Pellet Hardness Research Articles

Sintering trials and microstructural changes mechanism of analogues of americium oxides for radioisotope power systems

Radioisotope thermoelectric generators (RTGs) are deal energy supply devices for deep space and deep-sea exploration, and it is also the energy core of the operation of the working equipment. Except for 238Pu (Plutonium), 241Am (Americium) was also used as a nuclide in the radioactive energy system for future space exploration missions. In this work, neodymium oxide (Nd2O3) was used as analogues for Am2O3. Cold-press-and-sinter methods was used. Different particle parameters (morphology, size, and crystal structure) and synthesized parameters of Nd2O3 were investigated. The synthesized powders contained lath-shaped particles, and batches with different particle sizes and microscopic topography were made and sintered. The results show that the optimal precipitation temperature of Nd2O3 is 25 °C. The optimal thermal decomposition temperature range is 900 °C to 1100 °C, and the optimal thermal decomposition heating rate is 10 °C min−1. The samples of Nd2O3 pellets without cracking is obtained with relative density of 85%–90 %. The Vickers hardness of Nd2O3 pellets was also studied. This paper provides an important scientific guiding significance for the cold-press-and-sinter of radioisotope 241Am batteries in the future.

Effects of high-level dietary distillers dried grains with solubles supplemented with multienzymes on growth performance, nutrient utilization, intestinal morphology, and pellet quality in broiler chickens.

With the increasing cost of bulk raw materials and advancements in the feed enzyme industry, corn distillers dried grains with solubles (DDGS) have shown more opportunities for use in broiler diets. Supplementation with multiple enzymes could mitigate anti-nutritional factors in DDGS, enhance nutrient digestibility, and thereby increase its utilization in broiler diets, leading to reduced feed costs. This study evaluated the effects of multienzyme supplementation on growth performance, nutrient utilization, intestinal morphology, and pellet quality in broiler chickens fed diets containing conventional levels of DDGS (C-DDGS) and higher levels of DDGS (H-DDGS). A total of 800 1-day-old Cobb 500 chicks was assigned to four dietary treatments with eight replicates of 25 birds each: C-DDGS (5% DDGS in Starter and 10% in Grower), C-DDGS + Enzyme (C-DDGS diet supplemented with multienzyme), H-DDGS (10% and 20%) + Enzyme (H-DDGS diet supplemented with multienzyme, 10% DDGS in Starter and 20% in Grower), and H-DDGS (15% and 30%) + Enzyme. The C-DDGS + enzyme diet increased (p < 0.05) body weight gain (BWG), reduced the feed conversion ratio, enhanced (p < 0.05) digestibility of dry matter (DM), crude protein, and hemicellulose (HC), and improved (p < 0.05) intestinal villus height and villus: crypt ratio of broilers. The H-DDGS (10% and 20%) + enzyme diet exhibited no difference in (p > 0.05) growth performance, nutrient digestibility (except HC), and intestinal morphological parameters, whereas the H-DDGS (15% and 30%) + enzyme diet decreased (p < 0.05) feed intake and BWG and reduced (p < 0.05) energy and DM digestibility by impact (p < 0.05) intestinal morphology compared with the C-DDGS enzyme-free diet. The H-DDGS diet had lower (p < 0.05) pellet hardness and poorer durability than the C-DDGS diet. Supplementing multienzyme in the C-DDGS (5% and 10%) diet improved growth performance from day 0 to 28 and diminished growth performance in the H-DDGS (15% and 30%) diet by influencing intestinal morphology and feed pellet quality in broiler chickens. In addition, when supplemented with multienzyme, the dietary DDGS level can be safely included at levels of 10% in 0-7 days and 20% in 8-28 days of age.

Effects of feed conditioning temperature on pellet quality, growth performance, intestinal development and blood parameters of geese from 1 to 28 d of age

