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To address the problem in the existence of gate marks on the surface of a shredder shell plastic part, a hot runner mold with a complex inverted structure and a rear mold feeding mode was designed. The ejection action was completed through designing mechanical hooks. Considering the structural characteristics of the plastic parts with multiple inverted buckles surround them and internal bone positions, a four-sided slider splicing and core-pulling mechanism was designed for demolding on the lateral side of the rear mold. The back mold core was designed with multiple insert structures, which facilitated the processing, prevented the air trapping, improved the molding efficiency and quality. During the mass production, the various mechanisms of the mold operated smoothly, and the quality of the plastic parts was excellent, which could meet the requirements of design. [ABSTRACT FROM AUTHOR]

The handling of the remnants of rice crops in the field is not an easy operation, and farmers prefer burning, which causes air pollution, smog, and disease. This research reports the development of a novel precision crop seeder by handling the remnants of previous crops through mechanization. The precision seeder performed multiple operations in a single path, viz, chop residues, incorporate into soil, make mini trenches, and sow wheat with fertilizer application. The precision seeder has a 2040 mm working width, and specially designed C-type blades are used to shred the crop residue. A multiple-speed gearbox with a gear ratio of 1:0.52 is installed, with a further set of spur gears with 16, 18, and 20 teeth that provide 225, 250, 310, and 350 RPMs to the main rotor. In the middle of the seeder, after the main rotor shaft, 11 V-shaped trencher plates are fixed on the trencher roller for the making of trenches. The trencher roller is powered by star wheels, which showed good results. A zero-tillage-type sharp tip edge novel seeder unit was developed for the precise placement of seed and fertilizer. Seed and fertilizer were placed into the mini trenches through 11 seeder units through a ground wheel calibration system. The field capacity of the precision seeder was 0.408 ha/h and the operational cost was calculated 40.68 USD/ha. The seeder showed good results, with the production of 5028 kg/ha compared to conventional methods. The precision seeder provides a mechanized solution for wheat sowing with minimal operational costs by enhancing organic matter in soil with 13% more yield. [ABSTRACT FROM AUTHOR]

This paper describes the creativity, design, and construction of a customized sago machine with a kneading pipe, filter, storage tank, and shredder. The main objective of this innovation is to maximize the conversion of sago stems into superior starch. Sago, an essential food staple in many areas, is typically processed by hand, which results in tedious and time-consuming processes. This project focuses on developing an automated and efficient system to drastically increase productivity and the simplicity of use and transform the sago processing sector. [ABSTRACT FROM AUTHOR]

Sustainable development of agricultural production is a key factor in ensuring food security and growth of the country's export potential. One of the main reserves for the development of the agro-industrial complex is the involvement of fallow lands in agricultural industry, which is associated with the problem of technical and technological support for these works. The purpose of the work is to intensify the process of involving fallow lands in agriculture by developing a program of technical and technological support for this type of works, aimed at creating and accelerated implementation of a system of specialized machines. The authors systematized technologies and complexes of technical means, used in the involvement of fallow lands in crop production, depending on the stages of wild species overgrowth. For active involvement of fallow lands in agriculture, it is proposed to create a network of regional machine-technological stations equipped with modern domestic specialized equipment, providing services in removal of woody and shrubby vegetation and in initial tillage to agricultural producers in regions. The program assumes the development and organization of mass production of modern equipment for the involvement of fallow lands in agriculture, as well as implementation of a set of support measures aimed at accelerated technical equipment of machine-technological stations. Such an approach should make it possible for small and medium-sized agricultural producers to use financially affordable machinery services to involve fallow lands in agriculture, eliminating the need for its acquisition and maintenance, hiring and training of additional stuff. The implementation of the proposed program should allow agricultural producers to involve fallow lands in agricultural production with minimal costs, at the same time ensuring high growth rates of acreage and agricultural production volumes.

Waste plastic caps (PCs) are resources. The objectives were to know the production of plastic ropes (PRs) from PCs, and to know the name and functions of the instruments involved in PRs production. Plastic Recycling Machine consisting of shredder, washing machine, mixing machine, pellet forming machine, granular, extruder, and rolling machine are involved in rope formation. Shredders crush PCs to flakes. Clean flakes are pushed into the mixer machine, then to pellet forming machine. Granular machine makes the pellet to granule. Granules were put into the extruder machine to make mold and sent to the rolling machine for making rope.

The study involves an analysis of diverse technologies for recycling complex chemical power sources, including processes such as unsealing, crushing, grinding, leaching with sedimentation, and filtration. The recycling technology for spent lithium-cobalt power sources, developed at the National Research Center "Kurchatov Institute," is explored. This technology involves discharging lithium-cobalt power sources in a NaCl solution, unsealing in a shredder under an inert atmosphere, grinding in a rotary cutting mill equipped with a cyclone, and further grinding in a disintegrator to produce mechanically activated powders. The article provides data on the elemental composition and product yield following discharge, leaching, and precipitation. In addition, studies were carried out on pelletizing the resulting powders by pressing and rolling in a rotary granulator with a flat die. To enhance efficiency, the characteristics of channels with variable cross-sections were examined, and a physical and mathematical model for constructing force diagrams within the die channels was developed. Force distribution diagrams along the length of the channel were obtained for four types of powders, enabling the prediction of the behavior of powders with different morphologies during their rolling on a rotary granulator with a flat die. [ABSTRACT FROM AUTHOR]

Copyright of COMU Journal of Agriculture Faculty / ÇOMÜ Ziraat Fakültesi Dergisi is the property of Canakkale Onsekiz Mart University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describes the creativity, design, and construction of a customized sago machine with a kneading pipe, filter, storage tank, and shredder. The main objective of this innovation is to maximize the conversion of sago stems into superior starch. Sago, an essential food staple in many areas, is typically processed by hand, which results in tedious and time-consuming processes. This project focuses on developing an automated and efficient system to drastically increase productivity and the simplicity of use and transform the sago processing sector.

