干/湿法烘焙预处理对稻壳燃烧反应特性的影响

烘焙是提高生物质燃料性质的重要技术手段,探究干/湿法烘焙对稻壳热解燃烧反应特性的影响具有重要意义。该研究利用固定床与高压反应釜对稻壳进行了不同温度下的干法烘焙和湿法烘焙（水热碳化）预处理,并利用热重分析仪对稻壳、稻壳烘焙炭和稻壳水热炭开展了非等温燃烧反应特性分析,并且利用Coats?Redfern法与三种常见的气-固反应机理模型对样品的燃烧反应特性进行了动力学分析。最后,该研究对干法与湿法烘焙两种预处理方式对稻壳的热解燃烧反应特性的影响进行了比较。结果表明两种预处理方式对稻壳的热解与燃烧反应参数存在影响：均导致热解反应性降低,干烘焙提高稻壳燃烧反应性,且反应性随着干烘焙温度的提高而升高。但湿烘焙使稻壳燃烧反应性略有降低。在相同的预处理温度条件下,稻壳烘焙炭较稻壳水热炭具有更高的热解起始失重温度、更低的热解最大失重速率及其对应温度和热解反应性。对于稻壳、稻壳烘焙炭及稻壳水热炭的热解燃烧反应性,模型O1较其他两个模型的线性回归指数更高。干/湿法烘焙使稻壳热解活化能升高,而湿烘焙使燃烧活化能降低。此外,两个阶段样品的指前因子（A）均随活化能的增大而增大,二者间存在明显的线性关系（R2均大于0.95）,表明反应过程具有动力学补偿效应。     

糠醛渣与稻壳混合物的共热解特性研究

通过对不同混合比糠醛渣和稻壳的混合物进行热重分析试验,发现主要热解温度区间明显的分为两个阶段,表现出不同的热解机理;糠醛渣和稻壳的混合比对热解过程有影响,共热解不是两种生物质单独热解贡献的简单叠加。在热解反应活跃区间建立与糠醛渣和稻壳混合物固有热解特性相适应的分段分级热解动力学模型,计算得到热解动力学参数。最后应用Newton-coats数值求积方法对模型进行验证,并与实验曲线进行对比,结果表明该模型具有较强的可靠性和实用性。     

麦秸、稻壳及菌渣还田对设施菜地的青椒品质及产量的影响

针对设施菜地长期连作带来的土壤退化问题,研究不同种类农业废弃物(麦秸、稻壳及菌渣)还田对设施青椒光合色素含量、产量及品质的影响,以了解农业废弃物利用的可行性。结果表明:麦秸、稻壳及菌渣还田可以有效提高光合色素含量和抗氧化酶(超氧化物歧化酶、过氧化物酶、过氧化氢酶)活性,降低丙二醛含量,其中叶绿素含量以菌渣处理(T3)最高,为1.045 3 mg/g FW;类胡萝卜素含量以稻壳+麦秸处理(T4)最高,为0.257 8 mg/g FW;Chl.a/Chl.b值、Chl.(a+b)/Car.值均以菌渣处理(T3)最大,分别为3.22、4.12。此外,农业废弃物还田可以有效抑制青椒果实中类黄酮和花青素色素的形成。菌渣处理(T3)下的果实可溶性糖与Vc含量最高,分别较对照处理(T7)增加81.20%、15.84%,可溶性蛋白质和游离氨基酸蛋白质含量分别以稻壳+麦秸处理(T4)、稻壳处理(T1)最高。结果还显示,多种农业废弃物配施的青椒产量低于单一施入;菌渣单施处理(T3)产量最高,达48 255.75 kg/hm~2。     

白酒糟振打分离工艺探讨

白酒糟粗纤维过高,使其在配合饲料中的使用量受到很大限制。该文提出了一种降低白酒糟粗纤维含量的新工艺。用拆去筛底的锤片式粉碎机振打干燥后的白酒糟,再用振动筛筛分。探讨了振打分离工艺的作用机理,并与揉搓分离工艺机理进行了对比分析;介绍了振打分离工艺的有关试验和测试结果。     

