Initial TS Research Articles

Effects of aeration and season of the year on fish waste composting and compost quality

ABSTRACT Employing forced aeration (FA) in composting static windrows (SW) from fish waste (FW) has the potential to enhance the development of process and, organic fertiliser quality. However, due to the impact of season, the FA may lead to excessive drying of SW and, difficulty in thermophilic temperature maintenance. The aim of this study was to assess the effects of passive aeration (PA) and FA on the composting of FW in SW during the summer and winter seasons. The temperatures of the windrows remained within the thermophilic range for most of the composting period, with peak temperatures observed shortly after starting and turning the windrows (at 50 and 70 days). The aeration benefited the initial TS degradations, resulting in 86.66 and 45.99% of the TS total reduced to FA and PA piles, at 50 days during the winter. The C organic reduction was 77.77 and 76.33% in summer and winter to FA piles, respectively, but this reduction was 59.24% and 67.82% for winter and summer, respectively, in PA windrows. At 50 days, the N reduction in FA piles was already at 70.32% and 71.87% for winter and summer. The volatile solids reductions were significantly higher (p < 0.01) in FA piles during the summer. Although the FA has been shown to enhance the organic constituents’ degradation during the composting of FW, its adoption was not enough to improve the compost composition. Thus, by conducting piles on a small scale, with the perforated wall, as described in this study, the FA could be dispensed.

ОСОБЛИВОСТІ ПРОГРАМНИХ РІШЕНЬМОДЕЛЕЙ ЛОГІЧНИХ ДЕРЕВ КЛАСИФІКАЦІЇ НА ОСНОВІ СЕЛЕКЦІЇ НАБОРІВ ЕЛЕМЕНТАРНИХ ОЗНАК

Urgency of the research.Currently there are several independent approaches (concepts) to solve the classification problem in the general setting, and the development of various concepts, approaches, methods, and models that cover the general issues of the theory of artificial intelligence and information systems, all of these approaches in a recognition theory have their advantages and disadvantages and form a single tool to solve applied problems of the theory of artificial intelligence. This study will focus on the current concept of decision trees (classification trees). The general problem of software (algorithmic) construction of logical recognition trees (classification) is considered. The object of this research is logical classification trees (LСT structures). The subject of the research is actual methods and algorithmic schemes for constructing logical classification trees. Target setting.The main existing methods and algorithms for working with arrays of discrete information in the construc-tion of recognition functions (classifiers) do not allow you to achieve a predetermined level of accuracy (efficiency) of the classification system and regulate their complexity in the construction process. However, this disadvantage is absent in meth-ods and schemes for building recognition systems based on the concept of logical classification trees (decision trees). That is, the coverage of the training sample the set of elementary signs in the case of LCT generates a fixed tree data structure (model LCT), which provides compression and conversion initial data TS, and therefore allows significant optimization and savings of hardware resources of the system, and is based on a single methodology – the optimal approximation test sample set of elementary features (attributes) that are included in some schema (operator) constructed in the learning process.Actual scientific researches and issues analysis. The possibility of an effective and economical software (algorithmic) scheme for constructing a logical classification tree (LCT structuremodel) based on the source arrays of training samples (arrays of discrete information) of a large sample.The research objective. Development of a simple and high-quality software method (algorithm and software system) for building models (structures) LCTfor large arrays of initial samples by synthesizing minimal forms of classification and recog-nition trees that provide an effective approximation of educational information with a set of ranked elementary features (at-tributes) is created on the basis of ascheme for branched feature selection in a wide range of applied problems.The statement of basic materials. We propose a general program scheme for constructing structures of logical classifi-cation trees, which for a given initial training sample builds a tree structure (classification model), which consists of a set of elementary features evaluated at each step of building the model for this sample. A method and ready-made software system build logic trees the main idea is to approximate the initial random sampling of the volume set of elementary features. This method provides the selection of the most informative (qualitative) elementary features from the source set when forming the current vertex of the logical tree (node). This approach allows to significantly reduce the size and complexity of the tree (the total number of branches and tiers of the structure) and improve the quality of its subsequent analysis.Conclusions. The developed and proposed mathematical support for constructing LCT structures (classification tree mod-els) allows it to be used for solving a wide range of practical problems of recognition and classification, and the prospectsfor further research may consist in creating a limited method of logical classification tree (LCT structures), which consists in maintaining the criterion for stopping the procedure for constructing a logical tree by the depth of the structure, optimizing its software implementations, as well as experimental studies of this method for a wider range of practicalproblems.

