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The microstructure and properties of TZP ceramics fabricated from spray dried powder differing in granule morphology and deformability are determined.The effects of the feed slurry solids content on the granule character are discussed.The lower solid content results in hard and tough ‘donut’ shaped granules that resist deformation during compaction.The microphotograph shows that relatively large intergranular pores formed by incomplete deformation of granules persist during sintering and are the major strength limiting defects in fired material.Sintered material produced from uniform and deformable granules has a homogeneous microstructure and relatively high mean strength.

Silicon/flake graphite/carbon anode materials prepared with different dispersants by spray-drying method for lithium ion batteries

Silicon/flake graphite/carbon （Si/FG/C） composites were synthesized with different dispersants via spray drying and subsequent pyrolysis, and effects of dispersants on the characteristics of the composites were investigated. The structure and properties of the composites were determined by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurements. The results show that samples have silicon/flake graphite/amorphous carbon composite structure, good spherical appearances, and better electrochemical performance than pure nano-Si and FG/C composites. Compared with the Si/FG/C composite using washing powder as dispersant, the Si/FG/C composite using sodium dodecyl benzene sulfonate （SDBS） as dispersant has better electrochemical performance with a reversible capacity of 602.68 mA·h/g, and a capacity retention ratio of 91.58 % after 20 cycles.

Synthesis of porous nano/micro structured LiFePO_4/C cathode materials for lithium-ion batteries by spray-drying method

In order to enhance electrochemical properties of LiFePO4 （LFP） cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The results show that the spherical precursors with the sizes of 0.5-5 μm can be completely converted to LFP/C when the calcination temperature is higher than 500 ℃. The LFP/C microspheres obtained at calcination temperature of 700 ℃ are composed of numerous particles with sizes of -20 nm, and have well-developed interconnected pore structure and large specific surface area of 28.77 mE/g. The specific discharge capacities of the LFP/C obtained at 700 ℃ are 162.43, 154.35 and 144.03 mA.h/g at 0.5C, 1C and 2C, respectively. Meanwhile, the capacity retentions can reach up to 100% after 50 cycles. The improved electrochemical properties of the materials are ascribed to a small Li＋ diffusion resistance and special structure of LFP/C microspheres.

Spray Evaporation of Different Liquids in a Drying Chamber--Effect on Flow, Heat and Mass Transfer Performances

Almost without exception literature data and modeling effort are understandably devoted to water as the sprayed liquid since it constitutes the most common liquid used in spray drying applications. In selected applications, however, the liquid making up the solution or suspension may not be water. The objective of this work is to examine the differences in flow patterns, thermal behavior and drying rates caused by different liquids having different thermo-physical properties spray into a spray dryer using a computational fluid dynamic model.Numerical experiments were carried out for water (base case), ethyl alcohol and isopropyl alcohol-the latter two as model non-aqueous liquids. The chamber geometry was cylinder type with a co-current axial pressure nozzle and also an axial central exit so that the configuration is two dimensional and axi-symmetric. It is shown that the liquid properties can have major influence on the thermal field, droplet trajectories, residence times and overall evaporation capacity when all parameters of the problem are held fixed. Deviations from the single phase turbulent airflow in the same chamber without spray are different for the three liquids examined.

Synthesis and Characterization of Y_ (0.9-x)Gd_xEu_(0.1)BO_3 Phosphors by Spray Drying Process

Y 0.9-xGd xEu 0.1BO 3 phosphors were synthesized by spray drying (SD) method, and the results were compared with those by conventional solid state (SS) and citrate gel (CG) methods. The PL intensity of phosphors increases with the increase of x value in Y 0.9-xGd xEu 0.1BO 3 (prepared by SD) due to an energy migration process like Gd 3+-(Gd 3+) n-Eu 3+ occurred in the material. Compared with the latter two methods, the phosphor particles prepared by spray drying method have a better morphology, such as homogeneous size (about 1～3 μm) with spherical shape and smooth surface. Furthermore, the spray drying-derived phosphors have higher photoluminescence (PL) intensity than those by citrate gel method, but still a little lower than those by the solid state method.

