Cryogenic Mill Research Articles

Polymeric Biocomposite Based on Thermoplastic Polyurethane (TPU) and Protein and Elastomeric Waste Mixture.

Polymeric biocomposites based on TPU/recycled TPUW/mixed leather and SBR rubber waste unmodified/modified with polydimethylsiloxane/PE-g-MA in different percentages were made via the mixing technique on a Plasti-Corder Brabender mixer with an internal capacity of 350 cm3. The waste, which came from the shoe industry, was cryogenically ground with the help of a cryogenic cyclone mill at micrometric sizes and different speeds. For the tests, standard plates of 150 × 150 × 2 mm were obtained in a laboratory-scale hydraulic press via the method of compression between its plates, with well-established parameters. The biocomposites were tested physico-mechanically and rheologically (MFI) according to the standards in force on polymer-specific equipment, also via FT-IR spectroscopy and microscopy, as well as via differential scanning calorimetry-DSC. Following the tests carried out, according to the standard for use in the footwear industry, at least two samples present optimal values (of interest) suitable for use in the footwear industry by injection or pressing in forming moulds.

Isolation of High-Quality Total RNA from Small Animal Articular Cartilage for Next-Generation Sequencing.

Articular cartilage is characterized by a low density of chondrocytes surrounded by an abundant extracellular matrix (ECM) consisting of a dense mixture of collagens, proteoglycans, and glycosaminoglycans. Due to its low cellularity and high proteoglycan content, it is particularly challenging to extract high-quality total RNA suitable for sensitive high-throughput downstream applications such as RNA sequencing (RNA-Seq). Available protocols for high-quality RNA isolation from articular chondrocytes are inconsistent, resulting in suboptimal yield and compromised quality. This poses a significant difficulty in the application of RNA-Seq to study the cartilage transcriptome. Current protocols rely either on dissociation of cartilage ECM by collagenase digestion or pulverizing cartilage using various methods prior to RNA extraction. However, protocols for cartilage processing vary significantly depending on the species and source of cartilage within the body. Protocols for isolating RNA from human or large mammal (e.g., horse or cattle) cartilage samples are available, but this is not the case for chicken cartilage, despite the species being extensively used in cartilage research. Here, we present two improved RNA isolation protocols based on pulverization of fresh articular cartilage using a cryogenic mill or on enzymatic digestion using 1.2% (w/v) collagenase II. Our protocols optimize the collection and tissue processing steps to minimize RNA degradation and enhance RNA purity. Our results show that RNA purified from chicken articular cartilage using these methods has appropriate quality for RNA-Seq experiments. The procedure is applicable for RNA extraction from cartilage from other species such as dog, cat, sheep, and goat. The workflow for RNA-Seq analysis is also described here. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Extraction of total RNA from pulverized chicken articular cartilage Alternate Protocol: Extraction of total RNA from collagen-digested articular cartilage Support Protocol: Dissection of chicken articular cartilage from the knee joint Basic Protocol 2: RNA sequencing of total RNA from chicken articular cartilage.

Penetration of Vancomycin into Noninfected Bone in Patients Undergoing Total Joint Arthroplasty Evaluated by a Minimal Physiologically Based Population Pharmacokinetic Modeling Approach.

Arthroplasty is a healthcare priority and represents high volume, high cost surgery. Periprosthetic joint infection (PJI) results in significant mortality, thus it is vital that the risk for PJI is minimized. Vancomycin is recommended for surgical prophylaxis in total joint arthroplasty (TJA) by current clinical practice guidelines endorsed by the Infectious Diseases Society of America. This study aimed to develop a new assay to determine vancomycin concentrations in serum and bone, and a minimal physiologically based population PK (mPBPK) model to evaluate vancomycin bone penetration in noninfected patients. Eleven patients undergoing TJA received 0.5-2.0 g intravenous vancomycin over 12-150 min before surgery. Excised bone specimens and four blood samples were collected per patient. Bone samples were pulverized under liquid nitrogen using a cryogenic mill. Vancomycin concentrations in serum and bone were analyzed by liquid chromatography-tandem mass spectrometry and subjected to mPBPK modeling. Vancomycin serum and bone concentrations ranged from 9.30 to 86.6 mg/L, and 1.94-37.0 mg/L, respectively. Average bone to serum concentration ratio was 0.41 (0.16-1.0) based on the collected samples. The population mean total body clearance was 2.12L/h/kg0.75. Inclusion of total body weight as a covariate substantially decreased interindividual variability in clearance. The bone/blood partition coefficient (Kpbone) was estimated at 0.635, reflecting the average bone/blood concentration ratio at steady-state. The model predicted median ratio of vancomycin area under the curve (AUC) for bone/AUC for serum was 44%. Observed vancomycin concentrations in bone were overall consistent with perfusion-limited distribution from blood to bone. An mPBPK model overall well described vancomycin concentrations in serum and bone.

