Characterisation of industrial tomato by-products from infrared drying process

The thin-layer infrared drying behaviour of industrial tomato residues, peels and seeds, was experimentally investigated in the temperature range from 100 °C to 160 °C. The drying rate was found to increase with temperature, hence reducing the total drying time. In particular, as drying temperature was raised from 100 °C up to 160 °C, the time period needed to reduce the moisture content of the sample from 236.70 wt% down to 5.26 wt% (dry basis) was observed to decrease from 99.5 min to 35 min.Using a non-linear regression (Marquart's method) together with a multiple regression analysis, a mathematical model for the thin-layer infrared drying process of industrial tomato residues was proposed. The effective moisture diffusivity is dependent on moisture content; the average values for the diffusivity coefficients at each temperature were obtained using Fick's second law of diffusion, and varied from 5.179 × 10^?9 m²/s to 1.429 × 10^?8 m²/s over the temperature range. The temperature dependence of the effective diffusivity coefficient was described following an Arrhenius-type relationship. Activation energy for the moisture diffusion was determined as 22.23 kJ/mol.     

Thermogravimetric study of the pyrolysis of biomass residues from tomato processing industry

There is an increasing concern with the environmental problems associated with the increasing CO₂, NO_x and SO_x emissions resulting from the rising use of fossil fuels. Renewable energy, mainly biomass, can contribute to reduce the fossil fuels consumption. Biomass is a renewable resource with a widespread world distribution. Tomato processing industry produces a high amount of biomass residue (peel and seeds) that could be used for thermal energy and electricity. A characterization and thermogravimetric study has been carried out. The residue has a high HHV and volatile content, and a low ash, and S contents. A kinetic model has been developed based on the degradation of hemicellulose, cellulose, lignin and oil that describe the pyrolysis of peel, seeds and peel and seeds residues.     

Emissions from thermal degradation of pellets with different contents of olive waste and forest residues

The thermal decomposition of pellets made from pyrenean oak (PK) and olive waste pomace (OP) mixed under different proportions (0-100 wt.% of OP) was studied. Mass spectra measurements were accomplished simultaneously in order to elucidate the emissions generated during the weight loss of the lignocellulosic materials.The coupled TG-MS study allowed the monitoring of the emissions of CO₂, SO₂, NO, C₆H₆ and C₇H₈, and the differences found were related to the chemical composition of the precursors and also to the features of their thermal degradation. It was found that in general a high content of OP favors the release of these emissions at lower temperatures. On the other hand, the effect of OP content on the ion intensity height of the emissions is more marked in the range 25-75 wt.% of OP. The analysis of the emission profiles for each case allows a proper design of the experimental conditions in order to get a better control of the process.     

Characterization of liquefied wood residues from different liquefaction conditions

The amount of wood residue is used as a measurement of the extent of wood liquefaction. Characterization of the residue from wood liquefaction provides a new approach to understand some fundamental aspects of the liquefaction reaction. Residues were characterized by wet chemical analyses, Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), and scanning electron microscopy (SEM). The Klason lignin content of the residues decreased, while the holocellulose and α‐cellulose contents increased as the phenol to wood ratio (P/W) increased. A peak at 1735 cm^?1, which was attributed to the ester carbonyl group in xylan, disappeared in the FTIR spectra of the residues from liquefied wood under a sealed reaction system, indicating significantly different effects of atmospheric versus sealed liquefaction. The crystallinity index of the residues was higher than that of the untreated wood particles and slightly increased with an increase in the P/W ratio. The SEM images of the residues showed that the fiber bundles were reduced to small‐sized bundles or even single fibers as the P/W ratio increased from 1/1 to 3/1, which indicated that the lignin in the middle lamella had been dissolved prior to the cellulose during liquefaction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Characterization of siloxane residues from polydimethylsiloxane elastomers by MALDI-TOF-MS

The hydophobic recovery properties of polydimethylsiloxane (PDMS) elastomers after environmental degradation arises from the migration of low molecular weight siloxanes from the bulk to the surface. MALDI-TOF-MS analysis of the isotopic distribution of oligomers from the surface of vulcanized PDMS has enabled unambiguous assignment of these as predominantly cyclic siloxanes ranging from 13 to 47 repeat units with smaller proportions of methyl and hydroxyl terminated linear chains ranging from 12 to 24 repeat units. © 2000 Society of Chemical Industry.     

