Zinc Oxide Powder Research Articles

Controllable mechanism of hazardous jarosite transformation into recyclable hematite in the leaching solution of secondary zinc oxide powder

The controlled synthesis of recyclable hematite in the leaching solution of secondary zinc oxide powder is an urgent problem in the chemical industry and metallurgy fields. In this paper, the effects of the temperature, agitation speed, and seed addition on the contents of iron, sulfur, potassium, sodium, and zinc in the iron removal residues, as well as the iron concentration in the supernatant after iron removal were systematically studied. In addition to the temperature control already reported, we found that the agitation speed can also control the transformation between jarosite and hematite phases. The content of jarosite in the residues can be effectively controlled by adjusting the agitation speed, thereby significantly improving the quality of hematite product, as indicated by SEM-EDS and XRD results. Under temperature of 185 °C, an agitation speed of 500 rpm, and a seed addition of 15 g/L, the iron, sulfur and zinc contents in the filter residues and the iron concentration in the supernatant were 59%, 3.22%, 0.92%, and 4.182 g/L, respectively. Kinetic studies show that the rapid oxidation kinetics is not conducive to the formation of high-quality hematite products. These results can directly guide the process of transformation of harmful jarosite into recyclable hematite from the leaching solution of secondary zinc oxide powder, which is of great practical significance for the controlled and waste-free removal of iron from aqueous solutions in the chemical industry and metallurgy fields.

Growth of high-density Zinc Oxide (ZnO) nanoflowers in all aqueous two-step method and their application in second harmonic generation of femtosecond laser

This study presents a novel two-step all aqueous solution method for the growth of high-density Zinc Oxide (ZnO) nanoflowers, utilizing ZnO powder as a precursor. For this, initially, a seed layer of ZnO nanostructures is prepared using a non-conventional sol-gel technique in an all-aqueous medium. Subsequently, high-density ZnO nanoflowers are synthesized on these seed layers through the chemical bath deposition method. Four samples, each with varying numbers of seed layers (ranging from one to four) are prepared and analyzed using field emission scanning electron microscopy (FESEM). FESEM results indicate that the sample with three seed layers exhibits optimized morphological characteristics. Consequently, further detailed investigation is conducted exclusively on this optimized sample. Furthermore, a preliminary study is done on second harmonic generation (SHG) of this optimized sample.

Effect of Electron Irradiation on the Optical Properties of Zinc Oxide Powder Modified by Magnesium Oxide Nanoparticles

The effect of modifying ZnO powders with MgO nanoparticles (with a concentration of 0.1–10 wt. %) on their diffuse reflectance spectra in the region of 0.2–2.5 μm before and after irradiation with 30 keV electrons was studied. Modification of ZnO powder was carried out by MgO nanopowder with concentrations from 0.1 to 10 wt. % using a solid-state method at 650°C heating temperature. X-ray diffraction analysis showed that this method of modification there is no formation of additional phases. It has been established that zinc oxide structure symmetry belongs to the P63mc space group, magnesium oxide – to the Fm–3m space group. The spectral reflectance of such powders in the visible region is over 90%. Under irradiating by 30 keV electrons of initial and modified ZnO powders, as well as MgO nanopowder, a decrease in their reflectance recorded in the entire studied region of the spectrum. It has been established that modification with MgO nanoparticles at a concentration of 3 wt. % leads to an increase in radiation resistance by a factor of 1.32 compared to unmodified samples. This effect is determined by the sink of radiation defects on the large specific surface area of nanoparticles.

Eco-Friendly Green Synthesis of Zinc Oxide Nano/Microparticles Using Aqueous Leaf Extract of Polygonum cognatum Meisn. Plant

The environmentally friendly plant-based green synthesis approach provides a fabulous opportunity to produce versatile zinc oxide powders with multifarious morphology and/or size. In this study, it was mainly aimed at using Polygonum cognatum Meisn. extract to synthesize zinc oxide powder via a simple green synthesis route. For this purpose, zinc nitrate solution was mixed with an aqueous extract of fresh Polygonum cognatum Meisn. plant leaves to obtain a zinc-based precursor, and then zinc oxide powder was synthesized by means of calcination conducted at 400°C for 2 hours in air. Phase, spectroscopic, and microstructural analysis techniques, as well as Rietveld refinement method and Williamson-Hall analysis, were performed to investigate the powder characteristics. It was found that the synthesized high-purity zinc oxide powder had a hexagonal wurtzite crystal structure. Zinc oxide powder was observed to have a particularly large amount of nano-sized equiaxed particles (~25 nm in average diameter) together with micron-sized hourglass-like particles consisting of two hexagonal prisms (each

