Physical properties of peanut hull pellets

Peanut hull (peanut pods and waste materials from processing of peanuts) was pelleted through a 3/16-in. (4.76 mm) diameter die. The effect of change in moisture content (4.2-21.2%, wet basis) of the pellets (due to exposure of the pellets to low or high humidity storage environments) on physical properties were measured. Pelleting increased the bulk density of the peanut hull from 151 kg/m(3) to more than 600 kg/m(3). Bulk density, particle density and durability of the pelleted peanut hull of pellets were significantly affected by moisture content attained by the pellets during exposure to the low or high humidity environment. Air relative humidity significantly influenced the rate at which the pellets exchange moisture with the environment while air temperature did not. The values of the constants of the GAB model were obtained from moisture sorption isotherm at 25 degrees C.     

The effects of reed canary grass (<Emphasis Type="Italic">Phalaris arundinacea</Emphasis> L.) on wetland habitat and arthropod community composition in an urban freshwater wetland

Reed canary grass (Phalaris arundinacea L.) is an aggressive invader that dominates wetlands throughout the US. We examined the effects of reed canary grass on wetland habitat, both vegetation canopy architecture and soil environment, and its impacts the arthropod community in an urban wetland in Portland, OR, USA. Reed canary grass dominance resulted in reduced vegetation canopy complexity through reductions in native vegetation diversity and canopy height. In addition, reed canary grass dominance significantly changed the wetland soil environment, decreasing soil organic content and increasing soil moisture. The arthropod community responded to these habitat changes, being distinct between plots dominated by reed canary grass and those dominated by native vegetation. In addition, diversity measures were significantly lower in plots dominated by reed canary grass. Variables describing both vegetation canopy complexity and soil environment were more important predictors than relative abundance of reed canary grass in multiple regression models developed for dominant arthropod taxa and community metrics. Our results suggest that the mechanism by which reed canary grass affects the wetland arthropod community is primarily indirect, through habitat changes, rather than by directly altering its food source.     

Lab and Bench-Scale Pelletization of Torrefied Wood Chips—Process Optimization and Pellet Quality

Combined torrefaction and pelletization is used to increase the fuel value of biomass by increasing its energy density and improving its handling and combustion properties. In the present study, a single-pellet press tool was used to screen for the effects of pellet die temperature, moisture content, additive addition, and the degree of torrefaction on the pelletizing properties and pellet quality, i.e., density, static friction, and pellet strength. Results were compared with pellet production using a bench-scale pelletizer. The results indicate that friction is the key factor when scaling up from single-pellet press to bench-scale pelletizer. Tuning moisture content or increasing the die temperature did not ease the pellet production of torrefied wood chips significantly. The addition of rapeseed oil as a lubricant reduced the static friction by half and stabilized pellet production; however, the pellet quality, strength, and density were negatively affected. The pellets produced from pine wood torrefied at 250 and 280 °C were shorter than pellets produced from untreated wood and their quality did not match conventional wood pellet standards. However, the heating value of the torrefied pellets was higher and the particle size distribution after grinding the pellets was more uniform compared to conventional wood pellets.     

Effect of pellet size and pellet quality on pig performance

An experiment involving 1360 growing finishing pigs was undertaken to examine the effect of pellet size and pellet quality, as measured by the Holmen pellet durability test, on pig performance. A barley and soya bean meal diet was used and pellets were of two sizes, 5 and 10 mm diameter. Pellet quality was varied to give two types of pellet by steam conditioning and screening procedure during the pelleting process. The mean difference obtained in pellet durability was 11%.

Pig performance between 30 and 80 kg liveweight was not affected by either pellet size or pellet quality. There were small non-significant trends in favour of both the smaller pellets and the lower quality pellets. These trends, of the order of 1% or less, followed the same pattern as the dry matter content of the diets. The smaller diameter pellets were dried more efficiently in the cooling process and the low durability pellets had less steam added during the manufacturing process, which was reflected in the dry matter content of the finished diets.     