A 28-d experiment was conducted to investigate the effects of feed-conditioning temperature on the pellet quality, growth performance, intestinal development, and blood parameters of geese. A total of 180 one-day-old White Yuzhou goslings were randomly allotted to 5 treatment groups, with 6 replicates containing 6 birds each. Five diets were conditioned at 65, 70, 75, 80, and 85°C. Body weight and feed intake per pen basis were recorded from the arrival to the end of the trial. Blood and small intestine samples were collected on d 28 for analysis. The results showed that the pellet durability index (PDI), pellet hardness, and gelatinisation degree of starch (GDS) increased with increasing conditioning temperature (P < 0.05). The final body weight (FBW), average daily gain (ADG) and average daily feed intake (ADFI) of goslings significantly increased when conditioning temperature increased from 65 or 70°C to 80 or 85°C (P < 0.05), accompanied by unaffected feed conversion ratio (FCR) (P > 0.05). The villus height to crypt depth ratio (VH/CD) in the duodenum and ileum improved with increasing conditioning temperature (P < 0.05). Additionally, trypsin and amylase activity were enhanced when the conditioning temperature increased from 65 to 85°C (P < 0.05). No significant differences in the carcass traits and blood parameters of goslings were observed among the groups (P > 0.05). Overall, under the present experimental conditions, increasing the steam-conditioning temperature of pelleted feed improved pellet quality, growth performance, intestinal morphology, and digestive enzyme activity in goslings. Based on broken-line regression analysis, the lower critical conditioning temperature for ADG in geese from 1 to 28 d of age was 80.95°C.

Synthesis and Characterization of Ruminant Feed Based on Palm Kernel Cake Using EM4 Fermentation Method

The purpose of this study was to determine the effect of the addition of cassava as an adhesive and the use of palm kernel meal as a concentrate and the addition of other ingredients on the physical, mechanical and chemical properties of food ingredients in the form of pellets. The animal feed was made by mixing palm kernel meal, tofu dregs, rice bran, and cassava with a percentage of (68,5 : 15,75 : 5,25 : 10,5)% and mixing molasses and EM 4 in a ration 1 : 1. The test samples were made by going through the stages of weighing, chopping, mixing, fermentation, drying, and molding into pellets. The results showed that the animal feed mixture had a specific gravity of 1.70 gr/mL, porosity of 29.05%, water absorption of 72.62%, pellet hardness of 4.85%, and brittleness with 4.92%. Animal feed pellets have a brownish color and a normal smell like the smell of animal feed pellets in general. The fermentation process was carried out for 8 days until it reached a maturity temperature of 38.44°C. Based on the proximate analysis, it was found that the animal feed contained 10.50% protein, 2.30% total fat, 22.80% crude fiber, 28.50% carbohydrate, 3.00% ash content and 32.90% moisture content. This animal feed pellet with palm kernel meal concentrate and cassava adhesive can be used as an alternative to cattle feed as an energy source feed, because it has a protein content of less than 20%.

Effect of die length, moisture content and particle size on some mechanical and physical properties of poultry feed pellets

This study investigates the role of manufacturing characteristics on some mechanical and physical properties of poultry feed pellets. laboratory study of 3 x 3 x 3 factorial experiment laid out to study the effect of die lengths (L1 = 3, L2 = 4, and L3 = 5) cm, moisture content of feedstuff (M1 = 12, M2 = 14 and M3 = 16) % and particle sizes (P1 = 0.5, P2 = 1 and P3 = 1.5) mm and their interactions on some physical and mechanical properties of poultry feed pellets. Pellet Durability Index (PDI), pellet hardness, bulk density of pellets and feedstuff, unit density of pellets, and power consumption were measured and evaluated. Results revealed that the interaction of longer die lengths, higher moisture content, and smaller particle size treatment (L3M3P1) significantly increased the PDI (95.6%), hardness (6.4 Kg), and bulk density (683.97 Kg m-3) when it compared with other treatments. Unit density increased with the treatment (L3M2P2) when it compared with other treatments which it was 1453.29 Kg m3. The highest power consumption of 4.51 Kwh-1 was recorded with the treatment (L3M3P3) while the lowest value was for the treatment (L1M1P1) and it was 3.07 Kwh-1 but statistically, there were no significant differences in power consumption between the treatments, the differences were only mathematically. According to the results obtained in this work, we can conclude that when using the long die path combined with high moisture content and fine feedstuff can produce better pellets which are physically and mechanically accepted by farmers.

