Coarse Grinding Research Articles

Influence of particle size of Enogen Feed corn and conventional yellow dent corn on lactating sow performance.

Enogen Feed corn is a variety developed by Syngenta Seeds (Downers Grove, IL) that has been genetically modified to contain an -amylase enzyme trait (SYT-EFC). Originally, Enogen feed corn was developed for the ethanol industry due to its properties for reducing the viscosity of its corn mash. There is potential application for Enogen Feed corn to be used in livestock diets due to the potential for the increase in - amylase enzyme to increase the starch digestibility. Because of this, it may be possible to increase the particle size of ground Enogen Feed corn and maintain the same starch digestibility as finely ground conventional yellow dent corn. Therefore, our hypothesis was that an interaction between corn source and particle size would exist such that the performance of sows fed fine ground conventional yellow dent corn would be similar to sows fed coarse ground Enogen Feed corn. A total of 107 sows (Line 241; DNA, Columbus, NE) across four batch farrowing groups were used to evaluate sow and litter performance. Treatments were arranged in a 2 2 factorial with main effects of corn source (Enogen Feed corn or conventional yellow dent corn) and ground corn particle size (600 or 900 m). From farrowing to weaning, there was a tendency for a corn source particle size interaction (P = 0.065) in sow body weight (BW) change. Sows fed 900 m Enogen Feed corn had decreased BW loss compared to sows fed other treatments, which were similar in weight loss. For sow average daily feed intake from farrowing to weaning, there was a corn source particle size interaction (P = 0.048) with sows fed 900 m conventional yellow dent corn having lower feed intake than the sows fed 600 m conventional yellow dent corn, whereas sows fed 900 m Enogen Feed corn had greater feed intake compared to the sows fed 600 m Enogen Feed corn. There was a tendency for a particle size main effect (P < 0.10) for litter average daily gain (ADG) and total litter gain, with sows fed corn ground to 600 m having increased litter ADG and total litter gain compared to sows fed corn ground to 900 m. In summary, there were few differences in sow or litter characteristics among those fed Enogen Feed corn or conventional yellow dent corn. Reducing particle size of both corn sources tended to increase litter ADG and weaning weights.

The hematite ore liberation and separation properties in different comminution way

ABSTRACT In order to improve grinding efficiency and weaken over-grinding in the whole grinding process, the new process of “ultra-crushing in HPGR – classified separation” was proposed with an Anshan style hematite ore. The new process was discussed from the aspects of particle size distribution, liberation characteristics, and separation properties. Compared with the conventional impact crusher, there was no significant difference in coarse particles in HPGR. The “Particle Bed Breakage” characteristics of HPGR products are mainly concentrated in the fine particles (−0.18 mm), which is characterized by higher fines content (a yield of 38.43%), higher specific surface area and higher quartz liberation, etc. It’s worth mentioning that, fine-disseminated iron minerals are detached from the quartz mineral under large compressive-stress in HPGR, which is more conductive to the downstream separation. Magnetic separation tests showed the HPGR (−0.18 mm) tailings have the lowest grade of 7.29%, approximately one percentage point less than coarse grinding products. Based on the above analysis, the new process with a 0.18 mm prescreen size for an Anshan style hematite ore is feasible.

Functional morphology of the tongue in the domestic turkey (Meleagris gallopavo gallopavo var. domesticus)

Nowadays, microstructural and ultrastructural analysis of organs of the avian beak cavity points to new aspects of adaptation to food intake through the various feeding groups. These data should undoubtedly be considered in the time of mass production of compound feed in poultry, when many studies analyze the optimal size of food particles and their doses. Galliformes possess complex mechanisms of food collection and transport in the beak cavity. They collect food by pecking and transport food by using catch-and-throw and slide-and-glue mechanisms. The aim of current research is to conduct functional analysis of the tongue in poultry such as domestic turkey in context of type of food, method of food intake, and transport to the esophagus. The study involves observations of macroscopic and microscopic structures of the tongue mucosa by light microscopy and scanning electron microscopy techniques with histochemical analysis of lingual glands. The obtained results showed that the tongue in domestic turkey fills two-thirds of the beak cavity. The lingual structure responsible for pecking is a rigid plate called lingual nail that works similar to a shovel to collect food. The median groove presented on surface of the tongue indicated path of food transport. The conical papillae on border between the lingual body and root are responsible for the last stage of food transport, while the papillae on the sides of root stabilize the path of food transport. For the first time, the presence of 2 types of cornified mucosal epithelia, orthokeratinized and parakeratinized epithelium, was presented. The analysis of occurrence of complex tubular lingual glands indicates production of mucous secretions composed of neutral mucopolysaccharides, with addition of sialomucins and sulfomucins. Mucous secretions moisturize surface of the tongue, thus facilitating the transport of dry food. The presence of sulfur mucopolysaccharides responds to protective function. To sum up, the tongue in domestic turkey is adapted to collect fine or coarse ground feed in form of mash or pellets through pecking and its transport to the esophagus using the slide-and-glue and throw-and-catch mechanisms.

