses upon the integral response of the HDR containment atmosphere during spray periods and upon methods by which lumped parameter system codes, like CONTAIN, model the underlying condensation phenomena. Increases in spray water flowrates above a minimum value were ineffective at improving containment pressure reduction since the limiting resistance for energy transfer lies in the noncondensable-vapor boundary layer at the inner condensing surface. The spray created an unstable condition by cooling the upper layers of a heated atmosphere and thus inducing global natural circulation flows in the facility and subsequently, abrupt changes in lighter-than-air noncondensable (J{sub 2}/He) concentrations. Modeling results using the CONTAIN code are outlined and code limitations are delineated.

Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating

Energy Technology Data Exchange (ETDEWEB)

Zabihi, F.; Xie, Y.; Gao, S.; Eslamian, M., E-mail: Morteza.Eslamian@sjtu.edu.cn

2015-05-30

Highlights: • Nanostructure of spun-on and spray-on PEDOT:PSS thin films is studied. • A correlation is established between the film nanostructure and electrical conductivity. • Effect of process parameters is studied on the film characteristics. • A high solution concentration, high process temperature and multiple deposition layers are recommended. - Abstract: The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS

Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating

International Nuclear Information System (INIS)

Zabihi, F.; Xie, Y.; Gao, S.; Eslamian, M.

2015-01-01

Highlights: • Nanostructure of spun-on and spray-on PEDOT:PSS thin films is studied. • A correlation is established between the film nanostructure and electrical conductivity. • Effect of process parameters is studied on the film characteristics. • A high solution concentration, high process temperature and multiple deposition layers are recommended. - Abstract: The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS

A Grey-Box Model for Spray Drying Plants

DEFF Research Database (Denmark)

Petersen, Lars Norbert; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

2013-01-01

Multi-stage spray drying is an important and widely used unit operation in the production of food powders. In this paper we develop and present a dynamic model of the complete drying process in a multi-stage spray dryer. The dryer is divided into three stages: The spray stage and two fluid bed...

Numerical Modeling of Diesel Spray Formation and Combustion

NARCIS (Netherlands)

Bekdemir, C.; Somers, L.M.T.; Goey, de L.P.H.

2009-01-01

A study is presented on the modeling of fuel sprays in diesel engines. The objective of this study is in the first place to accurately and efficiently model non-reacting diesel spray formation, and secondly to include ignition and combustion. For that an efficient 1D Euler-Euler spray model [21] is

Inhalational and dermal exposures during spray application of biocides.

Science.gov (United States)

Berger-Preiss, Edith; Boehncke, Andrea; Könnecker, Gustav; Mangelsdorf, Inge; Holthenrich, Dagmar; Koch, Wolfgang

2005-01-01

Data on inhalational and potential dermal exposures during spray application of liquid biocidal products were generated. On the one hand, model experiments with different spraying devices using fluorescent tracers were carried out to investigate the influence of parameters relevant to the exposure (e.g. spraying equipment, nozzle size, direction of application). On the other hand, measurements were performed at selected workplaces (during disinfection operations in food and feed areas; pest control operations for private, public and veterinary hygiene; wood protection and antifouling applications) after application of biocidal products such as Empire 20, Responsar SC, Omexan-forte, Actellic, Perma-forte; Fendona SC, Pyrethrum mist; CBM 8, Aldekol Des 03, TAD CID, Basileum, Basilit. The measurements taken in the model rooms demonstrated dependence of the inhalation exposure on the type of spraying device used, in the following order: "spraying with low pressure" < "airless spraying" < "fogging" indicating that the particle diameter of the released spray droplets is the most important parameter. In addition inhalation exposure was lowest when the spraying direction was downward. Also for the potential dermal exposure, the spraying direction was of particular importance: overhead spraying caused the highest contamination of body surfaces. The data of inhalational and potential dermal exposures gained through workplace measurements showed considerable variation. During spraying procedures with low-pressure equipments, dose rates of active substances inhaled by the operators ranged from 7 to 230 microg active substance (a.s.)/h. An increase in inhaled dose rates (6-33 mg a.s./h) was observed after use of high application volumes/time unit during wood protection applications indoors. Spraying in the veterinary sector using medium-pressure sprayers led to inhaled dose rates between 2 and 24mga.s./h. The highest inhaled dose rates were measured during fogging (114 mg a

Automated Plasma Spray (APS) process feasibility study: Plasma spray process development and evaluation

Science.gov (United States)

Fetheroff, C. W.; Derkacs, T.; Matay, I. M.

1979-01-01

An automated plasma spray (APS) process was developed to apply two layer (NiCrAlY and ZrO2-12Y2O3) thermal-barrier coatings to aircraft gas turbine engine blade airfoils. The APS process hardware consists of four subsystems: a mechanical blade positioner incorporating two interlaced six-degree-of-freedom assemblies; a noncoherent optical metrology subsystem; a microprocessor-based adaptive system controller; and commercial plasma spray equipment. Over fifty JT9D first stage turbine blades specimens were coated with the APS process in preliminary checkout and evaluation studies. The best of the preliminary specimens achieved an overall coating thickness uniformity of + or - 53 micrometers, much better than is achievable manually. Factors limiting this performance were identified and process modifications were initiated accordingly. Comparative evaluations of coating thickness uniformity for manually sprayed and APS coated specimens were initiated. One of the preliminary evaluation specimens was subjected to a torch test and metallographic evaluation.

Plasma spraying of beryllium and beryllium-aluminum-silver alloys

International Nuclear Information System (INIS)

Castro, R.G.; Stanek, P.W.; Elliott, K.E.; Jacobson, L.A.

1994-01-01

A preliminary investigation on plasma-spraying of beryllium and a beryllium-aluminum-4% silver alloy was done at the Los Alamos National Laboratory's Beryllium Atomization and Thermal Spray Facility (BATSF). Spherical Be and Be-Al-4%Ag powders, which were produced by centrifugal atomization, were used as feedstock material for plasma-spraying. The spherical morphology of the powders allowed for better feeding of fine (<38 μm) powders into the plasma-spray torch. The difference in the as-deposited densities and deposit efficiencies of the two plasma-sprayed powders will be discussed along with the effect of processing parameters on the as-deposited microstructure of the Be-Al-4%Ag. This investigation represents ongoing research to develop and characterize plasma-spraying of beryllium and beryllium-aluminum alloys for magnetic fusion and aerospace applications

Plasma spraying of beryllium and beryllium-aluminum-silver alloys

International Nuclear Information System (INIS)

Castro, R.G.; Stanek, P.W.; Elliott, K.E.; Jacobson, L.A.

