Feed Size Research Articles

Trunk spines of trees: a physical defence against bark removal and climbing by mammals?

Background and Aims The defensive role of spines has previously been related to leaves, young shoots and reproductive organs. However, some woody species harbour spines on their trunks where none of those organs are present. Several explanations are plausible: they could be (1) climbing aids, (2) remnants from defence of leaves or reproductive organs during an earlier development phase, or (3) an as-yet undescribed defence. Here we investigate whether they could play a role against either bark feeding or preventing climbing animals accessing food resources in the tree canopy.MethodsWe described 31 woody species with spines on their trunk, growing in a botanical garden, to test whether morphological strategies could be identified and suggest what could be their most likely function. As testing their function is difficult experimentally for large pools of species, we performed virtual experiments to evaluate the potential roles of trunk spines against bark removal and climbing animals of different sizes. We then compared for each species and their confamilial non-spiny species the nutritional profiles of leaf, bark and reproductive organs to test whether trunk spines were associated with a nutritious organ (more likely targeted by herbivores).Key ResultsWe identified four morphological syndromes of trunk spines. Two corresponded to already known functions (anchorage for lianas and crown defence against large ground mammals), and two strategies are newly described trait syndromes with traits suggesting a defence against bark feeding and climbing mammals. By simulation, we show how each strategy could translate into defence against debarking and prevent herbivores from climbing.ConclusionsWe identified trunk spine strategies and the criteria to classify them, their most likely function and the likely feeding mode and size of animal against which different trunk spine strategies may be effective. We discuss further perspectives for testing their function and their ecological significance.

Application of artificial neural network method to predict the breakage properties of PGE bearing chromite ore

In the present investigation, systematic grinding experiments were conducted in a laboratory ball mill to determine the breakage properties of low-grade PGE bearing chromite ore. The population balance modeling technique was used to study the breakage parameters such as primary breakage distribution (Bi, j) and the specific rates of breakage (Si). The breakage and selection function values were determined for six feed sizes. The results stated that the breakage follows the first-order grinding kinetics for all the feed sizes. It was observed that the coarser feed sizes exhibit higher selection function values than the finer feed size. Further, an artificial neural network was used to predict breakage characteristics of low-grade PGE bearing chromite ore. The predicted results obtained from the neural network modeling were close to the experimental results with a correlation of determination R2 = 0.99 for both product size and selection function.

Determination of Work Index of Muro Iron Ore Using Marble and Granite as Reference Ores

The work index of Muro iron ore was determined using the modified Bond’s method also known as Berry and Bruce method. This study used iron ore obtained from Muro town, a community in Toto LGA, Nasarawa state as the test ore. Marble and Granite which was separately used as the reference ores were obtained from Muro environs. 100 g each of the test ore and the reference ores were subjected to the same grinding conditions in a ball mill. Size analysis of the feed to the ball mill and the product of the ball mill for both test ore and reference ores were carried out and the results tabulated accordingly. The 80% passing particle size of the ball mill feed and discharge for the samples were calculated using the Gaudian Schumann expression. The Bond’s equation was then used to calculate the work index of the Muro iron ore which was found to be 24.84 kWh/ t when marble was used as reference ore and 27.41 kWh/ t when granite was used as reference ore. The average work index of Muro iron ore was calculated as 26.13 kWh/ t, while the energy requirement for grinding the ore was found to be 3.62 kWh/ t. The value of the work index of Muro iron ore is within the limit of work index of iron ore quoted in literatures

Manipulations of brood age reveal limited parental flexibility in an insectivorous passerine

