Pyrolysis of grape bagasse: effect of pyrolysis conditions on the product yields and characterization of the liquid product

In this study, pyrolysis of grape bagasse was investigated with the aim to study the product distribution and their chemical compositions and to identify optimum process conditions for maximizing the bio-oil yield. Particular investigated process variables were temperature (350-600 °C), heating rate (10-50 °C/min) and nitrogen gas flow rate (50-200 cm³/min). The maximum oil yield of 27.60% was obtained at the final pyrolysis temperature of 550 °C, sweeping gas flow rate of 100 cm³/min and heating rate of 50 °C/min in a fixed-bed reactor. The elemental analysis and heating value of the bio-oils were determined, and then the chemical composition of the bio-oil was investigated using chromatographic and spectroscopic techniques such as column chromatography, ¹H NMR and FTIR. The fuel properties of the bio-oil such as flash point, viscosity and density were also determined. The bio-oils obtained from grape bagasse were presented as an environmentally friendly feedstock candidate for bio-fuels.     

Recycling rice straw ash to produce low thermal conductivity and moisture-resistant geopolymer adobe bricks

Rice straw ash (RSA) geopolymer adobe bricks were produced using the geopolymerization reaction among the RSA, soil, and alkaline activator at the Biosystem Engineering Department, Faculty of Agriculture, Alexandria University, Egypt, to optimize adobe brick advantages. The bulk density, water absorption, compressive strength, and thermal conductivity of the new composite were measured at RSA contents of 0%, 5%, 10%, and 20% and sodium hydroxide contents of 2.5%, 5%, 7.5%, and 10% after curing the composite for 28 days. Results indicated that increasing RSA from 0% to 20% increased the compressive strength and decreased the bulk density, water absorption, and thermal conductivity. Further, increasing sodium hydroxide from 2.5% to 10% increased the bulk density and compressive strength and decreased the water absorption. Significant effects of RSA and sodium hydroxide percentages and their interaction on all the studied characters were reported. The best conditions to minimize bulk density, water absorption, thermal conductivity, and optimize compressive strength of the composite were at 10% sodium hydroxide and 20% RSA. The minimum bulk density, water absorption, and thermal conductivity were 1.463 g/cm³, 8.3%, and 0.46 W/(m·K), respectively, while the maximum CS was 2.1 MPa after 28 days. Using RSA geopolymer adobe bricks on building interior walls is recommended to decrease bricks' thermal conductivity, water absorption, and weight.     

Effects of fluctuating moisture and temperature regimes on the persistence of quiescent conidia of Isaria fumosorosea

Conidia of Isaria fumosorosea were submitted to three regimes of temperature and moisture to simulate microclimatic conditions which prevail in temperate (43% RH and 28 °C to 98% RH and 15 °C), subtropical (75% RH and 35 °C to 98% RH and 25 °C), and arid areas (13% RH and 40 °C to 33% RH and 15 °C) with daily fluctuating cycles. Germination, conidial viability, and virulence to Spodoptera frugiperda larvae were less affected after 20 days exposure under temperate cycling conditions than under arid and subtropical conditions. Exposure of conidia for 20 days to constant nocturnal simulated conditions of any tested regime weakly affected conidial persistence, whereas diurnal conditions exerted the most detrimental effects of high temperatures. However, when tested at both 45 °C and 50 °C at 33% RH for 160 h, the persistence of I. fumosorosea conidia was relatively higher than expected. These results emphasize that climatic conditions prevailing in environments and ecological fitness of fungal isolates have to be taken into account for assessing microbial control strategies.     

Effect of increasing the surface area of primary sludge on anaerobic digestion at low temperature

Two sets of reactors were operated at 15 °C and at sludge retention times (SRTs) of 65 days and 30 days, respectively. Each set was operated at six different mixing velocities. Shear forces provided by mixing affected particle size distribution and resulted in different sludge surface areas. The aim was to investigate the effect of increasing primary sludge surface area on anaerobic digestion at low temperature. The maximum surface areas at the applied mixing velocities were 5926 cm²/cm³of sludge and 4672 cm²/cm³ of sludge at SRTs of 65 days and 30 days, respectively. The corresponding calculated methanogenesis were 49% and 15% at SRTs of 65 days and 30 days, respectively. Maximum total solids (TS) reductions were 26% and 11% at 65 days and 30 days SRTs, respectively. Lipase activity increased with increasing SRT and sludge surface area. Results clearly showed that increasing sludge surface area improved sludge digestion at 15 °C.     