The effect of particles size of Gd2O3 on the radiation protection mechanisms of ZnO

There are two mechanisms established for increasing the radiation resistance of optical properties of micron-sized zinc oxide (mZnO) powder modified by gadolinium oxide (nGd2O3) nanoparticles by means of relaxation of the primary radiation defects (electrons and holes): — in atoms of rare-earth element gadolinium; — on Gd2O3 nanoparticles. During modification with gadolinium oxide micron-sized particles, only one (first) mechanism for radiation resistance increasing is enabled. These results are obtained by recording diffuse reflectance spectra in high vacuum in the range of 0.2–2.5 μm under radiation exposure by accelerated electrons (in situ). The established mechanisms for increasing radiation resistance refer not only to the types of powders under the study, but also to other types of oxide semiconductor powders and rare-earth elements. These mechanisms can also be extended to the photo résistance of oxide powders modified by nanoparticles and solid solutions based on them.

Green synthesis and characterisation of ZnO from citrus hystrix extracts for photocatalytic application

The purpose of this ongoing research project is to enhance the quality of zinc oxide (ZnO) powder synthesised through a green synthesis process using extracts from C. hystrix. The objective is to explore the potential of C. hystrix as a sustainable source for the production of ZnO nanoparticles with improved properties. Through a series of experimental procedures, including characterisation techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–vis spectroscopy, the synthesised ZnO powder’s structural, morphological, and optical properties are evaluated. Additionally, the photocatalytic activity of the biosynthesised ZnO powder is assessed for its effectiveness in degrading organic pollutants under UV illumination. By systematically optimising the synthesis parameters and understanding the underlying mechanisms, this research endeavours to contribute to the advancement of green synthesis approaches for producing high-quality ZnO nanoparticles that demonstrate enhanced performance, thereby fostering sustainable and eco-friendly nanomaterial synthesis processes. Following the successful production of eco-friendly ZnO through green synthesis, the optimum sample will undergo several experiments using a doping method with various chemical substances.

Effect of Electron Irradiation on the Optical Properties of Zinc Oxide Powder Modified with Magnesium Oxide Nanoparticles

Effect of Electron Irradiation on the Optical Properties of Zinc Oxide Powder Modified with Magnesium Oxide Nanoparticles

Green Synthesis and Characterization of Zinc Oxide Nanoparticles Using Catharanthus roseus Extract: A Novel Approach.

Nanotechnology enables precise manipulation of matter at the molecular level, with nanoparticles offering diverse applications in medicine and beyond. Green synthesis methods, utilizing natural sources like plant extracts, are favored for their eco-friendliness. Zinc oxide (ZnO) nanoparticles are recognized for their ability to combat microbes and reduce inflammation, which holds promise for biomedical applications. Catharanthus roseus, renowned for its medicinal properties, warrants further exploration in oral health management due to its anti-inflammatory and antioxidant attributes. The current studyaimed to synthesize Catharanthus roseus-mediated ZnO nanoparticles and to evaluate their anti-inflammatory and antioxidant activity. Catharanthus roseus powder (1 g) was dissolved in distilled water (100 ml), heated at 60°C for 15-20 minutes, and filtered to obtain 20 ml extract. ZnO nanoparticles were synthesized by adding 0.594 g ZnO powder to 50 ml water, mixed with plant extract, and stirred for 72 hours, and the resulting solution was centrifuged. Nanoparticles were collected and analyzed for Fourier-transform infrared spectroscopy (FTIR) using Bruker's Alpha II FTIR spectrometer (Bruker, Billerica, Massachusetts, United States), antioxidant, and anti-inflammatory activities. FTIR analysis revealed characteristic peaks indicative of functional groups present in Catharanthus roseus-mediated ZnO nanoparticles, including O-H, N-O, C-O, C=C, and C≡C-H. Anti-inflammatory activity evaluation showed inhibition ranging from 48% to 89%, with the maximum inhibition at 50 μL concentration. Similarly, antioxidant activity ranged from 62% to 88%, with the maximum inhibition also seen at 50 μL concentration. Both assays effectively showcased the superior anti-inflammatory and antioxidant activity of the Catharanthus roseus-incorporated ZnO nanoparticles extract compared to the control. This suggests their potential as a viable therapeutic agent for further evaluation.