For birds with altricial nestlings, behavioural flexibility in provisioning may be essential to success, as it enables parents to respond to changes in offspring demand. While parents often increase the quantity of food they provide as nestlings grow, they may also adjust different aspects of this suite of behaviours (i.e. feeding rate, prey type and size and distribution within broods) flexibly in response to nestling age. We tested whether generalist insectivores, mountain bluebirds, Sialia currucoides , respond to abrupt shifts in the body size of nestlings the same way they do when nestlings age normally. During a short-term (within-day) manipulation of nestling age, we recorded provisioning behaviour of parents feeding their own (‘natal’) and an age-manipulated (increased or decreased by 4 days) brood on the same day, in addition to recording provisioning ∼4 days before or after, when natal broods were the same age as manipulated broods. Parents responded to the age manipulation by altering feeding rates, but when broods aged naturally, parents altered the types and sizes of prey they delivered. Parents fed less often and provided larger prey when feeding younger-than-expected broods than when feeding young natal broods. Parents given older-than-expected broods fed more larvae, and fed more often, but provided smaller prey than supplied to older natal broods. Parents feeding older natal broods distributed prey more equitably among nestlings than those feeding either experimental older broods or younger broods (both natural and experimental broods), but this was not due to biased feeding of nestlings according to their body weight. Females fed more often than males and increased the quantity of larvae they provided to younger-than-expected broods. We suggest that parent mountain bluebirds can perceive and respond to both rapid and gradual changes in offspring size, but they may use different cues to adjust feeding rate and prey use. • Provisioning flexibility may allow parents to cope with changes in offspring demand. • Mountain bluebirds typically alter prey type but not feeding rate as nestlings grow. • We briefly manipulated nestling age (± 4 days) to examine parental responses. • During manipulation of brood age, parents altered feeding rate but not prey use. • Parents may adjust feeding rate and prey use in response to different cues.

Chlamydia abortus in dairy cattle: Serostatus and risk factors in Algerian northeastern high plateaus

Chlamydia abortus is a zoonotic abortifacient bacterium causing a large variety of diseases with detrimental economic impact, mainly in ruminants. A total of 345 cows belonging to 42 herds were randomly sampled to conduct a cross sectional study, aiming to establish the seroprevalence of this pathogen (using iELISA test) and its associated risk factors (through a questionnaire) in dairy cattle from Oum-El-Bouaghi and Setif provinces (Northeastern Algerian high plateaus). All over the studied zone, specific chlamydial antibodies were detectable in 58 cows (16.8%) belonging to 13 infected herds (30.9%). The individual animal seroprevalence ranged from 12.6% (18/143) to 19.8% (40/202) in Oum-El-Bouaghi and Setif respectively and the herd one varied from 30% (06/20) to 31.8% (07/22) as well. At the herd level, none of the tested factors had an effect on chlamydial antibodies prevalence; while at the individual animal level, associations (univariately evaluated with p<0.05) were recorded for herd size, deficient disinfection and origin of cows and feed. Multivariable logistic regression analysis revealed origin of cows to be protective and history of infertility as potential risk factor in Setif only. These results are clear evidences that C. abortus is endemic in our dairy cattle population, in which it plays some role in their decreased reproductive performances.

Genetic Characterization of Pathogenic Escherichia Coli Isolated from Smallholding Dairy Buffaloes, their Products, and Some Environmental Sources

This study was conducted to evaluate the potential existence of pathogenicEscherichia coli in smallholding dairy buffaloes, their products as well as in some environmental sources. In total, 150 samples including an equal sample size (n = 25) of raw milk, Kareish cheese, water, feed, udder and rectal swabs were examined. Phenotypic and genotypic procedures were used to characterize the bacterial population. Twenty-eight isolates were confirmed as E. coli from the examined samples (18.66%). The recovered isolates were categorized as Enterohemorrhagic E. coli (n=11),Enteropathogenic E. coli(n=9), Enterotoxigenic E. coli(n= 5)and Enteroinvasive E. coli (n=3). All isolates were resistant to erythromycin followed by oxacillin (89.28%), and nalidixic acid (67.85%), while 96% of the recovered strains displayed high sensitivity to imipenem. A great proportion of the recovered E. coli (67.9%) exhibited multidrug resistance. The majority of isolates (92.9%) harbored stx1either alone or in association with stx2 which present in 60.7% (17/28) while eaeA genes were detected in 50% among the recovered isolates in association with stx1 or combined with stx2 (n =11). Twelve isolates (42.86%) expressed all the examined beta lactamase encoding genes; while only 25% of the isolates harbored all tested beta lactamase genes in common with stx1, stx2 and eaeA genes.The results herein indicated that the pathogenicE. coli could be present in the examined samples which pose a relevant threat and negative impact on animal as well as consumer health. The study emphasizes the necessity of developing long-term strategies to assure dairy food safety.