Preparation of carbon black from rice husk by hydrolysis, carbonization and pyrolysis

Carbon black is a form of amorphous carbon that is produced by incomplete combustion of petroleum- or some plant-derived materials and has a number of industrial uses. A process consisting of hydrolysis, carbonization and pyrolysis of rice husk was developed. Under optimal hydrolysis conditions (72 wt.% sulfuric acid, 50 °C, 10 min), a hydrolysis ratio of 52.72% was achieved. After carbonization of the hydrolysis solution by water bath, the solid carbon was further pyrolyzed. As the pyrolysis temperature was increased from 400 to 800 °C, the carbon content increased from 83.41% to 94.66%, the number of O-H, C-H, CO, and CC surface functional groups decreased, and based on Brunauer-Emmett-Teller (BET) results, the specific surface area and pore volume of carbon black increased from 389 to 1034 m²/g and from 0.258 to 0.487 cm³/g, respectively. X-ray diffraction pattern (XRD) and Raman spectroscopy analyses of samples pyrolyzed at 400-800 °C showed a localized graphitic structure. It is possible that the hydrolysis/carbonization/pyrolysis process developed in this study could also be applicable to the preparation of carbon black from other types of biomass.     

An investigation on the synthesis of borazine

Borazine is a promising precursor for boron nitride. A detailed investigation on the reaction of sodium borohydride and ammonium sulfate from 40 °C to 120 °C for synthesis of borazine was performed. The reaction was monitored by means of ¹¹B nuclear magnetic resonance (¹¹B NMR) and Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), mass spectroscopy (MS). The reaction produces mainly ammonia borane (AB), but not borazine at temperatures below 60 °C. Increases of temperature promote yield of borazine, which reaches the maximum around 110 °C. Whereas further increased temperature causes severe polymerization of borazine, and hence holds back yields of borazine.     

Diurnally cycling temperature and ventilation affect young turkeys' performance and sensible heat loss

The goals were to elucidate the effects of ventilation rate (VR) coupled with exposure to constant 20 °C or to diurnal temperature cycling on young turkeys' performance and sensible heat loss (SHL). In three experiments male British United Turkeys (BUT), from 3 to 6 weeks of age, were exposed to constant 20 °C, or to 35/25 °C or 30/20 °C diurnal temperature cycling, all at 50% RH and with VR (expressed as air velocity (AV)) ranging from 0.8 to 3.0 m s⁻¹. The 2nd and 3rd of these experiments included a positive control at constant 30 °C and VR of 1.5 m s⁻¹. Weight gain, feed intake, and feed efficiency were measured or calculated, as appropriate; SHL was calculated from measured surface temperature, and plasma concentrations of triiodothyronine (T₃) was determined in the 1st experiment. Changes of VR at constant 20 °C did not affect performance, but total SHL increased significantly with increasing VR. Under the 35/25 °C regime a significantly higher BW was recorded, with a similar pattern of feed efficiency, when VR during the hot part of the cycle was 1.5 or 2.0 m s⁻¹ than when it was 0.8 m s⁻¹. In the 3rd experiment, BW in the 35/20 °C treatment was significantly lower than that of the controls. In all experiments, turkeys maintained body temperature (T_b) within the normothermic range, and SHL varied with VR. It can be concluded that although diurnal temperature cycling reflects the natural situation, exposing young turkeys to constant 30 °C combined with optimal ventilation might yield the best performance results.     

Thermo-mechanical processing of sugar beet pulp. III. Study of extruded films improvement with various plasticizers and cross-linkers

Thermoplastic sugar beet pulp (thermo-mechanical processing was discussed in previous studies) was formed into film strips by extrusion. Film tensile properties are discussed according to the molecular structure of external plasticizer. Sorbitol, fructose and adipic acid have a marked antiplasticizing effect, while urea and xylitol gave higher ultimate tensile stress than glycerol for a comparable strain at break. Xylitol can be considered as the best plasticizer with UTS and EL of, respectively, 4.9 MPa and 11.3% and water absorption (85% RH, 25 °C) was less than 25%. Glycidyl methacrylate was directly used in the extrusion process as cross-linker. In high humidity atmosphere (97% RH, 25 °C), film water absorption was then kept under 40% while tensile strength and strain were improved of 50% and with a 30 min UV post-treatment the mass gain in absorption was even less than 30% after 5 days.     

