Extensive Grinding Research Articles

Bead milling liberates the antioxidant properties of nanosized tubers of Vernonia guineensis Benth (Asteraceae)

Vernonia guineensis Benth. (Asteraceae), locally known as ‘African ginseng’, is an herbaceous plant with various therapeutic properties, sold by herbalists, and used in several traditional African preparations. Nanosizing has the capability to potentiate those preparations in their pharmacological properties. Premilling and extensive grinding using a planetary ball mill were used to reduce the size of V. guineensis tubers towards antioxidant studies. Water was used as an environmental friendly, cost effective solvent and dispersant to generate a nanocolloidal suspension of V. guineensis tubers. Size and size distribution were determined via photon correlation spectroscopy at room temperature which allows discussion on stability by Zeta potential and polydispersity index. Phytochemical screening shows presence of alkaloids, coumarins, polyphenol, saponins, tanins, terpenes, and anthraquinones. The distribution curve in water shows a polydispersed system with large hydrodynamic particles of size close to 1000 nm and a Z-average of 484.5 nm. The preparation separate in two phases with polydispersity index 0.217 for the supernatant and 0.543 for the suspension. In the supernatant and suspension, the particles zeta potential were -12.3 mV and -13.7mV respectively. The Mastersizer analysis indicates that there are smaller particles in volume in the supernatant than in the suspension. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity shows an increase in antioxidant activity, compared to that of ascorbic acid, in the nanoformulated state. These findings allow us to conclude on the potential of size reduction when compared to solvent extraction in pharmacologic preparations.

Postprandial nutrient dynamics and their implications for formulated feed development for the ornate spiny lobster (Panulirus ornatus)

AbstractCrustacean feeding morphology and postprandial nutrient processing is a highly size‐selective procedure. The digestive system of lobsters is predicated on grinding feed to a fine particle size before digestion. Therefore, fine pregrinding of raw materials may bypass the need for extensive grinding in the proventriculus and expedite digestive and absorptive processes. Panulirus ornatus juveniles (N = 56) were allocated to four feed groups (n = 14). Groups A, B and C were fed nutritionally identical feeds featuring raw materials ground to 1000 µm (Feed A), 500 µm (Feed B) and 200 µm (Feed C) while the fourth group (Group S) acted as a 24‐h nonfeeding baseline control group. Sequential postprandial haemolymph extractions were performed at 0.5, 1, 1.5, 2, 3.5, 5.5 and 24 h across treatment groups. Haemolymph samples were assessed and analysed for brix (%), total proteins (g L–1), glucose (mmol L–1) and cholesterol (mmol L–1). Brix was found to have significant positive correlations with all the haemolymph biochemical properties while no significant correlations were identified between individual lobster size and haemolymph properties. Analysis of deviance applied to mixed effects models did not identify significant differences in haemolymph properties across feed groups. Trends identified here are indicative of diurnal rhythm patterns, likely orchestrated by the release of the crustacean hyperglycaemic hormone (CHH) when anticipating a meal. Additionally, the use of brix values, may not be optimal for identifying postprandial trends, yet could remain a valid indicator of longer‐term nutritional status.

NMR relaxometry – a new reliable and non-destructive method to estimate the fluid content of rock salt

Abstract. In the context of the site selection procedure for a high-level radioactive waste repository in Germany (StandAG, 2017), the fluid content of salt rocks is an important parameter to evaluate their barrier properties, i.e. the potential for gas formation (geoscientific weighing criteria 7 – geoWK-7) and the tendency to form fluid pathways (geoWK-6). Moreover, it can affect hydraulic conductivity (minimum requirement 1 – MA-1, geoWK-1 and geoWK-11), heat resistance (geoWK-8) and rock mechanical properties (geoWK-5), and it can be used for the spatial characterisation (geoWK-3) of the host rock (e.g. Kneuker et al., 2020). Fluids in rock salt (halite) are typically present in small, unconnected inclusions (commonly < 25 µm) located within crystals or arranged along crystal boundaries and fissures, and they can consist of brine, minor amounts of gases and hydrocarbons. When estimating the fluid content of rock salt, the main challenges are (i) the low fluid content (< 1 wt %), (ii) the low permeability of the bulk rock preventing fluid extraction and (iii) the spatial heterogeneous fluid distribution. In summary, the measurements are time intensive, and the results are highly dependent on the sample selection and preparation. Nuclear magnetic relaxation (NMR) relaxometry is an established petrophysical method in the oil and gas industry for the non-invasive characterisation of hydrocarbon host rocks and their fluids (e.g. Dunn et al., 2002), but it has not been used extensively for rock salt to date. We present the first results obtained from steeply inclined Zechstein rock salt (z2HS2) and compare them with a water content estimated by extensive grinding (< 30 µm) of the salt samples in dried acetone and the subsequent analysis of the extracted fluids using infrared spectroscopy (Mertineit et al., 2022). The first results show that NMR has promising features including (i) a low limit of detection (∼0.01 wt %), (ii) non-destructive and (iii) quick (5–10 min) measurements, (iv) no need for extensive sample preparation, and (v) the provision of an average fluid content over a large sample volume (100–900 mL).