An experimental investigation on plug formation using fuzzy cottonseeds

Within the field of pneumatic conveying horizontal (Plug-1) and vertical plug flows have been investigated only in the context of cohesive fine powders. This paper considers a series of experiments using fuzzy cottonseeds, which greatly differ in particle and bulk properties from fine powders, to investigate plug formation. In this study, several possible dense phase behaviours were observed, which were consistent in vertical and horizontal orientations and mostly influenced by the batch size of feeding into the rig due to its influence on particle arrangement. Particle arrangement at the plug base or rear was found to be critical for achieving stable plugs, with a requirement of the rear or base batch having the length of more or equal to pipe diameter. This work sheds light on the general features and mechanisms governing horizontal and vertical plug formation.

Could Fish Feeding Behaviour and Size Explain Prevalence Differences of the Nematode Eustrongylides excisus among Species? The Case Study of Lake Garda

The nematode Eustrongylides excisus is a parasite of freshwater fish- and fish-eating birds, with known differences on prevalence values among fish species. Thus, the present study aims to explore the hypothesis that the feeding behavior and the size of fish belonging to different trophic levels could explain such differences. For that, 14 sampling sites were selected to perform a fish parasitological survey on Lake Garda (Italy) during spring-summer 2020. Amplification of nuclear ribosomal internal transcribed spacer (ITS) rDNA sequences of nematodes morphologically ascribable to the genus Eustrongylides allowed to identify them as E. excisus. From the five studied fish species (Perca fluviatilis, Lepomis gibbous, Coregonus lavaretus, Alosa fallax lacustris and Micropterus salmoides), only three presented the parasite E. excisus: P. fluviatilis, L. gibbous and M. salmoides, with significant differences in prevalence values among species (p = 0.002). Additionally, there were differences in prevalence values within the same fish species captured from different sampling sites. Findings showed that mainly piscivorous fish were positive for E. excisus and how the prevalence was highest in M. salmoides. As regard the fish size, a negative correlation between body size and E. excisus was found in P. fluviatilis due to the feeding habit of juvenile perch which feed mainly zooplankton and benthic invertebrates (i.e., oligochaetes, which are the first intermediate hosts of E. excisus). The study findings advance novel knowledge in the field of pathogens of zoonotic importance in the aquatic environment.

Influence of Cold Spray Parameters on Bonding Mechanisms: A Review

The cold spray process is governed by the impact of high velocity feedstock particles onto a substrate without melting. Hence, the bulk material properties are retained. However, it is challenging to achieve good adhesion strength. The adhesion strength depends on factors such as the cold spray process parameters, substrate conditions, coating/substrate interactions at the interface and feedstock material properties. This review examines fundamental studies concerning the adhesion mechanisms of cold spray technology and considers the effect of cold spray input parameters such as temperature, stand-off-distance, pressure, process gas, spray angle, and traverse speed of the cold spray torch on the bonding mechanism and adhesion strength. Furthermore, the effects of substrate conditions such as temperature, hardness, roughness and material on the adhesion mechanism are highlighted. The effect of feedstock properties, such as feed rate, shape and size are summarized. Understanding the effect of these parameters is necessary to obtain the optimal input parameters that enable the best interfacial properties for a range of coating/substrate material combinations. It is expected that feedstock of spherical morphology and small particle size (<15 μm) provides optimal interfacial properties when deposited onto a mirror-finished substrate surface using high pressure cold spray. Deep insights into each parameter exposes the uncovered potential of cold spray as an additive manufacturing method.