Blood profile and meat quality of Holstein-Friesian steers finished on total mixed ration or flaxseed oil-supplemented pellet mixed with reed canary grass haylage

Holstein-Friesian steer beef production is renowned globally as a secondary product of the milk industry. Grass feeding is a common practice in raising Holstein steers because of its low cost. Furthermore, grass feeding is an alternative way to produce beef with a balanced n-6 to n-3 fatty acids (FAs) ratio. However, the performance and meat quality of Holstein-Friesian cattle is more likely to depend on a high-quality diet. The aim of this study was to observe whether feeding two mixed diets; a corn-based total mixed ration (TMR) with winter ryegrass (Lolium perenne) or flaxseed oil-supplemented pellets with reed canary grass haylage (n-3 mix) provided benefits on carcass weight, meat quality and FA composition compared with cattle fed with reed canary grass (Phalaris arundinacea) haylage alone. In all, 15 21-month-old Holstein-Friesian steers were randomly assigned to three group pens, were allowed free access to water and were fed different experimental diets for 150 days. Blood samples were taken a week before slaughter. Carcass weight and meat quality were evaluated after slaughter. Plasma lipid levels and aspartate aminotransferase (AST), γ-glutamyl transpeptidase (GGT), creatine kinase (CK) and alkaline phosphatase (ALP) activities were determined. Diet did not affect plasma triglyceride levels and GGT activity. Plasma cholesterol levels, including low-density and high-density lipoproteins, were higher in both mixed-diet groups than in the haylae group. The highest activities of plasma AST, CK and ALP were observed in the haylage group, followed by n-3 mix and TMR groups, respectively. Carcass weight was lower in the haylage group than in the other groups and no differences were found between the TMR and n-3 mix groups. Although the n-3 mix-fed and haylage-fed beef provided lower n-6 to n-3 FAs ratio than TMR-fed beef, the roasted beef obtained from the TMR group was more acceptable with better overall meat physicochemical properties and sensory scores. According to daily cost, carcass weight and n-6 to n-3 FAs ratio, the finishing diet containing flaxseed oil-supplemented pellets and reed canary grass haylage at the as-fed ratio of 40 : 60 could be beneficial for the production of n-3-enriched beef.     

Reed Canary Grass (Phalaris arundinacea) as a Biological Model in the Study of Plant Invasions

Invasive species pose a serious threat to native plant communities and are an important contributor to loss of biodiversity. In the case of Phalaris arundinacea, L. (Poaceae), reed canary grass, a cool-season, long-lived perennial plant native to Eurasia and North America, nonnative agronomically important genotypes were introduced to North America for numerous uses such as forage and soil stabilization. Following repeated introductions, reed canary grass became an aggressive invader that takes over natural wet prairies, stream-banks and wetlands. Reed canary grass can outcompete native plant species, resulting in monospecific stands with concomitant loss of plant and insect diversity and ultimately to alteration in ecosystem function. Abiotic factors such as disturbance, changes in hydrological regime, and particularly nutrient runoff to wetlands can enhance reed canary grass establishment and vegetative spread. In addition, the species' capacity for early season growth, rapid vegetative spread, high stem elongation potential, wide physiological tolerance, and high architectural plasticity make the species highly aggressive under a wide range of ecological conditions. The change in life-history and environmental conditions responsible for the enhanced aggressiveness observed between native and invasive genotypes are not yet understood. Hence, reed canary grass provides an ideal study system to test a number of ecological and genetic hypotheses to explain why some plant species become extremely aggressive when transported into a new geographical area. To date, genetic studies have found that invasive populations have high genetic diversity and that genotypes differ in their phenotypic plasticity and response to ecological conditions, which may contribute to their invasion success. Finally comparative studies currently underway on European native and American invasive genotypes of reed canary grass should shed light on the mechanisms responsible for reed canary grass's aggressiveness and should provide an experimental protocol to test ecological and genetic hypotheses about what makes a species invasive.     

