Percentage Of Small Particles Research Articles

Influence of mastication and its relationship with Body Mass Index before and after prosthetic rehabilitation in partially edentulous patients

BACKGROUND: The main purpose of prosthetic rehabilitation is to enhance the masticatory function by replacing the missing teeth with an artificial substitute, which improves nutrient-rich food intake. There are recent studies which indicate the influence of chewing behavior and energy intake, but little is known about the relationship between chewing on nutritional status. OBJECTIVE: This study intended to assess the changes in masticatory efficiency before and after prosthetic rehabilitation and its influence on nutritional status and body weight. METHODS: A total of 40 partially edentulous subjects aged between 45- 65 years were recruited. Body Mass Index was determined by measuring body weight using a medical grade weighing scale. Height was measured using wall mounted stature meter and Waist circumference was measured with an anthropometric measure tape. Masticatory efficiency was determined using the sieve method with peanuts as test food at baseline, at 3 and 6 months of prosthetic rehabilitation with a removable partial denture. RESULTS: Sieve test performed for evaluating masticatory efficiency showed an increase in the percentage of smaller particles by 28.3% in non-obese and 32.15% in the obese group. The obese/overweight group showed a decrease in BMI values and non-obese subjects showed no significant change in BMI.

Effect of grain size composition on mechanical performance requirement for particles in aggregate blend based on photoelastic method

The mechanical performance requirement (MPR) of blend for aggregate in each size is fundamental to use aggregate resources efficiently. In this study, a photoelastic experiment was designed to investigate the load transfer behaviors of single-size, two-size, and three-size blends. The relative change ratio of the average contact force of each size particles in multi-size blend to that in the corresponding single-size blend was proposed to quantify the change of MPR of blend for each size particles. Then, the effect of grain size composition on the MPR for aggregate in each size was assessed quantitatively. The test results show that the force distribution characteristics of each size particles are different in the blends with different grain size compositions. It demonstrates that the grain size composition has distinct effects on the MPR for each size particles. The addition of smaller size particles can raise or lower the MPRs for aggregates, which depends on the size ratio and the percentage of the smaller particles. Generally, in multi-size blends, the larger particles have a bigger average contact force and a bigger average contact number than the smaller particles. A bigger size ratio with a bigger percentage of smaller size particles can bring a decrease in the MPRs for aggregates. The gradation of blend has different effects on the MPRs for aggregates. It is feasible to improve the utilization efficiency of aggregate resources by selecting aggregates according to the specific MPRs of the blend. The utilization of alternative aggregates can also be facilitated through optimizing the blend gradation to adapt their mechanical properties.

Comparison of lunar and Martian regolith simulant-based geopolymer cements formed by alkali-activation for in-situ resource utilization

Future human space exploration and habitation on the lunar and Martian surfaces necessitates in-situ resource utilization (ISRU) for the development of construction materials tailored for infrastructure and environmental protection. Here we explore the use of lunar and Martian regoliths to create construction materials with properties suitable for such structures as landing pads. Alkali activation of a spectrum of lunar and Martian regolith simulants generates geopolymer binders under ambient and vacuum curing conditions as well as exposure to extreme high and low temperatures (600 and −80 °C). Compressive strength is reduced for binders prepared from each simulant after curing under vacuum and exposure to sub-zero temperatures. In lunar simulant binders, the compressive strength is increased after heating to 600 °C, but the opposite effect is observed in the Martian simulant binder. Amorphous aluminosilicate content and percentage of small particles in the simulants are hypothesized to have a positive impact on compressive strength under ambient curing. Iron and magnesium content may be responsible for decreased compressive strength of the Martian binder after heating. This study offers a robust framework for comparing performance of different simulants under the same curing protocols and environmental exposures, as well as offering insight as to the effects of vacuum curing, and exposure to high and low temperature environments on cured binder samples. Developing a landing pad by transporting activator to the lunar surface is shown to be conceptually feasible within current payload constraints.