Encapsulation of Lactobacillus acidophilus in solid lipid microparticles via cryomilling

We herein delved into the microencapsulation of Lactobacillus acidophilus (LA) into solid lipid microparticles (SLMs) via the cryomilling technique. For this aim, a frozen lipid mixture containing LA was pulverized at different times (7, 14, 21, 28, and 35 min) using a cryogenic mixer mill to produce probiotic-loaded SLMs. The impacts of different cryomilling durations on the SLMs properties (morphology, particle size, water activity, polymorphism, crystallinity, and thermal behavior) and the viability of LA were evaluated. Microencapsulation improved the viability of LA in simulated gastrointestinal fluids, heat stress, and different concentrations of salt and sucrose. SLMs also were suitable to be incorporated into foods. However, once the cryomilling time was prolonged, the viability of encapsulated LA declined, and particle size grew. The cryomilling technique showed great potential as an alternative approach for encapsulation due to the lack of solvent, short processing time, and simplicity.

Polymer composite based on NBR rubber compounded with rubber waste functionalized with potassium oleate

Waste is a material that occurs as a result of a biological or technological process that can no longer be used as such. Recycling and reusing waste make it possible to contribute to environmental protection and, of course, to the protection of human health by eliminating toxins during waste incineration. The purpose of this paper is to process and characterize polymer composites based on NBR rubber (butadiene-co-acrylonitrile rubber) and rubber waste functionalized with potassium oleate in terms of rheological characteristics (to determine the optimal vulcanization time), Brabender diagrams and physico-mechanical properties in normal state and after accelerated ageing at 70°C, for 168 h (using elastomer-specific equipment). Functionalized rubber waste (with potassium oleate up to 20% at 60°C) is introduced into the mixture in proportions of 10; 20; 30; 50%. The polymeric composites based on butadiene-co-acrylonitrile elastomer and rubber waste (ground with a cryogenic mill at 10,000 rpm, at the size of 0.35 mm) were compounded on a mixer with a capacity of 350 cm3 according to the working recipes. The mixtures were supplemented with vulcanization activators and accelerators on an electric roller, resulting in formulations in the form of 4 mm thick sheets, which are then subjected to the relevant characterizations according to the standards in force for the footwear industry.

Beginners guide to ribosome profiling

Beginners guide to ribosome profiling

Quantification of Bacterial DNA from Infected Human Root Canals Using qPCR and DAPI after Disinfection with Established and Novel Irrigation Protocols.

The removal of bacterial infections within the root canal system is still a challenge. Therefore, the cleansing effect of established and new irrigation-protocols (IP) containing silver diamine fluoride (SDF) 3.8% on the whole root canal system was analyzed using quantitative PCR (qPCR) and 4′,6-diamidino-phenylindole-(DAPI)-staining. Extracted human premolars were instrumented up to F2 (ProTaper Gold) under NaCl 0.9% irrigation and incubated with Enterococcus faecalis for 42 days. Subsequently, different ultrasonically agitated IP were applied to the roots: control (no irrigation), 1. NaOCl 3%, EDTA 20%, CHX 2%, 2. NaOCl 3%, EDTA 20%, 3. NaOCl 3%, EDTA 20%, SDF 3.8%, 4. SDF 3.8%, and 5. NaCl 0.9%. One half of the root was investigated fluorescent-microscopically with DAPI. The other half was grinded in a cryogenic mill and the bacterial DNA was quantified with qPCR. The qPCR results showed a statistically significant reduction of bacteria after the application of IP 1, 2, and 3 compared to the control group. While IP 4 lead to a bacterial reduction which was not significant, IP 5 showed no reduction. These data corresponded with DAPI staining. With qPCR a new molecular-biological method for the investigation of the complete root canal system was implemented. The novel IP 3 had an equally good cleansing effect as the already established IP.

