Effect Of Mechanical Processing Research Articles

Effect of milling atmosphere on stability and surface properties of ZnO/vermiculite hybrid nanocomposite powders

The zinc acetate dihydrate and anhydrous zinc chloride were used as precursors for the sonochemical preparation of the zinc oxide/vermiculite and organically modified zinc oxide/vermiculite_chlorhexidine nanocomposite materials. The nanocomposites were mechanically processed via a high-energy ball milling for 30 min at 300 rpm using two types of atmospheres an air or a nitrogen. Changes in temperature and pressure inside the grinding vessels were measured during mechanical processing in an air atmosphere. The ZnO(Cl)/V_30/300 sample reached the highest pressure (1161 mbar) and temperature (30.3 °C) in the milling vessels and for the ZnO(ac)/V_CH_30/300 sample the highest temperature difference was measured at the beginning and at the end of the milling (7 °C). The phase transformation, chemical composition and particle size of the hybrid nanocomposite materials were investigated using X-ray diffraction method, Fourier-transform infrared spectroscopy, X-ray fluorescence spectroscopy, carbon phase analysis and particle size distribution analysis. Changes in morphology and particle arrangement were characterised using scanning electron microscopy. The effect of mechanical processing in a protective atmosphere on surface properties such as specific surface area, surface conductivity and ζ-potential were demonstrated in relation to the type of precursor used for the preparation of ZnO nanoparticles in the structure of hybrid nanocomposite materials.

Deposition, Dietary Exposure and Human Health Risks of Heavy Metals in Mechanically Milled Maize Flours in Mbarara City, Uganda.

Consumption of maize and maize-based products contributes a significant percentage to the total food energy intake in Uganda. However, the production of maize-derived foodstuffs is performed traditionally or by small- and medium-scale processors using different processing techniques. This can lead to differences in the quality of these products from processors, raising food safety concerns. In this study, the effects of mechanical processing (milling) methods on deposition of heavy metals into milled maize flour and the associated consumption health risks were assessed. Atomic absorption spectrophotometry was used to quantitatively establish the concentration of iron (Fe), manganese (Mn), zinc (Zn), cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), cobalt (Co) and nickel (Ni) in 100 samples of maize milled using a wooden mortar (n = 2), a metallic mortar (n = 2), diesel engine-powered mills (n = 48) and electric motor-powered mills (n = 48). Results showed that the mean concentrations of heavy metals in mg/kg were Fe (11.60-34.45), Cu (0.50-8.10), Ni (0.50-1.60), Mn (0.70-25.40), Zn (4.40-15.90), Pb (0.53-10.20), Cd (0.51-0.85), Cr (0.50-1.53) and Co (0.50-1.51). The highest concentrations were found in flour milled using a traditional metallic mortar while the lowest levels were in those samples milled using a wooden mortar. The Fe, Pb and Cd contents of flours produced using the metallic mortar and some commercial mills was found to be higher than the permissible limits set by WHO/FAO. Human health risk assessment showed that there are potential carcinogenic health risks from adults' intake of heavy metals in maize flour milled using a metallic mortar. Therefore, processing of maize flour needs to be monitored by the relevant statutory bodies in Uganda to minimize the possibility of heavy metal contamination of food products and animal feeds.

Carcass, meat quality traits, and economic analysis of Nellore bulls fed with finishing feedlot diets containing mechanically processed corn silage