Preparation, Characterization and Drug-Release Behaviors of Crosslinked Chitosan/Attapulgite Hybrid Microspheres by a Facile Spray-Drying Technique

A series of chitosan/attapulgite (CTS/APT) hybrid microspheres were prepared by a facile spray-drying technique. The developed hybrid microspheres were characterized by Fourier transform infrared spectra (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and the zeta potential. The encapsulation efficiency and in vitro controlled release properties of the microspheres for drug were evaluated using diclofenac sodium (DS) as a model drug. Results indicated that the introduction of APT into crosslinked CTS microspheres can achieve narrow size distribution and make them more uniform. The isoelectric point of the microspheres increased from 8.14 to 9.18 with increasing the content of APT to 10 wt.%. DS loaded in hybrid microspheres is hardly released in simulated gastric fluid, but quickly released in simulated intestinal fluid. The electrostatic interaction between hybrid microspheres and DS can improve the encapsulation efficiency and controlled release behavior of CTS/APT microspheres, and the release mechanism fits Fickian diffusion.

Structure-dependent re-dispersibility of graphene oxide powders prepared by fast spray drying

The graphene oxide powder(GOP)obtained from the spray drying process often exhibits poor redispersibility which is considered due to the partial reduction of GO sheets.The reduction of drying temperature can effectively increase the redispersibility of GOP,but result in a decreased drying efficiency.Herein,we found that the redispersibility of GOP is strongly affected by its microstructure,which is determined by the feed concentration.With the increase of feed concentration,the GO nanosheet assembly varies from the disordered stacking to relatively oriented assembly,making the morphology of the GOP transform from balllike(the most crumpled one)to flakelike(the least crumpled one),and the 0.8 mgml 1 is the threshold concentration for the morphology,structure,and redispersibility change.Once the feed concentration reaches 0.8 mg ml 1,the appearance of the nematic phase in droplet ensures the relatively oriented assembly of GO sheets to form the layered structure with a low crumpling degree,which greatly improves the polar parts surface tension of the solid GOP,making the GOP easier to form hydrogen bonding with water during the redispersion process,thus stabilizing dispersion.This work provides useful information for understanding the relationships between the morphology,microstructure,and final redispersibility of GOPs.

A General Strategy for Efficiently Constructing Multifunctional Cluster Fillers Using a Three-Fluid Nozzle Spray Drying Technique for Dental Restoration

Multifunctional fillers are greatly required for dental resin composites(DRCs).In this work,a spray dryer with a three-fluid nozzle was applied for the first time to construct high-performance complex nanoparticle clusters(CNCs)consisting of different functional nanofillers for dental restoration.The application of a three-fluid nozzle can effectively avoid the aggregation of different nanoparticles with opposite zeta potentials before the spray drying process in order to construct regularly shaped CNCs.For a SiO_(2)–ZrO_(2) binary system,the SiO_(2)–ZrO_(2) CNCs constructed using a three-fluid nozzle maintained their excellent mechanical properties((133.3±4.7)MPa,(8.8±0.5)GPa,(371.1±13.3)MPa,and(64.5±0.7)HV for flexural strength,flexural modulus,compressive strength,and hardness of DRCs,respectively),despite the introduction of ZrO_(2) nanoparticles,whereas their counterparts constructed using a two-fluid nozzle showed significantly decreased mechanical properties.Furthermore,heat treatment of the SiO_(2)-ZrO_(2) CNCs significantly improved the mechanical properties and radiopacity of the DRCs.The DRCs containing over 10%mass fraction ZrO_(2) nanoparticles can meet the requirement for radiopaque fillers.More importantly,this method can be expanded to ternary or quaternary systems.DRCs filled with SiO_(2)-ZrO_(2)-ZnO CNCs with a ratio of 56:10:4 displayed high antibacterial activity(antibacterial ratio>99%)in addition to excellent mechanical properties and radiopacity.Thus,the three-fluid nozzle spray drying technique holds great potential for the efficient construction of multifunctional cluster fillers for DRCs.