Multivariate optimization and comparison between conventional extraction (CE) and ultrasonic-assisted extraction (UAE) of carotenoid extraction from cashew apple

Carotenoids are an essential component of cashew and can be used in pharmaceuticals, cosmetics, natural pigment, food additives, among other applications. The present work focuses on optimizing and comparing conventional and ultrasound-assisted extraction methods. Every optimization step took place with a 1:1 (w:w) mixture of yellow and red cashew apples lyophilized and ground in a cryogenic mill. A Simplex-centroid design was applied for both methods, and the solvents acetone, methanol, ethanol, and petroleum ether were evaluated. After choosing the extractor solvent, a central composite design was applied to optimize the sample mass (59–201 mg) and extraction time (6–34 min). The optimum conditions for the extractor solvent were 38% acetone, 30% ethanol, and 32% petroleum ether for CE and a mixture of 44% acetone and 56% methanol for UAE. The best experimental conditions for UAE were a sonication time of 19 min and a sample mass of 153 mg, while the CE was 23 min and 136 mg. Comparing red and yellow cashews, red cashews showed a higher carotenoid content in both methodologies. The UAE methodology was ca. 21% faster, presented a more straightforward composition of extracting solution, showed an average yield of superior carotenoid content in all samples compared to CE. Therefore, UAE has demonstrated a simple, efficient, fast, low-cost adjustment methodology and a reliable alternative for other applications involving these bioactive compounds in the studied or similar matrix.

Efficient liberation of electrode materials in spent lithium-ion batteries using a cryogenic ball mill

Efficient liberation is a key to the recycling of the electrode materials in spent lithium-ion batteries (LIBs). To improve the liberation of the electrode materials, a novel cryogenic grinding method of high selectivity was proposed. The low temperature characteristics of the traditional binder material PVDF and the current collector materials were tested. The results show that the glassy transition temperature of the binder PVDF is about 235 K. The binder would change from a high elastic state to a brittle state thus is easy to be crushed at a lower temperature. On the contrary, the impact strength of the current collector materials increases with the decrease of the temperature. Therefore, the grinding of electrode plates at low temperatures would be more selective grinding. The cryogenic grinding tests results show that, compared with that of room temperature, the content of the nickel-cobalt-manganese-lithium in the −0.15 mm particle size was increased from about 16–84%, the graphite content from 31.55% to 90.58%, and the content of aluminum and copper in the +1 mm grain size increased from 79.32% and 74.62–95.42% and 97.75%，respectively. This research may provide a new method to the recycling of spent LIBs.

Development and uncertainty estimation of cryogenic homogenization and static headspace–gas chromatography–mass spectrometry method for the simultaneous determination of twelve toxic volatiles in disposable menstrual products

Volatile organic compounds (VOCs) threaten the health of women who use disposable menstrual products (DMPs). In this study, we aimed to develop a simple and reliable analytical method using a cryogenic mill and static headspace–gas chromatography–mass spectrometry (HS-GC-MS) for the simultaneous determination of twelve toxic VOCs in DMPs, and estimate the measurement uncertainty of the method using the bottom-up approach to ensure the quality of analytical results. Static HS conditions for the direct thermal extraction of the target VOCs from the cryogenically ground sample powders were optimized in terms of extraction temperature and equilibrium time. The separation was achieved using a GC-MS equipped with a VF-624ms column. Cryogenic mill homogenized DMP into powder with 100-μm particles in scanning electron microscopy study. Sample powder was demonstrated to be homogenous as assessed by the homogeneity test. Validation studies showed that the method has reliable performance characteristics: linearity (R2 ≥ 0.9994), limit of quantification (LOQ, 8.4–50.5 ng g−1), precision (relative standard deviation ≤ 18.7%), and accuracy (recovery = 83.4–114.2%) for all the analytes. The proposed method was successfully applied to the commercial products of disposable sanitary pads and tampons. The content of styrene was the highest, followed by those of toluene, hexane, and ethylbenzene. The quantitative data exhibited acceptable precision, as evaluated using the intra-laboratory Horwitz ratio. The expanded uncertainties estimated at three concentration levels ranged from 6.4% to 77.9%. Our simple and reliable method will be useful for quality control testing or quantitative risk assessment and will contribute to resolving the safety issues associated with the risk of human exposure to trace volatile residues in DMPs.