Structural changes in smectites subjected to mechanochemical activation: The effect of the occupancy of the octahedral sites

The effect of the configuration and composition of the octahedral sheet on the mechanochemical stability of different smectites, both trioctahedral (natural and synthetic hectorites, Hc, and saponite, Sp) and dioctahedral (montmorillonites, Mt) subjected to a short period of high energy grinding (HIG) was evaluated. The higher extent of amorphization for dioctahedral than for trioctahedral smectites was confirmed from the results obtained from XRD analysis, infrared and MAS NMR spectroscopy. After extensive grinding, 29Si MAS NMR spectra indicated transformation of the Si-tetrahedra from a layered structure (Q3 sites) to Si-tetrahedra in a three-dimensional network (Q4 sites). However, the Q3 signal still dominated the spectra of trioctahedral samples, rather than the Q4 signal that indicates formation of an amorphous phase. 27Al MAS NMR spectra confirmed the transformation of the octahedral Aloct and tetrahedral Altet present in the layered structure of Mt into an amorphous phase containing both Altet and Aloct coordination. FTIR spectra of the unground samples showed the presence of absorption bands associated with OH groups attached to octahedra with Mg atoms in the central positions, while none of the bands attributed to structural OH groups in Mt could be seen in the spectra after grinding. The 1H NMR spectra exhibited strong signals of structural OH after 6 min of grinding for Hc and Sp. Similar trends were seen in the DTG and H2O mass profiles for the dehydroxylation step: the peaks attributed to structural OH groups were not observed in Mt after treatment, while they were still detected for both hectorites and saponite.

Sintering of Aluminum-Oxynitride Powder Prepared by Self-Propagating High-Temperature Synthesis

Sintering of aluminum-oxynitride powders prepared by self-propagating high-temperature synthesis in a nitrogen-containing gel was researched. Use of the powders without extensive mechanical grinding was problematical because of their low specific surface areas. Equipment fitted with grinding containers lined with high-density plates and grinding balls made of the same material, 9Al2O3·5AlN, were required to solve this problem.

Aerodynamic Properties of Biochar Particles: Effect of Grinding and Implications

This study reports the aerodynamic properties of ground biochar particles produced from the slow pyrolysis of mallee biomass at 400 °C, considering grinding times from 10 s to 16 min. The data show that extensive grinding (e.g., ≥1 min) substantially increases the amounts of particulate matter with an aerodynamic diameter of <10 μm (PM10) and <2.5 μm (PM2.5) in the ground biochars. Whereas the aerodynamic particle size distribution (PSD) of PM10 in biochar after grinding for 10 s shows no obvious peak, a bimodal PSD is observed for PM10 in the biochars after grinding for 1–16 min. The results suggest that care must be taken during biochar grinding to minimize the PM10 and PM2.5 produced. PM10 and PM2.5 in a biochar should also be quantified to assess environmental risks during biochar transport and applications.

Extensive grinding and pressurized extraction with water are key points for effective and species preserving extraction of arsenic from rice

Download options Please wait... Article information DOI https://doi.org/10.1039/C2AY25094B Article type Paper Submitted 26 Jan 2012 Accepted 08 Mar 2012 First published 12 Apr 2012 Download Citation Anal. Methods, 2012,4, 1237-1243 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Extensive grinding and pressurized extraction with water are key points for effective and species preserving extraction of arsenic from rice P. Alava, T. Van de Wiele, F. Tack and G. Du Laing, Anal. Methods, 2012, 4, 1237 DOI: 10.1039/C2AY25094B To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Pradeep Alava Tom Van de Wiele Filip Tack Gijs Du Laing

Polymorphic transformation of anhydrous caffeine under compression and grinding: a re-evaluation.