Effect of annealing temperature for structural, electrical, and ammonia sensing properties of pristine ZnO and ZnO/SiO2 nanoparticles

The main objective of this research was to study the electrical and gas-sensing properties of Zinc oxide (ZnO) nanoparticles. The samples were divided into two conditions in the preparation process. In the first condition, ZnO powder was annealed at temperatures of 650, 700, and 750 ๐C for 2 h, while the second condition involved mixing ZnO powder with SiO2 powder and annealing at temperatures of 650, 700 and 750 ๐C for 2 h. The characteristics of the prepared samples were studied by scanning electron microscopy (SEM) and the X-ray diffraction technique (XRD). The SEM images showed the agglomeration of the particles with micron-sized diameters. In addition, the XRD patterns of all samples exhibited the hexagonal structure of ZnO. Assessment of the electrical properties of the samples was carried out by forward bias from 0 – 15 V and reverse bias from 0 V to -15 V. The I – V characteristic curves showed diode-like rectifying behavior.The gas-sensing property of the samples was investigated by using ammonia gas, and ZnO nanoparticles annealed at 750 ºC for 2 h were found to have the highest sensitivity.

Clinical and Radiographic Evaluation of Zinc Oxide Eugenol, Zinc Oxide Powder with Aloe Vera Gel, and Endoflas Powder with Aloe Vera Gel as an Obturating Material in Primary Molars: An In Vivo Study.

The present study was conducted to compare three obturating materials-zinc oxide eugenol (ZOE), zinc oxide (ZO) powder with aloe vera gel, and Endoflas powder with aloe vera gel in primary molars. The study was conducted on 45 primary molars with chronic infection. A total of 45 primary molars were divided into three groups of 15 each. Group I was obturated with ZOE paste, group II was obturated with ZO powder and aloe vera gel, and group III was obturated with Endoflas powder with aloe vera gel. Clinical and radiographic success and failure at 3, 6, and 9 months were evaluated. A total of 15 molars in group I, 15 molars in group II, and 14 molars in group III showed clinical and radiographic success at the 9th-month follow-up. However, there was only one failure in group III during the 9th-month follow-up. It was concluded that all three groups showed promising results; ZOE is still considered standard material, whereas ZO powder with aloe vera gel can be used as an alternative to ZOE. Endoflas with aloe vera gel can also be used as an obturating material. Mohile S, Sharma N, Asopa K, et al. Clinical and Radiographic Evaluation of Zinc Oxide Eugenol, Zinc Oxide Powder with Aloe Vera Gel, and Endoflas Powder with Aloe Vera Gel as an Obturating Material in Primary Molars: An In Vivo Study. Int J Clin Pediatr Dent 2024;17(2):168-172.

Low Carbon and High Efficient Utilization of Zinc-bearing Dust in Iron & Steel Industry by Rotary Kiln Process

More than 50 million tons per year of zinc-bearing dust with large amounts of zinc and iron resources is produced by iron and steel smelting in China, which is classified as hazardous solid waste. The zinc-bearing dust is an important secondary resource, in which the zinc and iron can be recycled as raw materials for the iron and zinc industries after separating them. Rotary kiln reduction is one of the main methods for separating zinc and iron from zinc-bearing dust. In this study, the 5 mm composite pellets containing zinc-bearing dust is prepared by forced disturbed pelleting as reduction charge. The rotary kiln system with controllable temperature field and atmosphere field by multi-point quantitative air suppling is used as the main equipment of reduction. This technology can realize the treatment of raw materials with high iron and zinc content in rotary kiln, but also can effectively improve the production efficiency and the quality of zinc oxide powder, reduce the kiln-ringing. Compared with the conventional rotary kiln method, the processing capacity of zinc-bearing dust increase by 30%. The zinc removal ratio reaches 95% and the ZnO content of zinc oxide powder is 53.93 wt.%. The TFe content and ZnO content of reduction product are 60.56 wt.% and 0.25%, respectively. The annual operation ratio of zinc-iron separation by rotary kiln with zinc-bearing dust is 92%. The metallization rate of reduction product is controllable. The reduction product with metallization rate of 65.97% can be used as a sintering raw material, and the comprehensive energy consumption is 187kgce/t. The reduction product with metallization rate of 88% can 1 be used as a converter steelmaking raw material, and the comprehensive energy consumption is 253.1kgce/t.