Effects of mechanical processing (MP) of corn silage and its inclusion in feedlot diets on carcass and meat quality traits of Nellore (Bos indicus) were analyzed. Seventy-two bulls aged approximately 18months and with an initial average body weight of 392.8 ± 22.3kg were used. The experimental design was a 2 × 2 factorial arrangement, considering the concentrate-roughage (C:R) ratio (40:60 or 20:80), MP of silage and their interactions. After slaughter, hot carcass weight (HCW), pH, temperature, backfat thickness (BFT), and ribeye area (REA), yields of meat cuts (tenderloin, striploin, ribeye steak, neck steak, and sirloin cap), meat quality traits and economic analysis were evaluated. A lower final pH was found in the carcasses of animals consuming diets containing MP versus unprocessed silage (pH = 5.81 versus 5.93). Carcass variables (HCW, BFT, and REA) and meat cut yields were not affected by treatments. The C:R 20:80 increased the intramuscular fat (IMF) content by approximately 1%, without affecting moisture, ash, and protein contents. Meat/fat color (L*, a* and b*) and Warner-Bratzler shear force (WBSF) were similar among treatments. The results indicated that the MP of corn silage in finishing diets can provide better carcass pH results in Nellore bulls, without negatively influencing carcass weight, fatness, and meat tenderness (WBSF). The IMF content of meat was slightly improved using a C:R 20:80 and lower total costs per arroba produced (3.5%), daily costs per animal/day (4.2%), and cost per ton of feeds (5.15%) were found with MP silage.

Effect of surface cleaning on seam quality of laser beam welded mixed joints

In this study, different surface cleaning methods were used to remove greases and oils from the surface of the E235 steel tube component of the diamond segmented drill bit before laser beam welding. The mechanical, chemical and electromechanical cleaning methods were selected because they are suitable for removing greases and oils adhering to the surface during tube production. The cleaned samples were successfully welded using the same heat inputs by laser welding. The effect of mechanical processes with sandblasting and dry-ice blasting, chemical processes with isopropyl alcohol, acetone and alkaline acidic liquid, electromechanical process with a laser beam on micro-computer tomography, break-out value and micro-hardness measurement examined. The cleanliness of the surfaces and strength of the laser-welded joint was inferred from the break-out value (BOV), as this is the principal qualification value in mass production. The results were compared to the untreated sample. According to the results obtained in this study, any defects in the seams were analyzed, and no cracks founded by computer tomography. According to a shade of grey diagram, all the pretreated samples had a higher absorption than the untreated sample. While the chemical methods had a significant effect (59–66 %), the mechanical and electromechanical methods had a positive effect (22–48 %) compared to the untreated sample. In addition, the break-out values showed that the mechanical methods had a significantly higher effect (19 %) than the other surface cleaning methods. This test showed different results from the micro-CT scan. The microhardness test showed no difference between the hardnesses of the cleaned and uncleaned samples and no difference in seam thicknesses. The optimal oil removal process discusses in the conclusion part.

Mechanical activation effecton the structure and properties of SHS compounds

This article reviews the main properties of explosive incendiary compounds, their effectiveness and applications. The effects of mechanical processing on the kinetic characteristics of the transformation of powder mixtures are alsodiscussed.

Mechanical processing effects on the secondary plant cell wall arrangement in Sorghum bicolor

Unlocking one third of plant biomass as a renewable feedstock for fuels and materials depends on the effective deconstruction of the secondary plant cell wall. Over 90% of the native secondary plant cell wall is composed of cellulose and hemicellulose polysaccharides and the lignin aromatic polymers. Deconstruction refers to the processes which digest polymers into desired subunits. Present deconstruction processes are centered on lignin-first extraction to overcome the recalcitrance of biomass: the accumulation of indigestible plant polymers during deconstruction.

Cold-rolling induced residual stress effect on the shock response of crystalline-metallic glass (Cu–CuZr) nanolaminates by molecular dynamics simulation

The effect of mechanical processing and thereby induced residual stress on the shock response of the crystalline-amorphous nanolaminate is unexplored till date. Here, we have implemented molecular dynamics (MD) simulation to study the structural evolution of the cold-rolled crystalline Cu-metallic glass Cu63Zr37 nanolaminates during shock loading. Atomic stress analysis has revealed that specimen rolled from the metallic glass (MG) side accumulates compressive residual stress, whereas the specimen rolled from the crystalline side amasses tensile residual stress. The influence of the residual stress can be directly seen during the shock propagation through the pressure profiles, which shows reduced pressure for the specimen with tensile residual stress compared to the un-rolled specimen. Also, presence of stress fields due to partial dislocations reduces the intensity of the compressive stress in the nanolaminates. It is found that generation of rarefaction wave at higher piston velocity causes formation of tensile residual stress at crystalline/amorphous interface.