Microwave Sintering of W-15Cu Ultrafine Composite Powder Prepared by Spray Drying & Calcining-continuous Reduction Technology

The effects of microwave sintering and conventional H2 sintering on the microstructure and properties of W-15Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying ＆ calcining-continuous reduction technology were investigated. In comparison to the conventional HE sintering processing, microwave sintering to W-15Cu can be achieved at lower sintering temperature and shorter sintering time. Furthermore, higher performances in microwave sintered compacts were obtained, but high microwave sintering temperature or long microwave sintering time could result in coarser microstructures.

Survival of encapsulated probiotics through spray drying and non-refrigerated storage for animal feeds application

The objective of this study is to verify potential of various types of microorganisms during spray drying and non-refrigerated storage that can be enhanced substantially by selecting suitable protective colloids. Four selected probiotics tested are Lactbacillus plantarum B13 and B18, which are the bacteria probiotics and Kluyveromyces lactis and Saccharomyces blouradii, non-bacteria probiotics. Two levels of experiment occur starting with formulation study of encapsulation agent followed by the viability study of different probiotics after spray dry and two weeks nonrefrigerated storage. The formulation of 30% of gum Arabic, 15% of gelatin and 45% of coconut oil can homogenize well at least for two hours and can produce acceptable dried product (below 4% of moisture content) at low outlet temperature (70℃ -75℃). K. lactis, S. blouradii gives 2.57% and 2.4% of viability percentage after spray drying process and 25.84% and 2.04% after two weeks nonrefrigerated storage respectively. The colonies of non-probiotics bacteria after both conditions are between 1010 and 106 cfu/mL which is among the accepted level for industrial application. However, the survival of probiotics in a spray-dried form during non-refrigerated storage is higher at low of moisture content compared to others.

Preparation of Microcapsules Containing Grape Polyphenol with the Spray Drying Method Followed by the Layer-by-Layer Method

It was tried to prepare the microcapsules containing grape polyphenol with the spray drying method followed by the layer-by-layer method. As grape polyphenol was water soluble, the spray drying method was adopted to obtain the higher content. As the shell material of the first microcapsules prepared by the spray drying method, palmitic acid with the melting point of 60&degC was adopted in order to prevent grape polyphenol from dissolution into water. As the shell material of the second microcapsules prepared by the layer-by-layer method, chitosan was used to coat the first microcapsules and to give the microcapsules alcohol resistance. In the experiment, the spray drying conditions such as the inlet temperature and the spraying pressure, the oil soluble surfactant species and the chitosan concentration were changed. The mean diameters of microcapsules could be controlled in the range from 5 μm to 35 μm by changing the spraying pressure and the inlet temperature. The yield of microcapsules and the microencapsulation efficiency over 50% could be obtained under the conditions of P = 1.0 kgf/cm2 and Tin = 100&degC. Furthermore, the microencapsulation efficiency could be increased by adding the oil soluble surfactant with the larger HLB value. Coating with chitosan could considerably increase alcohol resistance.

Microencapsulation of L-Ascorbic Acid by Spray Drying Using Sodium Alginate as Wall Material

L-ascorbic acid is a water soluble vitamin (vitamin C) widely used as an additive in foods and cosmetics. It has high instability against certain environmental factors;the main cause of its deterioration is oxidation. Microencapsulation is an effective protection technique of L-ascorbic acid from its degradation reactions. This work is focused on the encapsulation of L-ascorbic acid by spray drying technique using sodium alginate as wall material. The microcapsules morphology was observed by scanning electron microscopy (SEM) and the encapsulation efficiency was determined by spectrophotometric analysis. Results showed that encapsulation efficiency was of 93.48% and after 30 days was of 92.55%;differences were not significant, so that the stability of L-ascorbic acid was not affected. Encapsulation yields obtained were low, at around 30%, but the microcapsules morphology obtained is spherical.