Study of the ball milling condition effect on physicochemical and structural characteristics of wheat flour

An investigation of the changes in the properties of starch due to mechanical and thermal effects was taken. The milling temperature and time were strictly controlled, and the particle size, relative crystallinity, damaged starch content, pasting characteristics, and thermal properties of the ground sample from different feed sizes were determined. The results showed that the feed particle size had a significant influence on the particle size distribution, peak viscosity, and final viscosity of the milled product at the initial milling stage. Minimum feed particle size (3.75 ~ 623 μm) flour has the largest peak viscosity (2,881.5 ± 58.7 cP & 2,895.0 ± 38.2 cP) after milling 15 min. The sieving results showed that better breakage effect for coarser particle size after same milling time, particularly under normal temperature. The data of relative crystallinity indicating that keeping a lower temperature range (<25℃) during the milling process may be beneficial to the protection of the starch crystallization. In addition, the difference of thermal properties of the milled products may be caused by the different degrees of starch exposure in endosperm granules and the change of surface protein properties during milling. Novelty impact statement The feed particle size has a significant effect on the peak and final viscosities of the short-time ball milling flour. Cryo-milling can protect the relative crystallinity of wheat granules. The degree of starch granule exposure affects the impact of mechanical force during milling.

RELATIONSHIP OF MOUTH OPENING AND LENGTH GROWTH TO FEED SIZE OF SNAKEHEAD LARVAE (CHANNA STRIATA)

RELATIONSHIP OF MOUTH OPENING AND LENGTH GROWTH TO FEED SIZE OF SNAKEHEAD LARVAE (CHANNA STRIATA)

Determinants of profitability of black soldier fly farming enterprise in Kenya

Black soldier fly (BSF) farming is emerging as a new farm enterprise in Kenya poised to provide high-quality and affordable alternative protein sources for animal feed production. Consequently, commercialisation and adoption require farmers to understand if the enterprise is economically viable. This study sought to assess the determinants of profitability of the BSF farm enterprise. A census survey was conducted whereby 34 well-established smallholder BSF farmers were interviewed. A double log regression analysis on the determinants of profitability of the BSF farm enterprise was done. The results revealed that 93.6% of the variation in enterprise gross margin was explained by the independent variables. Feed and household size contributed positively and significantly to the enterprise gross margin. Labour was significantly and negatively correlated to the enterprise gross margin. Farm size, gender, level of education, and age of the farmer did not significantly influence the gross margin of the enterprise. Furthermore, the survey showed that a 1% increase in man-hours spent in the BSF farming enterprise would result in a 0.34% reduction in the gross margin while a 1% increase in the usage of the rearing substrate would lead to a 1.38% increase in the gross margin. There is a need for farmers to reduce the man-hours spent in the BSF farms but at the same time increase significantly the utilisation of more rearing substrate to improve their profitability. However, a long-term socio-economic impact assessment on the BSF farming enterprise would be valuable to attract investors and interest in the insect production sector for animal feed.

Feeding performance of the larval stag beetle Aegus chelifer (Coleoptera: Lucanidae) explains adult body size variation and sexual dimorphism

Abstract In stag beetle larvae, food availability is considered a major cause of body size variation in adults, but this has not been explicitly tested. To evaluate wood use and the effects of food quantity on growth and adult body size, the feeding performance of the tropical stag beetle Aegus chelifer MacLeay (Coleoptera: Lucanidae), which is widely distributed in Southeast Asia, was investigated by rearing larvae with different food quantities. Apparent digestibility was approximately 9%, and the efficiency of conversion of ingested food ranged from 0.7% to 1.7%. Feeding period, total food consumption, and adult body size significantly increased alongside food quantity. Males had higher consumption rates than females did at the same larval weight due to shorter food retention time. Males showed greater variation in feeding, growth performance, and adult body size than females. Differences in feeding performance that depend on food availability may enhance their fitness and may further result in sexual differences and adult body size variation.