Room temperature hydrocarbon generation in olivine powders: Effect of mechanical processing under CO2 atmosphere

The present work focused on the weathering reaction of olivine under CO2 atmosphere to produce light hydrocarbons via mechanical process by using ball milling apparatus. The evolution of methane and light hydrocarbons with different amount of water is reported in detail, and the process efficiency compared with the thermally activated one. Methane and light hydrocarbons productions of at least three orders of magnitude larger, are detected for the mechanically activated process. Such significant improvement can be attributed to the extreme conditions experienced by the powders processed at each impact during ball milling, whit an estimated local temperature of 648 °C. Structural and microstructural characterization reveals the formation of serpentine and magnetite-based minerals, and the occurring of the carbonation process, which competes with serpentinization, confirming that carbon capture can take place during ball milling of olivine under low pressure of CO2.

Characterization of spray formed Al-alloys — A Review

Abstract A review on the characterization of mechanical, metallurgical, porosity, tribological and corrosion properties of spray deposited Al-alloys are presented in this paper. Al-alloys are potentially used in various applications specifically in bearing materials, aerospace due to low weight to high strength, proper lubrication, excellent wear and corrosion resistance. Al alloys being processed through spray forming technology, which possesses lower processing steps than the other conventional methods like ingot and powder metallurgy. Characterization of Al alloys spray deposits is carried out before and after mechanical processes to know their behaviour. Reviewed the characterization deportment of Al-alloys before and after spray deposition, effect of mechanical process like cold rolling, extrusion, aging, hot rolling, hot extrusion etc. and porosity on the metallurgical, hardness, tensile strength, elongation, tribological and corrosion properties.

Effect of mechanical processing on the pozzolanic efficiency and the microstructure development of wheat straw ash blended cement composites

Mechanical processing significantly affects the pozzolanic efficiency of mineral admixtures. In this study, wheat straw ash was subjected to various stages of grinding and used to make mortar and paste samples. The cement was replaced (by weight) with ash at various replacement levels up to 30% maximum and studied for different parameters. The effect of mechanical processing on the pozzolanic efficiency of ashes was investigated via compressive strength test, isothermal calorimetry, Thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, and ultrasonic pulse velocity test. The results showed that the pozzolanic efficiency of the ash particles profoundly increased due to the mechanical processing. Mechanical processing reduced the particle size of the ash which enhanced the hydration reaction and improved the microstructure of the cement composites due to pozzolanic and filler effects. An enhanced quality blended cement composite can be obtained by replacing cement with 20% wheat straw ash ground for at least 60 min.

Cu-BTC synthesis, characterization and preparation for adsorption studies

In this study, several samples of Cu-BTC, a member of the MOF adsorbent family, were synthesized following synthesis routes that represent some modifications of published recipes. The effects of mixing, reaction temperature and duration, and concentrations of the precursors on the synthesized samples are discussed. The results showed that pre-mixing of the precursors’ solutions, higher dilution of the precursors, and modest reaction duration and temperature gave the most stable sample. The sample stability after several CO2 adsorption-desorption cycles was examined, and the characterization methods: XRD, TGA and SEM were used to describe selected synthesized sample and the commercial one (Basolite® C300). The thermal and mechanical processing effects as well as optimum regeneration temperature and duration were also experimentally determined (423.15 K, 8 h) for both in-house and Basolite® C300 samples.

Effect of mechanical processing on thermal and mechanical properties of fibrous fumed alumina compacts

ABSTRACTIn the present study, the fibrous fumed alumina compact with low thermal conductivity is prepared with a mechanical processing technique. The thermal conductivity of the compact remains low up to a temperature of 350°C. For the fibrous compact, the mechanical processing parameters play important role on controlling the thermal insulation capability. The thermal conductivity of compact increases from 0.036 to 0.042 W/m∙K by increasing the rotating speed of rotor. On the other hand, the value remains low by increasing processing time. The strength is decreased due to the increase of processing time. Thus, a lower rotating speed and a shorter processing time could result in a compact with favorable thermal insulation and strength. The results can be related to the surface structure of the coated alumina fibers and granulated structure within the compacts.

The effect of mechanical processing on avenanthramide and phenol levels in two organically grown Italian oat cultivars.