Preparation of high emissivity NiCr_2O_4 powders with a spinel structure by spray drying

Spray-drying was used to produce the high emissivity NiCr2O4 powders with a spinel structure. Preliminary investigations focused on fabricating the high emissivity powders for infrared radiation coatings and finding the relationship between microstructure and emissivity. The NiCr2O4 powders were characterized for composition, microstructure, and infrared emissivity by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, infrared radiant instrument, and Fourier transform infrared spectra （FT-IR）. Thermogravimetry and differential thermal analysis show that the appropriate baking temperature for NiCr2O4 powder preparation is about 1200？C. The emissivity measurement and FT-IR spectra show that, because of the special spinel structure, the NiCr2O4 powders have a high emissivity about 0.91. Spray-drying is a suitable method to produce the high emissivity ceramic powders.

Structural and functional properties of hydrolyzed/glycosylated ovalbumin under spray drying and microwave freeze drying

Ovalbumin(OVA),the main protein in egg white,affects most of the functional properties of egg white protein in food processing.The aim of this study was to investigate the effects of spray drying(SD)and microwave freeze drying(MFD)on the preparation of hydrolyzed/glycosylated ovalbumin(HGOVA)and provide useful information on the applications of egg protein powders in the food industry.Results demonstrated that the structure of HGOVA was considerably changed,and its functional properties were improved compared with those of native OVA.SD and MFD processing did not lead to dissociation of HGOVA subunits.SD-HGOVA exhibited higher protein solubility,emulsifying activity,foaming capacities,and gel hardness than MFD-HGOVA.However,MFD-HGOVA was better than the SD-HGOVA in terms of color,emulsion stability,foam stability,water/oil absorption capacity,and thermal stability.Selection of an appropriate drying method could enhance the potential applications of HGOVA in the food industry.

Preparation of dry flowable formulations of Clonostachys rosea by spray drying and application for Sclerotinia sclerotiorum control

A dry flowable formulation of Clonostachys rosea with fungicidal activity against Sclerotinia sclerotiorum was prepared by spray drying. The formulation was optimized by a four-factor, three-level orthogonal experiment to screen inert ingredients and spray-drying conditions. The optimal dry flowable formulation of C. rosea included 30% C. rosea （ratio of conidia powder and its fermentation broth is 1：3）, 3% Morwet EFW, 4% K12, 10% Morwet D425, 9% sodium salt of polynaphthalene sulphonic acid （NNO）, 5% croscarmellose sodium, 5% （NH4）2SO4, 0.5% carboxymethyl cellulose sodium （CMC-Na）, 1% oxalic acid and palygorskite （carrier） up to 100%. The formulation exhibited good physical characteristics, such as high dispersibility, viability and a long shelf life. Plate antagonism tests and pot trials indicated that the dry flowable formulation was very effective against S. sclerotiorum, with control efficiency of up to 88.30%. This dry flowable formulation of C. rosea is a new potential commercial fungicide for spray drying to control S. sclerotiorum.

Wear mechanism for spray deposited Al-Si/SiC_p composites under dry sliding condition

Al-Si/15%SiCp(volume fraction) composites with different silicon contents were fabricated by spray deposition technique, and typical microstructures of these composites were studied by optical microscopy(OM). Dry sliding wear tests were carried out using a block-on-ring wear machine to investigate the effect of applied load range of 10-220 N on the wear and friction behavior of these composites sliding against SAE 52100 grade bearing steel. Scanning electron microscopy(SEM) and energy-dispersive X-ray microanalysis(EDAX) were utilized to examine the morphologies of the worn surfaces in order to observe the wear characteristics and investigate the wear mechanism. The results show that the wear behavior of these composites is dependent on the silicon content in the matrix alloy and the applied load. Al-Si/15%SiCp composites with higher silicon content exhibit better wear resistance in the applied load range. Under lower loads, the major wear mechanisms are oxidation wear and abrasive wear for all tested composites. Under higher loads, severe adhesive wear becomes the main wear mechanisms for Al-7Si/15%SiCp and Al-13Si/15%SiCp composites, while Al-20Si/15%SiCp presents a compound wear mechanism, consisting of oxidation, abrasive wear and adhesion wear.