Determination of thermal properties of composting bulking materials

Thermal properties of compost bulking materials affect temperature and biodegradation during the composting process. Well determined thermal properties of compost feedstocks will therefore contribute to practical thermodynamic approaches. Thermal conductivity, thermal diffusivity, and volumetric heat capacity of 12 compost bulking materials were determined in this study. Thermal properties were determined at varying bulk densities (1, 1.3, 1.7, 2.5, and 5 times uncompacted bulk density), particle sizes (ground and bulk), and water contents (0, 20, 50, 80% of water holding capacity and saturated condition). For the water content at 80% of water holding capacity, saw dust, soil compost blend, beef manure, and turkey litter showed the highest thermal conductivity (K) and volumetric heat capacity (C) (K: 0.12–0.81 W/m °C and C: 1.36–4.08 MJ/m³ °C). Silage showed medium values at the same water content (K: 0.09–0.47 W/m °C and C: 0.93–3.09 MJ/m³ °C). Wheat straw, oat straw, soybean straw, cornstalks, alfalfa hay, and wood shavings produced the lowest K and C values (K: 0.03–0.30 W/m °C and C: 0.26–3.45 MJ/m³ °C). Thermal conductivity and volumetric heat capacity showed a linear relationship with moisture content and bulk density, while thermal diffusivity showed a nonlinear relationship. Since the water, air, and solid materials have their own specific thermal property values, thermal properties of compost bulking materials vary with the rate of those three components by changing water content, bulk density, and particle size. The degree of saturation was used to represent the interaction between volumes of water, air, and solids under the various combinations of moisture content, bulk density, and particle size. The first order regression models developed in this paper represent the relationship between degree of saturation and volumetric heat capacity (r = 0.95–0.99) and thermal conductivity (r = 0.84–0.99) well. Improved knowledge of the thermal properties of compost bulking materials can contribute to improved thermodynamic modeling and heat management of composting processes.     

Growth and annual production of the brown alga Laminaria japonica (Phaeophyta, Laminariales) introduced into the Uwa Sea in southern Japan

The brown alga Laminaria japonica is distributed from southern Hokkaido to the northeastern Honshu in Japan. Recently, aquaculture of L. japonica has expanded to the southern coast of Japan and to China along the East China Sea. In order to elucidate the growth, biomass and productivity of L. japonica in a subtropical area, we cultivated and examined it in the Uwa Sea, in southwestern Japan over a period of 2 years. The seawater temperature ranged from 13.8 to 26.8 °C in 2001/2002 and from 13.1 to 27.2 °C in 2002/2003. In 2001/2002, the maximum density, maximum mean length and maximum mean wet wt. of L. japonica were 59.7 ± 28.0 ind. 50 cm^− 1 (mean ± S.D.), 187.5 ± 82.7 cm (360 cm in the largest individual) and 130.1 ± 94.6 g wet wt., respectively. In 2002/2003, these values were 94.7 ± 22.2 ind. 50 cm^− 1, 159.3 ± 74.4 cm (300 cm in the largest individual) and 95.2 ± 69.5 g wet wt., respectively. Thus, the length and weight increased when the density was low (2001/2002), and the length and weight decreased when the density was high (2002/2003). The maximum biomass was estimated to be 7200 ± 3400 g wet wt. 50 cm^− 1 in 2001/2002 and 7300 ± 2000 g wet wt. 50 cm^− 1 in 2002/2003. Annual production was estimated to be 33.3 kg wet wt. m^− 1 year^− 1 in 2001/2002 and 34.0 kg wet wt. m^− 1 year^− 1 in 2002/2003. The present study indicates that the annual production of L. japonica per rope of 1 m at Uwajima Bay, the Uwa Sea corresponded to 1.1-2.2 m² of that of Hokkaido in their native area. Thus, the present study indicates that L. japonica is highly adaptable because it is able to keep a high level of productivity when grown in water with a high temperature.     