Understanding and modelling the aquafeed extrusion process for Atlantic salmon feed with an empirical model

An empirical model was applied to quantitatively model the effects of extrusion variables and recipe compositions on quality of feed pellets. Lab extrusion trials were performed with an Atlantic salmon feed recipe with using a central component design (CCD). Comparing with a coated commercial feed made with the same recipe, the lab extrusion pellets had similar bulk density, hardness, and durability properties. A Response Surface Method (RSM) was also used to regress the extrusion trial data and compared with the empirical model results. The respective Absolute Average Deviation (AAD %) values of the empirical model and RSM regression were 4.1 % and 1.8 % for pellet bulk density, 7.4 % and 4.9 % for pellet hardness, 10.4 % and 10.0 % for pellet oil absorption, 13.7 % and 8.3 % for pellet water stability, and 11.3 % and 5.5 % for pellet durability. Using the model coefficients obtained from the extrusion results, the empirical model can partly extrapolate the pellet qualities of an additional extruded recipe, which has a slightly adjusted wheat gluten and wheat. The model performance was evaluated based on. R2, RSME (root-mean-square deviation), AAD % of the empirical model was better than the RSM model to predict the effects of extrusion variables on pellet quality parameters. The effects of the extrusion process variables and recipe composition on pellet quality parameters are predicted by the empirical model. Its demonstrates that the empirical model is a new method to understand extrusion trial results in different extrusion systems and recipes without changing its mathematical form of expression, which gives a common reference to compare an extruded recipe in different systems and has practical engineering applications.

Soybean molasses has a positive impact on the pelleting process and physical quality of dairy feed pellets

The influence of soybean molasses (SBMo) addition in dairy cow feed on the pelleting process and pellet quality was assessed in this study. For purpose of optimising production process of dairy feed pellets the SBMo content was varied at three levels (30, 60 and 90 g/kg) together with moisture content (MC – 130, 150 and 170 g/kg) of mash prior the pelleting process and sieve opening diameter (SOD – 5, 6 and 7 mm) of the hammer mill that was used for grinding of dry ingredients. The SBMo and required amount of water were added by a two-phase nozzle during mixing of ingredients and pelleting was done using a flat die pellet press. Experimental runs were performed according to Box-Behnken experimental design. The determined responses were: specific energy consumption (SEC), quantity of fines (QoF), pellet hardness (PH), pellet durability index (PDI) and bulk density (BD). Significance of input factors and their interactions, corresponding contributions and sum of squares were determined by using the statistical method of analysis of variance (ANOVA). Addition of SBMo decreased the SEC, PH and BD, and higher MC also decreased the SEC, PH and BD. The increase of SOD decreased the BD. The strongest contribution on SEC had the addition of SBMo (64.1%), while the strongest contribution on BD originated from the MC (71.2%). Models obtained in this research were used to optimise the input parameters in order to get the minimum SEC, maximum PH and maximum BD. The results of the optimisation for the input parameters were: SBMo content = 89.9 g/kg, MC = 130 g/kg, and SOD = 6.0 mm; and for the responses were: SEC = 33.9 kWh/t, PH = 12 Kahl unit kg, BD = 595.1 g/L. The obtained results showed that inclusion of SBMo at level of 90 g/kg could lead to the reduction of SEC and without significant influence on the pellet physical quality.

Reduced-order hybrid modelling for powder compaction: Predicting density and classifying diametrical hardness

Drawing on machine learning (ML) techniques and physics-based modelling, two feature-based reduced-order models are presented: one for the quantitative prediction of density and another for the classification of the diametrical hardness of pellets from a powder compaction process (pelleting). For interpretability, the models use as input only the parameters from a modified Drucker–Prager Cap (DPC) model calculated from process data monitoring and the applied maximal compression force. For quantitative density prediction, 8 features linked to first-principles models of powder compaction are generated, and the final model uses only 2. A critical part of the modelling, and also one of the main contributions, is a data augmentation step for the primary data set of this study by leveraging much smaller supplementary data sets that have measurements not present in the primary data set.The final results imply a significant reduction in the quantity of data needed for model input and cut down the cost of data acquisition, storage, and computational time. Additionally provided is a detailed analysis of the impact and relevance of the generated features on the model performance.The density prediction model, using only 2 features, reaches a mean absolute scaled error (MASE) of 12.9% and a mean absolute error (MAE) of 0.10 (where r2=0.975). The scaled (diametrical) hardness classifier has an F1 score of 0.915 using 4 features.