Analysis and Study of the Electrical Properties of Nano ZnO.Cu/Al Schottky Diode

Schottky diode (semiconductor/metal) ZnO.Cu/Al was prepared by using the bar-coating method to prepare films of ZnO.Cu on aluminum substrate. Powders of zinc oxide doped with copper were previously prepared with different Cu doping ratios. These powders were characterized using X-ray diffraction showed the have a polycrystalline structure, and also using a field emission scanning electron microscope to confirm the morphology of the prepared powders, which it turned out to be nanostructures with a relatively uniform distribution. The properties of the prepared Schottky diode were studied, and the diode parameters were calculated, including voltage barrier, saturation current, ideality factor, and rectification factor through the relationship between current and voltage at forward and reverse bias as a function to the different Cu doping ratio and the best rectification factor was 4.91at highest Cu doping ratio.

Non-enzymatic electrochemical voltammetric sensors based on thulium:zinc oxide for dopamine detection

In this study, zinc oxide (ZnO) powders with dopant rates of 1 mol% thulium (Tm) (1Tm:ZnO), 2 mol% Tm (2Tm:ZnO), and 3 mol% Tm (3Tm:ZnO) nanoparticles were synthesized by co-precipitation method. Subsequently, Polyaniline (PANI)/1Tm:ZnO, PANI/2Tm:ZnO, and PANI/3Tm:ZnO nanocomposite sensors were prepared using a low-cost and simple sonication method. The results showed that the prepared PANI/1Tm:ZnO-based biosensor detected dopamine in the concentration range of (0.8–6.5) µM with a sensitivity of 0.2568 µAµM−1cm−2. Using these sensitivity values of the sensor, the LOD and LOQ values of the PANI/1Tm:ZnO-based sensor were calculated as 1.92 µM and 5.8 µM, respectively. The incorporation of 1% Tm into ZnO host (PANI/1Tm:ZnO) significantly enhanced the sensitivity of the biosensors.

Study of The Effect of Calcination Temperature on the Phase Composition of ZnO Powder Synthesized via The Sol-Gel Method

This study investigated the effect of calcination temperature on the phase composition and crystal size of zinc oxide powders synthesised by the sol-gel method. Zn powder, HCl and NaOH were used as precursors in a multi-step process involving dissolution, titration, gel formation, leaching, drying and calcination at temperatures ranging from 300°C to 700°C for 2 hours. Rietveld analysis of X-ray diffraction (XRD) data using MAUD and Rietica software determined phase composition and crystal size. Initial analysis identified a single simonkolleite phase (Zn5(OH)8Cl2) prior to calcination, which disappeared at 500°C. Wurtzite (ZnO) appeared at 300°C, accompanied by secondary phases (NaCl and ZnCl2). The wurtzite content increased to 81.42 wt% at 700°C. Calcination temperature also influenced crystal size, which ranged from 27.34 nm to 110.61 nm for wurtzite at different temperatures. The results highlight the dynamic changes in phase composition and crystal size with different calcination temperatures, providing valuable insights into tailoring zinc oxide properties for various applications.

Optical and electric characteristics of CuO nanoparticle-doped ZnO thin films using thermionic vacuum arc deposition system