In vitro studies to characterise different physico-chemical properties of some feed grains and their impact in monogastric nutrition

Characterisation of the variations in physico-chemical properties of grains may help to improve the feeding value of grains for animal nutrition. Thus, this study aimed to obtain more extensive quantitative ideas concerning different physico-chemical properties of wheat, hybrid rye, and barley. The samples were ground in a hammer mill using screen size of 1, 3, and 6 mm, respectively. The cumulative mean particle distribution at >1.0 mm of the ground grains showed significant differences between wheat and hybrid rye (4.63 and 9.13%, respectively). At dry sieve analysis of 6 mm screen size, hybrid rye had significantly higher mean particle size distribution of >1.0 mm (26.8%) than for ground wheat and barley. Ground wheat using a 1 mm mesh sieve had the lowest water holding capacity and swelling capacity (1.89 g H2O/g dry matter (DM); p = .001 and 1.33 mL H2O/g DM; p = .021, respectively) compared to hybrid rye and barley. Ground hybrid rye using a 1 mm mesh sieve had the significantly highest extract viscosity (6.22 mPa s). Ground wheat had the lowest (p < .001) corrected sediment rate. In general, ground hybrid rye had always a higher feed particle size >1 mm regardless of the grinding size. Ground wheat had the lowest water holding capacity irrespective of the grinding mesh sieve. Finally, hybrid rye in general is characterised by high extract viscosity (6.22 mPa s at 1 mm grinding size), which decreased with coarser grinding (3.75 and 3.10 mPa s at 3 and 6 mm, respectively). Highlights Particle size distribution is directly affected by the grinding process. Water holding capacity and swelling capacity are two complementary measurements. Extract viscosity seems to be affected by grinding; however, the sedimentation rate is influenced by the grain type.

Maintaining continuity of nutrient intake after weaning. II. Review of post-weaning strategies.

Low feed consumption during the first 3 d post-weaning disrupts nutrient intake and results in what is commonly known as a post-weaning growth check. While most pigs recover from this initial reduction in feed intake (FI), some pigs fail to successfully make this transition leading to morbidity and mortality. In this review, our objective is to describe the different post-weaning strategies that can be used to minimize nutrient intake disruption and improve FI in the immediate post-weaning period. Providing weanling pigs with an environment that encourages them to search out and consume feed is important. This includes appropriate barn temperatures, resource availability, and nursery placement strategies. Research is needed to better understand the ideal environmental temperatures to encourage pen exploration and reduce time to initial FI. Likewise, mat and gruel feeding are commonly practiced throughout the industry to increase feed accessibility; however, limited research data is available to validate protocols or benefits. Nursery placement strategies include sorting light weight pigs into uniform body weight groups and average or heavy weight pigs into variable body weight groups to provide benefit to light pigs while reducing initial aggression in heavy pigs. Furthermore, water enrichment with nutrient dense products have been shown to improve growth performance and reduce morbidity and mortality in the early post-weaning period. Because young pigs are sensitive to palatability, diet form and complexity should also be considered. Weanling pigs prefer diets manufactured with coarse ground corn (700 μm) compared to fine ground corn. Additionally, weanling pigs are more attracted to large diameter pellets (12 mm) compared with small pellets. Despite these preferences, impacts on growth are relatively small. Feeding complex diets with high levels of lactose, animal protein products, or other palatable ingredients is another strategy shown to improve growth performance during the first week post-weaning; however, the initial benefits quickly diminished as pigs become older. Other strategies that warrant further investigation include the effect of crumble diets on feed preference and the concept of perinatal or social interaction flavor learning. In summary, strategic post-weaning nutrition and management practices must focus on maintaining continuity of nutrient intake in order to reduce morbidity and mortality in the immediate post-weaning period.