Characterization of solid residues from municipal solid waste incinerator

In China, the generation of municipal solid waste (MSW) incineration solid residues is expected to increase significantly in the future. Because of ever-increasing generation rates and the concentrations of potentially hazardous heavy metals, which may endanger the ambient environment, these solid residues are of particular concern. Thus, such issues have necessitated the study of the characterization of these solid residues. A detailed characterization of five samples of different type of ashes, collected from two types of MSW incinerators located in Shenzhen (southern China), was carried out in terms of chemical composition, morphology, mineralogy and leaching behavior. Results of chemical analysis and leaching tests suggest that the MSW incineration fly ash must be classified as hazardous waste and should be properly managed. Therefore, the results of this characterization would contribute to the development of adequate waste management strategies.     

Characterization of grape pomace and pyrenean oak pellets

One possibility for the elimination of the by-products generated in the viticulture industry can be their densification for subsequent use as a solid biofuel. In this work, washed grape pomace has been considered due to its thermal characteristics. Since it could show problems in the densification process, other by-products such as pyrenean oak residues, with good pelleting properties and available in this region, are also used.So that, samples of different concentrations from both residues were densified by means of a flat die pelletizer, obtaining pellets of 6 mm diameter. The densified samples were characterized in terms of the proximate and ultimate analyses, heating value and physical characteristics such as durability or bulk density. Also, the combustion profile of the pellets was studied by thermogravimetry and inorganic emissions such as sulphur dioxide and nitric oxide were considered, by means of coupled mass spectrometry (TG-MS).The results obtained showed that both residues show good characteristics for their densification and manufacture in pellets. Also, they show good physical and thermal properties for its use as biofuel, as well as its different blends. Therefore, it is possible to give a more efficient energetic use to both residues.     

我国利用尾矿和工业废渣生产微晶玻璃研究进展

近年来,我国在利用尾矿和工业废渣生产微晶玻璃研究上取得了长足进步,为减少工业废弃物排放、保护环境做出了很大贡献,综述了我国在利用尾矿和工业废渣生产微晶玻璃上的研究进展。     

辣椒、番茄中氟虫脲残留量的HPLC分析方法

建立了测定辣椒和番茄中氟虫脲残留量的高效液相色谱法。色谱柱为ThermoHypersil-ODSC18D250mm×4.6mm;流动相:甲醇∶水(80∶20,v∶v);流速:1.0ml/min;检测波长:254nm。试样用丙酮提取,二氯甲烷萃取,中性氧化铝柱净化,外标法定量。在0.05￣0.5mg/kg的添加浓度下,平均回收率为87.51%￣102.13%,变异系数为0.07%￣6.02%,仪器最低检出限为8.809×10-10g,最小检出浓度0.011mg/kg,该方法的准确度、精密度及灵敏度均满足农药残留分析的要求。     

Characterization of active-site aromatic residues in xylanase A from Streptomyces lividans

The role of four aromatic residues (W85, Y172, W266 and W274)in the structure–function relationship in xylanase A fromStreptomyces lividans (XlnA) was investigated by site-directedmutagenesis where each residue was subjected to three substitutions(W85A/H/F; W266A/H/F; W274A/H/F and Y172A/F/S). These four aminoacids are highly conserved among family 10 xylanases and structuraldata have implicated them in substrate binding at the activesite. Far-UV circular dichroism spectroscopy was used to showthat the overall structure of XlnA was not affected by any ofthese mutations. High-performance liquid chromatographic analysisof the hydrolysis products of birchwood xylan and xylopentaoseshowed that mutation of these aromatic residues did not alterthe enzyme's mode of action. As expected, though, it did reducethe affinity of XlnA for birchwood xylan. A comparison of thekinetic parameters of different mutants at the same positiondemonstrated the importance of the aromatic nature of W85, Y172and W274 in substrate binding. Replacement of these residuesby a phenylalanine resulted in mutant proteins with a K_M closerto that of the wild-type protein in comparison with the othermutations analyzed. The kinetic analysis of the mutant proteinsat position W266 indicated that this amino acid is importantfor both substrate binding and efficient catalysis by XlnA.These studies also demonstrated the crucial role of these activesite aromatic residues for the thermal stability of XlnA.     

Characterization of impurity effects in zinc electrowinning from industrial acid sulphate electrolyte

The individual effects of 15 impurities and their interaction with glue on zinc electrowinning from industrial acid sulphate electrolyte were characterized in terms of deposit morphology and preferred deposit orientation and in terms of current efficiency and zinc deposition polarization behaviour. The current efficiency decreased in a cyclical manner with increasing atomic number of the impurity element in each period of the periodic table. This decrease in current efficiency can be correlated to a corresponding increase in the rate of hydrogen evolution on the impurity metal. The various impurities produced four distinct zinc deposit morphologies and orientations and also produced characteristic changes in the cyclic voltammograms for the zinc deposition.     

