Grinding Method Research Articles

Implementation and precision of CFRP geometric configurations before adhesive bonding repair based on 1064 nm infrared pulsed fiber laser ablation

Before the adhesive bonding repair of the aircraft’s CFRP (Carbon Fiber Reinforced Polymer) structure, the common practice is to remove the damaged area material and form a predetermined repair geometric configuration using the grinding method according to the repair design shape. The geometric accuracy, dimensional accuracy, and surface characteristics of the geometric configuration have a significant impact on the adhesive bonding and repair effectiveness in CFRP structure repair. In the study, a 1064 nm infrared pulse laser was used to selectively and controllably remove the three layers of cured prepreg (fiber and resin) on the surface of the CFRP laminate structure. Based on the analysis of geometric accuracy and surface morphology, the effectiveness of CFRP adhesive bonding repair was verified. The results showed that, under the condition of undamaged CFRP fibers and thorough removal of the surface resin, the laser achieved a dimensional accuracy of ± 50 μm and a thickness accuracy of ± 20 μm for CFRP geometric configuration. The angular accuracy of rectangular configuration was less than ± 0.15°, and the roundness accuracy of circular configuration was greater than 0.995. The mechanical validation of the adhesive bonding repair indicated that the tensile strength recovery rate of CFRP repair structure after laser treatment was 84.7 %, and the failure mode was cohesive failure.

Cocrystals of a coumarin derivative: an efficient approach towards anti-leishmanial cocrystals against MIL-resistant Leishmania tropica.

Leishmaniasis is a neglected parasitic tropical disease with numerous clinical manifestations. One of the causative agents of cutaneous leishmaniasis (CL) is Leishmania tropica (L. tropica) known for causing ulcerative lesions on the skin. The adverse effects of the recommended available drugs, such as amphotericin B and pentavalent antimonial, and the emergence of drug resistance in parasites, mean the search for new safe and effective anti-leishmanial agents is crucial. Miltefosine (MIL) was the first recommended oral medication, but its use is now limited because of the rapid emergence of resistance. Pharmaceutical cocrystallization is an effective method to improve the physicochemical and biological properties of active pharmaceutical ingredients (APIs). Herein, we describe the cocrystallization of coumarin-3-carboxylic acid (CU, 1a; 2-oxobenzopyrane-3-carboxylic acid, C10H6O4) with five coformers [2-amino-3-bromopyridine (1b), 2-amino-5-(trifluoromethyl)-pyridine (1c), 2-amino-6-methylpyridine (1d), p-aminobenzoic acid (1e) and amitrole (1f)] in a 1:1 stoichiometric ratio via the neat grinding method. The cocrystals 2-6 obtained were characterized via single-crystal X-ray diffraction, powder X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis, as well as Fourier transform infrared spectroscopy. Non-covalent interactions, such as van der Waals, hydrogen bonding, C-H...π and π...π interactions contribute significantly towards the packing of a crystal structure and alter the physicochemical and biological activity of CU. In this research, newly synthesized cocrystals were evaluated for their anti-leishmanial activity against the MIL-resistant L. tropica and cytotoxicity against the 3T3 (normal fibroblast) cell line. Among the non-cytotoxic cocrystals synthesized (2-6), CU:1b (2, IC50 = 61.83 ± 0.59 µM), CU:1c (3, 125.7 ± 1.15 µM) and CU:1d (4, 48.71 ± 0.75 µM) appeared to be potent anti-leishmanial agents and showed several-fold more anti-leishmanial potential than the tested standard drug (MIL, IC50 = 169.55 ± 0.078 µM). The results indicate that cocrystals 2-4 are promising anti-leishmanial agents which require further exploration.

Impact of the grinding method on oil shale flotation

Oil shale’s natural floatability depends on its organic content which is negatively affected by the presence of inorganic impurities. Thus, the feed preparation, particularly in the crushing and grinding processes, affects the liberation of organic components as well as their surface properties. In this article, attrition scrubbing and ball milling, as different feed preparation techniques, were used to study their effects on oil shale flotation. The ground products using either technique were floated, using either pine oil or sodium oleate. The flotation results indicated that the organic recovery was improved using both reagents with higher improvement in the case of pine oil. Starting from 10% organics in the feed, the floated organics, at pH 3 using 0.4 kg/t pine oil and particle size of −0.1 + 0.045 mm, are improved to 23.5% and 17.8% using ball mill and attrition products, respectively. Interestingly, at a higher pine oil dosage, floated attrition products result in a higher grade and recovery than the ball mill products. The shearing mechanism in attrition is found to be more suitable for liberating organics in oil shale whereas maximum organic content and recovery of 25.7% and 91.4%, respectively were achieved using 7.5 kg/t pine oil.