稻壳与稻秆灼烧灰颗粒的微观形态特征及其能谱分析

应用扫描电镜(scanning electron microscopy,SEM)和能谱(energy disperse X-ray microanalysis,EDX)结合联用技术对稻壳和稻秆在600和815℃下灼烧产生的灰渣的微观形态特征及其元素组成进行了全面地研究,并考察了不同灰化温度对生物质灰的粒度分布、微观形态、颗粒表面、内部结构及元素组成等方面产生的影响。结果表明:灰化温度升高,灰粒的粒度减小,且分布较均匀,稻壳灰中多为团状颗粒,而稻秆灰以棒状颗粒居多;对于600℃稻壳灰,部分灰粒仍保留着稻壳的原始纤维结构,且灰中存在许多松散状的密实小颗粒,但并未出现粘结团聚,而600℃稻秆灰表面存在大量粘连着小颗粒的絮状物,表明此时灰中已经出现低熔点成分熔融而产生的弱粘结;815℃时2种生物质灰粒表面都出现熔融态的碱金属物质和以玻璃体突起形式存在的石英结构,而且都存在明显的团聚结渣现象;稻壳灰与稻秆灰的主要组成元素是C、O、Si、K和Ca,较少的Mg、Al、Fe、P等也被检出,而S只在稻秆灰中检出,稻壳灰中未检出S元素;灰化温度升高,稻壳灰的K含量明显下降,而稻秆灰中K、Na、Ca的含量变化较小,但是Cl、Fe、Al的含量均明显下降;稻秆灰的K、Na、Ca和Cl含量都远高于稻壳灰,稻秆灰比稻壳灰更易造成设备腐蚀、结渣等危害。     

白酒糟纤维素降解菌的优选及酒糟降解工艺

白酒酿造行业产生的酒糟含有大量纤维素,不仅原料利用率低,而且丢弃的酒糟会对环境产生污染。为了获得酒糟纤维素降解能力强的微生物并进行应用,从酱香型酒醅、清香型酒醅、浓香型大曲、竹林里的土壤腐殖质中分离筛选酒糟纤维素降解菌,并对菌种分类、理化特征和降解酒糟的特性进行研究。pH值、温度和酒精胁迫性试验进一步确定了最佳酒糟纤维素降解菌为B2菌株,该菌株在pH值3.0、温度44℃、酒精含量为体积分数4%环境中生长良好。基于形态学、生理生化和分子生物学分析,鉴定B2菌株为枯草芽孢杆菌(Bacillus subtilis)。在单因素试验结果的基础上,采用Box-Benhnken响应面法进行优化,确定了B2菌株降解酒糟的最佳工艺条件为酒糟添加量71 g/L、温度37℃、pH值6.4、接种量8%,此时酒糟降解率为15.23%。该研究丰富了酒糟纤维素降解菌的微生物资源库,同时为酒糟的资源化利用提供技术参考。     

稻秸秆与二种不同废弃物堆腐制备基质的研究

为了改良农作物秸秆制备栽培基质中p H值、EC值偏高,通气孔隙度、持水孔隙度等理化性质不良等问题,研究了在秸秆预处理(堆腐)过程中添加酒糟对基质理化性质的影响。以稻秸秆中混入体积比例20%的菇渣作为基质堆腐处理的对照(CK),采用在高温好氧堆腐及穴盘育苗试验的方法,研究了混入相同比例的酒糟及腐熟物料组配无机物珍珠岩等方法,对基质理化性质、蔬菜幼苗生长的影响。结果表明,在堆腐阶段稻秸秆+酒糟有利于高温堆腐进程,提高堆腐效率。堆腐温度大于50℃的高温维持天数较对照增加14 d,平均堆腐温度较对照增高9.50℃,稻秸秆+酒糟处理最终腐熟物p H值、EC值较对照分别下降15.0%、26.8%。稻秸秆+酒糟腐熟物组配珍珠岩后,进一步降低了EC值(P0.05),基质物理性质也得到提高(P0.05),从而促进了幼苗地上与地下部分的生长,稻秸秆+酒糟腐熟物料与珍珠岩的体积比例以7∶3较好。采用稻秸秆堆腐制备基质过程中,加入体积比例20%的酒糟能提高堆腐效率,有效改善腐熟物料中pH值、EC值等不良理化性质,为稻秸秆的基质化利用提供了方法。     

稻壳粉/改性脲醛树脂模压成型材料的力学性能

为了研究成型材料对模压花盆力学性能的影响,该文以改性脲醛树脂为基体树脂,稻壳与稻壳粉为增强材料,经混炼、热压、成型工序,制备出一种环保花盆。探讨了脲醛树脂改性、改性脲醛树脂用量、稻壳与稻壳粉比例以及湿循环处理对花盆力学性能的影响,采用热重分析仪(thermo-gravimetric analysis,TGA)及扫描电子显微镜(scanning electronic microscope,SEM)分析了秸秆花盆湿循环处理前后的热稳定性及微观结构。结果显示:改性脲醛树脂和稻壳粉有利于改善秸秆花盆的力学性能,当增强填料与基体树脂的比例为1:0.5,稻壳占稻壳粉的质量分数为30%时,花盆的静曲强度(modulus of rupture,MOR)、弹性模量(modulus of elastic,MOE)及拉伸强度(tensile strength,TS)分别达75.48 MPa、16.06 GPa、17.44 MPa;湿循环处理试验中,以稻壳为增强材料为例,当基体树脂为改性脲醛树脂时,其MOR、MOE及TS分别降低21.97%、24.91%、15.09%;当基体树脂为大豆蛋白改性脲醛树脂时,其MOR、MOE和TS分别降低9.92%、15.37%、30.10%。热重分析发现湿循环处理后花盆热稳定性有所提高,微商热重出现最大失重率的温度向高温侧偏移29.5℃。扫描电子显微镜分析表明湿循环处理后样品表面粗糙度增加,增强体与树脂发生分离。该研究结果为进一步研究秸秆花盆制作工艺和使用年限的相关性提供理论依据。     