Moisture Content and Mechanical Properties of Bio-Waste Pellets for Fuel and/or Water Remediation Applications

The current research is focused on the mutual comparison (mechanical properties, response to humidity) of agro-waste composite materials. The purpose of this work is directed at the valorization of agro-waste biomass products and to investigate their mechanical stability for transport or other applications (in dry and wet states). Three different types of agro-waste (oat hull (Oh), torrefied wheat straw (S), and spent coffee grounds (SCG)) were blended with kaolinite (K) and chitosan (CHT) at variable weight ratios to yield ternary composites. Mechanical properties were represented by measuring hardness (in compression mode) and elastic modulus (under tension mode). Young’s (elastic) modulus was measured both for dried and hydrated samples. The pelletized materials were prepared in two forms: crosslinked (CL) with epichlorohydrin and non-crosslinked (NCL). The hardness of the Oh pellets was poor (75 N) and decreased by four times with greater agro-waste content, while crosslinking affected the hardness only slightly. S pellets had the highest level of hardness at 40% agro-waste content (160 N), with a concomitant decrease to 120 N upon crosslinking. SCG pellets had the least change in hardness for both CL and NCL specimens (105–120 N). The trends of Young’s modulus were similar to hardness. Hydration caused the elastic modulus to decrease ca. 100-fold. In general, S and SCG composites exhibit the greatest hardness and Young’s modulus compared to Oh composites (CL or NCL) in their dry state.

Pelletisation of peat moss using binder from palm oil refinery waste (spent bleaching earth) and binder from grey oyster mushroom plantation waste (spent mushroom substrate)

Spent bleaching earth (SBE); a solid waste generated from refining palm oil process and spent mushroom substrate (SMS); a waste generated from grey mushroom plantation were explored as potential binding agents. The experimental work of pelletisation using a pelleting machine was carried out by varying the ratio of peat moss (PMS) to spent bleaching earth (SBE) and spent mushroom substrate (SMS) at 90:10, 80:20 and 70:30 (by weight %). Several analyses were conducted to determine the physical and thermal degradation characteristics of the peat moss pellet at different level of binders. Density and hardness tests were performed for physical analysis. Results from durability test shows that pellet from the tested ratios achieved pellet durability index (PDI) value of more than 97.5%. In terms of pellet hardness, pellet mixed with SBE was found to decrease its hardness when the amount of SBE in the mixture increases. On the contrary, for peat soil pellet mixed with SMS, when the amount of SMS in the mixture increases, the pellet hardness also increases. In terms of water resistance, peat soil pellet mixed with SBE showed high resistance towards moisture whereas peat soil pellet mixed with SMS was found to break during the test when the amount of SMS binder increased. The pelletisation of peat soil aimed to increase the density and strength of the material and consequently provide better thermal degradation characteristics It can be concluded that the most ideal formula among the tested ratios to produce biosolid fuel pellet with SBE as binding agent was 90:10 PMS:SBE whereas for pellet with SMS as binding agent was 70:30 PMS:SMS. This study thus brings opportunity for spent bleaching earth and spent mushroom substrate as potential binding agents to aid pelletisation of raw/biomass material.

Consolidation and reduction behaviour of pellets with sea sand vanadium titanomagnetite: a microscopic interpretation of macroscopic properties

ABSTRACT The compressive strength of pellets is of great significance for the evaluation of pellets quality indexes. In this paper, the chemical composition, mineral phase composition and microstructure of pellets were analyzed by ICPAES, XRD, OM and SEM-EDS through oxidation roasting and gas-based reduction experiments. The effect mechanism of thermal regulation on the compressive strength and reduction performance of pellets was explained by the micro-indicators such as porosity, Vickers hardness and morphological structure of pellets. The results showed that with the increase of the roasting temperature and the extension of the roasting time, the internal porosity of the oxidized pellets was reduced, while the compressive strength of the pellets was continuously improved, and the roasting temperature had a greater influence on the compressive strength. However, the increase in porosity of the reduced pellets weakened the intergranular bonding between the particles, which led to a reduction in compressive strength.

Effects of Wet Fermented Soybean Dregs on Physical and Mechanical Properties of Pellets of Corn Stover.