The Role of Biomass Composition and Steam Treatment on Durability of Pellets

Steam treatment has been reported to improve the durability of wood pellet likely by changing the physical and chemical structures of wood particles, but published literature is inconclusive about which structure change is the major reason for enhanced durability. In this work, steam treatment was combined either with alkaline or with SO₂ to study. The solids obtained after steam treatments along with a control sample were dried and each was compacted into pellets. The pellets were then tested for durability. Steam treatment alone dominated improvements in durability. The pellet durability increased with the amount of xylose, but xylose performed better in the pellet from raw poplar than did in the pellet from treated poplar. Water-soluble components contributed a maximum 4% of the durability of poplar pellets. The addition of lignin and sugars to substrates after steam treatment did not improve durability significantly. The surface modification that took place as a result of size reduction during steam treatment was the major reason, contributing about 50% of the durability of the pellet from steam-treated poplar. The acidity of steam treatment slightly affected the relative contributions of these structure changes on the durability. The new knowledge helps tailor the chemical and/or mechanical pretreatment involved in pelleting biomass to durable pellets.     

Selection of plants for roles in phytoremediation: the importance of glucosylation

Over-expression and transposon mutagenesis in root cultures of Arabidopsis thaliana demonstrated the importance of the family 1 glycosyltransferase UGT72B1 in catalysing the N -glucosylation of the persistent pollutant 3,4-dichloroaniline (DCA). In phytotoxicity studies with DCA in seedlings, over-expression of UGT72B1 enhanced sensitivity, whereas the knockouts were more resistant than the controls. In contrast, manipulating the expression of UGT72B1 had no effect on the O -glucosylation, or toxicity, of chlorophenols. When N -glucosylation was disrupted in plants, radioactivity derived from [¹⁴C]-DCA became covalently bound into high molecular weight insoluble material, principally associated with the lignin fraction. This suggested that insolubilization into stable cell wall components represented a more effective mechanism of DCA detoxification than the formation of N -glycosidic conjugates. A screen of plants used in remediation, identified low levels of N -glucosyltransferase activity in switchgrass and high activities in reed canary grass. When incubated with [¹⁴C]-DCA, reed canary grass plants accumulated soluble N -glycosides of DCA, whereas switchgrass formed insoluble residues. Consistent with the results obtained in studies with Arabidopsis , phytotoxicity trials with DCA demonstrated that switchgrass was more tolerant than reed canary grass. Our studies provide a new biochemical basis for selecting plants for useful remediating traits towards specific classes of pollutants.     

A preparation technique for analysis of explosives in plant tissues

A preparation technique for analysis of explosives compounds in plant tissue has been developed. The technique utilizes acetone extraction followed by ultrafiltration clean up. Ultrafiltration removes the large quantities of chlorophyll and polar organics that interfere with UV/Vis detection used in high‐performance liquid chromatography. The procedure was tested with 14 explosives‐related compounds spiked into reed canary grass extracts and method detection limits (MDLs) were calculated. In addition, the overall extraction efficiency for RDX in parrot feather and reed canary grass tissues was determined using ¹⁴C labeled compound. Scientists may find the technique useful for plant analysis at waste sites and for phytoremediation research.     

Specific energy requirement for compacting corn stover

Corn stover is a major crop residue for biomass conversion to produce chemicals and fuels. One of the problems associated with the supply of corn stover to conversion plants is the delivery of feedstock at a low cost. Corn stover has low bulk density and it is difficult to handle. In this study, chopped corn stover samples were compacted in a piston cylinder under three pressure levels (5, 10, 15 MPa) and at three moisture content levels (5%, 10%, 15% (wb)) to produce briquettes. The total energy requirement to compress and extrude briquette ranged from 12 to 30 MJ/t. The briquette density ranged from 650 to 950 kg/m3 increasing with pressure. Moisture content had also a significant effect on briquette density, durability and stability. Low moisture stover (5-10%) resulted in denser, more stable and more durable briquettes than high moisture stover (15%).     

The effect of 2,4-dichlorophenol and pentachlorophenol on antioxidant system in the leaves of Phalaris arudinacea

The purpose of this work was to evaluate the effect of 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP) on the activity of antioxidative system and lipid peroxidation in the leaves of reed canary grass (Phalaris arudinacea). The activity of catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), glutathione reductase (GR) and glutathione S-transferase (GST) as well as the content of glutathione, ascorbate and phenolic compounds were determined. An induced-increase in the APX, CAT, GPX and GR activities was stronger for PCP, while a significant increase in the GST activity was noted only for 2,4-DCP. Both compounds increased the content of phenolic compounds, oxidized and reduced glutathione as well as the content of ascorbic acid. PCP induced stronger increase in lipid peroxidation than 2,4-DCP. The observed changes revealed that chlorophenols induce oxidative stress and oxidative damage in the leaves of reed canary grass.     