1993-01-01

A preliminary investigation on plasma-spraying of beryllium and a beryllium-aluminum 4% silver alloy was done at the Los Alamos National Laboratory's Beryllium Atomization and Thermal Spray Facility (BATSF). Spherical Be and Be-Al-4%Ag powders, which were produced by centrifugal atomization, were used as feedstock material for plasma-spraying. The spherical morphology of the powders allowed for better feeding of fine (<38 μm) powders into the plasma-spray torch. The difference in the as-deposited densities and deposit efficiencies of the two plasma-sprayed powders will be discussed along with the effect of processing parameters on the as-deposited microstructure of the Be-Al-4%Ag. This investigation represents ongoing research to develop and characterize plasma-spraying of beryllium and beryllium-aluminum alloys for magnetic fusion and aerospace applications

Unit thermal performance of atmospheric spray cooling systems

International Nuclear Information System (INIS)

Porter, R.W.; Jain, M.; Chaturvedi, S.K.

1980-01-01

Thermal performance of an open atmospheric spray pond or canal depends on the direct-contact evaporative cooling of an individual spray unit (spray nozzle or module) and the interference caused by local heating and humidification. Droplet parameters may be combined into a dimensionless group, number of transfer units (NTU) or equivalent, whereas large-scale air-vapor dynamics determine interference through the local wet-bulb temperature. Quantity NTU were implied from field experiments for a floating module used in steam-condenser spray canals. Previous data were available for a fixed-pipe nozzle assembly used in spray ponds. Quantity NTU were also predicted using the Ranz-Marshall correlations with the Sauter-mean diameter used as the characteristic length. Good agreement with experiments was shown for diameters of 1--1.1 cm (module) and 1.9 mm

A multi-scalar PDF approach for LES of turbulent spray combustion

Science.gov (United States)

Raman, Venkat; Heye, Colin

2011-11-01

A comprehensive joint-scalar probability density function (PDF) approach is proposed for large eddy simulation (LES) of turbulent spray combustion and tests are conducted to analyze the validity and modeling requirements. The PDF method has the advantage that the chemical source term appears closed but requires models for the small scale mixing process. A stable and consistent numerical algorithm for the LES/PDF approach is presented. To understand the modeling issues in the PDF method, direct numerical simulation of a spray flame at three different fuel droplet Stokes numbers and an equivalent gaseous flame are carried out. Assumptions in closing the subfilter conditional diffusion term in the filtered PDF transport equation are evaluated for various model forms. In addition, the validity of evaporation rate models in high Stokes number flows is analyzed.

Effect of thermal spray processing techniques on the microstructure and properties of Ni-based amorphous coatings

International Nuclear Information System (INIS)

Lee, S.M.; Moon, B.M.; Fleury, E.; Ahn, H.S.; Kim, D.H.; Kim, W.T.; Sordelet, D.J.

2005-01-01

Metallic amorphous materials have been widely developed thanks to the outstanding properties including high chemical stability, mechanical strength, and magnetic properties. However, with the exception of a few compositions, the limiting factor is the critical cooling rate for the formation of the amorphous phase. For many applications, it is only the contact surface properties that are important, thus the use, of coating techniques such as thermal sprayings has several attractive features. In this paper, we present the microstructure of Ni-based amorphous coatings prepared by laser cladding and vacuum plasma spraying. The utilization of plasma spraying to deposit atomized powder enabled the formation of fully amorphous coating, laser cladding resulted in mostly crystallized structures. Glass forming ability and wear properties of the coatings were discussed as a function of the coating microstructure. (orig.)

Plasma spray technology process parameters and applications

International Nuclear Information System (INIS)

Sreekumar, K.P.; Karthikeyan, J.; Ananthapadmanabhan, P.V.; Venkatramani, N.; Chatterjee, U.K.

1991-01-01

The current trend in the structural design philosophy is based on the use of substrate with the necessary mechanical properties and a thin coating to exhibit surface properties. Plasma spray process is a versatile surface coating technique which finds extensive application in meeting advance technologies. This report describes the plasma spray technique and its use in developing coatings for various applications. The spray system is desribed in detail including the different variables such as power input to the torch, gas flow rate, powder properties, powder injection, etc. and their interrelation in deciding the quality of the coating. A brief write-up on the various plasma spray coatings developed for different applications is also included. (author). 15 refs., 15 figs., 2 tabs

Emulsions from Aerosol Sprays

Science.gov (United States)

Hengelmolen; Vincent; Hassall

1997-12-01

An electrostatic emulsification apparatus has been designed for the purpose of studying diffusion from oil droplets which have a mean size in the range of approximately 1.5-3.5 &mgr;m, with standard deviations of 40-50%. The emulsification technique involves the collection of a spray of electrically charged oil droplets onto a rotating water film which is sustained from a reservoir. In this way, emulsions with volume fractions of approximately 10(-3) are produced within several minutes at oil flow rates of around 10(-2) ml min-1. Phase-Doppler anemometry (PDA) was used to assess droplet size distributions for the sprays and emulsions. Results show that the mean emulsion droplet size was smaller than the mean spray droplet size by several orders of magnitude. At flow rates around 10(-2) ml min-1, the spray droplet size distribution was little affected by the applied potential between about -4.20 and -4.65 kV (mean droplet size between approximately 7.6 and 7.8 &mgr;m, with standard deviations of approximately 20%), whereas the mean droplet size of the corresponding emulsion decreased more rapidly with applied potential. Above an applied potential of approximately -4.30 kV, which corresponded to an emulsion droplet size below approximately 2 &mgr;m, the measured volume fraction of the emulsion decreased with respect to the volume fraction as calculated on the basis of total amount of injected oil. Copyright 1997 Academic Press. Copyright 1997Academic Press

Dry sliding wear of Al-Fe-Cr-Mn quasicrystalline phase former alloy obtained by spray forming; Estudo do comportamento ao desgaste de liga Al-Fe-Cr-Mn obtida por conformacao por spray

Energy Technology Data Exchange (ETDEWEB)

Yamasaki, S.M.T.; Rios, C.T.; Botta Filho, W.J.; Bolfarini, C.; Kiminami, C.S. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Gargarella, P.; Mendes, M.A.B., E-mail: marcio.andreato@gmail.co [Universidade Federal de Sao Carlos (PPG-CEMUFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

2010-07-01

Samples from different regions of a spray formed billet of Al{sub 92}Fe{sub 3}Cr{sub 2}Mn{sub 3} quasicrystalline phase former alloy were analyzed and their wear behavior has been studied. The microstructures observed depend on the cooling rate imposed to the material. The border of the billet exhibits a very fine structure with presence of quasicrystalline phase and the base showed a fine structure but without presence of quasicrystalline phase. Dry sliding wear tests were made using three loads and samples of these two different regions. The wear surfaces were analyzed by scanning electron microscopy and X-ray diffraction. Similar wear behavior was observed in the border and the base samples at the same load. The wear mechanism verified is the adhesive and the applied load increases the formation of Al{sub 2}O{sub 3}. These particles can take off the surface and act as abrasive, which can explain the large increase in the wear rate for the samples loaded at 30N.(author)

Numerical heat transfer model for frost protection of citrus fruits by water from a spraying system

Directory of Open Access Journals (Sweden)

Issa Roy J.