In this study, the thermionic vacuum arc (TVA) method was employed to fabricate thin films of zinc oxide (ZnO) doped with copper oxide nanoparticles (CuONPs). The primary objective was to investigate the influence of the substrate on the characteristics of the CuONPs-doped ZnO thin films. CuONPs were synthesized using both the solution plasma process and the high-voltage liquid plasma generation method, resulting in particle sizes ranging from 20 to 40 nm. The X-ray diffraction (XRD) pattern confirmed the polycrystalline nature of the CuONPs. The prepared CuONPs in powder form were blended with ZnO powder and utilized as an anode material for TVA discharge and coating. The structural, optical, elemental, and topological properties of the resulting thin films were systematically examined. The findings revealed that the deposited thin films exhibited a polycrystalline structure, with transparent and electrically conductive layers. Similar reflection values were observed for films deposited on both glass and indium tin oxide (ITO)-coated glass substrates. Nanostructures on the film surfaces were elucidated through field emission scanning electron microscopy images. The atomic ratios of Cu/Zn were determined as 1/3 and 1/10 for films deposited on uncoated and ITO-coated glass substrates, respectively. The mean grain size of the nanoparticles on the film surface measured approximately 17 nm for films deposited on uncoated glass substrates and 35 nm for those deposited on ITO-coated glass substrates. The film resistance was measured at 20 kΩ, indicating its suitability as a semiconductor. Analysis of the XRD pattern identified peaks corresponding to CuONPs and ZnO in the deposited films, affirming their polycrystalline nature. In conclusion, the deposited thin films exhibit favorable characteristics for semiconductor applications, and the coating method employed proves to be effective in producing high-quality thin films.

Synthesis of magnesium oxide and zinc oxide powders in a glow discharge plasma at atmospheric pressure

Investigation of the processes involved in the synthesis of magnesium oxide and zinc oxide powders using the thermal effects of an atmospheric-pressure glow discharge plasma in an inert gas flow are described. The discharge operates in a repetitively pulsed mode with pulse repetition rate of several tens of kilohertz and pulse duration up to 12 μs, discharge current of 600 mA and voltage up to 300 V. These parameters lead to thermal erosion of magnesium or zinc inserts in a molybdenum crucible. The chemical and phase composition of the erosion products were determined using TEM/EDS and X-ray diffraction analysis, and the composition of the plasma was assessed by optical emission spectrometry. This experimental approach allows fabrication of powders of these metal oxides with characteristic particle size 10–50 nm, and the formation of coatings of these materials in a one-step process.

Reconstituted dry powder formulations of ZnO-adjuvanted ovalbumin induce equivalent antigen specific antibodies but lower T cell responses than ovalbumin adjuvanted with Alhydrogel® or cationic adjuvant formulation 01 (CAF®01)

Most licensed human vaccines are based on liquid dosage forms but have poor storage stability and require continuous and expensive cold-chain storage. In contrast, the use of solid vaccine dosage forms produced by for example spray drying, extends shelf life and eliminates the need for a cold chain. Zinc oxide (ZnO)-based nanoparticles display immunomodulatory properties, but their adjuvant effect as a dry powder formulation is unknown. Here, we show that reconstituted dry powder formulations of ZnO particles containing the model antigen ovalbumin (OVA) induce antigen-specific CD8+ T-cell and humoral responses. By systematically varying the ratio between ZnO and mannitol during spray drying, we manufactured dry powder formulations of OVA-containing ZnO particles that displayed: (i) a spherical or wrinkled surface morphology, (ii) an aerodynamic diameter and particle size distribution optimal for deep lung deposition, and (iii) aerosolization properties suitable for lung delivery. Reconstituted dry powder formulations of ZnO particles were well-tolerated by Calu-3 lung epithelial cells. Furthermore, almost equivalent OVA-specific serum antibody responses were stimulated by reconstituted ZnO particles, OVA adjuvanted with Alhydrogel®, and OVA adjuvanted with the cationic adjuvant formulation 01 (CAF®01). However, reconstituted dry powder ZnO particles and OVA adjuvanted with Alhydrogel® induced significantly lower OVA-specific CD8+CD44+ T-cell responses in the spleen than OVA adjuvanted with CAF®01. Similarly, reconstituted dry powder ZnO particles activated significantly lower percentages of follicular helper T cells and germinal center B cells in the draining lymph nodes than OVA adjuvanted with CAF®01. Overall, our results show that reconstituted dry powder formulations of ZnO nanoparticles can induce antigen-specific antibodies and can be used in vaccines to enhance antigen-specific humoral immune responses against subunit protein antigens.

Effects of Dietary Acacia nilotica Fruit, Zinc Oxide Nanoparticles and Their Combination on Productive Performance, Zinc Retention, and Blood Biochemistry of Rabbits.