Effects of the undecomposed layer and semi‐decomposed layer of Quercus variabilis litter on the soil erosion process and the eroded sediment particle size distribution

AbstractSimulated rainfall experiments were performed on bare, undecomposed litter layer and semi‐decomposed litter layer slopes with litter biomasses of 0, 50, 100 and 150 g m−2, respectively, to evaluate the effect of the undecomposed layer and semi‐decomposed layer of Quercus variabilis litter on the soil erosion process and the particle size distribution of eroded sediment. The undecomposed layer and semi‐decomposed layer of litter reduced the runoff rate by 10.91–27.04% and 12.91–36.05%, respectively, and the erosion rate by 13.35–40.98% and 17.16–59.46%, respectively. The percentage of smaller particles (clay and fine silt particles) decreased and the percentage of larger particles (coarse silt and sand particles) increased with an increased rainfall duration on all treated slopes, while the extent of the eroded sediment particle content varied among the treated slopes with the rainfall duration, with bare slopes exhibiting the largest variability, followed by undecomposed litter layer slopes and finally semi‐decomposed litter layer slopes. The clay and sand particles were transported as aggregates, and fine silt and coarse silt particles were transported as primary particles. Compared with the original soil, sediment eroded from all treated slopes was mainly enriched in smaller particles. Furthermore, the loss of the smaller particles from the undecomposed litter layer slopes was lower than that from the semi‐decomposed litter layer slopes, indicating that the undecomposed litter layer alleviated soil coarsening to some extent. The findings from this study improve our understanding of how litter regulates slope erosion and provide a reference for effectively controlling soil erosion.

Beneficial effects of high-pressure homogenization on the dispersion stability of aqueous hydrolysate from Mytilus edulis

Owing to the formation of aggregation and gelation during storage, certain proteins and peptides exhibit limited applications in aqueous protein food products. The purpose of this study was to investigate the influence of homogenization and xanthan gum addition on the dispersion stability of Mytilus edulis hydrolysate (PHM). High-pressure homogenization (HPH) at 360 and 40 bar in the first and second values, respectively, and adding xanthan gum at a concentration of 1 mg/mL showed significantly improvement on the stability of the PHM solution. PHM-xanthan gum solutions (PHMX) showed the highest polypeptide precipitation rate and turbidity retention rate compared with those of PHM. Moreover, the centrifugal precipitation rate of PHMX without HPH was higher than that of homogeneous PHMX. After HPH treatment at 400 bar, the percentage of smaller particles in PHM and PHMX was increased, the aqueous system became more uniform, and the fluorescence intensity reached its maximum. HPH pre-treatment improved the polypeptide dispersion stability and turbidity retention rate of PHM and PHMX and reduced the fluorescence intensity. The interactions of xanthan gum and polypeptide render the network microstructure more uniform under the conditions of homogenization, thus improving the dispersion stability of PHMX solutions. Therefore, under the premise of adding xanthan gum, HPH can better enhance the dispersion stability of the polypeptide in PHM.

Comparison of external and submerged membranes used in anaerobic membrane bioreactors: Fouling related issues and biological activity

Anaerobic sludge filtration tests were performed with two experimental set-ups equipped with either submerged hollow-fiber membranes or external tubular membranes operated with low crossflow velocity and gas sparging in a gas-lift mode. Particle size distributions, extracellular polymeric substance concentrations, methanogenic activity, reversible and irreversible fouling rates, and chemical cleaning efficiency were all studied and compared. An increase in the percentage of smaller particles and a decrease in the concentration of volatile suspended solids in the external membrane set-up were observed. Both soluble protein and soluble polysaccharide concentrations were also higher in the external filtration. Operating at 12–15 L/m2 h for 7 days, the total resistance of the external membrane reached 9.3 × 1012 m−1, while the resistance of submerged membrane reached 1.1 × 1012 m−1 despite operating at 15–25 L/m2 h for 12 days. Finally, the type of fouling and the efficiency of chemical cleaning also differed in both configurations.

HO-1 protects smokers exposed to artificial stone dust for pulmonary function tests deterioration.