Simple SummaryCorn stover pellets are of poor quality (regarding physical and mechanical properties), and wet soybean dregs are viscous, which may improve the pelleting process. Furthermore, the soybean dregs have high nutritional value, which may increase the quality of feed. The relaxed density, dimensional stability coefficient and hardness of feed pellets were measured and analyzed in this study to clarify the influence mechanism of wet-fermented soybean dregs on the pelleting of corn stover. The results showed that fermented soybean dregs had a significant effect on corn stover pelleting. The comprehensive analysis showed that the addition of 5–10% fermented soybean dregs to corn stover improved the relaxed density, dimensional stability coefficient, and hardness of feed pellets by 10.76–23.51%, 7.32–15.74%, and 33.39–454.47%, respectively. The results could provide guidance on the research and development of high-quality forming technology and instruments using the mixture of corn stover and fermented soybean dregs and offer a new route for the utilization of high-moisture materials.Pelleting experiments were carried out in this study to clarify the influence mechanism of wet-fermented soybean dregs on the forming of corn stover. The effects of addition of water or wet fermented soybean dregs on the forming quality of corn stover were comparatively studied under different corn stover particle sizes and compression displacement. The fermented soybean dregs significantly affected the relaxed density, dimensional stability coefficient, and hardness of feed pellets. The relaxed density, dimensional stability coefficient, and hardness of feed pellets increased first and then decreased with the increase of fermented soybean dregs. The forming quality of corn stover added with fermented soybean dregs was higher than that of corn stover added with the same amount of water. The mechanism allowed soybean dregs to strengthen the bonding between corn stover particles and thus improved the quality of feed pellets. A certain amount of water was favorable for corn stover pelleting, but excessive water may decrease the quality of pellets. The comprehensive analysis showed that the addition of 5–10% fermented soybean dregs to the corn stover improved the relaxed density, dimensional stability coefficient, and hardness of feed pellets by 10.76–23.51%, 7.32–15.74%, and 33.39–454.47%, respectively.

Effects of fish meal replacement by three protein sources on physical pellet quality and growth performance of Pacific white shrimp (Litopenaeus vannamei)

The study investigated the effects of replacing fish meal with cottonseed protein concentrate (CPC), Tenebrio molitor (TM) and Clostridium autoethanogenum protein (CAP) on physical pellet quality and growth, feed utilization of Pacific white shrimp (Litopenaeus vannamei). A control diet (FM) was designed to contain 200 g/kg fish meal, then, 60 g/kg CPC, TM and CAP were used to replace the same amount of fish meal, respectively, to form four diets by pelleting. After the evaluation of physical quality, the four diets were fed to shrimp with initial body weight of 7.72 ± 0.01 g for 6 weeks. The results indicated that pellet hardness and bulk density were significantly increased (P < 0.05), when fish meal was substituted by CPC, TM and CAP, but no significant differences in starch gelatinization degree and pellet durability index were detected among the four diets (P > 0.05). In addition, the dissolution loss and powder content in CPC and CAP diets were significantly decreased (P < 0.05). Compared to FM group, TM group presented significantly higher feed conversion ratio (FCR) and lower protein retention(P < 0.05), but the other two groups showed no significant differences in growth performance (P > 0.05). Hepatopancreas amylase activity in CPC and CAP groups was significantly higher than that in FM group (P < 0.05), while no significant differences in the activities of hepatopancreas protease and pyruvate kinase, aspartate aminotransferase and alanine aminotransferase were found among the four groups (P > 0.05). The hepatopancreas and intestinal histology were normal in all groups without obvious injury. In conclusion, in the pelleted feed containing 200 g/kg fish meal, the replacement of 60 g/kg fish meal with CPC and CAP improved the physical pellet quality and had no negative effects on growth performance and nutrient utilization, but the replacement of 60 g/kg fish meal with TM decreased the growth performance and nutrient utilization of Pacific white shrimp.

Microstructure of zirconium carbide ceramics synthesized by spark plasma sintering

Zirconium carbide (ZrC) samples were prepared by spark plasma sintering (SPS), at temperatures of 1700 °C, 1900 °C and 2100 °C, all at pressure of 50 megapascal (MPa). The density of ZrC ceramic pellets was measured using a Micromeritics AccuPyc II 1340 Helium Pycnometer. The density of ZrC ceramic pellets was found to increase from (6.51 ± 0.032) g/cm3 to (6.66 ± 0.039) g/cm3 and (6.70 ± 0.017) g/cm3 when the temperature of the SPS was increased from 1700 oC to 1900 oC and 2100 oC respectively. Moreover, the hardness of ZrC ceramic pellets were measured using Rockwell hardness test. The hardness of ZrC ceramic pellets increased from (7.4 ± 0.83) to (17.0 ± 0.073) and (18.4± 0.05) gigapascals (GPa) at temperatures of 1700 oC, 1900 oC and 2100 oC respectively. X-ray diffraction shows the absence of spurious phases or impurity. XRD results showed that, all prepared ZrC samples has the same preferred orientation of the planes (i.e., 200). Furthermore, the average grain size of ZrC was calculated using Sherrers’s equation. The average grain size of the pure ZrC powder increased from 67.46 nm to 72 nm, 79 nm and 83 nm when the ZrC powder was sinteried at temperatures of 1700 oC, 1900 oC and 2100 oC respectively. The differences in the average grain size between the prepared samples leads to show different surface morphologies that monitored by scanning electron microscopy (SEM).