Manganese (II) Halides for X‐Ray Imaging and Moisture Detection

AbstractOrganic–inorganic hybrid metal halides are widely used in X‐ray detection and imaging due to their high X‐ray absorption efficiency, ease of synthesis, and efficient luminescence. However, the issue of lead toxicity remains a concern. In this study, non‐toxic, 0D 2,2′‐(Ethylenedioxy)bis(ethylamine) manganese (II) bromide (EDBEMnBr4) is synthesized using the simple mechanical grinding method and the solution method that exhibits intense green emission at ≈525 nm. Moreover, the change of structure under the influence of temperature and water significantly affects its fluorescence color under UV light. Scintillator materials with and without moisture exposure showed spatial resolutions of 7 and 4 lp mm−1, and low detection limits of 4.62 and 5.25 µGyair s−1, respectively, meeting medical industry standards (<5.5 µGyair s−1). Furthermore, based on the apparent change in luminescence color triggered by moisture for EDBEMnBr4, a preliminary attempt is made to apply it to humidity monitoring showing that the boundary of color change has a good linear dependence on humidity and time. This work provides new opportunities for Mn‐based metal halides in both X‐ray detection as well as moisture detection.

Investigating the effect of different grinding conditions and methods on the concentration of opium alkaloids in poppy seeds as a good reduction practice

In recent years, following intoxications and false positive drug tests for poppy seeds, dangerously high concentrations of opium alkaloids (OAs) have been found. For this reason, health authorities are demanding studies to establish effective practices to reduce OAs in these seeds. Grinding, a common culinary process for various recipes, has previously been associated with potential morphine degradation. However, these studies have not established effective grinding conditions to decrease the concentration of all main OAs. Furthermore, due to the large variation in OAs concentration that can occur even in the same bag, this can be a difficult task. In view of the above, this study aimed to evaluate for the first time the impact of different grinding types, varying grinding time or repetitions, to determine any degradation trends of the main OAs present in poppy seeds. As a result, it was obtained a notable 20% degradation of morphine in the second grinding with grinders where the oil content of the seeds is not released, hinting at oil’s protective role against morphine oxidation. Therefore, the choice of grinding method is crucial. However, while acknowledging this, relying solely on this method as a good practice for OAs reduction may be insufficient, as it seems to have minimal impact on other OAs with any of the tested methods and conditions.

The Cutting‐Edge Progress in Covalent Organic Framework‐Based Nanomedicine

Covalent organic frameworks (COFs) are a class of porous crystalline materials with exceptional properties, constructed through covalently linked organic units. COFs are extensively applied in the field of biomedicine, particularly in the context of anticancer treatments. First, this review summarizes the diverse synthetic methods of COFs, including solvothermal synthesis, microwave‐assisted synthesis, room temperature synthesis, interface synthesis, ionothermal techniques, mechanical grinding, and electrochemical methods, and their impacts on the material's structure and performance. Second, COFs exhibit tremendous potential in the field of cancer therapy because of their orderly lattice structure, tunable pore sizes, high surface area, and excellent thermal and chemical stability. Therefore, the article deeply explores the applications of COFs in diverse cancer treatment modalities, encompassing early diagnostic bioimaging, drug delivery, various phototherapies, chemodynamic therapy, sonodynamic therapy, radiation therapy, and their combined therapeutic strategies. Finally, the article points out current research challenges and future directions in this field.

Autologous Tooth Granulometry and Specific Surface Area with Three Grinding Methods: An In Vitro Study.