FTIR monitoring of oxazolidin-5-one formation and decomposition in a glycolaldehyde-phenylalanine model system by isotope labeling techniques

Imines or Schiff bases formed through the interaction of reducing sugars with amino acids are known to play a critical role not only in initiating the Maillard reaction but also in its propagation through isomerization reactions initiated by the intermediate oxazolidin-5-one. FTIR spectroscopic evidence for the formation of this intermediate in a phenylalanine-glycolaldehyde model system was provided by taking advantage of a strong absorption band centered at 1778 cm⁻¹. The identity of this peak was confirmed by observing a shift to 1736 cm⁻¹ when [¹³C-1]phenylalanine was used. The intensity of this peak decreased over time with concomitant increase of two bands in the carbonyl absorption region, one centered at 1730 and the other at 1720 cm⁻¹. The former band was shifted to 1685 cm⁻¹, while the band at 1720 remained unchanged when [¹³C-1]phenylalanine was used. The simultaneous formation of a carboxylic acid and a carbonyl band is consistent with the formation of an Amadori rearrangement product. Furthermore, time-dependent analysis of the formation and decomposition of the oxazolidin-5-one intermediate suggests that it is an important precursor of the Amadori rearrangement product. In addition, through the use of appropriate model systems, [¹⁵N]phenylalanine and second-derivative spectral analysis, evidence was also provided for the formation of decarboxylated imines at 80 °C.     

Effects of carbonization and solvent-extraction on change in fuel characteristics of sewage sludge

Urban sewage sludge was carbonized at 300-500 °C for 1 h, and combustible components were extracted through the solvent-extraction process. N-methyl-2-pyrrolidinone (NMP) was used as the solvent for extraction, and the extraction temperature was fixed at 360 °C. The atomic ratios of the solvent-extracted sludge of CS300 (ECS300) were shown to be 1.04 for H/C and 0.11 for O/C, which represented the characteristics of its coal band. Thus, its coal band was similar to that of a high-rank fuel such as bituminous coal. FT-IR analysis showed that the absorbance band of ECS300 was considerably different from that of dried sludge (RS) or the carbonized sludge at 300 °C (CS300) but similar to that of coal, although the ash content absorbance band of 800-1200 cm⁻¹ was of very low intensity. The combustion profile showed that combustion of ESC300 occurred at a temperature higher than the ignition temperature (T_i) or maximum weight loss rate (DTG_max) of coal.     

Production and characterization of biopolyols and polyurethane foams from crude glycerol based liquefaction of soybean straw

The feasibility of using crude glycerol to liquefy soybean straw for the production of biopolyols and polyurethane (PU) foams was investigated in this study. Liquefaction conditions of 240 °C, >180 min, 3% sulfuric acid loading, and 10-15% biomass loading were preferred for the production of biopolyols with promising material properties. Biopolyols produced under preferential conditions showed hydroxyl numbers from 440 to 540 mg KOH/g, acid numbers below 5 mg KOH/g, and viscosities from 16 to 45 Pa.s. PU foams produced under preferential conditions showed densities from 0.033 to 0.037 g/cm³ and compressive strength from 148 to 227 kPa. These results suggest that crude glycerol can be used as an alternative solvent for the liquefaction of lignocellulosic biomass such as soybean straw for the production of biopolyols and PU foams. The produced biopolyols and PU foams showed material properties comparable to their analogs from petroleum solvent based liquefaction processes.     

Control of Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) with entomopathogenic nematodes (Rhabditida: Heterorhabditidae,Steinernematidae) in peach orchards

Oriental fruit moth Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) is considered a major pest in temperate fruit trees, such as peach and apple. Entomopathogenic nematodes (EPNs) are regarded as viable for pest management control due to their efficiency against tortricid in these trees. The objective of this study was to evaluate the effectiveness of native EPNs from Rio Grande do Sul state against pre-pupae of G. molesta under laboratory and field conditions. In the laboratory, pre-pupae of G. molesta were placed in corrugated cardboard sheets inside glass tubes and exposed to 17 different EPNs strains at concentrations of 6, 12, 24, 48 and 60 IJs/cm² and maintained at 25 °C, 70 ± 10% RH and photophase of 16 h. Insect mortality was recorded 72 h after inoculation of EPNs. Steinernema rarum RS69 and Heterorhabditis bacteriophora RS33 were the most virulent strains and selected for field application (LC₉₅ of 70.5 and 53.8 IJs/cm², respectively). Both strains were highly efficient under field conditions when applied in aqueous suspension directed to larvae on peach tree trunk, causing mortality of 94 and 97.0%, respectively.     