Data-Driven Modelling of a Pelleting Process and Prediction of Pellet Physical Properties

In the manufacture of pelleted catalyst products, controlling physical properties of the pellets and limiting their variability is of critical importance. To achieve tight control over these critical quality attributes (CQAs), it is necessary to understand their relationship with the properties of the powder feed and the pelleting process parameters (PPs). This work explores the latter, using standard multivariate methods to gain a better understanding of the sources of process variability and the impact of PPs on the density and strength of the resulting pellets. A Kilian STYL’ONE EVO Compaction Simulator machine was used to produce over 1000 pellets, whose properties were measured, with varied powder feed mechanism and powder feed rate. Process data recorded by the Compaction Simulator machine were analysed using Principal Component Analysis (PCA) to understand the key aspects of variability in the process. This was followed by Partial Least Squares (PLS) regression to predict pellet density and hardness from the Compaction Simulator data. Pellet density was predicted accurately, achieving an R2 metric of 0.87 in 10-fold cross-validation, and 0.86 in an independent hold-out test. Pellet hardness proved more difficult to predict accurately, with an R2 of 0.67 in 10-fold cross-validation, and 0.63 in an independent hold-out test. This may however simply be highlighting measurement quality issues in pellet hardness data. The PLS models provided direct insights into the relationships between pelleting PPs and pellet CQAs and highlighted the potential for such models in process monitoring and control applications. Furthermore, the overall modelling process boosted understanding of the key sources of process and product variability, which can guide future efforts to improve pelleting performance.

Whey as a sustainable binder for the production of extruded activated carbon

Whey, the main by-product of the dairy industry, is proposed as a sustainable binder for the production of extruded activated carbon. Coconut shell char was mixed with controlled quantities of either rehydrated whey powders or partially dehydrated liquid whey. After extrusion, extrudates were dried, and carbonised or activated under N2 or CO2 atmosphere, respectively. A comprehensive study of the effect of different parameters including binder proportion, coconut shell char particle size and carbonisation temperature was carried out. The composition of whey prompted Maillard reactions boosted with temperature that conferred a resin-like behaviour to the binder. Quality parameters of the resulting extrudates were their ball-mill hardness, real and bulk densities. All whey-bound pellets retained their original shape after the high temperature treatment. The hardness of those whey extrudates was particularly remarkable considering the biomass origin of this binder. The carbonisation temperature had little effect in the hardness or densities of the carbon pellets. The best pellet formulation comprised the use of coconut shell char powders with particle sizes < 212 µm, in mixtures having a 7/3 char/dry whey mass ratio. The properties of the pellets obtained after the activation of such pellets were comparable to those of commercial activated carbon extrudates. The use of partially dehydrated liquid whey rather than re-hydrated dry whey rendered very similar results. The alkalinity of the binder made the resulting activated carbons adequate for H2S removal at room temperature. An economic estimation of the process placed whey in a practical position within the binder market.

Effects of dietary starch sources on pellet-processing characteristics, growth performance and caecal microflora of meat rabbits.

This study evaluated the effects of starch sources on pellet-processing characteristics as well as the growth performance and caecal microflora of rabbits. Ninety-six 35-day-old rabbits were randomly allocated to four groups with 24 rabbits per group and were fed diets with different starch sources (corn, wheat, potato or pea starch). The trial lasted for 40days. The greatest hardness and lowest powder ratio of feed pellets was associated with the use of potato starch (p>0.05). Pellet bulk density was the highest with corn starch, and the density was greater than that of pea starch by 5.91% (p < 0.05). The pulverisation ratio of corn starch pellets was the lowest, 43.67% lower than that of the pea starch pellets (p < 0.05). The average daily gain of rabbits in the corn starch group was higher than in the potato and pea starch groups, by 7.89% and 10.81%, respectively (p < 0.05). Rabbits in the corn starch group had the best feed conversion ratio (p > 0.05). The feed intake of rabbits in the potato starch group was higher than in the wheat and pea starch groups, by 4.30% and 5.16% respectively (p < 0.05). The dominant caecal bacteria phyla were Firmicutes, Bacteroidetes, Verrucomicrobia and Proteobacteria. There were 12 bacterial genera with proportions greater than 0.1%. The caecal proportion of Clostridium in the pea starch group was 1.8%, which was higher than those of the other groups (p = 0.057). There was no significant difference in caecal microbial diversity among groups (p > 0.05). The highest microbial clustering effect was found in the corn starch treatment. In conclusion, the best pellet quality was found using potato starch; for rabbit growth, the optimal source was corn starch.