Polymorphic transformations that may occur during mechanical treatment are of great interest for the production of pharmaceutical solids. Anhydrous caffeine is a well-known example of such transformations but a careful reading of the already existing literature shows that published results are contradictory. In this study, both forms of caffeine, form I and form II, respectively metastable and stable at ambient pressure and temperature, were submitted to compression in an instrumented alternative press and to grinding, and were studied before and after treatment by X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC). Compression experiments showed no changes of form II during compression, whereas form I was partially transformed into form II. Nevertheless, this transformation did not happen immediately. Form II appeared after a kinetically slow transformation and was clearly detectable only after a few days, fact that was never mentioned by previous authors. Same phenomenon was observed after the grinding of form I but also after an extensive grinding of form II. DSC and XRPD measurements indicated that polymorphic transformation did not happen directly, but that a new intermediate form was obtained after mechanical treatment, which slowly turned into form II within a few days.

Processing induced size effects in plastic yielding upon miniaturisation

Size effects in metals have received considerable attention in literature in the last decades. For preparing specimens dedicated processing techniques, such as laser-cutting, micro-milling, turning, etc., are used. Most of these processing methods intrinsically damage crystals just below the worked surface. In macroscopic applications, the effect on the overall mechanical behaviour can safely be neglected in most cases. Upon miniaturisation, however, the influence of the affected region becomes more important and may induce a processing induced size effect, which is far from negligible. Processing induced size effects are analysed by carefully characterising the plastic yielding in uniaxial tension of rectangular, 300 μ m -thick aluminium sheet specimens, with a well-defined homogeneous microstructure containing through-thickness grains. The specimens are processed to different widths by three independent machining techniques: (1) laser-cutting, (2) mechanical cutting, and (3) extensive grinding from a larger width. These independent techniques all result in a distinct processing induced size effect upon miniaturisation, i.e. an increase of up to 200% in yield stress for a decrease from about 12 to 3 grains over the specimen width. Using a simple Taylor averaging model, it is shown that the yield stress in the affected edge region increased to 210–350% of its initial (or bulk) value. In addition, it is found that even a prolonged anneal near the melting temperature can only partially remove the processing induced size effect. The results clearly demonstrate that processing induced size effects have to be considered in the design of miniaturised devices and parts as well as in scientific research relying on the testing of manufactured small-scale test specimens.

New nanocrystalline manganese oxides as cathode materials for lithium batteries: Electron microscopy, electrochemical and X-ray absorption studies

New nanostructured manganese oxy-iodides were prepared by redox reaction of sodium permanganate with lithium iodide in aqueous medium at room temperature. Transmission electron microscopy (TEM) showed that they are nanocrystalline with grain size in the 5–10 nm range. TEM and X-ray absorption confirmed the short-range ordered structure of these compounds, which contain octahedrally coordinated manganese atoms. The electrochemical properties were studied as a function of preparation conditions (Li/Mn ratio, carbon incorporation at the synthesis stage and grinding). Best electrochemical results were obtained either on samples with carbon black incorporated directly in the aqueous reaction medium at the synthesis stage, or on samples with carbon mixed after synthesis, submitted to extensive grinding. Typical capacities in the potential window 1.8–3.8 V are 160 and 130 mAh/g at the 40th and 100th cycle, respectively. Step-potential electrochemical spectroscopy and the evolution of X-ray absorption spectra on discharge are consistent with a single-phase lithium intercalation reaction with simultaneous manganese oxidation–reduction.

Nanosized manganese oxide as cathode material for lithium batteries: Influence of carbon mixing and grinding on cyclability

New manganese oxi-iodides were prepared by redox reaction of sodium permanganate with lithium iodide in aqueous medium at room temperature. The effects of Li/Mn ratio, carbon incorporation at the synthesis stage and grinding were systematically studied. Structural characterization showed that these materials are nanocrystalline. Best electrochemical results were obtained either on samples with carbon mixed after synthesized, submitted to extensive grinding before electrode fabrication, or on samples for which carbon black was incorporated directly in the aqueous reaction medium at the synthesis stage. Typical capacities in the potential window 1.8–3.8 V are160 and 130 mAh g −1 at the 40th and 100th cycle, respectively.

A method for preparation of magnetizable cellulose and its application in radioimmunoassays for T3 and T 4 1

An easy adoptable technique has been developed to prepare magnetizable cellulose by the process of wet grinding of a mixture of iron oxide (magnetite) and cellulose in a stirred ball mill. Anti rabbit IgG was covalently coupled to this magnetizable cellulose. The immunosorbent thus prepared has been used in radioimmunoassays of T3 and T4 for the separation of bound and free antigens. The reliability of the above immunosorbent has been validated by studying assay parameters such as non-specific binding (NSB), maximum binding (B0), CV etc. The single step process of wet grinding adopted here not only firmly binds magnetite and cellulose physically, but also lowers the size of the resulting magnetizable cellulose. The conventional method of preparation involves the coprecipitation of cellulose dissolved in cuprammonium hydroxide solution along with iron oxide, followed by extensive grinding and sieving of the iron oxide impregnated cellulose.