2012-01-01

Full Text Available A simplified model is developed to simulate the conditions associated with the protection of fruits from frost damage using water from a spraying system. The model simulates the movement of the solidifying water front on a single fruit, and based on that determines the spray frequency needed for a water film to continuously surround the ice-coated fruit to prevent the fruit temperature from dropping below 0ºC. Simulations are presented for the frost protection of sweet oranges (citrus sinensis. The effect of environmental conditions such as air temperature, air velocity, surface radiation and water film evaporation on the development of the ice layer encasing is considered. Simulations show the effect the encasing ice sheet thickness has on the fruit temperature if water from a spraying system is turned off permanently. Experimental tests are also conducted to determine the change in the thermal properties of citrus sinensis for operating temperatures that range from above freezing to sub-freezing. The results of the experimental tests and the numerical simulations shall lead to a better understanding of fruit protection from frost damage by the application of water from a spraying system.

Concept for a cyclonic spray scrubber as a fission product removal system for filtered containment venting

International Nuclear Information System (INIS)

Lebel, Luke S.; Piro, Markus H.; MacCoy, Reilly; Clouthier, Anthony; Chin, Yu-Shan

2016-01-01

Graphical abstract: - Highlights: • A new cyclonic spray scrubber concept for filtered containment venting is presented. • Mechanistic particle removal model paired with discrete particle CFD simulations. • Calculations predict that very high decontamination factors can be achieved. - Abstract: The application of a cyclonic spray scrubber as a technology for filtered containment venting is proposed in this paper. This study has paired a mechanistic model for the kinetic particle coagulation of with Euler–Lagrange discrete particle simulations in order to predict particle decontamination factors. The continuous phase behavior has been investigated using computational fluid dynamics simulations together with phase Doppler anemometry measurements. Calculations show that spray scrubbing of radionuclide-bearing aerosols could be very effective, and predict that decontamination factors can be in excess of 10 6 for micron sized particles and excess of 10 3 for submicron particles. In the wake of the accident at the Fukushima Daiichi Nuclear Power Plant, filtered containment venting is being viewed as an increasingly important severe accident mitigation technology. Cyclonic spray scrubbing could be implemented as a passive technology for decontaminating containment gases in an emergency prior to their discharge to the atmosphere, and is a novel approach for this application.

Center for Cold Spray Research and Development

Data.gov (United States)

Federal Laboratory Consortium — This is the only DoD facility capable of cold spray research and development, production, and field-repair. It features three stationary cold spray systems used for...

User friendliness, efficiency & spray quality of stirrup pumps versus hand compression pumps for indoor residual spraying.

Science.gov (United States)

Kumar, Vijay; Kesari, Shreekant; Chowdhury, Rajib; Kumar, Sanjiv; Sinha, Gunjan; Hussain, Saddam; Huda, M Mamun; Kroeger, Axel; Das, Pradeep

2013-01-01

Indoor residual spraying (IRS) is a proven tool to reduce visceral leishmaniasis vectors in endemic villages. In India IRS is being done with stirrup pumps, whereas Nepal, Bangladesh, and other countries use compression pumps. The present study was conducted with the objectives to compare the efficiency, cost and user friendliness of stirrup and compression pumps. The study was carried out in Gorigawan village of the Vaishali district in north Bihar and included a total population of 3259 inhabitants in 605 households. Spraying with 50 per cent DDT was done by two teams with 6 persons per team under the supervision of investigators over 5 days with each type of pump (10 days in total using 2 stirrup pumps and 3 compression pumps) by the same sprayers in an alternate way. The spraying technique was observed using an observation check list, the number of houses and room surfaces sprayed was recorded and an interview with sprayers on their satisfaction with the two types of pumps was conducted. On average, 65 houses were covered per day with the compression pump and 56 houses were covered with the stirrup pump. The surface area sprayed per squad per day was higher for the compression pump (4636 m²) than for the stirrup pump (4102 m²). Observation showed that it was easy to maintain the spray swath with the compression pump but very difficult with the stirrup pump. The wastage of insecticide suspension was negligible for the compression pump but high for the stirrup pump. The compression pump was found to be more user friendly due to its lower weight, easier to operate, lower operation cost, higher safety and better efficiency in terms of discharge rate and higher area coverage than the stirrup pump.

Ac conductivity and dielectric spectroscopy studies on tin oxide thin films formed by spray deposition technique

Energy Technology Data Exchange (ETDEWEB)

Barış, Behzad, E-mail: behzadbaris@gmail.com

2014-04-01

Au/tin oxide/n-Si (1 0 0) structure has been created by forming a tin oxide (SnO{sub 2}) on n-type Si by using the spray deposition technique. The ac electrical conductivity (σ{sub ac}) and dielectric properties of the structure have been investigated between 30 kHz and 1 MHz at room temperature. The values of ε', ε″, tanδ, σ{sub ac}, M' and M″ were determined as 1.404, 0.357, 0.253, 1.99×10{sup −7} S/cm, 0.665 and 0.168 for 1 MHz and 6.377, 6.411, 1.005, 1.07×10{sup −7} S/cm, 0.077 and 0.078 for 30 kHz at zero bias, respectively. These changes were attributed to variation of the charge carriers from the interface traps located between semiconductor and metal in the band gap. It is concluded that the values of the ε', ε″ and tanδ increase with decreasing frequency while a decrease is seen in σ{sub ac} and the real (M') and imaginary (M″) components of the electrical modulus. The M″ parameter of the structure has a relaxation peak as a function of frequency for each examined voltage. The relaxation time of M″(τ{sub M″}) varies from 0.053 ns to 0.018 ns with increasing voltage. The variation of Cole–Cole plots of the sample shows that there is one relaxation.

Nanoparticles by spray drying using innovative new technology: the Büchi nano spray dryer B-90.

Science.gov (United States)

Li, Xiang; Anton, Nicolas; Arpagaus, Cordin; Belleteix, Fabrice; Vandamme, Thierry F

2010-10-15

Spray drying technology is widely known and used to transform liquids (solutions, emulsions, suspension, slurries, pastes or even melts) into solid powders. Its main applications are found in the food, chemical and materials industries to enhance ingredient conservation, particle properties, powder handling and storage etc. However, spray drying can also be used for specific applications in the formulation of pharmaceuticals for drug delivery (e.g. particles for pulmonary delivery). Büchi is a reference in the development of spray drying technology, notably for laboratory scale devices. This study presents the Nano Spray Dryer B-90, a revolutionary new sprayer developed by Büchi, use of which can lower the size of the produced dried particles by an order of magnitude attaining submicron sizes. In this paper, results are presented with a panel of five representative polymeric wall materials (arabic gum, whey protein, polyvinyl alcohol, modified starch, and maltodextrin) and the potentials to encapsulate nano-emulsions, or to formulate nano-crystals (e.g. from furosemide) are also shown. Copyright © 2010 Elsevier B.V. All rights reserved.