In-situ reactive synthesis of dense nanostructured β-FeSi2 by Spark Plasma Sintering

β-FeSi2 is a promising material for thermoelectric application, especially if it can be nanostructured to decrease the lattice contribution to the thermal conductivity. It can be even more interesting if the entire chain of processes implemented to obtain it is not too time and energy consuming. In this paper we report a simple route to synthesize nano-β-FeSi2 by combining mechanical milling and reactive spark plasma sintering of Fe-Si alloys. A map of the pressure-temperature conditions using a spark plasma sintering setup was performed and shows that it is possible to obtain nano-β-FeSi2 pellets with a density above 90% using dwell times as short as 5 min. The impact, of both, the density and nanostructuring on the hardness of the β-FeSi2 pellets obtained by this process are presented as well as the impact of the thermoelectric properties of the materials.

Analysis of feed pelleting characteristics based on a single pellet press device

Pelleting is the most extensively used thermal processing method in feed industry. In this article, a single pellet press device was developed to investigate the pelleting processing of animal feed. Effects of moisture content (10%-18% w.b.), preheating temperature (60°C-100°C) and maximum compression force (0.2-0.6 kN) on feed pellet were determined and analyzed, as well as energy consumption. The results showed that unit density, pellet hardness and energy consumption were 0.87-2.92 g/cm3, 1.08-4.55 kg, and 3.27-12.66 J/g, respectively. Unit density was found to increase with the increase of preheating temperature and maximum compression force, but decrease with the increase of moisture content. Pellet hardness showed a first ascending then descending trend with the increase of moisture content, but exhibited a positive relationship with both preheating temperature and maximum compression force. Energy consumption increased with the increase of maximum compression force, but exhibited descending trends with the increase of moisture content and preheating temperature. Due to its features of low cost, high efficiency and easy control, the single pellet press device has a wide application prospect in feed processing. Keywords: feed, pelleting, energy consumption, preheating temperature, experiments DOI: 10.25165/j.ijabe.20221504.6155 Citation: Peng F, Xiang R, Fang F, Liu D. Analysis of feed pelleting characteristics based on a single pellet press device. Int J Agric & Biol Eng, 2022; 15(4): 65–70.

The use of tunicate (Ciona intestinalis) as a sustainable protein source in fish feed – Effects on the extrusion process, physical pellet quality and microstructure

The aim of this research was to study the effect of the replacement of fishmeal (FM) or soy protein concentrate (SPC) by tunicate meal (Ciona intestinalis) on the extrusion process, physical pellet quality, pellet expansion, and microstructure. The experiment was based on a 3-component simplex-centroid mixture design. Models with R2 in the range of 0.574–0.999 (P = 0.03 to < 0.0001) were established for specific mechanical energy (SME), temperature behind extruder die (Tdie), apparent dough viscosity in the extruder die (Vdie), pellet hardness, durability, expansion, and microstructure parameters. Increase in SME and Tdie were mainly explained by the reduced lipid content in the feed mix due to the replacement of FM with tunicate or SPC. Reduced Vdie was mainly an effect of increased tunicate level and with the lowest value found for the pure tunicate blend. There was an increase in volumetric expansion and open porosity by replacement of SPC with tunicate, explained by this decrease in Vdie. Reduced hardness and durability were found for blends high in SPC due to incomplete plasticisation. Extrudate expansion, fat adsorption capacity and leakage were explained by the extrudate microstructure measured by X-ray microtomography. Within the boundary of the chosen design, 64% of the FM can be replaced by tunicate meal without compromising physical feed quality. Due to its viscosity behaviour, tunicate meal can improve pellet expansion and fat absorption capacity of extruded feed.