Selection of Conditions of Ultrasound-Assisted, Three-Step Extraction of Ellagitannins from Selected Berry Fruit of the Rosaceae Family Using the Response Surface Methodology

The study examined the influence of the method of grinding the fruit—homogenisation and grinding using a cryogenic mill—on the extraction efficiency of the ellagitannins (ETs). Two methods of extraction support were compared: sonication and shaking. In the second stage, selection of the extraction with the best conditions was carried out using the response surface methodology (RSM). Ellagitannins were extracted in different variants of acetone concentration (40, 60, and 80%), duration of sonication (5, 10, and 15 min), and temperature (20, 35, and 50 °C). The extracts obtained were subjected to quantitative analysis by high-performance liquid chromatography with a diode-array detector (HPLC–DAD) and identification using a mass spectrometer. Grinding is an important stage in the extraction of ellagitannins from berries. Extracts from fruit shredded with a cryogenic mill were characterised by an average of 20% lower content of ellagitannins than extracts from homogenised fruit. Studies using RSM showed that the most important factor affecting the amount of extracted ellagitannins from all tested fruits is the concentration of acetone. The highest ETs concentration was obtained using 80% acetone solution (in the tested range 40–80%). In the case of raspberries, strawberries, and wild strawberries, under the conditions used, the temperature and duration of sonication did not significantly affect the extraction efficiency. An interaction between extraction time and solvent concentration was observed for blackberries, indicating optimal conditions for this fruit as 15 min and an acetone concentration of 80%, respectively.

Comparison of methods of DNA extraction from ixodid ticks

Ixodid ticks are ectoparasites of animals and humans that carry a wide variety of pathogenic microorganisms. Ticks can cause pathological conditions such as paralysis, fever, toxicosis and allergies, as well as a large number of infectious and invasive diseases. The aim of our study was to compare three methods of DNA extraction, to test their effectiveness and practicality in obtaining material from ticks and to determine their effect on the results of PCR-based studies. During 2018, questing ticks were collected from vegetation in Khmelnytsky region. Three different methods were used for DNA extraction: crushing of ticks with scissors and lysis in ammonium hydroxide, crushing with scissors followed by DNA extraction with a commercial kit Genomic Mini AX Tissue Spin (A&A Biotechnology, Gdynia, Poland), homogenization of ticks with programmable cryogenic grinder SPEX Sample Prep Freezer Mill 6875 followed by extraction of DNA with Genomic Mini AX Tissue Spin.
 A total of 72 ticks (60 D. reticulatus and 12 I. ricinus) from vegetation were examined by PCR for the presence of pathogens from genera/complex Babesia, Rickettsia and Borrelia burgdorferi sensu lato (s.l.). 
 Following the first method of DNA extraction, 4.2% of ticks tested positive for Babesia spp., and DNA of Rickettsia spp. and Borrelia burgdorferi s.l. was detected in 12.5% and 33.3% of ticks, respectively. Following the second method of DNA extraction, 4.2% of ticks tested positive for Babesia spp., and DNA of Rickettsia spp. and Borrelia burgdorferi s.l. was detected in 54.2% (13 positive specimens) and 33.3% of ticks, respectively. The third method also revealed 4.2% of ticks positive for DNA of Babesia spp. Rickettsia DNA was detected in 7 D. reticulatus and 2 I. ricinus ticks, (37.5%). DNA of Borrelia spp. was identified in 37.5% of ticks. Thus, the combined method of mechanical homogenization of ticks in combination with a commercial kit for DNA isolation, offers maximum efficiency in terms of speed, number and size of samples to be studied.

Mechanochemical generation of singlet oxygen.

Controlled generation of singlet oxygen is very important due to its involvement in scheduled cellular maintenance processes and therapeutic potential. As a consequence, precise manipulation of singlet oxygen release rates under mild conditions, is crucial. In this work, a cross-linked polyacrylate, and a polydimethylsiloxane elastomer incorporating anthracene-endoperoxide modules with chain extensions at the 9,10-positions were synthesized. We now report that on mechanical agitation in cryogenic ball mill, fluorescence emission due to anthracene units in the PMA (polymethacrylate) polymer is enhanced, with a concomitant generation of singlet oxygen as proved by detection with a selective probe. The PDMS (polydimethylsiloxane) elastomer with the anthracene endoperoxide mechanophore, is also similarly sensitive to mechanical force.