Mini-prep method suitable for a plant breeding program

Plant breeders need a nondestructive and inexpensive protocol to screen large numbers of plants early after sowing. Isolation of DNA represents one of the limiting steps in this process: normally a person is capable of isolating 25 to 50 samples per day. To speed up the isolation of DNA in marker-assisted plant breeding programs, a CTAB mini-prep was modified into an inexpensive and nondestructive procedure. With this protocol a single individual can isolate 200 to 250 samples per day of high-quality DNA that is immediately suitable for testing by PCR. The amounts of DNA isolated are sufficient for about 150 PCR amplifications. These improvements are achieved by eliminating time-consuming and noncritical steps in the standard protocol, such as extensive grinding, washing with ethanol, and treatment with RNAse A.

Molecular Characterization of Alkalilignin-1M30C: a Valid Alternative Preparation to the Björkman Lignin in the Analytical Study of Wheat Straw Lignin

Bjorkman lignin, obtained by extensive grinding and dioxane extraction, is considered one of the most suitable standard preparations close to the native lignin from lignocellulosic materials. In this study, alkalilignin extracted with 1 M NaOH at 30 °C (AL-1M30C), and the Bjorkman lignin from wheat straw (Triticum aestivum) were compared using spectroscopic and degradative techniques. The very small chemical differences between the two preparations are mainly that the Bjorkman method yields a lignin with slightly higher proportion of p-hydroxyphenyl units, and some co-extracted aliphatic fractions. The AL-1M30C preparation, on the other hand, showed a somewhat higher proportion of syringyl units, as well as the probable effects of the selective removal of structures associated with ester carbonyl groups. The evident similarity between both lignin samples suggests that AL-1M30C produced from wheat straw may represent a convenient alternative to Bjorkman lignin preparation for analytical purposes. These results also point towards the possibility of producing suitable lignin preparations from other Gramineae plants showing high solubility in alkaline reagents.

Sewage Sludge Proteins: I. Extraction Methodology

AbstractThe extraction and quantitation of sewage sludge proteins is a pre‐requisite to evaluating their role as labile C and N sources in sludge‐amended soil. The objective of this study was to develop extraction methodology for the routine quantitation of sewage sludge proteins. Seven sewage sludges were obtained and prepared by oven drying at 55 °C followed by extensive grinding and mixing to produce homogenous samples. Proteins were extracted using H2O, 10% (v/v) Triton X‐100 (a non‐ionic detergent), and 1 M NaOH, and they were analyzed using the Lowry protein assay with bovine serum albumin standards. Protein contents of extracts ranged from (in g kg−1, dry wt. basis): (i) H2O, 1.3 to 24; (ii) 10% Triton X‐100, 3.6 to 59; and (iii) 1 M NaOH, 53 to 280. Water and detergent‐extractable proteins were less than, and base‐extractable proteins were within, literature values reported for total sludge proteins. The coefficients of variation (CV) for each extractant and all sludges were, with one exception, below 6%. The three methodologies provided precise and reproducible data for the extraction of sewage sludge proteins. The detergent extraction procedure is recommended for routine use because of its shorter extraction time.

Phase Equilibria in the System Tl-Ca-Ba-Cu-O. I. Stability of the 2122 Phase Under Conditions of Oxygen Annealing

AbstractResults are presented for 850°C oxygen annealing experiments (up to 62 hr) on the 2122 (Tl:Ca:Ba:Cu) oxide phase, with and without intermediate grinding. Samples were characterized by powder X-ray diffraction and a.c. magnetic susceptibility. The 2122 phase appears to be thermodynamically stable in oxygen under conditions of both extensive grinding, and, annealing of long duration. However, onset Tc's vary from 71 K to 109 K for apparently single-phase 2122 samples with nearly identical X-ray powder patterns, depending upon the heat treatment.

The System TiO2‐Bi2Ti4O11

The system TiO2‐Bi2Ti4O11 was examined by Raman spectroscopy and X‐ray diffraction to determine whether TiO2 is soluble in Bi2Ti4O11. The Raman spectral data obtained from preparations made at ∼ 1050°C and cooled to room temperature led us to conclude that TiO2 is not soluble in the “high‐temperature” form of Bi2Ti4O11. It was also found that extensive grinding of the phase identified as the “high‐temperature” form converts it to the “low‐temperature” form, stable below 250°C.