An environmental and economic analysis of the wood-pellet chain: two case studies in Southern Italy

Purpose

Wood pellet heating systems are considered as an essential component of European plans to reduce greenhouse gas (GHG) emissions. The goal of this analysis was to estimate and compare the environmental impacts and the costs of the production of packed wood pellets. Two pellet production systems, using roundwood logs (case 1) and mainly sawdust (case 2), have been analysed in 2015 in Basilicata region (Southern Italy).

Methods

A life cycle assessment (LCA) analysis was applied to calculate the environmental impact indicators of each system, whilst a life cycle cost (LCC) analysis was implemented to evaluate the pellets’ cost production. Hence, the functional unit chosen was 1 t of produced pellets. The system boundaries considered for the purpose of the current investigation were from the tree felling to the pellet packaging. In particular, the following activities were considered: motor-manual felling and delimbing with a chainsaw, timber yarding with a tractor along the forest track, loading and transportation of the logs to the collection point, transportation of timber to the factories for a distance of 35 km, pellet production and pellet packaging in low-density polyethylene bags with a total weight of 15 kg bag^?1.

Results and discussion

The production of 1 t of pellets emitted about 83 kg of CO₂eq in case 1 and 38 kg in case 2. In addition, 2.7 kg of SO₂eq and 0.005 kg of PO³ ₄-eq were produced in case 1 and 1.4 kg of SO₂eq and 0.002 kg of PO³ ₄-eq in case 2. Mineral extraction was equal to 0.9 MJ surplus energy in both cases. Case 1 led to higher environmental impacts (about 50% more), essentially for the operation of pelletisation, and in particular for the higher consumption of electricity that characterised it, whereas the production costs were 172 and 113 € t^?1 in case 1 and case 2, respectively. In both study cases, consumption costs (costs for raw material, electricity consumption, fuel usage) were the most important cost items.

Conclusions

Our studies highlight how, in both cases, the operations carried out in the forest produced the minor part of the environmental impact but, at the same time, were the most expensive operations. Further, our studies show how mixing lumbering by-products (sawdust) and forest management products (lumbers) can be an efficient solution to reduce both manufacturing costs and environmental impacts to produce wood pellets.

     

Life cycle assessment of densified wheat straw pellets in the Canadian Prairies

Purpose  

Densification, a process used to manufacture pellets in order to increase biomass bulk density, plays a crucial role in the economics of biomass utilization. The Canadian Prairies produce large quantities of agricultural residues each year, in particular wheat straw. This study performs life cycle assessment of wheat straw pellets by evaluating environmental effects of the entire pellet production system comprising feedstock production (on-farm wheat straw production), harvesting, baling, transportation, and the industrial processing involving drying, grinding, pelletizing, and packing in the densification plant. The effects of each process on the environmental performance of wheat straw pellets were investigated.     

Dynamics of Copepod Faecal Pellets in Relation to a Phaeocystis Dominated Phytoplankton Bloom: Characteristics, Production and Flux

Copepod faecal pellet characteristics and production were measuredin spring 1995, 1996 and 1997 in the North Sea Southern Bightin order to define changes due to the development of the phytoplanktonbloom. Changes were related to the succession from diatomsto a Phaeocystis sp. bloom. Mean monthly pellet productiondecreased during the Phaeocystis bloom development to 0.27 pelletsind. ^–1 h ^–1, approximately 80% lower than beforeand after the bloom. Although phytoplanktonic pigments showedsignificant differences between inshore and offshore stations,there was no such significant difference for faecal pellet production.Faecal pellet sinking-rate decreased from 100 to 70 m day ^–1during the transition from a diatom- to a Phaeocystis-dominatedbloom. This was due to a decrease in pellet density and/or adecrease of the pellet volume. These results supported the ideaof lower feeding of copepods under Phaeocystis bloom conditions.As mean seasonal density of copepod faecal pellets was higher(1.37 g cm ^–3) than in other seas, accidental ingestionof sedimentary material as the cause of this high density isdiscussed.     