Background: The Heme Oxygenase system, along with its catabolism products, is involved in a variety of crucial physiological functions, including cytoprotection, inflammation, anti-oxidative effects, apoptosis, angiogenesis, and vascular regulation. Objectives: To analyze the Heme Oxygenase -1 (HO-1) mediated effect of mild deterioration of pulmonary function testing (PFT) in exposed artificial stone smoking workers. Methods: One hundred stone workers divided into current smokers, ex-smokers and never smokers underwent Low Resolution Computed Tomography, PFT, induced sputum (IS) Particle Size Distribution (PSD) and Real Time PCR in IS samples. Results: Smoking status had no significant effect on PFT results but it altered the IS differential cell counts. There was significantly less decline in PFT over time for the smokers group. There was a significantly lower fraction of small particles (<2 μm) in the IS of the current smokers group compared to the never- and ex-smokers groups. HO-1 gene expression was higher among smokers compared to never- and ex-smokers groups. A low percentage of small particles (<5 μm) correlated negatively to the percentage of neutrophils and positively to the percentage of macrophages in the sputum of the smokers group. Conclusions: We found significantly lower risk for decreased PFT deterioration among smokers workers exposed to artificial stone dust with higher HO-1 gene expression suggesting a possible protective effect of smoking by the involvement of HO-1 mechanism. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 276-284).

Wear of historical polyethylenes in hip prostheses. Biomechanical success and a biological failure.

;Polyethylene wear debris induced osteolysis is a major cause of failure in artificial hip joints. Sub micrometre size particles are taken up by macrophages which are stimulated to release osteolytic cytokines such as TNFα. This leads to bone resorption, loosening and failure. In vitro cell culture studies have shown particles in the size range 0.1 to 1 micrometre to be at least six times more reactive than larger particles. Studies of historically used gamma irradiated in air polyethylene show increased wear rate with damaged femoral heads and with aged and oxidised polyethylene. The aged and oxidised polyethylene also produced a greater percentage of smaller particles leading to increased osteolytic potential. Combined tribological and biological simulation models have been developed for pre-clinical assessment of osteolytic potential of artificial hip joints.

Long-lived non-equilibrium interstitial solid solutions in binary mixtures.

We perform particle resolved experimental studies on the heterogeneous crystallisation process of two component mixtures of hard spheres. The components have a size ratio of 0.39. We compared these with molecular dynamics simulations of homogenous nucleation. We find for both experiments and simulations that the final assemblies are interstitial solid solutions, where the large particles form crystalline close-packed lattices, whereas the small particles occupy random interstitial sites. This interstitial solution resembles that found at equilibrium when the size ratios are 0.3 [L. Filion et al., Phys. Rev. Lett. 107, 168302 (2011)] and 0.4 [L. Filion, Ph.D. thesis, Utrecht University, 2011]. However, unlike these previous studies, for our system simulations showed that the small particles are trapped in the octahedral holes of the ordered structure formed by the large particles, leading to long-lived non-equilibrium structures in the time scales studied and not the equilibrium interstitial solutions found earlier. Interestingly, the percentage of small particles in the crystal formed by the large ones rapidly reaches a maximum of ∼14% for most of the packing fractions tested, unlike previous predictions where the occupancy of the interstitial sites increases with the system concentration. Finally, no further hopping of the small particles was observed.

Tensile Fracture and Compression failure Behavior of Cenosphere Reinforced AA6061 Metal Matrix Composite

A small percentage of particles, present in the pulverized lignite coal fly-ash, contain thin-walled hollow spheres or cenosphere. Their amount depends on the carbon and iron contents existing in the fly-ash. The apparent density of these cenosphere is less than that of water and as such, they float on the ash slurry when it is impounded in the ash ponds. The Cenosphere are being used in different industrial applications, mainly due to their low density, high strength, and good thermal properties. Cenosphere derived from the lignite coal fly ash was used in this work as reinforcement for Aluminum Metal Matrix Composite (Al-MMC) to enhance its mechanical properties. Hence, the MMC uses fly ash derivative (Cenosphere) as reinforcement likely to overcome the cost barrier for wide spread uses in automotive and other industrial applications. Hence the experimental results shows that the %weight addition of cenosphere in the MMC significantly improves its tensile strength as well as Compressive strength of the matrix. It is mandatory to evaluate the failure load of the Metal matrix for future work, so that the Tensile and Compression tested specimens of (0%, 1%, 2%, 3% and 5%) weight of cenosphere are subjected to Scanning Electron Microscope (SEM), and XRD analysis to find the crack formation and growth. Thus the paper discuss about failure analysis of Cenosphere based Al-Alloy Metal Matrix Composite in lucid manner.