Remodeling of teeth by grinding

Pulp and dentin reactions to extensive grinding of human teeth were studied clinically and histologically. The facial portions of forty-eight premolars to be extracted for orthodontic reasons were reshaped to “lateral incisors” using diamond instruments and abundant water cooling. Following grinding and polishing with sandpaper discs and pumice, topical fluoride was administered. The patients were asked to report any increased sensitivity reactions. The teeth were extracted at 0, 1, or 3 weeks or 3 to 5 months and examined histologically. No significant discomfort was reported by the patients, except for an initial period of a few days during which there was increased sensitivity to temperature changes. The histologic findings indicated that extensive remodeling of young permanent teeth is possible with no or only minor pulp and dentin reactions. Some initial localized effects in terms of aspiration of odontoblast nuclei, hyperemia, absence of a cell-free zone, and slight cellular infiltration were sometimes observed, but the long-term observations indicated that these reactions were transient. Secondary dentin formation was not registered. It is important that gentle grinding techniques with abundant water spray be used and that smooth and self-cleansing surfaces which allow hypermineralization of the ground enamel and dentin be prepared. In a few teeth in which proximal retention areas were unintentionally prepared, caries developed and marked pulp reactions occurred. Therefore, great care must be taken not to introduce proximal steps when mesiodistal tooth width adjustments are performed. The present study has provided histologic and clinical evidence to indicate that even extensive recontouring by grinding may not be harmful to the teeth. This should encourage orthodontists to remodel teeth by grinding to improve the final occlusal and esthetic results in a number of different cases.

Quantitative analysis of calcite and Mg‐calcite by X‐ray diffraction: effect of grinding on peak height and peak area

ABSTRACTMineralogical analysis of calcite and Mg‐calcite by X‐ray diffraction requires that the samples be ground to a powder. Such grinding determines the particle size of the powder and the structural damage of the minerals. Both of these in turn affect the peak intensities recorded by the X‐ray machine. Most carbonate sediments are inhomogeneous; they contain both calcite and Mg‐calcite which are affected differently by grinding. Such differences cause quantitative analytical results to be inconsistent with the true mineralogical abundance. The two acceptable methods of analysis—(1) measurement of peak height from the base and (2) measurement of the area under the peak—were compared to determine if sample preparation affects the quantitative results. In samples with variable and relatively small amounts of calcite and Mg‐calcite the measurement of peak height yields more reproducible results than does the measurement of peak areas. Different proportions of particle size of the mineralogical components in a sample powder, affect proportionally more the peak areas than the peak heights. Extensive grinding causes structural damage of the component minerals which affects much more the peak areas than the peak heights. Thus for quantitative analyses of calcite and Mg‐calcite in inhomogeneous carbonate samples which require differing grinding times and have greatly variable amounts of calcite and Mg‐calcite, the peak height measurement seems to be a better method than peak area measurement.

Difficult carbonaceous materials and their infra-red and Raman spectra. Reassignments for coal spectra

Infra-red and Raman spectra of intractable carbonaceous materials are difficult to obtain. For coals, carbon blacks, and some chars infra-red spectra have been obtained with relative ease. Only recently have good infra-red transmission spectra of activated carbons been obtained. More difficult materials have now been successfully studied by the transmission infra-red method, most notably ground graphite (non-crystalline), through the use of efficient and extensive grinding. Intense infra-red bands are observed at about 1590 and 1360 cm −1 for ground graphite, carbon blacks, and some activated carbons. Laser-Raman spectra of coals, carbons, and graphites have two lines at about the same frequencies as the infra-red bands. However, the similarity of these laser-Raman spectra indicates in the case of coal that we may be observing the spectrum of carbonized coal rather than of coal, due to degradation of the sample by the laser beam. These new spectral results necessitate reassignment of some bands in the infra-red spectra of coals. Graphitic structures (non-crystalline) are believed to be responsible for the 1600 cm −1 band in coals and the broader 1360 cm −1 band, which fit closely the broad band contour in the infra-red spectra of coals from 1800 to 900 cm −1. The intensities of the 1600 and 1360 cm −1 bands in ground graphite are more than sufficient to account for the band intensities observed in the spectra of coals and chars. Diamond-like structures such as quaternary carbon atoms are weak absorbers and cannot be responsible for either of these bands.