Characterization and evaluation of fly-ash from co-combustion of lignite and wood pellets for use as cement admixture

Conventional coal fly-ash (CFA) and two coal-biomass fly-ashes (CBFAs) were obtained at a thermoelectric power station (Atikokan, Ontario) from combustion of undiluted lignite coal and co-combustion of lignite coal with up to 66% wood pellets (on a thermal basis). Fly-ashes were characterized and analyzed for use as cement admixtures. Co-combustion did not markedly change the fly-ash composition, owing to an extremely low ash content of wood pellets compared to lignite coal; toxic metals and minor elements were within ranges reported for other coal fly-ashes. All fly-ashes had losses on ignition (LOI) <1 wt% and therefore complied with ASTM LOI regulations for use in concrete. All fly-ashes contained major amorphous phases, along with quartz and periclase. Partial substitution of cement with fly-ash (up to 40 wt%) had a moderate effect on the entrained air content of mortars (up to 2.5%), but this difference vanished upon addition of air entraining agent (0.6 mL/kg of cementitious material). Substituted mortars exceeded 75% of the strength of ash-free mortar after 28 days of curing (therefore meeting ASTM requirements for strength development), and by 90 days, met or surpassed 100% of the strength of ash-free mortar. Amending mortar with 20 wt% CFA or CBFA had no effect on its durability following repeated freeze-thaw cycles when air content was kept constant. Also, no micromineralogical differences were observed between hydrated CFA- and CBFA-amended mortars, with fly-ash particles reacting with Ca ions originating from dissolution of cement clinker or calcium hydroxide.     

Characterization of lipids extracted from pickled lambskins by a new industrial degreasing process

In the manufacturing of leather from lambskins, skin degreasing is an important preliminary stage in which excess fats are removed. A new solvent-phase degreasing process, which leads to a complete recovery of extracted fats, has been studied and scaled up in our laboratory. In this paper, we study the characteristics of these extracted fatty substances that have not been reported previously. Extracted fats which, up to now, were considered waste, can be used. Different methods have been proposed for their possible utilization.     

Characterization and modeling of cooling and drying of pellets for animal feed

The process used to produce pellets for animal feed, especially the drying–cooling step, has not been extensively explored in the literature. However, with the increased industrial use of adjustable-speed drives to reduce fan energy consumption, the need for reliable simulation models has increased. In this work, different formulations of pellets were characterized and both their drying and drying–cooling kinetics were modeled. In comparing the results of the simulations with experimental results, the observed discrepancies were similar to the experimental uncertainties, indicating that our prediction tools yielded imperfect but acceptable results both in the thin-layer and deep-bed drying configurations. Furthermore, the approach centered on drying kinetics was also able to predict drying–cooling kinetics. This work suggests that one simple EMC equation, without temperature dependency, may correctly fit the behavior of several kinds of pellets and be sufficient for accurate simulations. The overall approach may be easily applied to many other kinds of pellets.     

Antioxidant protection of high-pressure processed minced chicken meat by industrial tomato products

Pressure-treatment at 300 MPa of minced chicken breast meat did not induce significant lipid oxidation during chill storage for up to 15 days, while pressure-treatment at 600 and 800 MPa enhanced formation of secondary lipid oxidation products measured as thiobarbituric acid reactive substances. However, a waste product from industrial tomato paste production was found to yield efficient protection against lipid oxidation in pressurized chicken meat. Addition of 0.30% tomato waste or of 0.10% final tomato paste to minced meat led to a lag phase of 6 days for formation of secondary oxidation products in meat pressure treated at 600 MPa. The waste product seemed special efficient in protecting chicken meat pressurized at 800 MPa, as a notably lower rate of formation of secondary oxidation products was found. Flavonoids washed out with the waste fraction may be more efficient as antioxidant than the other phenolics or carotenoids present in the other paste processing fractions. Addition of tomato paste fractions did not influence radical formation measured by electron spin resonance spectroscopy and the tomato waste is considered to be effective as antioxidant at subsequent reactions leading to secondary lipid oxidation products.     