Introduction. One of the main components in the diet of farm animals is concentrated feed, which in Russia is grinded by shredders. At the same time, in the final product, there is a high dust content, which can be reduced by using grinders with a different principle of grinding. The design of a milling shredder, in which grains are crushed by cutting, is proposed. Aim of the Article. The article presents theoretical studies of the influence of design and technological parameters of a milling shredder on the conditions of grain motion along the tooth of the working body. Materials and Methods. The theoretical study of the developed shredder was carried out using averaged acceleration methods. The tooth surface of the working organ was studied. Results. As a result of theoretical studies, equations describing the motion of a particle along the working body tooth surface were obtained. There has been developed a program to facilitate the process of analyzing the influence of the structural and technological parameters of the shredder on the process of particle motion along the tooth surface. Discussion and Conclusion. There is a directly proportional decrease in the time of motion of the particle along the working body tooth surface with increasing the angular velocity. At the same time, increasing the angle leads to the increase of the time of the particle along the tooth surface. The increase of angular velocity values leads to decreasing particle displacement along the axis. At the angle of 45° displacement along the axis is 1.1‒1.5 times less than at an angle of 70°. At high angular velocities, the moving along the axis is minimal. The analysis, given the need to create a smoother motion of the particle along the helical line, shows that the most rational will be the following values: angle 70° and angular velocity of the working body 185‒206 rad/s.

Plastic pollution is a problem that is affecting many aspects of human endeavour. Searches are being made for ecofriendly alternatives and waste management practices that can lessen the impact of plastic pollution. On the list are waste plastic reuse, use of bioplastics, reduction of reliance on plastic usage, and plastic waste recycling. In this technical brief, a plastic shredder was developed to recycle plastic waste in the value chain. Plastic shredder is a machine that turns used plastic bottles to smaller particle sizes to enhance portability, easiness and readiness for use into new products. While in operation, the prime mover drives the transmission shafts with low speed in the range of 25 to 65 rpm to give shredding torque that masticates materials fed in, into desired granular size. Bivariate Linear regression was the statistical model used to understand the relationship between the two variables of evaluation, the predictor x (speed) and the response variable y (shredding capacity). Since significance F (0.0216) is less than 0.05, there is 95% confidence that there is linear relationship between speed of rotation and shredding capacity of the machine. Model equation is therefore given as Y= 0.952 X1 – 11.725 ± 2.53. The machine respectively gave highest shredding capacity for PET bottles, Tin can and wastepaper as 56.52 kg h-1, 29.60 kg h-1 and 42.09 kg h-1 at optimum speed of 65 rpm. If operated for 8 hours in a day, it can favorably shred almost half a ton of plastic bottles (452.16 kg day-1 ). The machine was developed at an affordable cost of $817.72. The paper shredded with the machine can be pulped and made into poultry egg crates and paper print used in building industry. The machine is less stressful to operate and economical to run and maintain. If the machine is widely adopted, the menace caused by nonbiodegradable materials like plastic will be ended. [ABSTRACT FROM AUTHOR]

Stoneflies are a globally threatened aquatic insect order. In Arkansas, a diverse group of winter stonefly (Capniidae: Allocapnia) have not been surveyed since the 1980s, likely because species-level identification requires the rarely-collected adult form. Allocapnia mohri, a regional endemic, was previously commonly found in mountainous, intermittent streams from the Ouachita Mountains ecoregion north to the Ozark Highlands, but no species distributional models including land use or climate variables exist to our knowledge. We collected adults from 71 stream reaches from the historic Arkansas range from November to April 2020 and 2021. We modeled distributions using random forest (RF) models populated with landscape, climate, and both data to determine which were most predictive of species presence. Correlations between landscape or climate variables and presence were examined using multiple logistic regression. The landscape RF models performed better than the climate or landscape + climate RF models. A. mohri presence sites tended to have a greater elevation, a lower mean July temperature, and a greater percentage of very slow infiltration soils in the watershed, compared to absence sites. A. mohri was absent at the Ouachita Mountains sites and may be experiencing a range contraction or migration northward.

Stoneflies are a globally threatened aquatic insect order. In Arkansas, a diverse group of winter stonefly (Capniidae: Allocapnia) have not been surveyed since the 1980s, likely because species-level identification requires the rarely-collected adult form. Allocapnia mohri, a regional endemic, was previously commonly found in mountainous, intermittent streams from the Ouachita Mountains ecoregion north to the Ozark Highlands, but no species distributional models including land use or climate variables exist to our knowledge. We collected adults from 71 stream reaches from the historic Arkansas range from November to April 2020 and 2021. We modeled distributions using random forest (RF) models populated with landscape, climate, and both data to determine which were most predictive of species presence. Correlations between landscape or climate variables and presence were examined using multiple logistic regression. The landscape RF models performed better than the climate or landscape + climate RF models. A. mohri presence sites tended to have a greater elevation, a lower mean July temperature, and a greater percentage of very slow infiltration soils in the watershed, compared to absence sites. A. mohri was absent at the Ouachita Mountains sites and may be experiencing a range contraction or migration northward. [ABSTRACT FROM AUTHOR]

Polusi plastik telah menjadi perhatian global karena pembuangan sampah plastik yang buruk mencemari lingkungan. Pengelolaan limbah plastic secara mandiri dapat dilakukan ditingkat lokal sebagai alternatif upaya daur ulang mandiri. Mesin Shredder plastic sederhana banyak digunakan secara lokal dengan design yang mudah, perawatan dan suku cadang yang tersedia secara lokal. Mesin shredder plastic adalah mesin yang digunakan paling awal untuk memotong sampah plastik menjadi potongan-potongan kecil. Konsep desain sederhana mesin shredder yang ada saat ini adalah cukup umum. Poros dan bilah pisau adalah komponen paling penting dalam mesin shredder yang menentukan kinerjanya. Geometri bilah pisau dan orientasi bilah pisau yang dipasang ke dalam poros tunggal atau ganda secara langsung mempengaruhi kinerja mesin shredder. Permasalahan utama mesin shredder adalah pisau yang cepat tumpul sehingga menurunkan produktifitas mesin. Tulisan ini bertujuan untuk meninjau berbagai faktor yang memberikan efek langsung pada kinerja pisau shredding, serta menguji bilah pisau yang sudah diredesain dan difabrikasi. Berdasarkan data down time untuk pengasahan 9-bilah pisau orbital adalah 11-jam dan down time 2-bilah pisau stasioner adalah 3,5-jam sehingga total selama 150 Jam operasional atau 10% operasi. Sedangkan penggunaan pisau baru, selama 300 jam operasi masih bisa digunakan tanpa diasah.