Processes for forming exoergic structures with the use of a plasma and for producing dense refractory bodies of arbitrary shape therefrom

International Nuclear Information System (INIS)

Holt, J.B.; Kelly, M.D.

1990-01-01

Plasma spraying methods of forming exoergic structures and coatings, as well as exoergic structures produced by such methods, are presented. The methods include the plasma spraying of reactive exoergic materials that are capable of sustaining a combustion synthesis reaction onto a flat substrate or into molds of arbitrary shape and igniting the plasma sprayed materials, either under an inert gas pressure or not, to form refractory materials of varying densities and of varying shapes

[Research about effect of spray drying conditions on hygroscopicity of spray dry powder of gubi compound's water extract and its mechanism].

Science.gov (United States)

Zong, Jie; Shao, Qi; Zhang, Hong-Qing; Pan, Yong-Lan; Zhu, Hua-Xu; Guo, Li-Wei

2014-02-01

To investigate moisture content and hygroscopicity of spray dry powder of Gubi compound's water extract obtained at different spray drying conditions and laying a foundation for spray drying process of Chinese herbal compound preparation. In the paper, on the basis of single-factor experiments, the author choose inlet temperature, liquid density, feed rate, air flow rate as investigated factors. The experimental absorption rate-time curve and scanning electron microscopy results showed that under different spray drying conditions the spray-dried powders have different morphology and different adsorption process. At different spray-dried conditions, the morphology and water content of the powder is different, these differences lead to differences in the adsorption process, at the appropriate inlet temperature and feed rate with a higher sample density and lower air flow rate, in the experimental system the optimum conditions is inlet temperature of 150 degrees C, feed density of 1.05 g x mL(-1), feed rate of 20 mL x min(-1) air flow rate of 30 m3 x h(-1).

Influence of Cold-Sprayed, Warm-Sprayed, and Plasma-Sprayed Layers Deposition on Fatigue Properties of Steel Specimens

Czech Academy of Sciences Publication Activity Database

Čížek, J.; Matejková, M.; Dlouhý, I.; Šiška, Filip; Kay, C.M.; Karthikeyan, J.; Kuroda, S.; Kovařík, O.; Siegl, J.; Loke, K.; Khor, K.A.

2015-01-01

Roč. 24, č. 5 (2015), s. 758-768 ISSN 1059-9630 Institutional support: RVO:68081723 Keywords : Cold spray * Fatigue * Grit-blast Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.568, year: 2015

Structural characterisation of degradation products formed upon di-n-butyl phthalate radiolysis by high-performance liquid chromatography electro-spray tandem mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Tintaru, A.; Charles, L. [Univ Aix Marseille 1, CNRS, Lab Chim Provence Spectrometries Appl Chim Struct, UMR 6264, F-13397 Marseille (France); Univ Aix Marseille 2, CNRS, Lab Chim Provence Spectrometries Appl Chim Struct, UMR 6264, F-13397 Marseille (France); Labed, V. [CEA Marcoule, DTCD SPDE L2ED, F-30207 Bagnols Sur Ceze (France)

2010-07-01

Complete text of publication follows: Structural characterisation of 15 degradation products, formed upon di-n-butyl phthalate (DBP) radiolysis, has been achieved using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) coupling. The dissociation behaviour of protonated DBP was first established to be further used to characterise structural deviation in the degradation products. Based on accurate mass measurements, compounds shown by HPLC-MS analysis were all found to be DBP oxidation products, amongst which various sets of isomers could be distinguished. Collision-induced dissociation experiments performed on each electro-sprayed molecule first allowed unambiguous definition of the location of the additional oxygen atoms; that is, in the alkyl branch or on the aromatic ring. Although location of the oxygen atom in the alkyl branches could not always be precisely determined, relative abundances of some product ions allowed oxygenated functions to be identified

Suppression of Mediterranean fruit fly populations over mountainous areas through aerial phloxine B - protein bait sprays: Regional Medfly programme in Guatemala

International Nuclear Information System (INIS)

McQuate, Grant T.; Peck, Steven L.

2000-01-01

spray. A second spray cycle was begun in December 1997, targeted to start before the annual Mediterranean fruit fly population increase. The sprays were continued until early February 1998, after which a weekly release of sterile Mediterranean fruit flies was started and was planned to continue through mid-June, 1998. Here, we describe the 1997-1998 large area phloxine B protein bait spray programme in southwestern Guatemala. We present the catch results of traps monitored throughout the weekly spray programme, as well as trap catch results from the initial ten weeks of sterile fly release which followed the spray programme. Additionally, we discuss issues which may affect the success of large area suppression programmes which target Mediterranean fruit fly or other tephritid fruit fly species using xanthene dye protein bait sprays

Laser-Based Spatio-Temporal Characterisation of Port Fuel Injection (PFI Sprays

Directory of Open Access Journals (Sweden)

C. T. N. Anand

2010-06-01

Full Text Available In the present work, detailed laser-based diagnostic experiments were conducted to characterise the spray from low pressure 2-hole and 4-hole Port Fuel Injection (PFI injectors. The main objective of the work included obtaining quantitative information of the spatio-temporal spray structure of such low-pressure gasoline sprays. A novel approach involving a combination of techniques such as Mie scattering, Granulometry, and Laser Sheet Dropsizing (LSD was used to study the spray structure. The droplet sizes, distributions with time, Sauter Mean Diameters (SMD, droplet velocities, cone angles and spray tip penetrations of the sprays from the injectors were determined. The spray from these injectors is found to be ‘pencil like’ and not dispersed as in high pressure sprays. The application of the above mentioned techniques provides two-dimensional SMD contours of the entire spray at different instants of time, with reasonable accuracy.

Simulation of oblique evaporating diesel sprays, and comparison with empirical correlations and simulated straight sprays

International Nuclear Information System (INIS)

Chaudhry, I.A.; Mirza, M.R.; Rashid, M.J.

2010-01-01

The innovation in software analysis and various available programming facilities have urged the designers at various levels to do indispensable calculations for engine flows. Presently, the 3-D analysis approach is under practice to do simulations for various parameters involving engine operations using various soft wares, 'Fluent' being the trendiest at the moment for CFD modeling. The present work involves CFD modeling of diesel fuel sprays at a specified angle with cylinder axis. Fuel spray modeling includes sub-models for aerodynamic drag, droplet oscillation and distortion, turbulence effects, droplet breakup, evaporation, and droplet collision and coalescence. The data available from existing published work is used to model the fuel spray and the subsequent simulation results are compared to experimental results to test validity of the proposed models. (author)

Aerial electrostatic spray deposition and canopy penetration in cotton

Science.gov (United States)

Spray deposition on abaxial and adaxial leaf surfaces along with canopy penetration are essential for insect control and foliage defoliation in cotton production agriculture. Researchers have reported that electrostatically charged sprays have increased spray deposit onto these surfaces under widel...