Assessment of Anthropogenic Volatile Organic Compounds in Leaves of Two Urban Tree Species in Santiago de Chile

Anthropogenic volatile organic compounds (AVOCs) represent the third largest contribution in gaseous emissions in the urban and peri-urban region of Santiago, the capital of Chile. Some of these compounds are toxic or mutagenic, cause serious damage to human health, and decrease plant growth and development. There is little international information related to atmospheric AVOCs in leaf content from trees exposed to specific sources of pollution, and to our knowledge, there is no research on this topic in Chile. The purpose of this work was to study the leaf content of AVOCs from the Organic Range of Gasoline (ORG: range 6-10 C) emitted by local traffic during the austral summer and spring seasons in leaves of two exotic tree species (Liriodendron tulipifera and Platanus x acerifolia). Leaf samples collected around 2 meters height above the ground were pulverized with a cryogenic mill and eleven chemical components were quantified (toluene, 1,2,4-trimethylbenzene (1,2,4-TMB), styrene, ethylbenzene, ortho, meta and para-xylenes, naphthalene, 1,3,5-trimethylbenzene (1,3,5-TMB), isopropylbenzene and trichloroethene) using GC-MSD MSD. Benzene was detected but not quantified, because it was always under the quantification limit of the technique. Differences in concentrations were found for type of site exposure, season and tree species. The differences found in leaf content of AVOCs in P. x acerifolia exposed to vehicle traffic suggest that the concentration of these contaminants in leaves may be due to AVOC capturing. Considering the content of AVOCs in leaves and not in the whole individual tree, L. tulipifera presented a higher concentration of total AVOCs than P. x acerifolia for both seasons. The Prop-Equiv and OFP of L. tulipifera were very high in summer, being 13.6 and 14.8 times greater, respectively, than the corresponding values for P. x acerifolia.

Study on elements concentrations on seabird feathers by instrumental neutron activation analysis.

Seabirds are very sensitive to environmental changes and due to their large longevity they are also sensitive to cumulative impacts. These birds usually occupy the higher trophic levels. White-chinned petrel (Procellaria aequinoctialis) and black-browed albatross (Thalassarche melanophris) are Procellariiformes, which is a seabird order, composed of 4 families. In the last years, researches are being done and actions are being taken to reduce the mortality of albatrosses and petrels caused by human activities. Due to the great ecological importance of these birds and the developed work with Procellariiformes, this study purpose was to quantify the Br, Cl, Cu, K, Mg, Mn, Na and V elements in white-chinned petrel and black-browed albatross feathers. Bird specimens were killed accidentally by pelagic longline fisheries operating off southern Brazil. Feathers were cleaned with acetone and then milled in a cryogenic mill. Instrumental Neutron Activation Analysis (INAA) was used for quantification of the element concentrations and measurements of induced activities were performed in a High Purity Germanium (HPGe) detector for gamma ray spectrometry. The obtained results on feathers showed that concentrations in these birds are not higher than others studies with the same species and, with exception of Br, there are no significant differences between elements mean concentrations in the two seabirds.

Structural modification of fiber and starch in turmeric residue by chemical and mechanical treatment for production of biodegradable films

The dye extraction from turmeric rhizomes (Curcuma longa L.) is generated a residue with high starch content that in nature does not form film. Therefore, we decided evaluate how mechanical treatment (ball or cryogenic mill) and chemical treatment with alkali (NaOH 2.5% (1, 4, or 8 h) and bleaching with NaClO or H2O2 at 25 or 45 °C affect the chemical structure of the starch and fibers in turmeric residue, and its filmogenic capacity. Ball milling decreased the turmeric residue particle size more effectively favoring the chemical procedures. Only two types of chemical treatment consisting in alkaline treatment for 4 h and bleaching with NaClO and H2O2, respectively, for 4 h, at 25 °C yielded turmeric residues with filmogenic capacity. The chemical treatments oxidized the starch granules causing to lose their crystal structure as verified by DRX, and removed amorphous fibers such as lignin and hemicellulose increasing cellulose content in turmeric residue. FTIR analyses also revealed that the starch granules were oxidized. As bleaching agent, NaClO caused greater starch oxidation (the highest carboxyl and carbonyl groups contents) affording films with the best mechanical and functional properties. Although chemical treatment reduced the turmeric residue phenolic compounds, the films still presented antioxidant activity.