Compost has the main role inEgyptian organic farming, and its demand rapidly increased. But for small-scale orchards, it is a problem, many Egyptian orchards are small farms (≤ 0.5 ha), suffering from the lack of small-size shredders. Wastes particle size has an impact on the compost industry. Therefore the main object of this project was to design and manufacture a shredder and produce uniform raw material proper for making good compost in a short time. The prototype shredder could control the thickness of shredded orchard wastes according to the needs of compost producers to recycle orchard wastes (max. 5 cm diameter). The shredder machine consists of a frame, hopper, cutting shaft, cutting support, 2 pulleys, belt, and motor. The main part is the cutting shaft and the cutting support which gives the ability to control the thickness of shredded waste. The ANSYS program was used to analyze the shear stress, total deformation, and equivalent stress (Von Mises) to choose the proper material for the cutting shaft to do such an operation. The maximum shear stress, equivalent stress, and displacement deformation on the wood bulk were obtained using stainless steel material, followed by cast iron then structure steel, for that the recommended material for the shaft was structure steel and for the cutting knives was stainless steel. The cutting support is flexible to have the desired thickness of the cut material, but the study focused to get 2 mm thickness according to the compost expertise demand, but the machine could cut the wastes up to 4 mm thickness. The shredder machine operation was to feed the orchards wastes (tree branches max. 5 cm diameter) to a hopper at a 45o angle between the adjustable support (protruding), and the shaft with sharp cutting fixed knives, to cut the wastes depending on the shear stress between the wood and the knives, then the cut pieces will grumbling down by the shaft acceleration and gravity in the bottom of the shredder to be collected later. [ABSTRACT FROM AUTHOR]

This research presented the modeling and simulation approach, as a failure prevention and design optimization tool for determining the dynamic optimal performance of a rotor bearing system, in respect to stability at specified speed range, through selection of appropriate bearing damping coefficient, at the conceptual design stage. The mathematical model of the system was developed, followed by the design of the Simulink model from the mathematical model equations. The model was then linearized before the simulation to obtain the step response plots. Varying values of damping coefficient for the system model were simulated and result showed the underdamped, critically damped, and overdamped working conditions of the system. The critical damping, which represents the optimal operational state for the system state, was established at the point where the least value of settling time, rise time of and zero overshoot was recorded. The model performance was confirmed/validated using bode diagrams and pole-zero map. The research showed that a proper design and selection of damping coefficient of bearing are important as a means of reducing the amplitude of vibration, which could result in mechanical failure of any designed shredder rotor bearing system when in operation. [ABSTRACT FROM AUTHOR]

Solid waste management is found to be a matter of great concern all over the world. As the population grows, the volume of food waste also increases. Vegetable waste discarded from markets, waste discarded from slaughterhouses, and food waste left out after large social gatherings are becoming unmanageable heaps of organic waste. Composting is an effective process that can be used for the biodegradation of solid waste. Researchers have studied the influence of many parameters to accelerate the composting process such as adjusting the C/N ratio, pH, temperature, and moisture content. Reducing the size of larger pieces into small particles is found to accelerate the microbial activity and hence composting. This paper discusses the development and fabrication of a shredding machine used for cutting large volumes of vegetable waste. As per the studies conducted, the shredding machine can cut down 360 kg of vegetable waste into shredded waste within one hour. The quantity of petrol required for operating the engine for one hour was observed as one liter. Hence the fabricated shredding machine is found as cost-effective. The portable unit can be taken to various locations where solid organic waste has to be shredded and hence there is no need to transport waste which is a cumbersome task that consumes more energy. [ABSTRACT FROM AUTHOR]

Litter decomposition is an ecosystem process that allows energy and nutrients transfer from dead plant matter into detrital food webs. Several studies revealed that leaf litter decomposition rates differ across biomes, but the reasons for these differences are not yet clear. Here, we test the role of several leaf litter physical and chemical characteristics as predictors of decomposition rates and whether life forms (evergreen vs. deciduous) differ in decomposition rates. Leaves from dominant riparian trees were collected in four ecoregions (temperate deciduous forest, subtropical seasonal semideciduous forest, tropical Cerrado and subtropical dense ombrophylous forest) and their physical and chemical characteristics were measured. We then determined leaf litter decomposition, colonization by aquatic hyphomycetes and macroinvertebrates in a same stream (i.e., under the same environmental conditions), and consumption rates by shredders under laboratory conditions. Deciduous and evergreen tree species did not differ in the measured litter characteristics, but deciduous leaves decompose faster than evergreens. Leaf litter from tree species from the four ecoregions differed in their physical and chemical characteristics. Litter from temperate deciduous species decomposed faster than litter from the other three ecoregions, generally supported higher aquatic hyphomycete species richness and sporulation rates and higher consumption rates by shredders. There were significant negative correlations between litter decomposition and associated biotic variables and litter initial lignin concentration and lignin:N ratio. We conclude that lignin concentration and lignin:N ratio are important predictors of litter decomposition, although other unmeasured parameters such as micronutrients may also play important roles in this key ecosystem process. [ABSTRACT FROM AUTHOR]

To improve service life of shredder cutters, new technologies such as ultrasonic vibrationassisted cutting and cooling technology (jet and spray) are introduced into the design of the cutter for a two-axis horizontal shredder. Ultrasonic vibration-assisted cutting technology is theoretical analyzed, and result shows that the effect of friction reduction only happens when the speed of cutting is less than vibration speed. Therefore, the vibration-assisted cutting get a friction reduction of 52.5% and a cutting temperature reduction of 10.5% when the vibration-assisted cutting with an amplitude of 25 μm and a frequency of 20 kHz is performed on the shredder with the rotational speed of 60 r/min. Three cooling methods are proposed to lower the temperature of shredder tools such as air jet cooling, water jet cooling, and spray cooling. They are all simulated with Ansys-fluent software on the basis of the Lagrangian model. Simulation results show that water jet cooling can realize better cooling effect, whereas its cooling effect will not improve obviously until the jet diameter increases to around 4 mm. In addition, the cooling effect of the spray with vibration cutting which has less coolant consumption is very close to that of the water jet without vibration cutting. Therefore, the mode of spray cooling with vibration cutting can be used instead of the mode of water jet cooling for higher coolant utilization. By comparing with the traditional cutting of shredder, the spray cooling with vibration cutting has a cutting temperature reduction of 65%.