Studies on effective utilization of Citrus Maxima fibers based PVC composites

Abstract Thermoplastic PVC matrix was reinforced with waste fiber portion of Citrus Maxima (CM) fruit for making composites. The CM fibers were separated, dried at 50–60 °C for 24 h, coarse ground and sieved. PVC/CM fiber composite film with different fiber loading (10–70 wt%) were cast using solvent casting method. Sheets were cast in large petri dish using tetrahydrofuran (THF) as solvent and dried in an oven thoroughly at 50–60 °C. The evaluation of mechanical properties was done as per ASTM D882; stereo image of the fractured specimen and FTIR was used for the study of morphology and microstructure of the composite. Incorporation of fibers into PVC made the material stiff, leading to significant increase in Tensile Modulus, Breaking Strength and Yield Stress at higher filler loadings. Uniform distribution of the fibers in the microstructure of PVC matrix led to the formation of cross-ply structure and improved the mechanical properties. These results indicate that the fiber portion from CM can be effectively used as an eco-friendly reinforcing additive to form PVC composites.

266 Dietary strategies in diets without zinc oxide for nursery pigs

Abstract A total of 300 pigs (DNA 241 × 600; initially 4.2 kg) were used to evaluate the effects of different nutritional strategies to replace zinc oxide (ZnO) in nursery diets. Treatments consisted of A) Positive control (21% CP; ZnO providing 3,000 ppm Zn from d 0 to 7, and 2,000 ppm Zn from d 7 to 25); B) Negative control (NC; no ZnO); C) NC plus 1.2% Na diformate; D) NC with 4% coarse ground wheat bran; E) NC with low crude protein (18%) by adding high levels of feed grade amino acids; and F) the combination of NC with 18% crude protein (CP), 1.2% Na diformate, and 4% coarse ground wheat bran. There were 5 pigs per pen and 10 pens per treatment in a completely randomized design. Data were analyzed with the Proc Mixed procedure in SAS. For the overall period (d 0 to 46), pigs fed diets containing ZnO had greater (P &amp;lt; 0.001) ADG, ADFI, and final BW than other treatments, with pigs fed the NC with 18% CP having the lowest performance. Pigs fed the NC diet without any nutritional alternative had the lowest fecal dry matter (DM; P &amp;lt; 0.050) and highest fecal scores (P &amp;lt; 0.050). Pigs fed diets with ZnO had similar fecal DM and scores as pigs fed the diet containing the combination of 1.2% Na diformate, 4% coarse ground wheat bran, and low (18%) CP, but greater (P &amp;lt; 0.023) fecal DM than pigs fed the alternatives used individually. This study suggests none of the strategies used alone were effective at replacing ZnO while the use of low CP and amino acids reduced performance further. Combining the three alternatives tested as a replacement to ZnO improved fecal DM content and fecal score but did not result in improved growth performance.