This study aims to examine the effects of supplementing male rabbit diets with nanoparticles of zinc oxide (Nano-ZnO) and Acacia nilotica fruit powder (ANFP) on production sustainability under hot climatic conditions. Eighty Californian male rabbits aged 40 days old (average body weight 738.5 ± 11 g) were divided into four treatment groups and administered one of the following diets: control diet, Nano-ZnO (50 mg/kg), ANFP (5 g/kg), or a combination of Nano-ZnO (50 mg/kg) and ANFP (5 g/kg) for a period of 60 days. Each of the 20 rabbits used in a treatment was regarded as a replicate. The results showed that adding Nano-ZnO and ANFP individually or in combination to rabbits' diets improved (p < 0.05) growth performance in comparison to control. In addition, zinc contents in serum or the testis tissues in the Nano-ZnO- and ANFP-treated rabbits were significantly greater (p < 0.05) than those in the control group. In addition, serum levels of creatinine, alanine aminotransferase, and aspartate aminotransferase were decreased (p < 0.05) by supplementation of Nano-ZnO, ANFP, or their combination. Carcass criteria did not differ among the treatments. Overall, the findings of the present study indicate that rabbits fed diets containing Nano-ZnO and ANFP, as well as their combination, showed improvements in growth performance, kidney and liver functions, as well as zinc retention in tissues under hot climatic conditions. The combination of Nano-ZnO and ANFP exhibited the best performance in the rabbits. More research on the synergistic effects of Nano-ZnO and ANFP in the sustainable production of rabbit meat is required.

Magnetically recyclable ZnO coated Fe3O4 nanocomposite for MO dye degradation under UV-light irradiation

We describe the synthesis of zinc oxide (ZnO) coated magnetite (Fe3O4) [ZnO/Fe3O4] nanocomposite and its photocatalytic application towards the methyl orange (MO) dye degradation. ZnO/Fe3O4 nanocomposite was prepared by opting the ex-situ mechanical stirring process of ZnO powder and solvothermally prepared Fe3O4 nanoparticles. The photocatalytic properties of the ZnO/Fe3O4 nanocomposite were investigated, and the degradation of methyl orange (MO) dye was found to be 84% in 120 min under UV light. The electron transfer mechanism might explain the still debatable MO dye degradation mechanism in the present case. The photogenerated electrons transfer to the conduction band (CB) of Fe3O4 from the CB of ZnO under UV light exposure. This results in the creation of defect levels (i.e., Fe2+ or Fe3+) in ZnO, lowering the CB of ZnO. The reusability and efficient magnetic separability of ZnO/Fe3O4 photocatalyst was established by 60% degradation after four cycles under UV light irradiation. The nanocomposite's XRD pattern before and after photocatalytic degradation exhibited no structural change, demonstrating the photocatalyst's outstanding stability. Our investigations demonstrated the potential for MO dye degradation by ZnO/Fe3O4 nanocomposite under UV light irradiation.

ZnO Treatment on Mechanical Behavior of Polyethylene/Yellow Birch Fiber Composites When Exposed to Fungal Wood Rot.

Wood plastic composite (WPC) usage and demand have increased because of its interesting chemical and mechanical properties compared to other plastic materials. However, there is a possibility of structural and mechanical changes to the material when exposed to the external environment; most research on wood plastic is performed on the material with elevated fiber content (40-70%). Therefore, more research needs to be performed regarding these issues, especially when the fiber content of the WPC is low. In this study, composite materials composed of high-density polyethylene (HDPE) reinforced with yellow birch fibers (20 and 30%) were made by injection molding. The fibers were treated with dissolved zinc oxide (ZnO) powder in sodium oxide (NaOH) solution, and the fabricated material was exposed to fungal rot. ZnO treatment in this case is different from most studies because ZnO nanoparticles are usually employed. The main reason was to obtain better fixation of ZnO on the fibers. The mechanical properties of the composites were assessed by the tensile and Izod impact tests. The impact energies of the samples fabricated with ZnO-treated fibers and exposed to Gloephyllum trabeum and Trametes versicolor decreased, when compared to samples fabricated with ZnO-nontreated fibers. The mechanical properties of the samples composed of ZnO-treated fibers and exposed to rot decreased, which were reported by a decreased Young's modulus and impact energies. The usage of ZnO treatment prevented mycelium proliferation, which was nonexistent on the samples. It has been noted that the decrease in mechanical properties of the treated samples was because of the action of NaOH used to dissolve the ZnO powder.