Anaerobic Co-digestion of Urban Sewage Sludge with Agricultural Biomass

Three different types of urban sewage sludges (the mixed sludge, the dewatered secondary sludge and the sludge filtered by screens) were used for individual anaerobic digestion and co-digestion with agricultural biomass. The initial TS level (4%) and substrate to inoculum ratio (3:1) were maintained into all runs at mesophilic conditions, and the co-substrates was mixed at the recommended VS ratio of 1:1 (sludge: straw under the co-digestion conditions. It was found that the mixed sludge exhibited prominent anaerobic digestion performance, selected as a potential reagent for the co-digestion with biomass. The total volume of the produced methane from co-digestion of the mixed sludge and wheat stalk reached to 187.01 ± 3.27 mL g−1 VSadded, which was about 1.52 times higher than that from the individual digestion of the sludge. The experimental value of methane yield from co-digestion of the mixed sludge with wheat stalk is about 9.46% more than that of the estimated value, imply the enhanced interactions between the sludge and biomass during the co-digestion process. The pH of the co-digestion system of the mixed sludge and the wheat stalk was maintained at a relevant stable value around 6.50. It indicated that the buffering capacity of the digestion system could improved by adding the mixed sludge. The modified Gompertz model and the first-order kinetic model were proposed to simulate the co-digestion process between the mixed sludge and agricultural straw. The estimated kinetic parameters indicated that the maximum releasing rate of methane was significantly increased during the co-digestion process.

Co-digestion of Sorghum Stalk and Sludge for Biogas Production

The recycling of residual agricultural biomass using anaerobic digestion allows for the recovery of biomass carbon and nutrients as sources of energy and fertilizer. The obstacles that are encountered in this process include the lignocellulosic structure of biomass tissue and its high carbon-to-nitrogen (C:N) ratio. This study evaluates the co-digestion system of pretreated sorghum stalks and wastewater sludge. The stalks were pretreated by partial bio-oxidation to improve their bacterial accessibility. The digesters were fed a mixture of stalk and sludge at ratios of 100:0, 80:20, 60:40, and 40:60 (total solids [TS] basis). The digesters were run in batches at 35-36 ° C, with an initial TS of 15%. The digesters’ performance was evaluated in terms of biogas production rate and yield. The digesters that were run with feed ratios of 80:20 and 60:40 showed shorter lag phase, higher biogas generation rates, and higher biogas yields compared to those run with feed ratios of 100:0 and 40:60. The highest specific biogas production (of 122 L/kg TS) was achieved by the digesters run at ratios of 80:20 and 60:40. The digesters run only with stalks (ratio 100:0) resulted in specific gas production of 67 L/kg TS, whereas those fed on a feed ratio of 40:60 generated only 13 L/kg TS. We conclude that the co-digestion of sorghum stalks and wastewater sludge at a proper ratio improves biogas production.

The influence of total solids content and initial pH on batch biohydrogen production by solid substrate fermentation of agroindustrial wastes