A postextraction socket becomes a clinical challenge due to the fact that a series of changes associated with bone remodelling and resorption of the socket that occur after extraction, which limits the aesthetic and functional prognosis of implant-supported rehabilitations. It has been studied that the use of the autologous tooth-derived graft (ATDG) has regenerative properties and could therefore be useful for solving this type of problem. There is no consensus in the scientific literature on a standardized protocol for the use of the autologous tooth. Therefore, the aim of the present study was to evaluate the most relevant parameters to achieve the best properties of ground ATDG using three methods, namely Gouge forceps, electric grinder, and manual, that made up the study group (SG) and compared with the control group (CG) consisting of Bio-Oss®. The sample obtained by the electric grinder had the highest value of specific surface area (2.4025 ± 0.0218 m2/g), while the particle size as average diameter (751.9 µm) was the lowest and most homogeneous of the three groups. Therefore, the electric grinder allowed for obtaining ATDG with more regenerative properties due to its specific surface-area value and particle size in accordance with the xenograft with the greatest bibliographical support (Bio-Oss®). The higher specific surface increases the reaction with the physiological media, producing faster biological mechanisms.

Strong microwave absorption performance of simply grinding FAPbI3/CNTs composite absorbers

The distinctive physical and chemical characteristics of organic-inorganic lead halide perovskite make it a promising candidate for microwave absorption applications. However, the high-efficiency microwave absorption of halide perovskite-based composites is concentrated at high frequencies, while electronic equipment operates at low-frequency bands. Exploring simple and efficient methods to achieve optimal microwave absorption efficiency at low frequencies continues to pose a considerable challenge. Here, FAPbI3 was synthesized by a simple solvent-free hand grinding method and mixed with carbon nanotubes (CNTs) to obtain a series of FAPbI3/CNTs (FC) composites. By modulating the mass ratio of the components, FAPbI3 modulates the absorption bands, CNTs can effectively establish a conductive network to enhance both polarization loss and conductive loss and regulate impedance matching. The lower permittivity of FAPbI3 gives FC an advantage in terms of low-frequency microwave absorption. The FC-4 composite exhibits a minimum reflection loss (RLmin) of −55.67 dB at a low frequency of 6.88 GHz with a thickness of 3.5 mm. Meanwhile, microwave absorption performance can reach 99 % covering almost the entire C band when utilizing a thickness ranging from 3 to 5 mm. Additionally, according to adjusting the load of FAPbI3 in the mixture, the FC-3 composite displays the highest microwave absorption value among the composites based on halide perovskites. With a thickness of 1.4 mm, the reflection loss at 17.4 GHz reaches an impressive minimum value of −71.89 dB. This study represents the first research specifically focused on FAPbI3 perovskite in the domain of microwave absorption. FC composites display remarkable capabilities in absorbing microwaves, indicating their promising prospects for advancement within the realm of microwave absorption. This research may provide valuable insights for the design of low-frequency and high-efficiency microwave absorbers.

Comparison of preparation methods of rat kidney single-cell suspensions

Preparation of kidney tissue single-cell suspensions is the basis of single-cell sequencing, flow cytometry and primary cell culture, but it is difficult to prepare high quality whole kidney single-cell suspensions because of the complex structure of the kidney. We explored a technique called stepwise enzymatic digestion (StE) method for preparing a single-cell suspension of rat whole kidney tissue which contained three main steps. The first step is to cut the kidney into a homogenate. The second step is the digestion of renal tubules using Multi Tissue Dissociation Kit 2 and the last step is the digestion of glomeruli using type IV collagenase. We also compared it with two previous techniques, mechanical grinding method and simple enzymatic digestion method. The StE method had the advantages of high intrinsic glomerular cells and immune cells harvest rate, high singlets rate and high cell viability compared with the other two techniques. In conclusion, the StE method is feasible, highly efficient, and worthy of further research and development.

Discovering potential of different parts of Moringa oleifera’s plants as clarifying agent in coffee effluent treatment

Selection of coagulant for coagulation-flocculation treatment process involves more factors than we generally expect. Embracing emerging global concerns on green technologies and sustainability, researchers have been focusing on natural coagulant as an alternative to minimize environmental impact due to toxic chemical coagulants. Moringa oleifera has long been discovered as a highly potential agent in water clarification treatment, but most of the research done focuses only on the seeds of the plant. In this research, various parts of this plant species were studied namely soft stems, leaves, seeds and pods. These coagulants were prepared through drying and grinding methods, without any chemical activation or extraction to avoid unnecessary chemical burden on produced sludges or treated water after treatment. In treating coffee effluents, all these four coagulants from different parts (soft stems, leaves, seeds and pods) were able to remove good amount of turbidity compared to the control without coagulant. The performance of all four types of prepared coagulants were analyzed using jar test within similar dosage range to identify which part of M. oleifera that can serve the best coagulant. The highest removal of turbidity was achieved by the pods with 60-62% removal at a dosage as low as 0.03 and 0.04 g/L with 24-hour sedimentation. A similar range of turbidity removal was achieved by leaves coagulant at 0.06 g/L with similar operational conditions. These findings give evidence that different parts of M. oleifera plants possess good water clarifying ability, even better than the seeds that had been discovered beforehand.