Copyright of BHM Berg- und Hüttenmännische Monatshefte is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rubber crumb is a disperse material produced by grinding used car tires. It takes the form of irregular granules of size 0.1–7 mm. Rubber waste such as treadmills, rubber mats, and conveyer belts is also used to produce crumb, but worn-out tires predominate. Particle motion in the second stage of a two-stage mill (shredder) is considered. The influence of the following parameters is analyzed: the particle speed, the potential energy, and the rotary kinetic energy. The rotor speed n may be 100 and 150 rpm. Simulation using EDEM software indicates that the performance of the two-stage mill is superior in every respect at n = 100 rpm. [ABSTRACT FROM AUTHOR]

This article presents the device and the principle of operation of forage grain crushers that use the centrifugal force of inertia to supply the working bodies—which occurs as a result of rotation of the rotor with a vertical axis. The results of some tests of machines working on this principle have been characterized. Attention is drawn to the disadvantages of most research works, namely the lack of premises for creating shredders of this class with a wide range of performance. The aim of this work is to establish the relationship between the design and technological parameters for the operation of a centrifugal-rotary shredder using the theory of similarity and a dimensional analysis. Moreover, the experimental data show an empirical relationship when calculating the efficiency for the shredder model considered above. By applying the similarity criteria, dimensionless complexes were obtained, which allow to determine the significance of the parameters selected at the initial stage for the efficiency of the shredder. The novelty of this research is the application of the theory of similarity and the use of dimensional analysis, which allowed for scaling the results of the experimental data and obtaining a centrifugal-rotary shredder with higher efficiency, while maintaining the quality of the obtained product. This technique indicates the energy costs of the grinding process, which can be used to select the ratio of parameters in the shredder that would ensure that a minimum amount of energy is consumed.

Abstract: Freshwater ecosystems rely on allochthonous resources. Integration of these subsidies depends on diversity of both terrestrial resources and aquatic shredder and decomposer communities, but the diversity effects on leaf litter breakdown and decomposition are less clear in aquatic than terrestrial ecosystems. We need a better understanding of this relationship because aquatic communities are rapidly changing with species invasions and anthropogenic impacts. Here, we experimentally disentangled the effects of leaf and shredder richness on leaf litter breakdown by macroinvertebrates in mesocosm experiments using three species of amphipods, a dominant guild of crustaceans in European freshwater ecosystems. Increased leaf richness led to lower‐than‐predicted leaf consumption by native shredders, with mixed evidence of resource‐switching or prioritization of preferred food items within a leaf mix. Higher shredder species richness never promoted leaf consumption rates compared to predictions from relevant single‐species experiments, and instead sometimes substantially decreased leaf consumption. We then conducted a meta‐analysis of leaf litter consumption rates by seven widely distributed amphipod species (the three used in the experiments and four additional species). As expected based on our own experiments, nonnative amphipod species generally had lower biomass‐adjusted leaf litter consumption rates, although their larger body size led to higher per‐individual leaf consumption rates. Contamination of the water by metals, pesticides, and other chemicals additionally significantly decreased leaf litter consumption by multiple native and nonnative species compared to unpolluted systems. While the meta‐analysis suggested that litter consumption, and thus breakdown, would decline if native shredders are replaced by nonnative heterospecifics, complete species replacement is not the only outcome following immigration in a meta‐community context. Our experiments suggest that breakdown rates could remain reasonably high where native species coexist with nonnative arrivals. Experiments that neglect the ecological realism of species coexistence will necessarily mischaracterize effects on ecosystem functioning. [ABSTRACT FROM AUTHOR]

Invasive species can affect native communities by replacing competitors, overexploiting prey species or altering ecosystem structure. One example is the Ponto-Caspian amphipod Dikerogammarus villosus which has established large populations in European rivers and is widely considered as the main cause for the decline of native benthic invertebrates. This effect has been mainly associated with direct predation, whereas the indirect effects via competition for primary resources are poorly understood and possibly underestimated. To assess the probability of these indirect effects, we performed five outdoor flow-through mesocosm experiments in three European rivers, manipulating the density of D. villosus. We quantified its in-situ food consumption during three 24-h gut content surveys in the mesocosms. Gut evacuation rates for correction were measured in the laboratory for different food sources and under continuous feeding. We analysed the invader's effects on primary resources by quantifying periphyton biomass and community leaf litter decomposition in the mesocosms at different D. villosus densities. The remarkably high food consumption rates (0.38-1.27 mg mg-1 d-1, in dry mass/dry body mass) of D. villosus can be attributed to its high gut evacuation rates. The leaf litter decomposition rates indicate that D. villosus is an efficient shredder; however, there was no effect on periphyton biomass. Our results indicate that D. villosus may be a strong competitor with primary consumers in benthic food webs of invaded rivers, with both direct and indirect negative effects on benthic communities. High consumption rates together with opportunistic feeding behaviour probably promote the invasion success of this amphipod. [ABSTRACT FROM AUTHOR]

The decomposition of plant litter plays a fundamental role in the cycling of carbon and nutrients and is driven by complex interactions of biological and physical controls, yet little is known about its variability and controls across spatial scales. Here we address the indirect effects of riparian canopy cover on litter decomposition and decomposers and their variability within a set of hierarchical scales (watershed, stream segments and reaches) controlling for confounding factors that could co-vary with canopy cover (for example, temperature and nutrients), in high-altitude subtropical streams. Total, microbial and invertebrate-driven decomposition rates were approximately 1.4-6.6 times higher in closed-canopy than in open-canopy watersheds. Riparian canopy cover accounted for 62-69% of total variability of decomposition rates and indirectly (via light availability and litter inputs) promoted fungal facilitation of shredders through leaf litter conditioning. In contrast to what we expected, much of the spatial variability in the decomposition occurred at smaller scale (4-20% of total variability among reaches versus <1% among watersheds) and coincided with the greatest variability in shredder abundance and fungal biomass (70 and 17% among reaches, respectively). We conclude that riparian canopy cover may be an important control of natural variability of litter decomposition at the watershed scale through its effects on fungal decomposers and shredder consumption. We also provide evidence of higher reach and minor watershed variability of litter decomposition in stream networks. Our results point to the importance of identifying the sources of natural variability of decomposition and how they interact within and among spatial scales. [ABSTRACT FROM AUTHOR]