Staphylococcal enterotoxin A: Partial unfolding caused by high pressure or denaturing agents enhances superantigenicity

The effect of transient exposure of Staphylococcus aureus enterotoxin A (SEA) to high pressure and/or denaturing agents was examined by assessing the toxin superantigenicity and immunoreactivity, and by monitoring pressure-induced changes in fluorescence emission spectra. Pressurization of SEA at 600 MPa and 45 °C in Tris–HCl buffer (20 mM, pH 7.4) resulted in a marked increase in both T-cell proliferation (superantigenicity) and immunoreactivity. In opposite, pressurization at 20 °C did not change significantly SEA superantigenicity and immunoreactivity, indicating some toxin baro-resistance. Exposure of SEA to 8 M urea at atmospheric pressure or at 600 MPa and 20 °C, also led to a marked increase of superantigenicity (but not of immunoreactivity). In contrast, exposure of SEA to sodium-dodecylsulfate (30 mM) led to an increase of immunoreactivity with some effect on superantigenicity after pressurization at 45 °C only. High pressure up to 600 MPa induced spectral changes which at 20 °C were fully reversible upon decompression. At 45 °C, however, a sharp break of the centre of spectral mass mainly due to tryptophan residues was observed at 300 MPa, and irreversible spectral changes mainly related to tyrosine residues subsisted after pressure release, indicating a marked protein conformational transition. Urea 8 M further increased SEA structural changes at 600 MPa and 20 °C. These results indicate that SEA, under a combination of high pressure and mild temperature, as well as in the presence of urea, partly unfolds to a structure of strongly increased T-cell proliferative ability.     

Temperature and diet affect carbon and nitrogen isotopes of fish muscle: can amino acid nitrogen isotopes explain effects?

Stable isotope ratios of carbon (δ¹³C) and nitrogen (δ¹⁵N) are widely used in food-web studies to determine trophic positioning and diet sources. However in order to accurately interpret stable isotope data the effects of environmental variability and dietary composition on isotopic discrimination factors and tissue turnover rates must be validated. We tested the effects of temperature and diet on tissue turnover rates and discrimination of carbon and nitrogen isotopes in an omnivorous fish, black bream (Acanthopagrus butcheri). Fish were raised at 16 °C or 23 °C and fed either a fish-meal or vegetable feed to determine turnover rates in fish muscle tissue up to 42 days after exposure to experimental treatments. Temperature and diet affected bulk tissue δ¹⁵N turnover and discrimination factors, with increased turnover and smaller discrimination factors at warmer temperatures. Fish reared on the vegetable feed showed greater bulk tissue δ¹⁵N changes and larger discrimination factors than those reared on a fish-meal feed. Temperature and diet affected bulk tissue δ¹³C values, however the direction of effects among treatments changed. Analyses of δ¹⁵N values of individual amino acids found few significant changes over time or treatment effects, as there was large variation at the individual fish level. However glutamic acid, aspartic acid and leucine changed most over the experiment and results mirrored those of treatment effects in bulk δ¹⁵N tissue values. The results demonstrate that trophic discrimination for δ¹⁵N and δ¹³C can be significantly different than those typically used in food-web analyses, and effects of diet composition and temperature can be significant. Precision of compound-specific isotope analyses (0.9‰) was larger than our effect size for bulk δ¹⁵N diet effects (0.7‰), therefore future experimental work in this area will need to establish a large effect size in order to detect significant differences. Our results also suggest that compound-specific amino acid δ¹⁵N may be useful for determining essential and non-essential amino acids for different animals.     