Calculations for reproducible autologous skin cell-spray grafting.

Science.gov (United States)

Esteban-Vives, Roger; Young, Matthew T; Zhu, Toby; Beiriger, Justin; Pekor, Chris; Ziembicki, Jenny; Corcos, Alain; Rubin, Peter; Gerlach, Jörg C

2016-12-01

Non-cultured, autologous cell-spray grafting is an alternative to mesh grafting for larger partial- and deep partial-thickness burn wounds. The treatment uses a suspension of isolated cells, from a patient's donor site skin tissue, and cell-spray deposition onto the wound that facilitates re-epithelialization. Existing protocols for therapeutic autologous skin cell isolation and cell-spray grafting have defined the donor site area to treatment area ratio of 1:80, substantially exceeding the coverage of conventional mesh grafting. However, ratios of 1:100 are possible by maximizing the wound treatment area with harvested cells from a given donor site skin tissue according to a given burn area. Although cell isolation methods are very well described in the literature, a rational approach addressing critical aspects of these techniques are of interest in planning clinical study protocols. We considered in an experimental study the cell yield as a function of the donor site skin tissue, the cell density for spray grafting, the liquid spray volume, the sprayed distribution area, and the percentage of surface coverage. The experimental data was then used for the development of constants and mathematical equations to give a rationale for the cell isolation and cell-spray grafting processes and in planning for clinical studies. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Flare spray on the solar disk observed on June 2, 1974 and accompanied radio bursts

Energy Technology Data Exchange (ETDEWEB)

Maeda, K [Hyogo Coll. of Medicine (Japan). Dept. of Physics; Tamenaga, T; Kubota, J

1978-09-01

The time variation of H..beta.. absorption spectrum due to spray matter is consistent with that expected from the explosive ejection model that all of the matter is ejected with various initial upward velocities during a short interval and uniformly decelerated due to gravity along a straight path. The velocity distribution in the spray is determined by this model. It is found that an impulsive microwave burst and intensive type III bursts occurred prior to the spray ejection (about 1 min). The traveling direction of the spray matter agrees with that of energetic electrons; the latter is estimated from the radioheliograph data on the basis of the plasma hypothesis and an assumed electron density distribution in the corona. From the Stark broadening of H..beta.. line and the enhancement of continuous emission, the electron density and effective thickness of the hydrogen emitting region shortly after the maximum phase of the flare are estimated to be 1.6 x 10/sup 13/ cm/sup -3/ and 8.7 x 10/sup 7/ cm, respectively. A study of turbulent velocities of absorption lines originating in different levels of the flare shows that the disturbances from the flare attained to the formation depth of FeI No. 318 lines but did not reach the photospheric level.

A Numerical Comparison of Spray Combustion between Raw and Water-in-Oil Emulsified Fuel

Directory of Open Access Journals (Sweden)

D. Tarlet

2010-03-01

Full Text Available Heavy fuel-oils, used engine oils and animal fat can be used as dense, viscous combustibles within industrial boilers. Burning these combustibles in the form of an emulsion with water enables to decrease the flame length and the formation of carbonaceous residue, in comparison with raw combustibles. These effects are due to the secondary atomization among the spray, which is a consequence of the micro-explosion phenomenon. This phenomenon acts in a single emulsion droplet by the fast (< 0.1 ms vaporization of the inside water droplets, leading to complete disintegration of the whole emulsion droplet. First, the present work demonstrates a model of spray combustion of raw fuel. Secondly, the spray combustion of water-in-oil emulsified fuel is exposed to the same burning conditions, taking into account the micro-explosion phenomenon. Finally, the comparison between the results with and without second atomization shows some similar qualitative tendencies with experimental measurements from the literature.

Spray drying of liquid radioactive wastes

International Nuclear Information System (INIS)

Abrams, R.F.; Monat, J.P.

1984-01-01

Full scale performance tests of a Koch spray dryer were conducted on simulated liquid radioactive waste streams. The liquid feeds simulated the solutions that result from radwaste incineration of DAW an ion exchange resins, as well as evaporator bottoms. The integration of the spray dryer into a complete system is discussed

Structure and property evaluation of a vacuum plasma sprayed nanostructured tungsten-hafnium carbide bulk composite

International Nuclear Information System (INIS)

Rea, K.E.; Viswanathan, V.; Kruize, A.; Hosson, J.Th.M. de; O'Dell, S.; McKechnie, T.; Rajagopalan, S.; Vaidyanathan, R.; Seal, S.

2008-01-01

Vacuum plasma spray (VPS) forming of tungsten-based metal matrix nanocomposites (MMCs) has shown to be a cost effective and time saving method for the formation of bulk monolithic nanostructured thermo-mechanical components. Spray drying of powder feedstock appears to have a significant effect on the improved mechanical properties of the bulk nanocomposite. The reported elastic modulus of the nanocomposite nearly doubles due to the presence of HfC nano particulates in the W matrix. High resolution transmission electron microscopy (HRTEM) revealed the retention of nanostructures at the select process conditions and is correlated with the enhanced mechanical properties of the nanocomposite

Cold spray NDE for porosity and other process anomalies

Science.gov (United States)

Glass, S. W.; Larche, M. R.; Prowant, M. S.; Suter, J. D.; Lareau, J. P.; Jiang, X.; Ross, K. A.

2018-04-01

This paper describes a technology review of nondestructive evaluation (NDE) methods that can be applied to cold spray coatings. Cold spray is a process for depositing metal powder at high velocity so that it bonds to the substrate metal without significant heating that would be likely to cause additional residual tensile stresses. Coatings in the range from millimeters to centimeters are possible at relatively high deposition rates. Cold spray coatings that may be used for hydroelectric components that are subject to erosion, corrosion, wear, and cavitation damage are of interest. The topic of cold spray NDE is treated generally, however, but may be considered applicable to virtually any cold spray application except where there are constraints of the hydroelectric component application that bear special consideration. Optical profilometry, eddy current, ultrasound, and hardness tests are shown for one set of good, fair, and poor nickel-chrome (NiCr) on 304 stainless steel (304SS) cold spray samples to demonstrate inspection possibilities. The primary indicator of cold spray quality is the cold spray porosity that is most directly measured with witness-sample destructive examinations (DE)—mostly photo-micrographs. These DE-generated porosity values are correlated with optical profilometry, eddy current, ultrasound, and hardness test NDE methods to infer the porosity and other information of interest. These parameters of interest primarily include: • Porosity primarily caused by improper process conditions (temperature, gas velocity, spray standoff, spray angle, powder size, condition, surface cleanliness, surface oxide, etc.) • Presence/absence of the cold spray coating including possible over-sprayed voids • Coating thicknessOptical profilometry measurements of surface roughness trended with porosity plus, if compared with a reference measurement or reference drawing, would provide information on the coating thickness. Ultrasound could provide similar