This work relied on the use microcosms to evaluate the individual and the combined effects of different levels of copper sulfate (0.0, 0.013, 0.064 and 0.318 mg Cu L −1 ) – a fungicide commonly exceeding allowable thresholds in agricultural areas – and a range of water temperature increase scenarios (15, 20 and 25 °C) on freshwater species belonging to different functional groups. Hence, the growth inhibition of primary producers (the microalgae Raphidocelis subcapitata and the macrophyte Lemna minor ), as well as the survival and feeding behavior of a shredder species (the Trichoptera Schizopelex sp.) were evaluated. The results revealed that copper was toxic to primary producers growth, as well as shredders growth and survival, being the growth of L . minor particularly affected. Higher water temperatures had generally enhanced the growth of primary producers under non-contaminated (microalgae and macrophytes) or low-contaminated (macrophytes) conditions. Despite the tendency for a more pronounced toxicity of copper under increasing water temperatures, a significant interaction between the two factors was only observed for microalgae. Since the test organisms represent relevant functional groups for sustaining freshwater systems functions, the present results may raise some concerns on the impacts caused by possible future climate change scenarios in aquatic habitats chronically exposed to the frequent or intensive use of the fungicide copper sulfate. [ABSTRACT FROM AUTHOR]

Pruning residues can provide a significant amount of biomass despite being rarely used as a renewable sources to replace fossil fuels. Exploiting such residues entails creating a sustainable and cost-effective supply chain in which the harvesting and initial processing of the residues play a crucial role. The study is a detailed and accurate survey of the harvesting technologies available in Europe for harvest pruning. After defining the main harvest technologies and the distribution of manufacturers in Europe, the survey details the main groups of implements: shredders, chippers and balers. For each group, the most important configurations are discussed, together with the main characteristics of the machine. Some of the main innovations are detailed (modular machines, non-stop balers, densification of the biomass) which can improve the quality of the product and the economic sustainability of the chain. [ABSTRACT FROM AUTHOR]

In order to accelerate deployment of distributed recycling by providing low-cost feed stocks of granulated post-consumer waste plastic, this study analyzes an open source waste plastic granulator system. It is designed, built, and tested for its ability to convert post-consumer waste, 3D printed products and waste into polymer feedstock for recyclebots of fused particle/granule printers. The technical specifications of the device are quantified in terms of power consumption (380 to 404 W for PET and PLA, respectively) and particle size distribution. The open source device can be fabricated for less than $2000 USD in materials. The experimentally measured power use is only a minor contribution to the overall embodied energy of distributed recycling of waste plastic. The resultant plastic particle size distributions were found to be appropriate for use in both recyclebots and direct material extrusion 3D printers. Simple retrofits are shown to reduce sound levels during operation by 4dB-5dB for the vacuum. These results indicate that the open source waste plastic granulator is an appropriate technology for community, library, maker space, fab lab, or small business−based distributed recycling.

Leaf-shredding amphipods play a critical role in the ecosystem function of leaf litter breakdown, a key process in many low order streams. Fungicides, however, may adversely influence shredders' behavior and the functions they provide, while there is only limited knowledge concerning effects on their reproductive performance. To assess the latter, a semi-static 56-day partial life-cycle bioassay using the model shredder Hyalella azteca ( n = 30) was performed applying two environmentally relevant concentrations of a model fungicide mixture (i.e., 5 and 25 μg/L) composed of five fungicides with different modes of toxic action. Variables related to the food processing (leaf consumption and feces production), growth (body length and dry weight), energy reserves (lipid content), and reproduction (amplexus pairs, number and length of offspring) were determined to understand potential implications in the organisms' energy budget. While the fungicides did not affect leaf consumption, both fungicide treatments significantly reduced amphipods' feces production (∼20%) compared to the control. This observation suggests an increased food utilization to counteract the elevated and stress-related energy demand: although growth as well as energy reserves were unaffected, amplexus pairs were less frequently observed in both fungicide treatments (∼50–100%) suggesting a tradeoff regarding energy allocation favoring the maintenance of fundamental functions at the organism level over reproduction. As a result, the time to release of first offspring was delayed in both fungicide treatments (7 and 14 days) and the median number of offspring was significantly lower in the 25-μg/L treatment (100%), whereas offspring length remained unaffected. The results of this study thus indicate that chronic fungicide exposures can negatively impact shredders' reproductive performance. This may translate into lower abundances and thus a reduced contribution to leaf litter breakdown in fungicide-impacted streams with potentially far-reaching consequences for detritus-based food webs. [ABSTRACT FROM AUTHOR]

This paper presents the development of particleboard based on common reed, reproducing the industry standard manufacturing process applied to wood chipboard. One of the main properties of the resulting board was its resistance to water, due to the hydrophobic properties of the common reed, despite there being no incorporation of melamine or any other waterproofing additive. The boards that were developed were analyzed using 2 mm and 4 mm sieves for fibre selection, a manufacturing pressure of 3 N/mm2 and 25 N/mm2, and a volume of urea formaldehyde resin content ranging from 5.2% to 13% (8 to 20% liquid format). Standard destructive tests were performed. It was found that under certain applied conditions, namely high pressure and adequate resin proportion (a pressure of over 3 N/mm2 and over 15% liquid resin), Arundo donax L. particleboard demonstrated full recovery from the swelling test. This finding highlights an unmatched property in terms of recovery from the swelling test of the designed board. This property confers a interesting property to be used in high humidity environments without the need for special resin or waterproofing process.

Computer-aided design is now the primary design tool, providing opportunities for improving project quality, allowing for in-depth analysis of the specific features of the solution. In the methodology, computer simulation applications were used. Computer simulation aims to reconstruct the course of the studied process from its mathematical model using a computer and to examine the influence of the environment (input signals) and the internal properties of the object (process parameters) on the characteristics of the object. In designing the shredder, in addition to the selection of structural features, it is also possible to perform strength and kinematic simulations, resulting in a higher quality of the target solution. The results of the simulation work presented in the paper indicate a wide range of possible applications - also in the field of food engineering and processing of polymers - eg shredder mechanisms. Particular attention has been paid to the reduction of energy consumed by the deformation of samples, eg by pre-compaction of sample before introduction to the working area of the shredder. It has been estimated that the gap between the rotating discs should be minimized. Establishing design guidelines has resulted in a number of concept designs.