Measurement of key compositional parameters in two species of energy grass by Fourier transform infrared spectroscopy

Two energy grass species, switch grass, a North American tuft grass, and reed canary grass, a European native, are likely to be important sources of biomass in Western Europe for the production of biorenewable energy. Matching chemical composition to conversion efficiency is a primary goal for improvement programmes and for determining the quality of biomass feed-stocks prior to use and there is a need for methods which allow cost effective characterisation of chemical composition at high rates of sample through-put. In this paper we demonstrate that nitrogen content and alkali index, parameters greatly influencing thermal conversion efficiency, can be accurately predicted in dried samples of these species grown under a range of agronomic conditions by partial least square regression of Fourier transform infrared spectra (R² values for plots of predicted vs. measured values of 0.938 and 0.937, respectively). We also discuss the prediction of carbon and ash content in these samples and the application of infrared based predictive methods for the breeding improvement of energy grasses.     

Densification of Thermally Treated Energy Cane and Napier Grass

Densification of thermally treated energy crops by torrefaction is required to increase the bulk density and to reduce the handling, transport, and storage cost for bioenergy applications. In this study, we investigated the densification characteristics of thermally treated energy cane and napier grass grown on marginal lands at various applied forces and binder levels. The addition of starch (0, 10, and 15%) and lignosulfonate (0, 5, and 10%) was examined to enhance the strength and durability of raw and torrefied briquettes, respectively. Although the use of starch binder relatively increased the bulk density, it did not improve the hardness and durability of untreated energy crop briquettes. The addition of 10% lignosulfonate binder increased the torrefied briquette density of up to 11% for energy cane and up to 38% for napier grass and decreased the compression energy by up to 35% for both samples. Moreover, the hardness (compressive resistance) was tripled, and the durability was relatively improved for both torrefied briquettes. The increase in applied force not only increased the bulk density but also increased the specific energy required for densification. However, there was no substantial change in hardness and durability when the compression force was increased from 15 to 20 kN for all samples. In overall, densification of thermally treated energy crops is required, and the quality of the briquettes can be improved by the use of appropriate binders for efficient handling, transport, and storage.     

Potential local adaptation in populations of invasive reed canary grass (Phalaris arundinacea) across an urbanization gradient

Urban stressors represent strong selective gradients that can elicit evolutionary change, especially in non‐native species that may harbor substantial within‐population variability. To test whether urban stressors drive phenotypic differentiation and influence local adaptation, we compared stress responses of populations of a ubiquitous invader, reed canary grass (Phalaris arundinacea). Specifically, we quantified responses to salt, copper, and zinc additions by reed canary grass collected from four populations spanning an urbanization gradient (natural, rural, moderate urban, and intense urban). We measured ten phenotypic traits and trait plasticities, because reed canary grass is known to be highly plastic and because plasticity may enhance invasion success. We tested the following hypotheses: (a) Source populations vary systematically in their stress response, with the intense urban population least sensitive and the natural population most sensitive, and (b) plastic responses are adaptive under stressful conditions. We found clear trait variation among populations, with the greatest divergence in traits and trait plasticities between the natural and intense urban populations. The intense urban population showed stress tolerator characteristics for resource acquisition traits including leaf dry matter content and specific root length. Trait plasticity varied among populations for over half the traits measured, highlighting that plasticity differences were as common as trait differences. Plasticity in root mass ratio and specific root length were adaptive in some contexts, suggesting that natural selection by anthropogenic stressors may have contributed to root trait differences. Reed canary grass populations in highly urbanized wetlands may therefore be evolving enhanced tolerance to urban stressors, suggesting a mechanism by which invasive species may proliferate across urban wetland systems generally.     