Optimization of Spray Drying Processing Technology of Mulberry Powder

With concentrated juice of mulberry as raw material, the influence of type and dosage of dry aid, the inlet air tempera- ture, inlet flow rate, and rotating speed on spray drying was studied. The spray drying processing conditions of mulberry pow- der were optimized by the L9 （3^4） orthogonal test on the basis of single factor experiment. The results showed that optimum technical parameters to produce mulberry powder were： lS-cyclodextrin as dry aids with dosage of 30%, inlet air temperature of 180 ℃, rotating speed of 18 000 r/min and inlet flow rate of 30 mL/min. The mulberry powder under this optimum process conditions had a loose structure and bright color, fruity flavor was rich, the anthocyanin content for 54.67 mg/g, moisture content for 5.6% and sensory scores for 83.

Preparation of spherical spinel LiCr_(0.04)Mn_(1.96)O_4 cathode materials based on the slurry spray drying method

Regular spherical chromium doped spinel lithium manganese oxides （LiCr0.04Mn1.96O4） with an average particle size of about 20μm were prepared by the slurry spray drying process. The materials were compared with non-spherical LiCr0.04Mnl.96O4 materials prepared by the common drying process, and all materials were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, laser particle analyzer and Brunaner-Emmett-Teller （BET） specific surface area test. Electrochemical performances of these cathode materials were studied by cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS） and Li/LiCr0.04Mn1.9604 battery test. The results show that the spherical active material is single spinel structure, compact, and with narrow particle size distribution and low BET specific surface area. Compared with the non-spherical material, the spherical material prepared by the spray drying process shows a lower electrochemical impedance, a fewer electrochemical polarization and a better charge/discharge rate capability and capacity retention at elevated temperatures.

Spray freeze drying of small nucleic acids as inhaled powder for pulmonary delivery

The therapeutic potential of small nucleic acids such as small interfering RNA(siRNA) to treat lung diseases has been successfully demonstrated in many in vivo studies. A major barrier to their clinical application is the lack of a safe and efficient inhaled formulation.In this study, spray freeze drying was employed to prepare dry powder of small nucleic acids.Mannitol and herring sperm DNA were used as bulking agent and model of small nucleic acid therapeutics, respectively. Formulations containing different solute concentration and DNA concentration were produced. The scanning electron microscope(SEM) images showed that the porosity of the particles increased as the solute concentration decreased. Powders prepared with solute concentration of 5% w/v were found to maintain a balance between porosity and robustness. Increasing concentration of DNA improved the aerosol performance of the formulation. The dry powder formulation containing 2% w/w DNA had a median diameter of 12.5 μm, and the aerosol performance study using next generation impactor(NGI) showed an emitted fraction(EF) and fine particle fraction(FPF) of 91% and 28% respectively. This formulation(5% w/v solute concentration and 2% w/w nucleic acid) was adopted subsequently to produce siRNA powder. The gel retardation and liquid chromatography assays showed that the siRNA remained intact after spray freeze drying even in the absence of delivery vector. The siRNA powder formulation exhibited a high EF of 92.4%and a modest FPF of around 20%. Further exploration of this technology to optimise inhaled siRNA powder formulation is warranted.

Preparation and Characterization of Porous Spherical LiFePO_4/C by Spray Drying and Carbothermal Method

The porous spherical LiFePO4/C powders were prepared by spray drying and carbothermal method （SDCTM）. Cheaper trivalent iron ion was used as the precursor. The pure olivine phase can be prepared with the spray drying and subsequent heat-treatment. The average particle size is around 10μm, and the value of porosity is 63.04%. The results indicate that the initial discharge capacity decreases with increasing charge/ discharge rate and reduces from 138.8 mAh · g^-1 at C/20 rate to 98.3 mAh ·g^-1 at 2C rate, while the polarization between the charge and discharge plateaux is enlarged from 53 mv to 347 mv. However, the average discharge efficiency is up to 99.5% at 2C rate compared to 80.6% at C/20 rate from the second cycle.