Preparation and in vivo absorption evaluation of spray dried powders containing salmon calcitonin loaded chitosan nanoparticles for pulmonary delivery

Science.gov (United States)

Sinsuebpol, Chutima; Chatchawalsaisin, Jittima; Kulvanich, Poj

2013-01-01

Purpose The aim of the present study was to prepare inhalable co-spray dried powders of salmon calcitonin loaded chitosan nanoparticles (sCT-CS-NPs) with mannitol and investigate pulmonary absorption in rats. Methods The sCT-CS-NPs were prepared by the ionic gelation method using sodium tripolyphosphate (TPP) as a cross-linking polyion. Inhalable dry powders were obtained by co-spray drying aqueous dispersion of sCT-CS-NPs and mannitol. sCT-CS-NPs co-spray dried powders were characterized with respect to morphology, particle size, powder density, aerodynamic diameter, protein integrity, in vitro release of sCT, and aerosolization. The plasmatic sCT levels following intratracheal administration of sCT-CS-NPs spray dried powders to the rats was also determined. Results sCT-CS-NPs were able to be incorporated into mannitol forming inhalable microparticles by the spray drying process. The sCT-CS-NPs/mannitol ratios and spray drying process affected the properties of the microparticles obtained. The conformation of the secondary structures of sCTs was affected by both mannitol content and spray dry inlet temperature. The sCT-CS-NPs were recovered after reconstitution of spray dried powders in an aqueous medium. The sCT release profile from spray dried powders was similar to that from sCT-CS-NPs. In vitro inhalation parameters measured by the Andersen cascade impactor indicated sCT-CS-NPs spray dried powders having promising aerodynamic properties for deposition in the deep lung. Determination of the plasmatic sCT levels following intratracheal administration to rats revealed that the inhalable sCT-CS NPs spray dried powders provided higher protein absorption compared to native sCT powders. Conclusion The sCT-CS-NPs with mannitol based spray dried powders were prepared to have appropriate aerodynamic properties for pulmonary delivery. The developed system was able to deliver sCT via a pulmonary route into the systemic circulation. PMID:24039397

Regimes of spray formation in gas-centered swirl coaxial atomizers

Energy Technology Data Exchange (ETDEWEB)

Sivakumar, D.; Kulkarni, V. [Indian Institute of Science, Department of Aerospace Engineering, Bangalore (India)

2011-09-15

Spray formation in ambient atmosphere from gas-centered swirl coaxial atomizers is described by carrying out experiments in a spray test facility. The atomizer discharges a circular air jet and an axisymmetric swirling water sheet from its coaxially arranged inner and outer orifices. A high-speed digital imaging system along with a backlight illumination arrangement is employed to record the details of liquid sheet breakup and spray development. Spray regimes exhibiting different sheet breakup mechanisms are identified and their characteristic features presented. The identified spray regimes are wave-assisted sheet breakup, perforated sheet breakup, segmented sheet breakup, and pulsation spray regime. In the regime of wave-assisted sheet breakup, the sheet breakup shows features similar to the breakup of two-dimensional planar air-blasted liquid sheets. At high air-to-liquid momentum ratios, the interaction process between the axisymmetric swirling liquid sheet and the circular air jet develops spray processes which are more specific to the atomizer studied here. The spray exhibits a periodic ejection of liquid masses whose features are dominantly controlled by the central air jet. (orig.)

Holodiscus (K. Koch) Maxim.: ocean-spray

Science.gov (United States)

Nancy L. Shaw; Emerenciana G. Hurd; Peter F. Stickney

2008-01-01

Holodiscus is a taxonomically complex genus including about 6 species of western North America and northern South America (Hitchcock and others 1961; Ley 1943). The 2 generally recognized North American species (table 1) - creambush ocean-spray and gland ocean-spray - are deciduous, multistemmed shrubs with simple, alternate, deciduous, toothed to shallowly lobed,...

Autoignition of liquid-fuel sprays

International Nuclear Information System (INIS)

Mitzutani, Y.

1991-01-01

This paper reports on the published autoignition data of liquid fuel sprays that were extensively reviewed by classifying them into the following three categories; liquid fuels injected into a stagnant hot atmosphere, liquid fuels injected into a hot air stream (vitiated or unvitiated), and droplet cluster ignited behind an incident or reflected shock. Comparison of these data with the counterparts of gaseous fuels and single droplets revealed that it was the ignition process dominated by droplet evaporation whereas it was the one dominated by chemical kinetics. It consisted, depending on the experimental condition, of the data and of the ignition process dominated by the shattering of droplets by an incident shock. In addition, theoretical works on spray autoignition were reviewed, pointing out that they were still far from universally predicting the ignition delays of liquid fuel sprays

Differentially pumped spray deposition as a rapid screening tool for organic and perovskite solar cells

Science.gov (United States)

Jung, Yen-Sook; Hwang, Kyeongil; Scholes, Fiona H.; Watkins, Scott E.; Kim, Dong-Yu; Vak, Doojin

2016-01-01

We report a spray deposition technique as a screening tool for solution processed solar cells. A dual-feed spray nozzle is introduced to deposit donor and acceptor materials separately and to form blended films on substrates in situ. Using a differential pump system with a motorised spray nozzle, the effect of film thickness, solution flow rates and the blend ratio of donor and acceptor materials on device performance can be found in a single experiment. Using this method, polymer solar cells based on poly(3-hexylthiophene) (P3HT):(6,6)-phenyl C61 butyric acid methyl ester (PC61BM) are fabricated with numerous combinations of thicknesses and blend ratios. Results obtained from this technique show that the optimum ratio of materials is consistent with previously reported values confirming this technique is a very useful and effective screening method. This high throughput screening method is also used in a single-feed configuration. In the single-feed mode, methylammonium iodide solution is deposited on lead iodide films to create a photoactive layer of perovskite solar cells. Devices featuring a perovskite layer fabricated by this spray process demonstrated a power conversion efficiencies of up to 7.9%. PMID:26853266

Differentially pumped spray deposition as a rapid screening tool for organic and perovskite solar cells.

Science.gov (United States)

Jung, Yen-Sook; Hwang, Kyeongil; Scholes, Fiona H; Watkins, Scott E; Kim, Dong-Yu; Vak, Doojin

2016-02-08

We report a spray deposition technique as a screening tool for solution processed solar cells. A dual-feed spray nozzle is introduced to deposit donor and acceptor materials separately and to form blended films on substrates in situ. Using a differential pump system with a motorised spray nozzle, the effect of film thickness, solution flow rates and the blend ratio of donor and acceptor materials on device performance can be found in a single experiment. Using this method, polymer solar cells based on poly(3-hexylthiophene) (P3HT):(6,6)-phenyl C61 butyric acid methyl ester (PC61BM) are fabricated with numerous combinations of thicknesses and blend ratios. Results obtained from this technique show that the optimum ratio of materials is consistent with previously reported values confirming this technique is a very useful and effective screening method. This high throughput screening method is also used in a single-feed configuration. In the single-feed mode, methylammonium iodide solution is deposited on lead iodide films to create a photoactive layer of perovskite solar cells. Devices featuring a perovskite layer fabricated by this spray process demonstrated a power conversion efficiencies of up to 7.9%.