Hydrogen is a valuable clean energy source, and its production by biological processes is attractive and environmentally sound and friendly. In México 5 million tons/yr of agroindustrial wastes are generated; these residues are rich in fermentable organic matter that can be used for hydrogen production. On the other hand, batch, intermittently vented, solid substrate fermentation of organic waste has attracted interest in the last 10 years. Thus the objective of our work was to determine the effect of initial total solids content and initial pH on H2 production in batch fermentation of a substrate that consisted of a mixture of sugarcane bagasse, pineapple peelings, and waste activated sludge. The experiment was a response surface based on 22 factorial with central and axial points with initial TS (15–35%) and initial pH (6.5–7.5) as factors. Fermentation was carried out at 35 °C, with intermittent venting of minireactors and periodic flushing with inert N2 gas. Up to 5 cycles of H2 production were observed; the best treatment in our work showed cumulative H2 productions (ca. 3 mmol H2/gds) with 18% and 6.65 initial TS and pH, respectively. There was a significant effect of TS on production of hydrogen, the latter decreased with initial TS increase from 18% onwards. Cumulative H2 productions achieved in this work were higher than those reported for organic fraction of municipal solid waste (OFMSW) and mixtures of OFMSW and fruit peels waste from fruit juice industry, using the same process. Specific energetic potential due to H2 in our work was attractive and fell in the high side of the range of reported results in the open literature. Batch dark fermentation of agrowastes as practiced in our work could be useful for future biorefineries that generate biohydrogen as a first step and could influence the management of this type of agricultural wastes in México and other countries and regions as well.

Storing energy crops for methane production: Effects of solids content and biological additive

The effect of storage on chemical characteristics and CH4 yield (taking into account loss of VS during storage) of a mixture of grasses and ryegrass, ensiled as such (low solids content) and after drying (medium and high solids) with and without biological additive, were studied in field and laboratory trials. Up to 87% and 98% of CH4 yield was preserved with low solids grass (initial TS 15.6%) and high solids ryegrass (initial TS 30.4%), respectively, after storage for 6months, while under suboptimal conditions at most 37% and 52% of CH4 yield were lost. Loss in CH4 yield was mainly due to VS loss, presumably caused by secondary fermentation as also suggested by increasing pH during storage. Biological additive did not assist in preserving the CH4 yield.

２０‐４０ＫにおけるＳｍ‐Ｂａ‐Ｃｕ‐Ｏバルクに対するパルス着磁による捕捉磁場と発熱解析

Pulse-field magnetization (PFM) has been investigated for a bulk Sm-Ba-Cu-O superconductor cryo-cooled at 20 - 40 K using pulse magnetic fields Bex of 3.83 - 6.07 T. The temperature rise ΔT after applying the pulse fields increases as the bulk superconductor's initial temperature Ts decreases and as the applied field Bex increases. The generated heat Q, estimated using ΔT and the specific heat C of the bulk superconductor, decreases with decreasing Ts for lower Bex (=3.83 T), but increases with decreasing Ts for higher Bex (≥5.53 T). There is a slight increase in the pinning loss Qp determined from the magnetization M vs the applied field μ0Ha hysteresis curve at a lower Ts. These results can be explained by the increase in pinning force Fp at lower temperatures. The lowering of Ts is one of the promising approaches for enhancing trapped field BTP using PFM.

Kinetics of the aerobic biological degradation of shredded municipal solid waste in liquid phase

The organic fraction of municipal solid waste (OFMSW) should be utilised by means of biological methods. The biodegradation of solid wastes can be intensified owing to application of the bioreactors. Estimation of the optimum values of the organic load is one of the most important tasks for the aerobic biodegradation processes. The kinetic model of biological oxidation of the organic wastes has been presented in this paper. The experiments were carried out in batch 6-l working volume stirred tank bioreactors at constant temperature of 25°C. Initial total solids have been at the levels of 15, 19, 34, 55 and 66 g l −1. The kinetics of microbial decomposition of organic substances was described by means of an unstructured model. The satisfactory time courses for substrate chemical oxygen demand in the solid (COD S) and liquid phase (COD L) and biomass concentration (RNA) have been achieved. Also, the influence of the initial TS on the kinetics of the biodegradation process was investigated and the optimum value of initial TS for this type of processes was estimated at 34–55 g l −1.