Preparation and Characterization of Usnic Acid Nanocrystals with the Wet Grinding Method Using a Planetary Ball Mill

Preparation and Characterization of Usnic Acid Nanocrystals with the Wet Grinding Method Using a Planetary Ball Mill

Chiral 5-fluorouracil-arginine cocrystals screened by wet powder grinding method: Leading to synergistic anti-tumor and alleviate cardiotoxicity

Arginine (ARG) is a precursor for producing NO, which can relax vascular smooth muscle. We herein report cocrystals screened by powder grinding using chiral ARG to improve the bioavailability of 5-fluorouracil (5-FU) and alleviate 5-FU induced cardiotoxicity. The results of powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) inferred the formation of new solid phases. Hydrogen bonding interactions between C=O group and N-H were supported by Fourier transform infrared (FTIR) spectroscopy. The spectra intensity of circular dichroism (CD) of cocrystals were higher than that of ARG after combined with non-optically active 5-FU. The bioavailability and cytotoxicity of 5-FU were enhanced by cocrystallization. Notably, L-cocrystal prepared using biologically active L-ARG released lower dose NO in human umbilical vein endothelial cells (HUVEC) cells than that of D-cocrystal. D-cocrystal performed higher NO release ability by non-enzymatic pathway, indicating a greater potential to alleviate cardiotoxicity. 5-FU-induced cardiotoxicity in rats was effectively alleviated, proved by the least increased LDH, cTnI and CK-MB level induced by D-cocrystal.

Mesoporous Silica MCM-41 from Fly Ash as a Support of Bimetallic Cu/Mn Catalysts for Toluene Combustion.

The main outcome of this research was to demonstrate the opportunity to obtain a stable and well-ordered structure of MCM-41 synthesized from fly ash. A series of bimetallic (Cu/Mn) catalysts supported at MCM-41 were prepared via grinding method and investigated in catalytic toluene combustion reaction to show the material's potential application. It was proved, that the Cu/Mn ratio had a crucial effect on the catalytic activity of prepared materials. The best catalytic performance was achieved with sample Cu/Mn(2.5/2.5), for which the temperature of 50% toluene conversion was found to be 300 °C. This value remains in line with the literature reports, for which comparable catalytic activity was attained for 3-fold higher metal loadings. Time-on-stream experiment proved the thermal stability of the investigated catalyst Cu/Mn(2.5/2.5). The obtained results bring a valuable background in the field of fly ash utilization, where fly ash-derived MCM-41 can be considered as efficient and stable support for dispersion of active phase for catalyst preparation.

Auricularia auricula-judae Attenuates the Progression of Metabolic Syndrome in High-Fat Diet-Induced Obese Rats: Enzymatic Pre-Digestion Technology Is Superior to Superfine Grinding Method

Auricularia auricula-judae (AAJ) has been cultivated for food in China for centuries, and is also used as a folk medicine for the regulation of glucose and lipid metabolism. However, there are few studies on the effects of different processing technologies on the therapeutic efficacy of AAJ to date. This study investigated the effectiveness of the AAJ made by using superfine grinding and enzymatic pre-digestion technologies, respectively, in a high-fat diet obese rat model. It was found that oral administrations of two AAJ products significantly alleviated dyslipidemia by decreasing serum lipid levels and restoring liver functions. AAJ products made by using pre-digestion technology have appreciable potential to ameliorate lipid metabolic disorders over other products, possibly due to the higher levels of dietary fiber, crude polysaccharides, and total flavonoids released from AAJ during processing. By analysis of transcriptome sequencing and protein expression, it was clear that starch and sucrose metabolism and glycerolipid metabolism-related factors involved in fatty acid synthesis and metabolism in the liver of obese rats were significantly improved. This study gives further evidence that AAJ significantly ameliorates the progression of glucose and lipid metabolism in obese rats. Moreover, this study demonstrated for the first time that the pre-digestion method may be a better and more efficient processing approach for the improvement of AAJ bioavailability.