Fuel Pellets from Wheat Straw: The Effect of Lignin Glass Transition and Surface Waxes on Pelletizing Properties

The utilization of wheat straw as a renewable energy resource is limited due to its low bulk density. Pelletizing wheat straw into fuel pellets of high density increases its handling properties but is more challenging compared to pelletizing woody biomass. Straw has a lower lignin content and a high concentration of hydrophobic waxes on its outer surface that may limit the pellet strength. The present work studies the impact of the lignin glass transition on the pelletizing properties of wheat straw. Furthermore, the effect of surface waxes on the pelletizing process and pellet strength are investigated by comparing wheat straw before and after organic solvent extraction. The lignin glass transition temperature for wheat straw and extracted wheat straw is determined by dynamic mechanical thermal analysis. At a moisture content of 8%, transitions are identified at 53°C and 63°C, respectively. Pellets are pressed from wheat straw and straw where the waxes have been extracted from. Two pelletizing temperatures were chosen??one below and one above the glass transition temperature of lignin. The pellets compression strength, density, and fracture surface were compared to each other. Pellets pressed at 30°C have a lower density and compression strength and a tendency to expand in length after the pelletizing process compared to pellets pressed at 100°C. At low temperatures, surface extractives have a lubricating effect and reduce the friction in the press channel of a pellet mill while no such effect is observed at elevated temperatures. Fuel pellets made from extracted wheat straw have a slightly higher compression strength which might be explained by a better interparticle adhesion in the absence of hydrophobic surface waxes.     

饲料蛋白源和养殖密度对草鱼生长性能、体成分和血清生化指标的影响

为探究饲料蛋白源和养殖密度对草鱼生长以及生理健康的影响,以初始体质量为(5.36±0.18) g的草鱼(Ctenopharyngodon idella)为试验对象,采用双因素正交实验,研究饲料非粮蛋白源(豆粕、乙醇梭菌蛋白、黄粉虫、棉籽浓缩蛋白和小球藻)和初始养殖密度(0.11、0.16和0.21 kg/m³;对应为20、30和40尾/网箱)及其交互作用对草鱼生长性能、体成分和血清生化指标的影响。养殖试验在池塘网箱(1.0 m×1.0 m×1.5 m)中进行,养殖周期为60d。结果表明:随着养殖密度的增加,各蛋白源组草鱼饲料系数均呈增长趋势,特定生长率、增重率和蛋白质效率和肝体比均呈降低趋势。在不同养殖密度下,黄粉虫组饲料系数均显著高于其他蛋白源组(P<0.05),特定生长率、增重率和蛋白质效率均显著低于其他蛋白源组(P<0.05)。当养殖密度为0.11和0.16 kg/m³时,试验草鱼生长性能接近,其特定生长率显著优于0.21 kg/m³密度组(P<0.05)。饲料蛋白源和养殖密度对草鱼全鱼水分和粗蛋...     

Genetic and Environmental Controls on the Establishment of the Invasive Grass, Phalaris arundinacea

Whether an exotic species becomes integrated into a community or aggressively takes it over depends upon many interacting factors. Using contextual analyses, we combined genetic data about an invasive plant with information about the neighboring species, the community, and the environment to determine what factors enable a genotype or species to invade. We transplanted 50 individuals of each of three clones of the invasive grass Phalaris arundinacea, reed canary grass, into 150 random locations within a Vermont pasture. For each individual, we recorded clonal identity, neighbor identity, community indices (species richness and species diversity), and an environmental variable (soil moisture). The response variables were survivorship, above-ground biomass, below-ground biomass and the ratio of above- to below-ground biomass. Clonal identity affected both survivorship and below-ground biomass. The fastest tillering clone had poor survivorship but survivors produced a large amount of below-ground biomass, making this clone more likely to successfully overwinter. Neighbor species affected above- and below-ground biomass. Reed canary grass produced more above- and below-ground biomass when Anthoxanthum odoratum, a common pasture grass species, was abundant. Community attributes also influenced growth. Although we expected diverse plots to repel the invasion, plants in the more diverse plots had higher amounts of below-ground biomass. Finally, environmental effects also influenced growth. Reed canary grass produced more above-ground biomass in wetter plots, confirming that it does well under wet conditions.