The Influence of Spray Parameters on the Characteristics of Hydroxyapatite In-Flight Particles, Splats and Coatings by Micro-plasma Spraying

Science.gov (United States)

Liu, Xiao-mei; He, Ding-yong; Wang, Yi-ming; Zhou, Zheng; Wang, Guo-hong; Tan, Zhen; Wang, Zeng-jie

2018-04-01

Hydroxyapatite (HA) is one of the most important bioceramic materials used in medical implants. The structure of HA coatings is closely related to their manufacturing process. In the present study, HA coatings were deposited on Ti-6Al-4V substrate by micro-plasma spraying. Results show that three distinct HA coatings could be obtained by changing the spraying power from 0.5 to 1.0 kW and spraying stand-off distance from 60 to 110 mm: (1) high crystallinity (93.3%) coatings with porous structure, (2) high crystallinity coatings (86%) with columnar structure, (3) higher amorphous calcium phosphate (ACP, 50%) coatings with dense structure. The in-flight particles melting state and splat topography was analyzed to better understand the formation mechanism of three distinct HA coatings. Results show that HA coatings sprayed at low spraying power and short stand-off distance exhibit high crystallinity and porosity is attributed to the presence of partially melted particles. High crystallinity HA coatings with (002) crystallographic texture could be deposited due to the complete melting of the in-flight particles and low cooling rate of the disk shape splats under higher spraying power and shorter SOD. However, splashed shape splats with relative high cooling can be provided by increasing SOD, which leads to the formation of ACP.

Efficient spray-coated colloidal quantum dot solar cells

KAUST Repository

Kramer, Illan J.

2014-11-10

(Figure Presented). A colloidal quantum dot solar cell is fabricated by spray-coating under ambient conditions. By developing a room-temperature spray-coating technique and implementing a fully automated process with near monolayer control - an approach termed as sprayLD - an electronic defect is eliminated resulting in solar cell performance and statistical distribution superior to prior batch-processed methods along with a hero performance of 8.1%.

Efficient spray-coated colloidal quantum dot solar cells

KAUST Repository

Kramer, Illan J.; Minor, James C.; Moreno-Bautista, Gabriel; Rollny, Lisa R.; Kanjanaboos, Pongsakorn; Kopilovic, Damir; Thon, Susanna; Carey, Graham H.; Chou, Kang Wei; Zhitomirsky, David; Amassian, Aram; Sargent, E. H.

2014-01-01

(Figure Presented). A colloidal quantum dot solar cell is fabricated by spray-coating under ambient conditions. By developing a room-temperature spray-coating technique and implementing a fully automated process with near monolayer control - an approach termed as sprayLD - an electronic defect is eliminated resulting in solar cell performance and statistical distribution superior to prior batch-processed methods along with a hero performance of 8.1%.

Comparative examination of the microstructure and high temperature oxidation performance of NiCrBSi flame sprayed and pack cementation coatings

Science.gov (United States)

Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Skolianos, S.; Chrissafis, K.; Stergioudis, G.

2009-01-01

Coatings formed from NiCrBSi powder were deposited by thermal spray and pack cementation processes on low carbon steel. The microstructure and morphology of the coatings were studied by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Flame sprayed coatings exhibited high porosity and were mechanically bonded to the substrate while pack cementation coatings were more compact and chemically bonded to the substrate. The microhardness and the high temperature oxidation resistance of the coated samples were evaluated by a Vickers microhardness tester and by thermogravimetric measurements (TG), respectively. Pack cementation coatings showed higher hardness and were more protective to high temperature environments than the flame sprayed coatings.

Shear Strengthening of RC Beams Using Sprayed Glass Fiber Reinforced Polymer

Directory of Open Access Journals (Sweden)

Sayed Mohamad Soleimani

2012-01-01

Full Text Available The effectiveness of externally bonded sprayed glass fiber reinforced polymer (Sprayed GFRP in shear strengthening of RC beams under quasi-static loading is investigated. Different techniques were utilized to enhance the bond between concrete and Sprayed GFRP, involving the use of through bolts and nuts paired with concrete surface preparation through sandblasting and through the use of a pneumatic chisel prior to Sprayed GFRP application. It was found that roughening the concrete surface using a pneumatic chisel and using through bolts and nuts were the most effective techniques. Also, Sprayed GFRP applied on 3 sides (U-shaped was found to be more effective than 2-sided Sprayed GFRP in shear strengthening. Sprayed GFRP increased the shear load-carrying capacity and energy absorption capacities of RC beams. It was found that the load-carrying capacity of strengthened RC beams was related to an effective strain of applied Sprayed GFRP. This strain was related to Sprayed GFRP configuration and the technique used to enhance the concrete-FRP bond. Finally, an equation was proposed to calculate the contribution of Sprayed GFRP in the shear strength of an RC beam.

Quantitative Assessment of Spray Deposition with Water-Sensitive Paper

Science.gov (United States)

Spray droplets, discharged from the lower six nozzles of an airblast sprayer, were sampled on pairs of absorbent filter and water-sensitive papers at nine distances from sprayer. Spray deposition on filter targets were measured by fluorometry and spray distribution on WSP targets were assessed by t...

X-ray vision of fuel sprays

International Nuclear Information System (INIS)

Wang, J.

2005-01-01

With brilliant synchrotron X-ray sources, microsecond time-resolved synchrotron X-ray radiography and tomography have been used to elucidate the detailed three-dimensional structure and dynamics of high-pressure high-speed fuel sprays in the near-nozzle region. The measurement allows quantitative determination of the fuel distribution in the optically impenetrable region owing to the multiple scattering of visible light by small atomized fuel droplets surrounding the jet. X-radiographs of the jet-induced shock waves prove that the fuel jets become supersonic under appropriate injection conditions and that the quantitative analysis of the thermodynamic properties of the shock waves can also be derived from the most direct measurement. In other situations where extremely axial-asymmetric sprays are encountered, mass deconvolution and cross-sectional fuel distribution models can be computed based on the monochromatic and time-resolved X-radiographic images collected from various rotational orientations of the sprays. Such quantitative analysis reveals the never-before-reported characteristics and most detailed near-nozzle mass distribution of highly transient fuel sprays

A comparison between spray drying and spray freeze drying to produce an influenza subunit vaccine powder for inhalation

NARCIS (Netherlands)

Saluja, V.; Amorij, J-P.; Kapteyn, J. C.; de Boer, A. H.; Frijlink, H. W.; Hinrichs, W. L. J.