PNEUMOMEDIASTINUM AND PNEUMOTHORAX DUE TO NONINVASIVE POSITIVE PRESSURE VENTILATION IN COVID-19 PNEUMONIA

SESSION TITLE: Medical Student/Resident Disorders of the Pleura Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Barotrauma as a consequence of high alveolar pressures is well described in invasive mechanically ventilated (IMV) patients with pneumonia or pneumonitis. Limited data exists on the incidence of barotrauma in patients with Coronavirus Disease 19 pneumonia (COVID-19). We present a case of barotrauma occurring in a non-intubated patient with COVID-19 receiving noninvasive positive pressure ventilation (NPPV). CASE PRESENTATION: A 43-year-old male with obesity presented with 2 days of cough and dyspnea. Polymerase chain reaction (PCR) testing confirmed COVID-19. He initially required 5L of oxygen (O2) per minute by nasal cannula. Due to worsening hypoxemic respiratory failure (HRF) on day 3, the patient was placed on high-flow nasal cannula (HFNC) at 90% FiO2 at a flow rate of 30 L/min . By day 7, the patient had worsening HRF and increased work of breathing. He was transitioned to continuous positive airway pressure (CPAP) at 100% FiO2 with continuous pressure set at 12 cm H2O. On day 13, he developed tachycardia and desaturation. Chest CT found gas dissecting along the axial interstitium resulting in pneumomediastinum, bilateral pneumothoraces, and extensive subcutaneous emphysema. The lung parenchyma exhibited coarse ground glass opacities and early evidence of fibrotic changes. Chest tubes were placed in each hemithorax with resolution of his pnemothoraces after 5 days. His O2 requirements decreased, and he was transferred to a rehabilitation hospital on 10 L/min O2 by facemask on day 25. DISCUSSION: Barotrauma leading to pneumomediastinum and pneumothoraces are a well-documented complication of mechanical ventilation.1 In an effort to mitigate the morbidity and mortality associated with mechanical ventilation, many clinicians have shifted toward using NPPV in HRF in COVID-19, however NPPV may not necessarily protect patients against a complication more commonly associated with IMV.2,3 Progressive and cumulative alveolar injury may predispose COVID-19 patients to barotrauma regardless of mode of ventilation.3 CONCLUSIONS: Due to the mortality associated with IMV in COVID-19, many clinicians have shifted toward using NPPV to manage HRF. However, patients receiving NPPV may still be subject to complications such as barotrauma. Additionally, given our evolving understanding of COVID-19 and the pulmonary parenchymal distortion seen in many patients, a deterioration in respiratory status should prompt clinicians to search for evidence of barotrauma, even in patients receiving NPPV. Reference #1: Mentzer SJ, Tsuda A, Loring SH. Pleural mechanics and the pathophysiology of air leaks. J Thorac Cardiovasc Surg. 2018;155(5):2182-2189. Reference #2: Xu XP, Zhang XC, Hu SL, et al. Noninvasive Ventilation in Acute Hypoxemic Nonhypercapnic Respiratory Failure: A Systematic Review and Meta-Analysis. Crit Care Med. 2017;45(7):e727-e733. Reference #3: Sun R, Liu H, Wang X. Mediastinal Emphysema, Giant Bulla, and Pneumothorax Developed during the Course of COVID-19 Pneumonia. Korean J Radiol. 2020;21(5):541-544. DISCLOSURES: no disclosure on file for Nikhil Barot; No relevant relationships by Michael Kahn, source=Web Response No relevant relationships by Nader Kamangar, source=Web Response No relevant relationships by Jay Thetford, source=Web Response

A Process Mineralogical Evaluation of Chromite at the Nkomati Nickel Mine, Uitkomst Complex, South Africa

A process mineralogical study based on three texturally and mineralogically different chromite-bearing ore types at the Nkomati nickel mine was undertaken, with focus on chromite. Chromite is a by-product of the Ni-Cu-Co-PGE ore at Nkomati Nickel mine. These being the PCMZ_MG (medium-grade Ni-Cu sulphide silicate ore with disseminated chromite), PCMZ_HG (high-grade Ni-Cu sulphide silicate ore containing disseminated chromite) and MCHR (massive chromite unit) ore types. These were processed using benchtop flotation followed by gravity concentration using a shaking table at different grind sizes. Quantitative mineralogical data was obtained using a 600F Mineral Liberation Analyser for the unprocessed and processed ores at three selected target grinds. The Mineral Liberation Analyser data indicated that increased milling does not relate to increased chromite grades and recoveries, particularly for the disseminated PCMZ type ores based on laboratory-scale gravity concentration. The recovery is controlled largely by the chromite chemistry. The results also showed that the MCHR samples that underwent a pre-flotation stage before gravity separation had better Cr2O3 grades (45% to 47%) and recoveries (52% to 61%) than MCHR ore that did not undergo a pre-flotation stage, which recorded grades ranging from 44% to 46% and recoveries ranging from 43% to 60%. This holds promise for the blending of MCHR ores with the PCMZ ores. The PCMZ ores also displayed better Cr2O3 grades and recoveries at coarser grinds. The optimal target grind to process all three ore types is a P80 of 75 μm, which is the current grind size employed at Nkomati Nickel mine. Due to the low nickel price and grade the Nkomati Nickel mine is currently under care and maintenance.