麦秸、菌渣和稻壳还田对日光温室番茄品质及产量的影响

为了探究麦秸、菌渣和稻壳还田对日光温室番茄品质、产量及土壤养分的影响,以金棚8号为试验材料,设7个还田处理:T1(稻壳)、T2(麦秸)、T3(菌渣)、T4(稻壳+麦秸)、T5(麦秸+菌渣)、T6(菌渣+稻壳),空白为对照(CK)。结果表明,还田处理能够显著提高番茄果实Vc含量(T5除外),其中T2和T6的Vc含量较高,分别为1.51 mg·kg~(-1)FW和1.48 mg·kg~(-1)FW。各处理组果实番茄红素含量为122.35~169.79 mg·kg~(-1)FW,较CK增加15.50%~60.29%,且处理间差异显著。果实可溶性糖含量与Vc含量的变化趋势基本一致,以T2最高,T6次之,分别较CK增加41.90%和38.10%。此外,还田可有效降低果实有机酸含量,改善果实品质,有机酸含量以T5最低,为0.25%FW;T2和T5的糖酸比分别为8.28和8.64,口感较佳。与CK相比,产量以T5最高,达106 131.97 kg·hm~(-2),其次是T6(104 065.20 kg·hm~(-2)),较CK分别增产6.51%和4.44%。土壤碱解氮、有效磷含量、速效钾含量分别为167.69~209.71、78.01~86.25和206.25~348.27 mg·kg~(-1)。综合考虑品质、产量指标,以T6较为适宜。本研究结果为设施番茄优质高产和农业废弃物科学还田提供了理论依据。     

稻壳及硅烷添加量对木塑复合材料力学性能的影响

采用一步法连续挤出技术将稻壳粉和聚乙烯进行熔融复合制备复合材料,用硅烷作为偶联剂,研究了稻壳粉与硅烷添加量对复合材料力学性能的影响。实验结果表明：稻壳和硅烷添加量对复合材料界面有很大影响,复合材料的冲击强度、弯曲强度以及抗拉强度随稻壳添加量的增加而明显下降。添加适量的偶联剂可以改善复合材料界面相容性和稻壳在复合体系中分散均匀性,从而改善力学性能。     

Effect of the corn breaking method on oil distribution between stillage phases of dry-grind corn ethanol production

The majority of fuel ethanol in the United States is produced by using the dry-grind corn ethanol process. The corn oil that is contained in the coproduct, distillers' dried grains with solubles (DDGS), can be recovered for use as a biodiesel feedstock. Oil removal will also improve the feed quality of DDGS. The most economical way to remove oil is considered to be at the centrifugation step for separating thin stillage (liquid) from coarse solids after distilling the ethanol. The more oil there is in the liquid, the more it can be recovered by centrifugation. Therefore, we studied the effects of corn preparation and grinding methods on oil distribution between liquid and solid phases. Grinding the corn to three different particle sizes, flaking, flaking and grinding, and flaking and extruding were used to break up the corn kernel before fermentation, and their effects on oil distribution between the liquid and solid phases were examined by simulating an industrial decanter centrifuge. Total oil contents were measured in the liquid and solids after centrifugation. Dry matter yield and oil partitioning in the thin stillage were highly positively correlated. Flaking slightly reduced bound fat. The flaked and then extruded corn meal released the highest amount of free oil, about 25% compared to 7% for the average of the other treatments. The freed oil from flaking, however, became nonextractable after the flaked corn was ground. Fine grinding alone had little effect on oil partitioning.     