Shredders play a central role in the breakdown of leaf material in aquatic systems. These organisms and the ecological function they provide may, however, be affected by chemical stressors either as a consequence of direct waterborne exposure or through alterations in food-quality (indirect pathway). To unravel the biological relevance of these effect pathways, we applied a 2 × 2-factorial test design. Leaf material was microbially colonized for 10 days in absence or presence of the fungicide epoxiconazole (15 μg/L) and subsequently fed to the shredder Asellus aquaticus under exposure to epoxiconazole (15 μg/L) or in fungicide-free medium over a 28-day period ( n = 40). Both effect pathways caused alterations in asselids' food processing, physiological fitness, and growth, although not always statistically significantly: assimilation either increased or remained at a similar level relative to the control suggesting compensatory behavior of A. aquaticus to cope with the enhanced energy demand for detoxification processes and decreased nutritional quality of the food. The latter was driven by lowered microbial biomasses and the altered composition of fatty acids associated with the leaf material. Even with increased assimilation, direct and indirect effects caused decreases in the growth and lipid (fatty acid) content of A. aquaticus with relative effect sizes between 10 and 40%. Moreover, the concentrations of two essential polyunsaturated fatty acids (i.e., arachidonic acid and eicosapentaenoic acid) were non-significantly reduced (up to ~ 15%) in asselids. This effect was, however, independent of the exposure pathway. Although waterborne effects were generally stronger than the diet-related effects, results suggest impaired functioning of A. aquaticus via both effect pathways. [ABSTRACT FROM AUTHOR]

The River Continuum Concept (RCC) predicts that riverine food webs shift from a reliance on allochthonous energy in headwaters to autochthonous production in lower reaches. However, estimates of resource reliance often fail to account for resource segregation within the food web. Stable-isotope biomarkers can be used to estimate the relative importance of allochthonous and autochthonous material to specific groups and within the food web. δ13C and δ15N isotope ratios were calculated for allochthonous (conditioned leaf litter) and autochthonous (biofilm and bryophytes) basal energy sources, macroinvertebrate functional feeding groups (shredder, grazer, collector-filterer, collector-gatherer, predator), and resident fish species at 17 locations spanning the headwaters to lower reaches of 2 river systems in eastern Canada. Stable-isotope mixing models and correlations were used to identify longitudinal trends in the food webs of both rivers. In headwater streams, allochthonous material was the predominant resource for shredders, whereas all other primary, secondary, and tertiary consumers predominantly used autochthonous basal resources. Stable-isotope ratios of allochthonous material varied minimally between sites. Both autochthonous basal sources were significantly 13C-enriched and 15N-depleted in lower-reach relative to headwater sites. Shredders displayed minimal variation across sites, whereas longitudinal variation in all other primary consumers, macroinvertebrate predators, and fishes was closely correlated with autochthonous basal sources. These results highlight the role of resource segregation within river food webs and indicate that the RCC may not predict energy pathways in all temperate river systems. [ABSTRACT FROM AUTHOR]

Leaf litter decomposition is an important process providing energy to freshwater biota. Flow regulation and dams can strongly alter freshwater ecosystems, but little is known about the effect of small impoundments on leaf litter decomposition rates in headwater streams. In this study, we examined the effect of small water storage impoundments (80 to 720 m3) on leaf litter decomposition by comparing sites located within 10-m upstream and downstream of nine impoundments (Rhineland Palatinate, Germany) and sites located further upstream and downstream. The impoundments did not have a statistically significant effect on most physico-chemical variables. However, the abundance of shredders and leaf litter decomposition rates decreased in study sites located within 10-m upstream of the area flooded by impoundments. Small impoundments can locally reduce leaf litter decomposition rates in headwater streams. The effect of small impoundments on ecosystem functioning is minor and may require less attention by freshwater managers than other stressors, though this may differ for other ecological aspects such as connectivity. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Human activity can degrade the habitat quality for aquatic communities, which ultimately impacts the functions these communities provide. Disentangling the complex interaction between environmental and anthropogenic parameters as well as their alteration both along the stream channel, over the seasons, and finally their impact in the aquatic ecosystem represents a fundamental challenge for environmental scientists. Therefore, the present study investigates the implications of successive land uses (i.e., vineyard, urban area, highway and wastewater treatment plant (WWTP)) on structural and functional endpoints related to the ecosystem process of leaf litter breakdown during a winter and summer season in a five km stretch of a second-order stream in southern Germany. This sequence of the different land uses caused, among others, a downstream decline of the ecological status from “high” to “bad” judged based on the SPEAR pesticides index together with significant shifts in the macroinvertebrate community composition, which coincided with substantial impairments (up to 100%) in the macroinvertebrate-mediated leaf decomposition. These effects, seem to be mainly driven by alterations in water quality rather than morphological modifications of the stream's habitat since the key shredder Gammarus was not in direct contact with the local habitat during in situ bioassays but showed similar response patterns than the other endpoints. While the relative effect size for most endpoints deviated considerably (sometimes above 2-fold) among seasons, the general response pattern pointed to reductions in energy supply for local and downstream communities. Although the present study focused on a single low-order stream with the main purpose of describing the impact of different land uses on various levels of biological organization, which limits the direct transferability and thus applicability of results to other stream ecosystems, the findings point to the need to develop adequate management strategies mitigating land use specific exposures during all seasons to protect ecosystem integrity. [ABSTRACT FROM AUTHOR]

Restoration has been increasingly applied over the last decades as a way to improve the ecological conditions in stream ecosystems, but documentation of the impact of restoration on ecosystem functions is sparse. Here, we applied a space-for-time approach to explore effects of stream restoration on metabolism and organic matter decomposition in lowland agricultural streams. We included stream reaches that were restored >10 years ago and compared ecosystem functioning in these streams with those in channelized and naturally meandering stream reaches from the same geographical region. Specifically, we tested the following hypotheses: 1) rates of stream metabolism (gross primary production, GPP, and ecosystem respiration, ER) and organic matter decomposition in restored reaches resemble rates in naturally meandering reaches more than rates in channelized stream reaches and 2) higher resemblance in ecosystem metabolism and organic matter decomposition between restored reaches and meandering reaches can be attributed to the improved physical habitat conditions in the restored stream reaches. Overall, we did not find that stream metabolism or organic matter decomposition differed among restored, channelized and naturally meandering stream reaches even though habitat conditions differed among the three stream types. Instead, we found a large variation in ecosystem function characteristics across all sites. When analyzing all stream types combined, we found that GPP increased with increasing plant coverage and that ER increased with increasing stream size and with the coverage of coarse substratum on the stream bottom. Organic matter decomposition, on the other hand, only slightly increased with the number of plant species and declined with increasing concentrations of nutrients. Overall, our findings suggest that physical habitat improvements in restored stream reaches can affect ecosystem functions, but also that the restoration outcome is context-dependent since many of the physical characteristics playing a role for the measured functions were only to some extent affected by the restoration and/or clouded by interference with factors operating at a larger-scale. [ABSTRACT FROM AUTHOR]