Effect of particle size of insoluble fibre on growth performance, apparent ileal digestibility and caecal microbial population in broiler chickens fed barley-containing diets

ABSTRACT 1. This study was conducted to investigate the effect of particle size of insoluble fibre on growth performance, apparent ileal digestibility (AID) and caecal microbial population in broiler chickens fed barley-containing diets. 2. The dietary treatments included: a barley-based diet (control, CTL) or test diets which contained high-fibre ingredients, either sunflower hulls (SFH), sugarcane bagasse (SB) or wheat bran (WB) ground through a 1.0 (fine) or 3.0 mm (coarse) screen that were added to the control diet at 30 g/kg. 3. For the entire experimental period, insoluble fibre inclusion improved ADG (P < 0.05) and FCR (P < 0.05) compared to the CTL group. Broilers fed SFH had higher (P < 0.05) ADG and better (P < 0.05) FCR than broilers fed SB. 4. Fibre inclusion increased the relative weight of breast and thigh and decreased relative weight of liver compared to the CTL group, but coarse grinding of the SB decreased relative weight of abdominal fat (P < 0.05). 5. The digestibility of nutrients increased with dietary inclusion of insoluble fibre compared to the CTL group. Coarse grinding of SFH increased AID of crude protein compared to the coarse grinding of WB or SB. Fine grinding of various types of fibre improved the AID of fat (as ether extract) and organic matter (P < 0.05). 6. Fine grinding of the WB decreased caecal populations of E. coli. The inclusion of SFH increased caecal populations of Lactobacillus spp. (P < 0.05). Coarse grinding of various types of fibre decreased the caecal population of coliforms (P < 0.05). 7. The inclusion of WB increased digesta viscosity in the ileum compared to samples from the SB and SFH groups (P < 0.05). Coarse grinding of various types of fibre decreased the digesta viscosity in the ileum (P < 0.05). 8. Overall, the data showed that dietary inclusion of insoluble fibre improved growth performance, increased AID of nutrients and decreased ileal viscosity in the birds fed diets containing barley.

Исследование процесса получения суспензии частиц композиционного гидрогелевого материала

The paper presents comprehensive investigation results concerning obtaining a composite hydrogel material in the form of an aqueous slurry. We considered the issue of grinding hydrogel in water so as to obtain an aqueous slurry of hydrogel particles featuring the desired particle size distribution. We selected polyacrylamide to be the composite hydrogel material and used an anti-Stokes phosphor as a filler. We describe a multi-stage method for producing hydrogel, a coarse grinding process for hydrogel blocks, and a fine grinding technology employing an immersion disperser. We obtained slurries featuring a narrow particle size distribution (160--1000 µm). We provide data on investigating how the manufacturing process parameters and modal parameters of the equipment used affect the particle size distribution in the resulting hydrogel material. We propose a technology for producing composite hydrogel particle slurry in a single process cycle

Complex Dental Structure and Wear Biomechanics in Non‐Avian Dinosaurs and Pleistocene Mammals

Reptiles rarely approached the biomechanical sophistication for feeding or dietary diversity seen in mammals. Their teeth are typically non‐occluding, semi‐conical structures with simplistic parallel‐crystallite enamel surrounding an orthodentine core. Conversely, most mammals possess multi‐cusped teeth that are drawn across one another during mastication and self‐wear to their functional morphology. The most complex dental architectures are seen in herbivorous mammals. Their teeth are composed of up to four constituents (incl. prismatic enamel) that strategically wear creating coarse grinding or slicing surfaces. These allow them to comminute tough and/or abrasive plants and liberate nutrients inaccessible to other animals. Non‐avian dinosaurs stand out among reptiles in that precise, mammal‐like dental occlusion and self‐wearing teeth evolved on at least four occasions. These topographies enabled access to myriad floral types and facilitated their respective ecological diversifications. My research group and colleagues showed that the teeth of these dinosaurs are histologically more complex than formerly appreciated. Using cutting‐edge material science and tribological engineering indentation techniques we discovered that wear and fracture relevant material properties are preserved in the fossil dental tissues of dinosaurs and Pleistocene mammals. This led to development of a 3D Archard’s wear model from which we determined how horse‐like occlusal surfaces for the grinding of plant matter occurred in hadrosaurids, and fuller‐like slicing surfaces developed and functioned in ceratopsians. In current research we are studying how the grinding dentitions of mammoths similarly formed through self‐wear. Notably our paleontologically‐inspired wear model is seeing broad industrial applications.Support or Funding InformationNSF CMMI (Civil, Mechanical and Manufacturing Innovation) Eager and AFOSR (Air Force Office of Scientific Research) to GME, SP and BAK

Investigation of air-blown two-stage entrained-flow gasification of micronized coal