Experimental Investigation on the Permeability Evolution of Compacted Broken Coal

Given the importance of airflow seepage properties to coal self-oxidation in gob, this paper develops a method and self-designed apparatus to assess seepage properties of compacted broken coal. This study mainly focuses on the strain, porosity and permeability evolution under the different conditions of particle size, vertical stress and temperature. The studied results show: (1) The strain, porosity and permeability were enlarged when the particle size increased under the same loading stress. The porosity and permeability reduced when the vertical stress increased. (2) The non-Darcy coefficient was negative in all tests, but the absolute value of the non-Darcy coefficient generally increased when the vertical stress increased. (3) The experiment results indicated that the larger the particle was, the easier to be compacted. The larger the grain diameter was, the lower the porosity and permeability were, which shown that the void volume in broken coal with larger grain diameters could be easily compacted. (4) The permeability was reduced when the temperature increased, which indicated the permeability of the compacted broken coal decreased during low-temperature oxidation in gob. (5) By the effects of stress and the particle size diameter on the porosity and permeability, the vertical stress recovery and generally increase are advantageous to reduce the porosity and permeability in gob. It is favorable to reduce the porosity and permeability and prevent coal self-heating by reducing the degree of fragmentation and percentage of small particles or consolidate the small particles.

Microfluidic manufacture of rt-PA -loaded echogenic liposomes.

Echogenic liposomes (ELIP), loaded with recombinant tissue-type plasminogen activator (rt-PA) and microbubbles that act as cavitation nuclei, are under development for ultrasound-mediated thrombolysis. Conventional manufacturing techniques produce a polydisperse rt-PA-loaded ELIP population with only a small percentage of particles containing microbubbles. Further, a polydisperse population of rt-PA-loaded ELIP has a broadband frequency response with complex bubble dynamics when exposed to pulsed ultrasound. In this work, a microfluidic flow-focusing device was used to generate monodisperse rt-PA-loaded ELIP (μtELIP) loaded with a perfluorocarbon gas. The rt-PA associated with the μtELIP was encapsulated within the lipid shell as well as intercalated within the lipid shell. The μtELIP had a mean diameter of 5μm, a resonance frequency of 2.2MHz, and were found to be stable for at least 30min in 0.5% bovine serum albumin. Additionally, 35% of μtELIP particles were estimated to contain microbubbles, an order of magnitude higher than that reported previously for batch-produced rt-PA-loaded ELIP. These findings emphasize the advantages offered by microfluidic techniques for improving the encapsulation efficiency of both rt-PA and perflurocarbon microbubbles within echogenic liposomes.

Experimental heat transfer coefficients between a surface and fixed and fluidized beds with PCM

This work presents an experimental study to determine the capacity of a phase change material (PCM) in granular form to be used in fixed and bubbling fluidized beds for thermal energy storage. The experimental measurements are focused on determination of the heat transfer coefficient between a heated surface immersed in the bed and the granular PCM. The flow rate is varied to quantify its influence on the heat transfer coefficient. The PCM used is Rubitherm GR50 with a phase change temperature of approximately 50° C. The PCM is available in two different particle sizes, 0.54 mm and 1.64 mm, of which the finer is used in the fluidized bed and the coarser is used in the fixed bed. In addition, the results obtained for the PCM are compared with the heat transfer coefficients measured for sand, a material commonly used for thermal storage.In comparing the heat transfer coefficients for fixed and fluidized beds, the heat transfer coefficients in the fluidized bed with PCM are nearly three times higher than those for the fixed bed at the same gas flow rate. This increase in the heat transfer is a result of two main factors: first, the continuous renewal of PCM particles from the heated surface when they are fluidized, and second, the large quantities of energy in latent form absorbed by the PCM. In the fixed bed there is no renovation of particles, consequently only a small percentage of particles are able to change its phase. Hence, there is no increase in the heat transfer coefficient due to this fact.

Effect of Non-electrical Parameters on the Size of Nickel Microspheres Produced by an Ultrasound-aided Electrical Discharge Machining