Avenanthramides (AVNs), free and bound phenols and their antioxidant capacities (ORAC) were evaluated in two Avena sativa L. cultivars, Donata and Flavia. The cultivars (cvs.) were grown in loamy and medium texture soils and assessed after industrial dehulling and milling. Total dietary fiber, β-glucan, starch and proteins were also evaluated. Cv. Donata showed 2.8 fold higher AVN storage as compared to cv. Flavia, which was linked with genotype. The accumulation of AVN content was also influenced by the texture of the soil. Dehulling resulted in a 75 and 37% AVN decrease in cv. Donata and Flavia, respectively. The dehulled grains of cv. Donata showed 40% reduction in free phenolic content, whereas the dehulled grains of both cvs. showed 67% reduction in bound phenols. Milling affected the bound phenolics and their antioxidant capacity. Cv. Flavia showed 1.3 fold higher β-glucan than that of cv. Donata. Total dietary fiber was reduced by 50 and 12% after dehulling and milling, respectively, while marginal changes in proteins were observed after milling. The results suggest that the choice of genotype and the kind of dehulling processes that are employed are essential considerations in the production of oat-based products with high AVN content and extra health benefits.

Effect of mechanical processing on sugar cane bagasse ash pozzolanicity

This work intends to contribute to the understanding about the effect of sugar cane bagasse ash (SCBA) on the hydration of cement-based pastes by focusing on the influence of different particle size (or specific surface area). Isothermal calorimetry, thermogravimetry, chemical shrinkage, and strength pozzolanic index tests were performed to compare the hydration and chemical evolution of pastes containing SCBA with different fineness and pastes with inert (quartz) and pozzolanic (rice husk ash) materials. The results showed that a clear change in the kinetics of hydration and portlandite content by comparing the SCBA with different particle sizes. In addition, the different SCBAs had a marked effect on the chemical shrinkage and portlandite, with an intermediate behavior between the pastes with quartz and rice husk ash. Finally, with increasing in specific surface area and soluble fraction of SCBA, its pozzolanic activity was progressively enhanced due to both portlandite consumption and physical effects.

Effects of mechanical processing and annealing on optical coherence properties of [formula omitted]:LiNbO3 powders

Optical coherence lifetimes and decoherence processes in erbium-doped lithium niobate (Er3+:LiNbO3) crystalline powders are investigated for materials that underwent different mechanical and thermal treatments. Several complimentary methods are used to assess the coherence lifetimes for these highly scattering media. Direct intensity or heterodyne detection of two-pulse photon echo techniques was employed for samples with longer coherence lifetimes and larger signal strengths, while time-delayed optical free induction decays were found to work well for shorter coherence lifetimes and weaker signal strengths. Spectral hole burning techniques were also used to characterize samples with very rapid dephasing processes. The results on powders are compared to the properties of a bulk crystal, with observed differences explained by the random orientation of the particles in the powders combined with new decoherence mechanisms introduced by the powder fabrication. Modeling of the coherence decay shows that paramagnetic materials such as Er3+:LiNbO3 that have highly anisotropic interactions with an applied magnetic field can still exhibit long coherence lifetimes and relatively simple decay shapes even for a powder of randomly oriented particles. We find that coherence properties degrade rapidly from mechanical treatment when grinding powders from bulk samples, leading to the appearance of amorphous-like behavior and a broadening of up to three orders of magnitude for the homogeneous linewidth even when low-energy grinding methods are employed. Annealing at high temperatures can improve the properties in some samples, with homogeneous linewidths reduced to less than 10kHz, approaching the bulk crystal linewidth of 3kHz under the same experimental conditions.

Effect of Mechanical Processing on Intrinsic Stress and its Distribution in Polycarbonate Screw Cap

The polycarbonate (PC) screw cap part had cracking problem during storage, which mechanism needed to be studied. The effect of mechanical processing on the intrinsic stress and its distribution in PC screw cap part was investigated in the paper. The analytical results indicated that the round pieces cut from polycarbonate bar had certain intrinsic stress residue from processing course, which decreased obviously after de-stress heat treatment. Mechanical processing also led to obviously increased intrinsic stress in screw cap part, which could be decreased obviously by another de-stress heat treatment. But the heat treatment increased the aging degree and cracking probability for polycarbonate screw cap part, and was not suggested to carry out on screw cap. Based on the experimental results, some suggestions were also given to lower the intrinsic stress in screw cap.