Fabrication of polycrystalline diamond micro-milling cutter with different grain sizes by picosecond laser

Polycrystalline diamond (PCD) is an excellent material for machining micro-tools due to its high hardness and wear resistance. However, the diameter of micro-milling tools is generally required to be less than 500 μm. When preparing micro-milling tools with a large aspect ratio, the processing load introduced by traditional grinding methods is easy to cause tool fracture. Therefore, a composite structure of carbide tool holder and diamond tool head is proposed in this paper. A technique of picosecond laser machining PCD micro-milling tool was studied, and the overall manufacturing process of tool blank preparation, nanosecond laser roughing and picosecond laser finishing was formed. A two-dimensional ablation mathematical model for tangential machining of PCD with a multi-pulse picosecond laser was established, and experiments verified the reliability of the mathematical model. In addition, the effects of picosecond laser pulse pitch, pulse energy, and track spacing on the surface quality of PCD materials with different particle sizes and cutting edge radius were studied by orthogonal experiments. The results showed that after picosecond laser processing, the surface roughness (Sa) of PCD with a particle size of 2 μm was the best, which can reach 0.33 μm, and the cutting edge radius of PCD micro-milling tool with a particle size of 25 μm was the smallest, which can get 1.67 μm. Using the optimized picosecond laser parameters, the high-sharpness single-edge micro-milling cutters with different particle sizes PCD with a diameter of 100 μm, aspect ratio greater than 3, and a cutting edge radius less than 3 μm were successfully fabricated.

Enhancement of Physicochemical and Pharmacokinetic Characteristics of Ranolazine drug substance using Cocrystalization Technique

Biopharmaceutical Classification System II drug, Ranolazine exhibits pH-dependent solubility and thus shows variable absorption along the gastrointestinal tract. Due to poor aqueous solubility particularly in basic pH, an attempt has been made to improve solubility through the cocrystallization technique. Cocrystals of Ranolazine with Nicotinamide have been synthesized at different molar ratios (1:1, 1:2, 1:3 2:1, and 3:1) through solvent-assisted grinding, slurry preparation, and solvent evaporation method and subsequently characterized by different analytical methodologies. Conformational characterization studies have been performed using techniques like melting point analysis, powder X-ray diffraction, and differential scanning calorimetry. Saturation solubility of Ranolazine alone along with cocrystals prepared in different molar ratios was conducted in water and buffers of different pH (1.2, 4.5, and 6.8) to establish enhancement in solubility. Ranolazine: Nicotinamide 1:2 cocrystals were found to be stable in accelerated and long-term stability conditions. In-vivo study performed in rats to demonstrate enhanced bioavailability. Ranolazine cocrystals with Nicotinamide were shown to have enhanced solubility in basic pH and improved peak plasma concentration, the area under the curve, and relative bioavailability by 2-folds.

An error compensation method for single point oblique axis grinding considering the grinding wheel wear

With the increasing amount of high quality optical products, the manufacturing requirement for the high-precision optical glass lenses is on the rise. Grinding is typically the main manufacturing process for the optical mold. The degree of wheel wear has a direct impact on the precision of the grinding process. In this paper, the wear rule of grinding wheel in the grinding process of optical aspheric surface is studied with the in-site wear measurement system. A new image processing method and a wear degree evaluation method are proposed. The wear prediction model for the grinding wheel is established. Then a modified compensation method of optical aspheric surface considering grinding wheel wear is proposed. The optical aspheric surface is then compensated using a modified multinomial equation considering grinding wheel wear. The results demonstrate that the profile error of optical aspheric surface can be reduced to less than 150 nm. The proposed compensation method that takes into account the grinding wheel wear can highly improve the grinding precision and efficiency of optical aspheric surface as compared with the conventional compensation method.