The aim of this work was to intensify the air-blown conversion of coarse grinding coal into the fuel syngas by means of mechanical activation of some part of the coal without the involvement of other methods of conversion intensification (oxygen enrichment of blast, heating of blast or fuel, etc.). Experimental studies were carried out at the Institute of Thermophysics of the Siberian Branch of the Russian Academy of Sciences (IT SB RAS) using special setup with the two-stage coal and air input. We have performed a comprehensive experimental and computational study of air-blown gasification of coarse coal (Gcoal2) by combustion products of micronized coal (Gcoal1) at the ratio of primary and secondary coal gc = Gcoal1/Gcoal2 = 0.82–0.39 (90/110–90/230 kg/kg), stoichiometric factor α = 1.39–0.51 and the temperature in the flame from 1.200 to 1.300 to 1.500–1.600 °C. It has been found that micronization of primary coal allows maintaining a stable autothermal mode of air-blown gasification of coarse bituminous coal without involving the additional methods of conversion intensification at α = 0.5. The CFD simulation based on experiments determined the conditions for implementation of the investigated process.

Characterization of paste microstructure for durability properties of concrete

In this study, paste samples from different cementitious systems were characterized by using X-Ray Micro Computed Tomography (µ-CT) and Fluorescence Microscopy techniques. Quantitative and qualitative aspects of defects from paste samples were investigated to develop indicators of durability related properties of corresponding concrete samples. In the first phase of this study, hour glass shaped 3D printed molds were used to investigate five cementitious combinations consisting of three cement types (Coarse Ground portland cement, Type IL Portland Limestone Cement and Type I/II ordinary portland cement) and fly ash as a supplementary cementitious material. In the second phase, metal molds were used to compare the results of Coarse Ground portland cement with Type I ordinary portland cement, 5% of which was replaced with colloidal nanosilica. Potential correlations between paste and concrete have been presented. This work was supported by US Department of Energy and North Dakota Department of Commerce.

Pelleting on the Nutritional Quality of Broiler Feeds

In the pelleting process, mash feed passes through a conditioner were it is exposed to steam under high pressure and pushed through the die to form pellets. To determine the effect of adding different amounts of water and different thermal processing parameters on the pellet conversion percentage, pellet durability index (PDI) and solubility of protein in KOH of broiler feed. The processing factors were combined in a 4x2 factorial scheme: four moisture addition levels (0%; 0.7%; 1.4%; 2.1%), and two thermal processes (conditioning-pelleting or conditioning-expanding-pelleting). Eight samples of each treatment were collected to evaluate quality parameters. The feed used in this study was a typical corn-soybean broiler diet processed in a commercial feed mill. The pellet conversion percentage and PDI responded linearly and positively in the range of 0 to 2.1% moisture addition. Positive and linear equations relating moisture addition in the conditioner with pellet conversion percentage and PDI were obtained (p&lt;0.001). Expansion improved PDI and pellet percentage respectively by 18% and 21% when compared to simple conditioning-pelleting feed processing. However, an adverse effect on protein quality was observed when higher processing temperature was used. No particle size effect was observed for conditioned-expanded-pelleted feed. Medium particle size resulted in better PDI and higher pellet conversion percentage (p &lt; 0.001) compared to coarse grinding (% pellets – 66.97% versus 64.96%; PDI – 77.30% versus 66.10%).

Influence of different comminution flowsheets on the separation of vanadium titano-magnetite

Comparative separation tests of vanadium titano-magnetite (VTM) were conducted in this study by employing a high-pressure grinding roller (HPGR) and a jaw crusher (JC); these were followed by a parallel and stage separation, respectively. The results revealed that the products generated with the HPGR are finer with a wider size distribution than those obtained with the conventional JC. The newly formed ore grains after grinding were similar to those of the JC products with a grinding fineness of 65% passing 74 μm. The HPGR product is more beneficial for iron oxide mineral liberation at a coarse grinding fineness. Owing to the preferential liberation of iron-bearing minerals in the primary grinding, a marketable titanium magnetite concentrate can be obtained by magnetic separation via the parallel separation of Fe–Ti. The argillation of iron oxides is more severe during the grinding stage of ilmenite with the JC than with the HPGR. Once the particle size decreased, particularly to less than 19 μm, the difficulty of capturing ilmenite using a magnetic field increased sharply and led to poor floatability.