물리적 연육 처리 및 강화약쑥 첨가에 따른 계육 너비아니의 저장 안정성에 미치는 영향

물리적 연육 처리 및 강화약쑥 첨가에 따른 계육 너비아니의 저장 안정성에 미치는 영향

Scanning Electrochemical Microscopy for the In Situ Characterization of Solid–Electrolyte Interphases: Highly Oriented Pyrolytic Graphite versus Graphite Composite

AbstractThe solid–electrolyte interphase (SEI) is of key importance for the performance and safety of lithium‐ion batteries. Recently, scanning electrochemical microscopy (SECM) has been used to study in situ the SEI. Here, we compare the SEI of graphite composite electrodes to the SEI at macroscopic samples of binder‐free, highly oriented pyrolytic graphite (HOPG) where effects of mechanical processing and particle–particle as well as electrolyte–binder interactions should be absent. Both, short‐term changes of SEI passivity on the timescale of seconds and minutes and long‐term changes over hours are found on HOPG as well as on graphite composite electrodes, but the SEI at HOPG is more stable compared to graphite composite electrodes. In addition, the microelectrode probe of the SECM is used to induce local SEI damage to monitor its reformation. Subsequently, secondary processes such as local crack formation, gas formation due to electrolyte reduction, and HOPG expansion are studied.

Structural Properties of Mechanically Activated Rare-Earth Manganites

The effect of mechanical processing in different types of activators on the structure and physicochemical properties of the oxides LnMnO3+δ (Ln = Sm, Nd, La) has been studied. The optimal modes of mechanical activation for transformation the oxides under consideration to nanostructured state have been defined. Mechanical processing has been shown to cause a significant change of Jahn-Teller distortion parameters and temperatures of the cooperative Jahn-Teller phase transition. The presence of connection between redox processes and destruction of orbital ordering has been demonstrated. Very low values (10 -21 -10 -24 m 2 /s) of the oxygen bulk diffusion coefficient have been obtained for the oxides under consideration in the temperature range of 400 - 750°C. The diffusion activation energies are close to 1 eV, indicating the oxygen diffusion proceeds through structural defects at these temperatures.

The effect of mechanical processing of wheaten straw on intake and rumen parameters following grain feeding in sheep

While the effect of roughage chop length on decreasing the risk of acidosis in cattle is well established, there is limited information on the effect of roughage processing on intake and rumen parameters in sheep. Intake and rumen parameters were assessed in 10-month-old crossbred wethers (n = 24, 48.4 kg ± 5.3) offered wheaten straw as finely chaffed (6 mm), coarsely chaffed (15–20 mm) or unprocessed (40 mm) lengths, along with barley grain. Animals were offered 300 g/head of barley grain on the first day of grain introduction, 450 g/head.day for Days 2–3, 550 g/head.day for Days 4–6, 650 g/head.day for Days 7–9 and 750 g/head on Day 10. Rumen fluid was collected 3 h post-feeding from each animal the day before grain introduction and on Days 1–3 of grain introduction. During Days 1–3 of grain introduction, roughage intake within 3 h of feed being offered was greater (P < 0.05) in sheep offered finely chaffed (0.20 kg ± 0.03) than those offered either coarsely chaffed (0.09 kg ± 0.03) or unprocessed (0.08 kg ± 0.03) straw. Rumen pH did not differ between treatments, but increased grain feeding significantly (P < 0.001) reduced pH. Sheep offered finely chaffed straw had a greater (P < 0.05) daily straw intake (0.59 kg ± 0.06) than sheep offered coarsely chaffed straw (0.37 kg ± 0.06), while sheep offered unprocessed straw had an intermediate intake (0.49 kg ± 0.06); sheep consumed all grain offered. Shorter straw particle lengths may have a role in reducing the risk of acidosis during grain introduction.