Spark erosion is a method for producing nickel microspheres. To reduce the size of microspheres, a combined machining technology called ultrasound-aided electrical discharge machining(EDM) is proposed. To investigate the effect of non-electrical parameters on the size of microspheres, the experiments are carried out by changing ultrasonic parameters(frequency and intensity) and dielectric mediums(kerosene and pure water). The morphology and composition of microspheres are characterized by using scanning electron microscope(SEM) and X-ray diffraction(XRD). Smile View software is used to measure the size of the microspheres and Origin Pro software is used for statistical analysis to determine the size distribution percentages. The results show the percentage of small particles(in the range of 0 to10 μm) increases significantly by introducing ultrasound. Meanwhile, the percentage of small particles decreases with increasing ultrasonic frequency and increases with increasing ultrasonic intensity. The size of microspheres prepared in pure water is generally smaller than kerosene. In the pure water, the percentage of microspheres with a smaller size(less than 1 μm) and a small size(less than 5 μm) are 6%~10% and 50%~80% respectively. The effect of ultrasound in pure water is better than kerosene on reducing the size of microspheres. The microspheres made up of almost purenickel(≥99%) are produced in pure water. In addition, a few hollow microspheres are found in the experiments with ultrasound and the formation mechanism of the hollow spheres is analyzed preliminary.

Idle emission characteristics of a light-duty diesel van at various altitudes

As operating conditions producing severe pollution, high altitude conditions need more attention. In this present paper, regulated emissions and particulate matter distributions of a light-duty diesel van at idle at different altitudes were measured and discussed. Seven altitudes varying from 70 m to 3200 m were introduced and investigated. It was found that CO emission increased corresponding to an increase in altitude. In the cases where altitude was lower than 2400 m, the mass flows of hydrocarbon emissions were quite similar. And the hydrocarbon emissions at 3200 m were much higher than that at lower altitudes. NOx and NO emissions at high altitude were rather close to that near sea level. NO2 ascended when altitude was rising in the cases where the altitude was lower than 2400 m; but a decrease at 3200 m was observed. Generally, particulate matter positively correlated to the increased altitude despite the slight fluctuation at relatively low altitudes. Number distribution of particulate matter manifested that a majority of particles were with relatively small aerosol diameters. With the rising of altitude, the percentage of small particles became lower in the total particulate matter. In average, larger number of particles was exhausted at high altitude. With regard to mass distribution, larger particles hold larger percentages by weight than smaller particles at all investigated altitudes. The percentage shared by PM2.5 in the total particulate matter varied from 48.3% to 74.8% in the tests at different altitudes.

Nutrient fluxes between water column and sediments: Potential influence of the pearl oyster culture

This study quantifies benthic nutrient fluxes and sedimentation rates in the Ahe Atoll lagoon (French Polynesia), in two stations located under pearl oyster frames, and two control stations away from the pearl culture facility. Dissolved inorganic nitrogen fluxes ranged between 2 and 35μmolNm−2h−1 and Soluble Reactive Phosphorus varied between −3 and 8.2μmolPm−2h−1. Particulate sedimentation rates beneath the oysters were approximately five times higher than in the control zone and the percentage of small particles (⩽63μm) were about the twice. In contrast, sediment composition was similar under and outside the direct influence of oyster frames. In this ecosystem, where primary production is dependent on the available nitrogen, our study revealed that, while highly variable, benthic fluxes could sometimes contribute up to 28% of the nitrogen demand for primary production.

Effects of Substrate Geometry on Performance of Twin-Fluid Atomizer in Metal Powder Production

Uniform and spherical metal powders have been widely used in many industrial applications. This paper investigates the control of particle size and size distribution by the impingement of the molten spray on the substrate with different geometries. The idea is to combine the atomization process with the classification process. Result shows that a significant reduction of the particle size occurred when the substrate was placed in the spray jet. The mean particle size was lowered to 8.0μm with a low transmission ratio of the spray jet in the existence of the ring type substrate. The particle size increased from 8.78μm to 12.67μm as the transmission ratio was increased from 13.92% to 75.80%. The reduction in particle size was due to the effect of the blockage of the substrate on the spray. The particle size increased from 6.72μm to 6.98μm when the disk-type substrate was placed at Z = 150mm and 200mm, respectively. The particle size of this case was smaller than the case with ring type substrate because the transmission ratio of the disk type substrate was lower. The percentage of small particles (i.e., V15-) were higher than 60% and the percentages of V25-45 were 4.19% and 0.37% when the disk-type substrate was placed at Z=150mm and Z=200mm, respectively, indicating that almost all of the particles were below 25μm under these conditions. Hence this technique is very effective in controlling the particle size in the metal powder production.