Structures of Berthing Facilities Recommended for Erection in Severe Climatic Conditions of the Arctic (Review)

The article gives an overview of the constructions of berthing facilities recommended for erection in severe climatic conditions. The main conditions for the application of each type of structure are singled out. Features of operating conditions of structures on the Arctic shelf are analyzed. Recommendations are given for choosing the optimal type of structures when there are weak soils at the base of the construction site, as well as under ice and seismic influences. The berthing facilities constructed in severe climatic conditions, both in Russia and abroad, are analyzed. The expediency of using shells of large diameter, which are thin metal or reinforced concrete casings (usually cylindrical shells), whose cavities are filled with coarse ground, have been substantiated in the harsh climatic conditions of the Arctic. The main advantages of this type of structures are described, and a number of problems are emphasized that are primarily related to the interaction of the shell and the filler material. The difficulties in organizing the transfer of the load from the shell structure to the ground base are singled out.

Systematically Improving Espresso: Insights from Mathematical Modeling and Experiment

Summary Espresso is a beverage brewed using hot, high-pressure water forced through a bed of roasted coffee. Despite being one of the most widely consumed coffee formats, it is also the most susceptible to variation. We report a novel model, complimented by experiment, that is able to isolate the contributions of several brewing variables, thereby disentangling some of the sources of variation in espresso extraction. Under the key assumption of homogeneous flow through the coffee bed, a monotonic decrease in extraction yield with increasingly coarse grind settings is predicted. However, experimental measurements show a peak in the extraction yield versus grind setting relationship, with lower extraction yields at both very coarse and fine settings. This result strongly suggests that inhomogeneous flow is operative at fine grind settings, resulting in poor reproducibility and wasted raw material. With instruction from our model, we outline a procedure to eliminate these shortcomings.

Material removal characteristics of ultra-precision grinding silicon carbide ceramics

ABSTRACTSilicon carbide (SiC) ceramic has been widely applied to fabricate functional components relying on their excellent physical, chemical and mechanical properties. Meanwhile, it is always highly concerned to seek suitable manufacturing technology and processes for machining such difficult-to-cut material with high-precision, high-efficiency and low-cost. In the present paper, material removal characteristics of reaction-bonded silicon carbide (RB-SiC) and pressureless sintered silicon carbide (S-SiC) were investigated by ultra-precision grinding experiments. #120, #600, #2000 and #12000 diamond cup wheel were employed for coarse, semi-finished, fine and finish grinding, respectively. The surface topographies, surface morphologies and grinding grooves were measured. The results indicated that there are distinguishing material removal characteristics between RB-SiC and S-SiC, and #2000 diamond wheel can be chosen as the final grinding wheel for most high-performance SiC ceramic products. The present study provides a technological reference to ultra-precision grinding of hard materials.

Effects of feeding intact, ground and/or pelleted rapeseed on nutrient digestibility and growth performance of broiler chickens

ABSTRACTIn this study, the effect of grinding or pelleting of rapeseed on the digestibility, apparent metabolisable energy (AMEN), growth performance and gizzard weight of broiler chickens was evaluated. In Exp. 1, four treatments were tested (240 broiler chickens, 20 replications, 3 birds per cage). Birds received either a basal diet or were fed with rapeseed of different sized particles (fine, medium and coarse ground, respectively). In Exp. 2, 10 treatments were assessed (360 chickens, 12 replications, 3 birds per cage), where five different diets (a basal diet and four diets with intact rapeseed, fine ground, medium ground or coarse ground rapeseed, respectively) were fed non-pelleted or pelleted. In Exp. 3, two treatments were compared (224 broiler chickens, 14 replications, 8 birds per floor pen): fine ground rapeseed (FG) and intact rapeseed (IS). Compared with medium and coarse ground rapeseed, fine grinding increased in Exp. 1 the AMEN of rapeseed and the precaecal digestibility (PD) of dry matter and ether extract (EE) (p < 0.05). In Exp. 2, the content of AMEN and the PD of EE and crude protein (CP) increased as the degree of grinding increased when diets were not pelleted (p < 0.01). In contrast, the significantly highest values for these parameters were measured after pelleting without effect of grinding, resulting in a significant interaction between pelleting and grinding (p < 0.001). In Exp. 3, performance of chickens was not affected by dietary treatments, but gizzard weight and the PD of CP were higher when IS were included in the diet (p < 0.05). The results suggested that fine grinding may be used to increase the feeding value of full-fat rapeseed for broiler chickens. Nevertheless, pelleting of diets with rapeseed seemed to be much more effective in the reduction of particle size than grinding.