Soil Temperature Simulation with Varying Residue Management

AbstractMaintaining crop residue on the soil surface is an important part of conservation tillage. Although broad effects of residues on soil temperature (Ts) are well documented, the methods to predict soil temperatures under various surface residues and tillage conditions are limited. Using the Ts at 0‐, 0.05‐, 0.10‐, and 0.30‐m depths, we developed a simplified model to predict Ts for a uniform soil from air temperature (Ta) data. Data were collected under various tillage and surface residue conditions after wheat (Triticum aestivum L.) harvest. Residue management treatments were disk, sweep, and no‐tillage (with standing or shredded residues). The model predicts maximum and minimum Ts at 0‐, 0.05‐, 0.10‐, and 0.30‐m depths using maximum and minimum Ts measured at 2‐m above the soil surface, residue mass, apparent thermal diffusivity, and initial Ts profiles. Mean absolute deviation between simulated and measured maximum and minimum surface Ts were 0.53 and 0.44 °C or less, respectively. Root zone maximum and minimum T, were simulated within 0.14 to 0.91 and 0.27 to 0.95 °C, respectively, of the measured Ts. Greater precision of maximum and minimum soil temperature predictions with depth was obtained by using apparent thermal diffusivity calculated from initial Ts profiles. The proposed model can be useful in predicting Ts profiles required for crop growth modeling.

Changes in Solids and Carbon content of dairy-cattle slurry in farm tanks

Changes in Total Solidsby weight and volume (TS w and TS v), Fixed and Volatile Solids (FS and VS) and Total Carbon (TC) in dairy-cattle liquid manure slurry during undisturbed storage in covered concrete tanks, 12·3 × 7·2 × 3·0m deep were studied. Slurry with nearly 10% TS w was stored from January to October (285 days) in two tanks and , similarly, from June to Novemmber (146 days). Slurry samples were periodically collected from each of the tanks at two locations at depths of 0·3, 1·0, 1·8 and 2·5 m below surface. Slurry TS v were determined by high-speed centrifuging. Substantial spatial and temporal concentration variations occurred in slurry TS w, TS v,FS and VS. Most of the concentration change and loss of TS w, TS v and VS was limited to the top 1 m of the slurry. Settling of solids did not appear to be an important process in the stores slurry. Large concentration changes were limited to the top 0·3 m only for about 6 months after winter and 3 months after summer-filling of the tanks. Thus, most of the initial organic matter and biogas generation potential was probably retained in the slurry at depths of 1 m or more. The rate and location of TS w concentration decreases suggested that VS biodegradation occurred mainly due to aerobic processes, starting near the surface and progressing downwards with time. Mass balances indicated that about one quarter of the initial TS w, VS and TC were lost by the end of the storage period in all tanks. Correlations between TS w and TS v and between wet-basis TC and TS w or TS v were highly significant.

Hypothalamic temperature during desynchronized sleep.

The influence of changes in heat loss at specific heat exchangers, appraised by recording ear skin temperature (Ts), on the hypothalamic temperature (Thy) rise during desynchronized sleep (DS) was studied in unrestrained cats at different ambient temperatures (Ta). The correlations of initial and final Thy changes (delta iThy and delta fThy) with initial and final Ts changes (delta iTs and delta fTs), respectively, are statistically not significant. However, a significant negative correlation was found between delta fiThy, i.e. delta fThy-delta iThy, and delta fiTs, i.e. delta fTs-delta iTs. The latter result shows that only after its initial rise is Thy affected by changes in heat loss at specific heat exchangers during DS. Accordingly, delta fThy and delta fiThy are positively correlated with Ta. However, also delta iThy, although not affected by heat loss changes at specific heat exchangers, shows a positive correlation with Ta. On the basis of these results and of the data in the literature, it is concluded that three independent factors underlie Thy changes during DS, namely heat loss at specific heat exchangers, hypothalamic blood flow and thermogenesis.

Quantum statistical theory of flash desorption

The nonequilibrium initial value problem of phonon-mediated flash desorption of a gas from a solid surface is formulated explicitly and flash desorption times td=td(Tg, Ts) are calculated, using a nonlocal separable surface potential, as a function of both initial and final temperatures Tg and Ts, respectively. We find that for fixed Tg, td can be approximated by Frenkel’s formula over a limited range of flash temperatures Ts. We fit our theory to flash desorption data for He desorbing from Constantan and find excellent agreement. Predictions on 4He (H or D) desorbing from LiF (NaF) are given. Our theory is formulated both in one and three dimensions and it is shown by numerical examples that the theory of flash desorption works equally well in either case.

Initial Ts- in Italian Zolfo and Zuppa

Initial Ts- in Italian Zolfo and Zuppa