The challenge in preparing particle suspensions for aquatic microplastic research

The occurrence of small particles consisting of organic polymers, so-called microplastic (MP), in aquatic environments attracts increasing interest in both public and science. Recent sampling campaigns in surface waters revealed substantial numbers of particles in the size range from a few micrometers to a few millimeters. In order to validate sample preparation, identification and quantification and to investigate the behavior of MP particles and potential toxic effects on organisms, defined MP model particles are needed. Many studies use spherical compounds that probably behave differently compared to irregularly shaped MP found in environmental samples. However, preparation and handling of MP particles are challenging tasks and have been systematically investigated in the present study. Polystyrene (PS) as a commonly found polymer with a density slightly above that of water was selected as polymer type for milling and fractionation studies. A cryogenic ball mill proved to be practical and effective to produce particles in the size range from 1 to 200 µm. The yield of small particles increased with increasing pre-cooling and milling durations. Depending on the concentration and the size, PS particles do not completely disperse in water and particles partly creep vertically up along glass walls. Stabilized MP suspensions without use of surfactants that might harm organisms are needed for toxicological studies. The stabilization of PS particle suspensions with ozone treatment reduced the wall effect and increased the number of dispersed PS particles but increased the dissolved organic carbon concentration and changed the size distribution of the particles.

Modeling breakage and motion of black pepper seeds in cryogenic mill

The present investigation aims to represent three-dimensional motion and breakage phenomena of black pepper seeds in the cryogenic mill (hammer mill) using discrete element method (DEM). In DEM modeling, bonded particle model was coupled with Hertz-Mindlin contact model. Calibration method was used to select appropriate model (bond) parameters. The calibrated set of bond parameters includes 3.12 × 1011 Pa m−1 normal stiffness; 1.56 × 1011 Pa m−1 shear stiffness; 3.88 × 108 Pa critical normal stiffness; 1.94 × 108 Pa critical shear stiffness. Besides, the validity of calibrated parameters was tested in the hammer mill. The observed qualitative and quantitative results (breakage and flow pattern) of numerical and experimental approaches were in good agreement. Based on these results, a few prefatory suggestions were provided to improve the design aspects of the mill. Overall, DEM modeling offered a better understanding of particle breakage and flow pattern in the mill.

Evaluation of a Freezer Mill for Bone Pulverization prior to DNA Extraction: An Improved Workflow for STR Analysis.

Traditional methods for bone pulverization typically generate heat, risking stability of DNA sample. SPEX™ has developed cryogenic grinders which introduce liquid nitrogen to cool the sample and aid in the grinding process. In this study, the Freezer Mill 6970 EFM was used with two DNA extraction methods and routine downstream STR analysis procedures. DNA from as little as 0.1 g of bone powder was used to develop full STR profiles after freezer mill pulverization, and the method was reproducible. Further, no contamination was detected upon cleaning/reuse of the sample vials. There were no significant differences in DNA yield, STR alleles detected, or peak heights using the freezer mill as compared to traditional grinding, and successful DNA profiles were achieved from as low as 0.1 g of bone powder with this method. Overall, this work indicates that this cryogenic mill method may be used as a viable alternative to traditional tissue grinders.

Effect of Mill Type on Morphology of AA6013 Aluminium Powder

In conventional recycling method, metal chips are cast after pressing and melting in electric arc furnace. Material loss occurs during the recycling from liquid metal due to the several reasons. Direct recycling method which produces the aluminium powder from aluminium chips using mechanical mill can be an alternative to conventional recycling method. Thus material and energy losses, and labour cost will be reduced by direct recycling method without melting. In this study, the particle morphology of powder direct recycled from AA6013 aluminium alloy chips with cryogenic, disc and ball type grinders is investigated. Mechanical milling resulted flaky and irregular shaped AA6013 particles. It was ascertained that the chips did not break sufficiently in despite of the long duration milling mechanisms by ball mill. Cryogenic mill provides the energy required for milling mechanisms to act. Disc mill has the highest impact energy was determined. Consequently, efficiency of ball mill is lower than the efficiency of cryogenic and disc type mills. Shape factors of powders produced with ball and cryogenic mills were found greater than that of the powder produced by disc mill. Disc mill has the most efficient and effective impact energy which produces the smaller particles per minute, was determined.