Supercritical water gasification of an aqueous by-product from biomass hydrothermal liquefaction with novel Ru modified Ni catalysts

Supercritical water gasification (SCWG) of glucose solution (50-200 g/L), a simulated aqueous organic waste (composed of glucose, acetic acid and guaiacol) and a real aqueous organic waste stream generated from a sludge hydrothermal liquefaction process was performed in a bench-scale continuous down-flow tubular reactor with novel 0.1RuNi/γ-Al₂O₃ or 0.1RuNi/activated carbon (AC) catalyst (10 wt.% Ni with a Ru-to-Ni molar ratio of 0.1). 0.1RuNi/γ-Al₂O₃ was very effective in catalyzing SCWG of glucose solution and the simulated aqueous organic waste, attaining an H₂ yield of 53.9 mol/kg dried feedstock at 750 °C, 24 MPa and a WHSV of 6 h⁻¹. However, the γ-Al₂O₃-supported catalyst was not resistant to the attack of alkali and nitrogen compounds in the real waste during the SCWG of the real aqueous organic waste, whereas the AC-based catalyst exhibited higher stability. This research provides a promising approach to the treatment and valorization of aqueous organic waste via SCWG.     

Preparation,application, and optimization of Zn/Al complex oxides for biodiesel production under sub-critical conditions

Biodiesel produced by transesterification is a promising green fuel in the future. A new heterogeneous catalyst, Zn/Al complex oxide, was prepared for biodiesel production. The results showed that the catalyst derived from a hydrotalcite-like precursor with a zinc/aluminum atom ratio of 3.74:1 and calcined at 450 °C gave the highest conversion of 84.25%. Analysis of XRD, XPS, FI-IF, TG-DTA, BET and alkalinity tests demonstrated that it is the unique structure of hydrotalcite-like compound precursor that gave the catalyst a high alkalinity greater than 11.1. The optimal reaction condition for Zn/Al complex oxide was under methanol sub-critical condition: 200 °C, 2.5 MPa, 1.4% (wt) catalyst dosage, and 24:1 methanol to oil ratio. Under these conditions, the conversion reached 84.25% after 90 min, which was better than Mg/Al complex oxides. The excellent tolerance to water and free fatty acid was exhibited when the oil feed had fewer than 6% FFA or 10% water content with a conversion greater than 80%.     

A kinetic evaluation of anaerobic treatment of swine wastewater at two temperatures in a temperate climate zone

A static granular bed reactor (SGBR) was used to treat swine wastewater at 24 and 16 °C. At 24 °C, the organic loading rate (OLR) was 0.7-5.4 kg COD/m³ day and the average chemical oxygen demand (COD) removal efficiency was 88.5%, respectively. Meanwhile, at 16 °C, the OLR was 1.6-4.0 kg COD/m³ day and the average COD removal efficiency was 68.0%, respectively. The SGBR acted as a bioreactor as well as a biofilter. After backwashing, the recovery of COD removal was not a function of an OLR but recovery time, while that of TSS removal was not a function of either recovery time or the OLR. The maximum substrate utilization rate (k_max) ratio was 1.89 between 24 and 16 °C, and the half velocity constant (K_s) ratio was 1.22, and the maximum specific growth rate (μ_max) ratio was 4.71. In addition, the temperature-activity coefficient in this study was determined to be 1.09.     

Novel regenerated cellulose films prepared by coagulating with water: Structure and properties

Regenerated films were successfully prepared from cellulose/NaOH/urea solution by coagulating with water at temperature from 25 to 45 °C. The results of solid ¹³C NMR, wide angle X-ray diffraction, scanning electron microscopy (SEM) and tensile testing revealed that the cellulose films possessed homogeneous structure and cellulose II crystalline, similar to that prepared previously by coagulating with 5 wt% H₂SO₄. By changing the coagulation temperature from 25 to 45 °C, tensile strength of the films was in the range of 85-139 MPa. Interestingly, the RC35 film coagulated at 35 °C exhibited the highest tensile strength (σ_b = 139 MPa). The inclusion complex associated with cellulose, NaOH and urea hydrates in the cellulose solution were broken by adding water (non-solvent), leading to the self-association of cellulose to regenerate through rearrangement of the hydrogen bonds. This work provided low-cost and “green” pathway to prepare cellulose films, which is important in industry.