A New Simple Method for Age Determination of Harbour Porpoises (Phocoena phocoena)

Age determination of marine mammals is important for understanding the impact of anthropogenic disturbances as well as for population management. Toothed whales are usually age-determined by counting annually formed layers in their teeth. This includes a time-consuming sequence of preparations, usually involving chemical treatment. This study tested a quicker and simpler method for age determination of harbour porpoises (Phocoena phocoena), originally developed for age determination of foxes and other terrestrial carnivores. The tooth was ground with fine-grained sandpaper, and the age lines were directly read using a binocular microscope. To evaluate the usability of the grinding method for harbour porpoises, three tests were used: (1) the number of growth layer groups (GLGs) in teeth from 66 harbour porpoises by the grinding method were compared by two readers; (2) GLGs in teeth from six harbour porpoises prepared by the grinding method and by the decalcification method were compared in a blinded set-up with two readers; and (3) the GLGs in teeth from two individuals with known ages prepared by both the grinding method and the decalcification method, respectively, were compared. A Bland–Altman plot showed high agreement between the determined age of individuals by the two different methods. The average age difference was -0.56 years, and the 95% confidence interval for the average difference was [-4.3, 3.2] years. The grinding method is therefore considered to be a valid alternative and quicker method for age determination of harbour porpoises.

Catalytic evaluation of solid state hand-crafted bimetallic nanocore-shell composite via green reducing agent

The material fabrication via greener way as well as the magnetic nature for easy recoverability of the catalyst offers a way to put forth on material as Azadirachta indica (AI) decorated Fe3O4 @Ag-Cu nanocomposite. The nanocomposite (NC) was prepared by an eco-friendly one-step hand-made grinding method. Herein, the AI powder acts as a greener reducing and stabilizing agent for preparing nanocomposite (NC). The successfully synthesized bimetallic catalyst was examined with the help of HR-TEM, FE-SEM, XPS, VSM, XRD, FT-IR, and UV–vis studies. On average, the size of NC range was around 21 ± 3 nm, and the NC was spherical in shape while the metal nanoparticles (MNPs) were uniformly distributed over the surface of the AI extract. The green catalyst prepared by varying ratios of the metals was examined for the treatment of pollutant water-containing dyes and pharmaceutical waste. The core advantage of the green synthesized catalyst was tested for the photo-reduction of well-known pharmaceutical waste, such as paracetamol and ciprofloxacin in an efficient manner, and their rate constants were 3.82 × 10−2 min−1 and 1.27 × 10−2 min−1 respectively. Furthermore, the NC acquires the capability to degrade carcinogenic pollutants like Xylene Cyanol FF (XC) and Malachite Green (MG) at 86% and 82%, respectively. Despite this, it shows good antibacterial activity towards gram-positive (B. subtilis and S. aureus) as well for gram-negative bacteria (E. coli, P. aeruginosa). The catalyst was also employed for the reduction of 4-Nitrophenol (4-NP). A comparative strategy for the reduction of the pollutants with the help of sodium borohydride vs the photo-reduction were analyzed in these strategical studies. was Thus, the bimetallic catalyst flagged a better way to reduce pharma compounds and several noxious pollutants due to its low cost, highly efficient, and reusability holding good for many cycles.

Structural reconfiguration of Al/CaO adsorbent by Ni doping to improve sintering resistance and arsenic removal performance

CaO-based adsorbents have poor adsorption performance due to high temperature sintering. In this study, a trace amount of Ni was added to an Al/CaO adsorbent using the Pechini hydrothermal method and anhydrous grinding method. The modified adsorbent was then used to remove As2O3, and both experimental and theoretical approaches were employed. The experimental results showed that the addition of Ni transformed the surface of the adsorbent from a two-dimensional network structure to a three-dimensional cluster structure, significantly increasing its specific surface area and improving its adsorption capacity for As2O3. The adsorption capacity reached 933.1 mg/kg at 900 °C, which was 3.79 times higher than that of pure CaO and 8.2 times higher than that of Al2O3. Additionally, the presence of nano-scale NiO particles prevented the sintering of CaO grains, allowing the adsorbent to maintain its pore structure even after the reaction. Density functional theory (DFT) calculations showed that NiO was the most active site for As2O3 adsorption on the surface of Al/Ni-CaO. Ni acted as an electron transport bridge, enhancing electron transfer on the material's surface and increasing adsorption energy. These findings are important for future research on high-temperature removal of As2O3 with doped CaO-based adsorbents.