Thermomechanical beneficiation of recycled concrete aggregates (RCA)

In order to move towards a circular economy, it is relevant to maximize the usage of waste materials in construction activities. One such resource that could be extracted from abundant waste are Recycled Concrete Aggregates (RCA). Many methods have been proposed in the last few decades to improve the quality of RCA, with limitations in terms of energy demand or low yield. In the present study, an attempt has been made to employ thermo-mechanical beneficiation to obtain high-quality coarse and fine aggregates, with high yield (>90%). Heating temperature, feed size and residing duration are variables that have been optimized. When waste concrete chunks are heated for about 60 min at 500 °C (932°F) and milled with steel ball charge, the resulting RCA fractions conform to the limits set by stringent codes and guidelines. The beneficiated coarse RCA thus obtained could give concrete performance comparable to that of pristine granite aggregate concrete.

Hiding among holes: mechanisms underlying the evolution of masquerade in flea beetles (Chrysomelidae)

1. The herbivorous flea beetles (Chrysomelidae: Alticini) have evolved a masquerading strategy by hiding among their own feeding damage. Similarities between beetle bodies and their feeding damage may act as a defence that reduces detection by visual predators.2. We analyse the evolutionary origin of flea beetles' camouflage using the French fauna (284 species) as a case study. We assess two competing hypotheses: (H1) the type of leaf tissue is the primary determinant of the colour and size of beetle species feeding on them, because each type of leaf tissue may have a tendency to result in a particular type of damage or, (H2) the morphological characteristics of the beetle explain the damage pattern, because beetle species evolve strategies to produce feeding damage that matches its own characteristics.3. We assessed bipartite networks of feeding interactions (beetle species and host plants). Beetle‐host interactions were non‐randomly distributed and highly modular, with more than 25% of the network modules showing beetle colour and size distributions significantly different from null expectations.4. Our results suggest that the evolutionary origin of flea beetles masquerading can be partially explained by both hypotheses. Some host plants seem to restrict feeding damage appearance on their leaves, favouring the survival of specific beetles with matching colour and size (H1). However, in most plant taxa, it is suggested, the existence of beetle‐associated constraints exert a selective pressure for the beetle to damage leaves in a particular way, similar to its own colour and size (H2).

Crushing characteristics of different minerals by cylindrical ball mill in cascading motion state

During the grinding process of the impact and abrasion actions synchronously coexist and continuously occur, the two actions may exert forces in different areas and transform to each other periodically. So it is difficult to characterize the respective crushing characteristics of the impact and abrasion actions. Based on the kinematics theory of grinding media, to ensure the grinding medium to be in cascading motion state in which minerals are crushed by only abrasion action of medium, to investigate the crushing characteristics of three kinds of minerals of quartz, pyrrhotite, and pyrite. Moreover, the difference in the ability to resist the crushing in the grinding process and the influence of feed sizes on the crushing were investigated by analyzing and comparing the breakage rate of the different minerals and the yield of specific product size - t 10 value under different test conditions. The research results indicated that the grinding resistance of quartz is the strongest, followed by pyrite and pyrrhotite. Besides, a smaller feed size resulted in a more grinding and crushing effect on the minerals. Therefore, during production, the grinding system should be adjusted according to the change in the material property to prevent over-grinding.

