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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.

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.

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]

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]

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%.

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.

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]

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]

Abstract: The annual variation in population density of the stream macroinvertebrate Gammarus pulex is frequently linked to annual courses of both, resource availability and temperature, which is calling for a mechanistic analysis of the system. To this effect, we coupled a size structured population model for the consumer and a quality structured resource model for its main resource, leaf litter standing stock. We introduced temperature dependence of processes and a lumped internal energy storage for reproduction and energy reallocation. One-year''s field data on body length frequencies of G. pulex, in-stream leaf litter standing stock, leaf fall and temperature were used to calibrate the model for parameters not yet determined in independent experiments. The model reproduced the seasonal pattern of both dynamics acceptably. Independently measured feeding rates of G. pulex were used to confirm the simulated relationship between resource and consumer. Such, we revealed the contribution of temperature and food response to changes in population density. Temperature effects of mortality and reproduction roughly concur with each other, while the energy response of reproduction is pivotally distinct. In the face of model application for projection of climate change effects, further attention should particularly be paid to the specific temperature response of G. pulex and to the contribution of non-shredding decomposition (physical abrasion and microbial colonization) to loss of leaf litter standing stock. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

Exposure was assessed in four facilities where used tires are turned into rubber granulates. Particulate exposure levels were measured using filter samples and gravimetric analysis. In parallel, volatile organic compounds (VOCs) screening was carried out using samples taken on activated carbon supports, followed by an analysis using a gas chromatograph coupled to a spectrometric detector. The exposure level medians are between 0.58 and 3.95 mg m−3. Clogging of the textile fiber separation systems can lead to worker exposure; in this case, the measured concentrations can reach 41 mg m−3. However, in contrast to the data in the literature, VOC levels >1 p.p.m. were not detected. The particulate mixtures deposited on the installation surfaces are complex; some of the chemical agents are toxic to humans. The results of this study indicate significant exposure to complex mixtures of rubber dust. Optimizing exhaust ventilation systems inside the shredders, with a cyclone for example, is essential for reducing the exposure of workers in this rapidly developing sector. [ABSTRACT FROM PUBLISHER]

Abstract: Present work elaborates on systems and engineering procedures to create particleboards based on Common Reed. Particleboard was manufactured using the shredding blades, usually applied by wood-particleboard industry. Diverse types of boards were manufactured keeping the same proportion of urea formaldehyde resin (for indoor use), but with different particle proportions according to ISO standard sieves, and varying the pressure from 3N/mm2 to 25N/mm2. Mechanical Density, bending resistance and elasticity tests were performed and results were compared against commercial wood particleboards. Results allowed us to state that particle size and pressure plays a significant role in common reed particleboard properties. Common reed particleboards were classified according to UNE EN standards, taking into account relevant standard tests carried out as well as additional classification standard-rules. [Copyright &y& Elsevier]

Current aquatic environmental risk assessment of plant protection products or biocides does not consider effects on organisms involved in leaf litter breakdown, a fundamental ecosystem process in streams. Therefore, direct ecotoxicological implications of tebuconazole, a frequently used triazole fungicide, on the leaf-shredding amphipod Gammarus fossarum, were assessed. While acute toxicity was low (96h-LC50=1347μg/L), feeding rate, a sublethal endpoint, was significantly reduced after seven days of exposure to 600μg/L. At the same concentration, but during a three week exposure under semi-static conditions, gammarids showed significant reductions in feeding, but also in assimilation and growth. At 200μg/L, however, only assimilation was significantly affected. As these endpoints can be used to evaluate the ecotoxicity of a broad range of chemicals and to deduce possible implications in the functioning of ecosystems, the inclusion of similar experimental set-ups might further improve aquatic environmental risk assessment. [Copyright &y& Elsevier]

The article examines the impact of Bt maize leaf detritus on aquatic invertebrates in headwater streams. It was found that the insect Lepidostoma liba grows slower when it is fed with Bt maize compared to non-Bt maize. There is no significant difference found in total abundance or biomass of benthic macroinvertebrate abundance between Bt and non-Bt streams. Shannon diversity in both streams is low while highly tolerant taxa is dominant in Bt and non-Bt streams.

Previous studies which have tested the feeding preferences of shredders for fungal species and the food quality of fungi used detritus uniformly colonized by a fungus, which is not the case for decaying leaves in streams. It is not known whether shredders in different development stages exhibit variations in feeding preference and larval performance. This study examined the feeding preferences and the growth of the third and the fifth instars of Pycnopsyche gentilis larvae using fungal-colonized patches and whole leaves, respectively, having different fungal species compositions ( Alatospora acuminata, Anguillospora filiformis, Articulospora tetracladia, Tetrachaetum elegans, and all species combined). The aquatic hyphomycetes used were co-dominant on leaves in the stream inhabited by the caddisfly. During 14 d of feeding, the larvae of both instars did not show significant differences in feeding preferences for the patches growing on oak leaves, although the third instar larvae were slightly more selective than the fifth instar larvae. When fed with maple leaves for 18 d, larval growth rates, gross growth efficiencies, and survivorship were not significantly different among the fungal treatments. However, the larval growth of both instars fed with fungal-colonized leaves was always significantly greater than the growth of larvae fed with diets of uncolonized leaves. The third instar larvae grew faster than the fifth instar larvae, but the growth efficiencies of the two instars were similar. These results suggest that P. gentilis larvae exhibit less selectivity in their feeding than other caddisfly shredders that have been examined and that the dominant fungi colonizing leaves in their habitat are similar in palatability and food quality for this shredder. [ABSTRACT FROM AUTHOR]