Large amounts of fungicides are applied globally and partly enter freshwater ecosystems. A few laboratory studies examined their effects on decomposer communities and the ecosystem process of litter decomposition (LD), whereas the field situation remains largely unknown. We conducted a field study with 17 stream sites in a German vineyard area where fungicides represent the dominant pest control agent. Passive samplers were used to monitor 15 fungicides and 4 insecticides in streams and their toxicity was described using the toxic unit approach, whereas sediment samples were taken to characterise total copper concentrations. Microbial and leaf-shredding invertebrate community composition and related LD rates were assessed at each site. The structure of microbial and shredder communities as well as fungal biomass changed along the fungicide toxicity gradient. The changes in microbial endpoints were associated with a reduction of microbial LD rate of up to 40% in polluted streams. By contrast, neither the invertebrate LD rate nor in-situ measured gammarid feeding rates correlated with fungicide toxicity, but both were negatively associated with sediment copper concentrations. A subsequent laboratory experiment employing field fungicide concentrations suggested that the microbial community changes are causal. Overall, our results suggest that fungicides can affect LD under field conditions. [ABSTRACT FROM AUTHOR]

Copper (Cu) exposure can increase leaf-associated fungal biomass, an important food component for leaf-shredding macroinvertebrates. To test if this positive nutritional effect supports the physiological fitness of these animals and to assess its importance compared to waterborne toxicity, we performed a 24-day-bioassay in combination with a 2×2 factorial design using the amphipod shredder Gammarus fossarum and a field-relevant Cu concentration of 25 μg/L ( n = 65). Waterborne toxicity was negligible, while gammarids fed leaves exposed to Cu during microbial colonization exhibited a near-significant impairment in growth (∼30%) and a significantly reduced lipid content (∼20%). These effects appear to be governed by dietary uptake of Cu, which accumulated in leaves as well as gammarids and likely overrode the positive nutritional effect of the increased fungal biomass. Our results suggest that for adsorptive freshwater contaminants dietary uptake should be evaluated already during the registration process to safeguard the integrity of detritus-based ecosystems. [ABSTRACT FROM AUTHOR]

Anthropogenic nutrient enrichment of forested headwater streams can enhance detrital quality, decrease standing stocks, and alter the community structure of detrivorous insects, reducing nutrient retention and decreasing ecosystem functioning. Our objective was to determine if stoichiometric principles could be used to predict genus-specific shifts in shredding insect abundance and biomass across a dissolved nutrient and detritus food quality/quantity gradient. Detritus, insect, and water samples were collected from 12 Ozark Highland headwater streams. Significant correlations were found between stream nutrients and detrital quality but not quantity. Abundance and biomass responses of four out of five tested genera were accurately predicted by consumer-resource stoichiometric theory. Low carbon:phosphorus (C:P) shredders responded positively to increased total phosphorus and/or food quality, and high C:P shredders exhibited neutral or negative responses to these variables. Genus-specific declines were correlated with decreased overall biomass in shredder assemblages, potentially causing disruptions in nutrient flows to higher level consumers with nutrient enrichment. This work provides further evidence that elevated nutrients may negatively impact shredding insect communities by altering the stoichiometry of detritus-detritivore interactions. A better understanding of stoichiometric mechanisms altering macroinvertebrate populations is needed to help inform water quality criteria for the management of headwater streams. [ABSTRACT FROM AUTHOR]

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1. We compared leaf litter conditioning in two artificial stream channels that were connected to a second-order stream (both in- and outflow). The water in one channel had the same temperature as the stream and in the other channel was warmed (3 °C above ambient stream water temperature). In addition to measuring leaf decomposition by microbes, we ran feeding trials in the artificial streams and the laboratory that addressed the feeding preferences, resource acquisition and performance of a dominant detritivore. 2. Oak leaves were conditioned for three weeks in both channels and then offered during the following five weeks to Sericostoma vittatum larvae kept in cages in the same channels. Additionally, leaves conditioned in both conditions were simultaneously offered to the larvae in a feeding preference laboratory trial. Leaves conditioned in the channel with elevated temperature had reduced toughness, fewer phenols and lower carbon : nitrogen ratios. However, individuals did not prefer these leaves over those conditioned at ambient stream temperature. 3. We observed lower carbon : nitrogen imbalances and increased consumption rates in the stream channel at warmer temperature but these were not translated into higher growth rates. Higher metabolic rates of the S. vittatum individuals and other temperature-mediated factors such as changes in leaf quality could explain the increased consumption. We observed higher lipid storage and earlier pupation of S. vittatum at warmer temperatures, suggesting that individuals allocated resources to metamorphosis and reproduction, rather than to somatic growth. 4. We argue that microbial and invertebrate-mediated organic matter cycling will be faster in streams under future warming scenarios. However, these systems will likely become less efficient in carbon retention via effects on larval performance (growth and developmental time) and timing of prey availability to the stream and coupled riparian food webs. [ABSTRACT FROM AUTHOR]

During past decades, several mechanisms such as resource quality and habitat complexity have been proposed to explain variations in the strength of trophic cascades across ecosystems. In detritus-based headwater streams, litter accumulations constitute both a habitat and a resource for detritivorous macroinvertebrates. Because litter edibility (which promotes trophic cascades) is usually inversely correlated with its structural complexity (which weakens trophic cascades), there is a great scope for stronger trophic cascades in litter accumulations that are dominated by easily degradable litter species. However, it remains unclear how mixing contrasting litter species (conferring both habitat complexity and high quality resource) may influence top-down controls on communities and processes. In enclosures exposed in a second-order stream, we manipulated litter species composition by using two contrasting litter (alder and oak), and the presence-absence of a macroinvertebrate predator ( Cordulegaster boltonii larvae), enabling it to effectively exert predation pressure, or not, on detritivores (consumptive versus non-consumptive predation effects). Leaf mass loss, detritivore biomass and community structure were mostly controlled independently by litter identity and mixing and by predator consumption. However, the strength of predator control was mediated by litter quality (stronger on alder), and to a lesser extent by litter mixing (weaker on mixed litter). Refractory litter such as oak leaves may contribute to the structural complexity of the habitat for stream macroinvertebrates, allowing the maintenance of detritivore communities even when strong predation pressure occurs. We suggest that considering the interaction between top-down and bottom-up factors is important when investigating their influence on natural communities and ecosystem processes in detritus-based ecosystems. [ABSTRACT FROM AUTHOR]