Research on the characteristics of particles size for grinding products with a ball mill at low speed

Grinding is a process where the particle size of the material is reduced under the combined effects of the impact action and the abrasion action of steel balls (grinding medium). Even though there are studies related to the grinding process, only a few studies systematically reported the low-speed grinding process. In this paper, the two common minerals: pyrite and quartz are subjected to low-speed grinding using the ball mill technique where the mill rotation is optimized to facilitate the grinding medium to be in the state of cascading. In addition, the relative grindability and grinding kinetic analysis are used to elucidate the particle size distribution characteristics, and rules for achieving the ground product's particle size at low-speed grinding. Further, discussions are made on the grinding characteristics of the mill when the grinding medium is in the cascading motion. The results show that i) finer feed size induces a significant change in the particle size of the ground products; ii) the grinding fineness of pyrite is higher given the same grinding time, whereas the grinding fineness of quartz increases sharply when the grinding time is prolonged; and iii) the grinding processes of the two minerals follow first-order linear kinetic model at low-speed grinding. These findings provide a theoretical foundation to carry out further research on the motion law and grinding characteristics at low- speed grinding.

Beneficiation of difficult-to-wash Indian low volatile coking coal fines by Falcon concentrator

ABSTRACT The fast depleting reserves of high-grade Indian coking coal and its resultant dependence on import makes the emerging situation a fit case for exploring innovative and high efficacy techniques such as non-conventional gravity-based systems for clean coal recovery viz., advanced centrifugal gravity separators like Falcon concentrators for fine and ultra-fine coal particles processing using enhanced gravitational force. The above methodology has been adopted for low volatile coking (LVC) coal due to the high ash content associated washability characteristics and high near gravity material content. Attempt was made using laboratory Falcon SB40 concentrator for cleaning the LVC coals assaying 32.6% ash. Considering the physical properties, coal petrography and washability studies, as received coal was ground to three size fractions of –500 μm, –250 μm and –150 μm and subjected to separation in Falcon separator. Experiments were conducted using Design Expert software to evaluate the effects of four significant process variables such as feed size, pulp density, gravitational force value and water pressure. The relationship between the response functions (ash content, combustible recovery and separation efficiency) and process variables is presented as empirical model equations. Under the optimum operating conditions, LVC coal was cleaned to 18.4% ash content with 57.8% combustible recovery using Falcon concentrator.

Production and physico-chemical properties analysis of co-pyrolytic oil derived from co-pyrolysis of scrap tires and sawdust

ABSTRACT In this study, the co-pyrolysis of scrap tires and sawdust at different blend ratio was conducted in a fixed bed co-pyrolysis reactor. The main objective of this study was to investigate the effects of various mixing ratios of scrap tires and sawdust on the product yields. Moreover, the effects of co-pyrolysis temperature and feed size on the product yields were also studied. Results showed that optimal co-pyrolysis temperature, which provides maximum bio-oil yield was 450°C as well as optimal feed size was 2.36 mm. The maximum bio-oil yield 50 wt% was obtained for mixing ratio 4:1 of scrap tires and sawdust. The physico-chemical properties of various mixing ratio of scrap tires and sawdust were investigated and found higher calorific value for 4:1 blend ratio. It has been also compared with some conventional fuel in order to observe its suitability as an alternative fuel.

Separation Efficiency of Different Methods to Treatment of a Low-Grade Iron Ore

In the present study, characterization and beneficiation tests were performed on an iron ore sample to evaluation of separation efficiency (SE) of different methods. Results showed that the decrease in feed size fraction increases the SE irrespective to beneficiation method. It was determined from the liberation analyses that the increase in SE values ​​at finer size fractions is related with higher liberation. Calculated SE values revealed that operational parameters significantly affect the SE of all methods and the net forces acting on particles play an important role on SE of different size fractions. Mean SE of different size fractions showed that separation efficiencies of gravity concentration and magnetic separation takes similar values above 1 mm, however, SE of magnetic separation is significantly higher than gravity concentration below 1 mm for studied sample. For low grade ores, it is very crucial to develop a flow sheet to achieve the optimum grade and recovery while decreasing the cost likely by using optimum method. Therefore, SE calculations used in this research can be used as a basic method to compare the efficiency of different beneficiation methods. SE method has advantages because they are fast methods for the efficiency evaluation by using experimental results.