Characterization of ThO2 and (Th,U)O2 pellets consolidated from NSD-sol gel derived nanoparticles

Sinterable ThO₂ and mixed 70%ThO₂-30%UO₂ nanopowders were synthesized and calcined at a low temperature by surfactant assisted sol-gel process using three different nonionic structure directing (NSD) agents: TritonX100, Polysorbate 80 and Polysorbate 20. The produced powder samples, with high surface area and micro and meso pores, were pressed and sintered to form high density ThO₂ and (Th,U)O₂ pellets. The calculated green and sintered densities of the fabricated pellets, and the results of their microstructural characteristics studies, utilizing SEM images, show that developed synthesizing method yields a satisfactory sinterability of the synthesized ThO₂ and ThO₂-UO₂ nanopowders at low temperature. Also, the final grain size of the pellets reached less than a micrometer in size. The ThO₂ and (Th,U)O₂ pellets fabricated by synthesized powder using Triton X100 had a higher density and better grain growth. The uranium presence in the mixed oxide pellets led to better sinterability and more normal grain growth.     

脱硫石膏料球的分解

为研究脱硫石膏在成球状态下的分解特性,根据石膏分解气固反应和固固反应机制,探索脱硫石膏料球分解反应的影响因素及其影响规律。研究结果表明:脱硫石膏料球很难在弱还原性气氛条件下分解;在掺入石油焦作为固体还原剂后,脱硫石膏能够较好地实现分解。正交实验结果表明:掺入石油焦的脱硫石膏料球较优的分解条件为:分解温度1 200℃、分解时间30 min、碳硫摩尔比n(C)/n(S)为1.0、料球粒径为5~7 mm。     

硅铝质工业废弃物蒸压反应活性研究

通过测定活性二氧化硅、氧化铝含量及红外光谱分析等方法研究粉煤灰、煤粉炉渣等硅铝质工业废弃物的蒸压反应活性。结果表明,硅铝质工业废弃物的蒸压反应活性与其活性二氧化硅、氧化铝含量及红外光谱1 100 cm^-1附近强吸收区的Si-O伸缩振动频率存在明显的对应关系,即活性二氧化硅、氧化铝含量越高,红外光谱1 100 cm^-1附近强吸收区的Si-O伸缩振动频率越低,蒸压反应活性越强,蒸压制品强度越高。     

Valorization of some lignocellulosic agro‐industrial residues to obtain biopolyols

BACKGROUND: The valorization of renewable and abundant resources (date seed, olive stone, corncob, rapeseed cake and apple pomace) from agro‐industrial activities was performed by mild liquefaction using polyhydric alcohols to obtain biopolyols that constitute an attractive choice for polyurethanes and other industrial sectors. RESULTS: The results indicated that liquefaction yields above 90% were obtained for almost all resources (except for rapeseed cake residue) at a minimum ratio of 0.25 mass/liquefying solvent by using weight ratio polyethylene glycol:glycerol:sulphuric acid of 80:20:3, at quite reasonable reaction temperature and time; 160 °C and 60 min, respectively. The values determined for hydroxyl number and viscosity in polyols from date seeds were found to be in the range of those typical of commercial polyols used in polyurethane foam production. On the other hand, the multifunctional liquids from apple pomace, olive stone, corncob and rapeseed cake could be used not only as precursor in polyurethane production but also for replacement of a certain amount of the polyhydroxy alcohol in polyester synthesis. CONCLUSION: The results obtained demonstrated the viability of using polyhydric alcohol liquefaction to generate bio‐based polyols, thus opening new avenues of exploitation of these by‐products. Copyright © 2011 Society of Chemical Industry     

Characterization of purified phospholipids from krill (Euphausia superba) residues deoiled by supercritical carbon dioxide

Purification of phospholipids (PL) from the Antarctic krill (Euphausia superba) using a two-step extraction process has been investigated. Using supercritical carbon dioxide (SC-CO₂) extraction with optimal extractions conditions of 45 °C, 25MPa, and CO₂ flow rate of 22 g/min, most of the neutral lipids were extracted. PC, PE and PI were then extracted in a second step conducted with modified existing method using ethanol, hexane and acetone as solvents. The major PL of krill residues was quantified by high performance liquid chromatography (HPLC-ELSD). The fatty acid compositions of total PL, PC, PE and PI were analyzed by gas chromatography (GC). A significant amount of polyunsaturated fatty acids (PUFA) was present in both total and PLs fractions. The purified PLs were characterized by their acid value, peroxide value, and the oxidative stability. The purity of PL ranged between 93 and 97% and was evaluated by spectrophotometry.