Abstract: The intensification of agriculture has promoted the use of pesticides such as fungicides and insecticides. Many pesticides readily leach into natural water bodies and affect both organisms and ecosystem processes such as leaf breakdown, a crucial process in headwater streams. As leaf breakdown in streams involves sequential steps by different groups of organisms (first microbial conditioning, then invertebrate shredding), pesticides targeting different organisms are likely to affect one or the other step, and a mixture of contaminants might have interactive effects. Our objective was to evaluate the effect of a fungicide (imazalil) and an insecticide (diazinon) on stream fungal and invertebrate activities, and their effects on leaf consumption. After an initial assay to define ‘effective concentration’ of both pesticides in a laboratory experiment, we manipulated pesticide presence/absence during the conditioning and shredding phases. Both pesticides affected fungal community and reduced the performance of the shredding amphipod Echinogammarus berilloni, and leaf consumption. The impact of pesticides on fungal sporulation depended on the length of the exposure period. In addition, pesticides seemed to cause an energetic imbalance in the amphipod, affecting body condition and mortality. The combined effect of both pesticides was similar to those of the fungicide. Overall, our results show that the effects of pesticide mixtures on leaf breakdown are hard to predict from those observed in either fungi or macroinvertebrate performance. [Copyright &y& Elsevier]

Nutrient enrichment affects bacteria and fungi associated with detritus, but little is known about how biota associated with different size fractions of organic matter respond to nutrients. Bacteria dominate on fine (<1 mm) and fungi dominate on coarse (>1 mm) fractions, which are used by different groups of detritivores. We measured the effect of experimental nutrient enrichment on fungal and bacterial biomass, microbial respiration, and detrital nutrient content on benthic fine particulate organic matter (FPOM) and coarse particulate organic matter (CPOM). We collected FPOM and CPOM from 1 reference and 1 enriched stream. CPOM substrates consisted of 2 litter types with differing initial C:nutrient ratios (Acer rubrum L. and Rhododendron maximum L.). Fungal and bacterial biomass, respiration, and detrital nutrient content changed with nutrient enrichment, and effects were greater on CPOM than on FPOM. Fungal biomass dominated on CPOM (~99% total microbial biomass), whereas bacterial biomass dominated on FPOM (~95% total microbial biomass). These contributions were unchanged by nutrient enrichment. Bacterial and fungal biomass increased more on CPOM than FPOM. Respiration increased more on CPOM (up to 300% increase) than FPOM (~50% increase), indicating important C-loss pathways from these resources. Microbial biomass and detrital nutrient content were positively related. Greater changes in nutrient content were observed on CPOM than on FPOM, and changes in detrital C:P were greater than changes in detrital C:N. Threshold elemental ratios analyses indicated that enrichment may reduce P limitation for shredders and exacerbate C limitation for collector-gatherers. Changes in CPOMdominated pathways are critical in predicting shifts in detrital resource quality and C flow that may result from nutrient enrichment of detritus-based systems. [ABSTRACT FROM AUTHOR]

Streams receiving agricultural runoff are typically enriched with nutrients, which variously impact stream communities. We examined the effects of phosphate and nitrate enrichment on leaf litter breakdown, microbial biomass and the nutrition of an invertebrate shredder to determine how nutrients are transferred through the stream detrital food web. Using artificial streams, individuals of Anisocentropus kirramus (Trichoptera: Calamoceratidae) were fed leaves of Apodytes brachystylus (Icacinaceae) under different nutrient regimes. We measured the amount of leaf material consumed or decomposed and the microbial biomass colonising the leaves. The dry mass, and protein, lipid and carbohydrate composition of A. kirramus larvae were determined after 28-day feeding on the leaves. Supplements of phosphorus, but not nitrogen, enhanced leaf breakdown, microbial growth and growth of larvae. Microbial biomass and dry mass of larvae increased with nutrient enrichment and they were significantly correlated. Thus, the phosphorus supplement was transmitted through the detrital food web via the microbial pathway, resulting in higher nutritional quality of leaves and enhanced physiological condition of the shredder. Understanding such subtle relationships is important in determining the impacts of anthropogenic contaminants on freshwater ecosystems. [ABSTRACT FROM AUTHOR]

This work aims to design and build a machine shredder greens Angustifolia Haw Agave, starting from the determination of the rational values of the variables that influence the pulping process and operating parameters. To project design was based on selecting an appropriate model of shredder machine prototype for conditions agave producers of the State of Oaxaca, Mexico, later by calculation, were determined the dimensions and operating parameters. Finally, experimental model was constructed to determine the optimum values of the defibering gap and of the exit and feed speed of the sheet. This test shows the relationship between the defibering gap and defibered quality, besides, the relationship between the input and output speeds of the sheet with respect to energy consumption of the process. [ABSTRACT FROM AUTHOR]

Decomposition of senesced primary production starts processing chains in aquatic systems. Shredding macroinvertebrates convert coarse particulate organic matter (CPOM) to fine particulate organic matter (FPOM) that supports 2 other feeding groups, collecting and filtering macroinvertebrates. This linkage is often invoked by aquatic ecologists, but the effect of detritivore assemblage composition on production of FPOM is relatively understudied. I manipulated detritivore assemblage composition (Limnephilus sp., Caecidotea sp., and Hyalella azteca) in aquatic mesocosms stocked with green speckled alder leaves (Alnus incana rugosa). I measured production rate, size distribution, and stoichiometry of FPOM produced through time. Detritivore species richness had a positive effect on FPOM production resulting from inclusion of the functionally dominant shredder, Limnephilus sp., in mixed-species treatments (e.g., sampling effect). Mixed-species treatments had significantly faster particle production than predicted from single-species treatments. The significant increases in particle production in mixed-species treatments could have resulted from release of Limnephilus sp. from intraspecific competition, facilitation between shredders, or both processes. FPOM size distribution and C:N varied significantly among treatments and was affected by species interactions in mixed-species treatments. The presence of Limnephilus sp. significantly skewed the FPOM size distribution and increased the mass of particles >250 μm by ~60%. These results suggest that the specific shredding insects in an assemblage could strongly affect production of FPOM and the size distribution and stoichiometry of FPOM produced by the benthos of a stream. [ABSTRACT FROM AUTHOR]