2010-01-01

The aim of this study was to investigate two different processes to produce a stable influenza subunit vaccine powder for pulmonary immunization i.e. spray drying (SD) and spray freeze drying (SFD). The formulations were analyzed by proteolytic assay, single radial immunodiffusion assay (SRID),

High temperature tribological properties of plasma-sprayed metallic coatings containing ceramic particles

International Nuclear Information System (INIS)

Dallaire, S.; Legoux, J.G.

1995-01-01

For sealing a moving metal component with a dense silica-based ceramic pre-heated at 800 C, coatings with a low coefficient of friction and moderate wear loss are required. As reported previously, plasma-sprayed coatings containing solid lubricants could reduce sliding wear in high-temperature applications. Plasma-sprayed metal-based coatings containing ceramic particles have been considered for high temperature sealing. Selected metal powders (NiCoCrAlY, CuNi, CuNiIn, Ag, Cu) and ceramic particles (boron nitride, Zeta-B ceramic) were agglomerated to form suitable spray powders. Plasma-sprayed composite coatings and reference materials were tested in a modified pin-on-disc apparatus in which the stationary disc consisted of a dense silica-based ceramic piece initially heated at 800 C and allowed to cool down during tests. The influence of single exposure and repeated contacts with a dense silica-based ceramic material pre-heated to 800 C on the coefficient of friction, wear loss and damage to the ceramic piece was evaluated. Being submitted to a single exposure at high temperature, coatings containing malleable metals such as indium, silver and copper performed well. The outstanding tribological characteristics of the copper-Zeta-B ceramic coating was attributed to the formation of a glazed layer on the surface of this coating which lasted over exposures to high temperature. This glazed layer, composed of fine oxidation products, provided a smooth and polished surface and helped maintaining the coefficient of friction low

Formulation and Development of Metered Dose Inhalations of Salbutamol in Solution Form

Science.gov (United States)

Khale, Anubha; Bajaj, Amrita

2011-01-01

In the present study attempts were made to prepare metered dose inhalation of salbutamol in solution form and compared it with the marketed metered dose inhalation in suspension form. Solution form of the drug was found better than marketed suspension formulation with respect to homogeneity and content uniformity. Propellant blend P-11 and P-12 in the proportion 30:70 was selected as it gave optimum vapour pressure. Surfactant oleic acid in concentration 10 mg per can was selected as it gave best results with clarity, spray pattern, vapour pressure, content per spray and rate of evaporation. Ethyl alcohol 2 ml per can was used as a cosolvent to give a clear solution, optimum vapour pressure, maximum content per spray and fair rate of evaporation. The selected formulation was subjected to the physico-chemical evaluation tests as per the standard pharmacopoeial procedures and the characteristics of the formulations were further compared with a conventional marketed formulation. In vitro study reveled the net respirable fraction was better than marketed preparation. PMID:22923867

Spot Spraying Reduces Herbicide Concentrations in Runoff.

Science.gov (United States)

Melland, Alice R; Silburn, D Mark; McHugh, Allen D; Fillols, Emilie; Rojas-Ponce, Samuel; Baillie, Craig; Lewis, Stephen

2016-05-25

Rainfall simulator trials were conducted on sugar cane paddocks across dry-tropical and subtropical Queensland, Australia, to examine the potential for spot spraying to reduce herbicide losses in runoff. Recommended rates of the herbicides glyphosate, 2,4-D, fluoroxypyr, atrazine, and diuron were sprayed onto 0, 20, 40, 50, 70, or 100% of the area of runoff plots. Simulated rainfall was applied 2 days after spraying to induce runoff at one plant cane and three ratoon crop sites. Over 50% of all herbicides were transported in the dissolved phase of runoff, regardless of the herbicide's sediment-water partition coefficient. For most sites and herbicides, runoff herbicide concentrations decreased with decreasing spray coverage and with decreasing herbicide load in the soil and cane residues. Importantly, sites with higher infiltration prior to runoff and lower total runoff had lower runoff herbicide concentrations.

Ceramic Materials Selection of Fuel Crucibles based on Plasma Spray Coating for SFR

Energy Technology Data Exchange (ETDEWEB)

Song, Hoon; Kim, Jonghwan; Kim, Hyungtae; Ko, Youngmo; Woo, Yoonmyung; Oh, Seokjin; Kim, Kihwan; Lee, Chanbock [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-07-01

The plasma-sprayed coating can provide the crucible with a denser, more friable coating layer, compared with the more friable coating layer formed by slurry-coating, which was used to prevent the interaction between melt and crucibles. Plasma-sprayed coatings are consolidated by mechanical interlocking of the molten particles impacting on the substrate and are dense by the heat applied by the plasma. The increased coating density is advantageous because it should not require frequent re coating and U-Zr melt penetration through the protective layer is more difficult in a dense coating than in a porous coating. In this study, we used Vacuum Plasma Spray method to investigate permanent coatings for re-usable crucibles for melting and casting of metallic fuel onto niobium substrates. Niobium was selected as a substrate because of its refractory nature and the coefficient of thermal expansion is similar to that of many of the candidate materials. After the HfC, ZrC, TiC, TaC, Y{sub 2}O{sub 3}, and 8% YSZ coatings were applied the resulting microstructure and chemical compositions was characterized to find the optimum process conditions for coating. Thermal plasma-sprayed coatings of refractory materials can be applied to develop a re-usable crucible coating for metallic fuel, such as the U-Zr alloy proposed for sodium cooled fast reactors.

Salivary pH after a glucose rinse: effect of a new mucoadhesive spray (Cariex) based on sodium bicarbonate and xylitol.

Science.gov (United States)

Abbate, G M; Levrini, L; Caria, M P

2014-01-01

This study evaluated whether sodium bicarbonate applied on the oral mucosa through a new mucoadhesive spray (Cariex) could control a drop in salivary pH after a glucose rinse, and therefore enhance the buffering potential of saliva. A sample of 50 healthy adults was selected. At day 1, the measurement of salivary pH was performed in the lower fornix in correspondence with the lower molars. Each subject rinsed with 10 ml of a 10% glucose solution and then pH was monitored continually for 40 minutes. At day 2, the same experimental procedure was repeated and three shots of the spray were administered on the oral mucosa. The tested spray is composed of sodium bicarbonate, xylitol, and excipients. Without the mucoadhesive spray, salivary pH became significantly lower following the glucose rinse (p pH remained lower than 6.0 was reduced statistically significantly (p salivary pH was observed for the 40 minutes in which the pH recording was performed. Conclusions: The use of a sodium bicarbonate spray on the mucosa was shown to control the lowering of salivary pH following carbohydrate consumption, and might therefore add to the prevention of caries and dental erosion.