Sampling Uncertainties for the Detection of Chemical Agents in Complex Food Matrices

Using uncertainty associated with detection of aflatoxin in shelled corn as a model, the uncertainty associated with detecting chemical agents intentionally added to food products was evaluated. Accuracy and precision are two types of uncertainties generally associated with sampling plans. Sources of variability that affect precision were the primary focus of this investigation. Test procedures used to detect chemical agents generally include sampling, sample preparation, and analytical steps. The uncertainty of each step contributes to the total uncertainty of the test procedure. Using variance as a statistical measure of uncertainty, the variance associated with each step of the test procedure used to detect aflatoxin in shelled corn was determined for both low and high levels of contamination. For example, when using a 1-kg sample, Romer mill, 50-g subsample, and high-performance liquid chromatography to test a lot of shelled corn contaminated with aflatoxin at 10 ng/g, the total variance associated with the test procedure was 149.2 (coefficient of variation of 122.1%). The sampling, sample preparation, and analytical steps accounted for 83.0, 15.6, and 1.4% of the total variance, respectively. A variance of 149.2 suggests that repeated test results will vary from 0 to 33.9 ng/g. Using the same test procedure to detect aflatoxin at 10,000 ng/g, the total variance was 264,719 (coefficient of variation of 5.1%). The sampling, sample preparation, and analytical steps accounted for 41, 57, and 2% of the total variance, respectively. A variance of 264,719 suggests that repeated test results will vary from 8,992 to 11,008 ng/g. Foods contaminated at low levels reflect a situation in which a small percentage of particles is contaminated and sampling becomes the largest source of uncertainty. Large samples are required to overcome the “needle-in-the-haystack” problem. Aflatoxin is easier to detect and identify in foods intentionally contaminated at high levels than in foods with low levels of contamination because the relative standard deviation (coefficient of variation) decreases and the percentage of contaminated kernels increases with an increase in concentration.

Effect of acute exogenous hyperinsulinaemia on very low density lipoprotein subfraction composition in normal subjects.

Subtle abnormalities of very-low-density lipoprotein (VLDL) composition and distribution seem to be associated with increased cardiovascular risk. The aims of this study were first, to evaluate whether hyperinsulinaemia per se is able to produce VLDL abnormalities and second, whether this occurs through a stimulation of lipolytic enzymes. Eight normal male volunteers, age 36 +/- 7 years (M +/- SD), body mass index (BMI) 26+/-3 kg m-2, underwent a 5-h euglycaemic hyperinsulinaemic clamp (1.2 mU insulin/kg b.w. min-1). Nine sex, age and BMI comparable subjects underwent control experiments (saline infusion). Three VLDL subfractions of decreasing size were isolated by density gradient ultracentrifugation; lipoprotein lipase (LPL) and hepatic lipase (HL) post-heparin plasma activities were determined by the 3H-labelled triolein method. Hyperinsulinaemia ( approximately 65 mU mL-1) produced the expected plasma free fatty acid suppression. Triglyceride levels were reduced in total VLDL (- 27 +/- 32% vs. + 38 +/- 52% after saline, P < 0.05) and in the larger VLDL (- 56 +/- 19 vs. + 34 +/- 38, P < 0.001). Moreover the relative contribution of the larger subfraction was decreased (- 39 +/- 15% vs. - 3 +/- 21%, P < 0.01), while the percentage of smaller particles was increased (+17 +/- 20 vs. - 9 +/- 22, P < 0.05). LPL and HL activities were decreased to the same degree during either insulin or saline infusion. Exogenous hyperinsulinaemia produced lipoprotein abnormalities partially similar to those previously shown in type 1 diabetic patients, indicating that these abnormalities may be secondary to insulin therapy.

The effect of spray parameters on the properties of high velocity oxy-fuel NiAl intermetallic coatings

A high velocity, oxy-fuel (HVOF) thermal spray process has been used to deposit two commercially available NiAl intermetallic powders, one reaction sintered and the other inert gas atomised. It was possible to deposit high quality coatings of NiAl intermetallic at rates comparable to those of non-metallic coatings. The coatings were characterised in terms of microstructure, oxygen content, porosity and permeability, Young's modulus and hardness. Coating characteristics and properties were found to be dependent on both the powder's particle size and the spray parameter's oxygen to fuel ratio. The preferred spray parameter was that of a high oxygen to fuel ratio equivalent to 80% stoichiometry, a spherical inert gas atomised powder with a narrow particle size range between 15–45 μm and a small percentage of particles >50 μm.