Long-term fertilization with pig-biogas residues results in heavy metal accumulation in paddy field and rice grains in Jiaxing of China

Pig-biogas residue is widely used as organic fertilizer for rice (Oryza sativa L.) in China. To evaluate the risk of heavy metal contamination in paddy soil and rice grains caused by long-term pig-biogas residue fertilization, this study was conducted in paddy fields which had been fertilized continuously with pig-biogas residue for 8 years. We found that pig-biogas residues contained high concentrations of arsenic (As), cadmium (Cd), copper (Cu) and zinc (Zn). As a result, the concentrations of these four metals in paddy soils and rice grains sampled from biogas residue fertilized fields were significantly higher than those from control fields. In addition, in biogas residue fertilized fields, the concentrations of these four metals rapidly increased in the tillage layer compared with those in deep soil layers, and biological availability was significantly higher than in control fields. Moreover, we found that the accumulation of these four metals in paddy soils and rice grains increased in the second year compared with the first year. To reduce heavy metal accumulation in rice grains, we screened for rice genotype among 20 local rice genotypes. We found obvious genotypic differences in grains’ accumulation of heavy metals, and identified some rice genotypes which had low accumulation of multiple heavy metals. These low-accumulating genotypes predicate the possibility to reduce heavy metal accumulation in rice grains grown in pig-biogas residue fertilized fields.     

Residual Effects of Compost and Green Manure of Pea with Other Organic Wastes on Nutrient-Use Efficiency of Successive Rice after Wheat

Adoption of legumes in cereal-based cropping systems and improvement of organic fertilizers are important to reduce chemical fertilizer use. We supplied compost and green manure (GM) of green pea plant residue (GP), without supplementation or supplemented with dried chicken manure (CM) and/or rapeseed oil residue (RR), for wheat and examined the effects of compost and GM (remaining fertilizer) on the rice of pea–wheat–rice system in two factorial pot experiments. Additions of pea residue resulted in an increase of 30% grains of rice compared to without addition, and compost increased 25% grains against GM. Supplementation increased 63–70% of rice grains as compared to the control. Nitrogen (N) and potassium (K) recovery efficiencies were correlated with yield, which suggested that composting and supplementation enabled effective nutrients accumulation in plant, resulting in better yield. Therefore, it is recommended that composting of GP with CM plus RR improves effectiveness of pea on rice of a pea–wheat–rice system.     

The effect of dietary fiber from wheat processing streams on the formation of carboxylic acids and microbiota in the hindgut of rats

Colonic fermentation of dietary fiber produces carboxylic acids and may stimulate the growth of beneficial bacteria. This study investigated how byproducts of wheat processing (distillers' grains and two fractions from the wet fractionation to starch and gluten, one of which was treated with xylanase) affect the composition of the cecal microbiota and the formation of carboxylic acids in rats. Differences were mostly found between diets based on supernatants and pellets, rather than between fiber sources. Cecal pools and levels of most carboxylic acids in portal blood were higher for rats fed the supernatant diets, while cecal pH and ratios of acetic to propionic acid in portal blood were lower. The diet based on supernatant from distillers' grains gave the highest level of bifidobacteria. Molecular weight and solubility are easier to modify with technological processes, which provides an opportunity to optimize these properties in the development of health products.     

多菌灵在水稻及土壤中的消解动态和残留规律研究

采用田间试验方法,研究了多菌灵在稻田水、土壤和稻秆中的消解动态,测定了多菌灵在水稻和土壤中的最终残留量。样品采用甲醇和稀盐酸的混合溶液提取,经液-液分配净化,HPLC紫外分析测定。结果表明,田水、土壤、稻秆、谷壳、糙米中多菌灵添加浓度为0.05~1.0mg·kg-1时,平均回收率为83.16%~95.44%,变异系数在1.23%~5.32%之间,方法的最低检测浓度为：田水0.005mg·L-1,土壤0.005mg·kg-1,稻秆0.050mg·kg-1,谷壳0.050mg·kg-1,糙米0.025mg·kg-1。多菌灵在田水、土壤和稻秆中的消解动态均符合一级动力学方程,半衰期分别为2.53~3.41d、6.20~7.27d、3.27~3.91d,原始沉积量与施药量、施药次数密切相关。以231g·hm-2和346.5g·hm-2间隔7d施用多菌灵2次和3次,末次施药21d后多菌灵的最高残留量为：土壤未检出（≤0.005mg·kg-1）,稻秆0.524mg·kg-1,谷壳0.528mg·kg-1,糙米未检出（≤0.025mg·kg-1）。多菌灵在稻秆和谷壳中的残留量相对较高,以该稻秆和谷壳作为饲料有一定的风险;多菌灵在糙米中的残留量低于我国和食品法典委员会（CAC）及日本的最大残留限量（MRL）标准。     

Bio-active compost from pea plant enriched with chicken manure and oilseed rape cake and its effect on yields and nutrient recovery efficiencies of wheat and rice

Two factorial pot experiments were conducted to evaluate the effect of biodecomposer (BD) and nutrient supplemented compost of pea residue on wheat and rice. Compost was prepared with green pea plant residue (PP), in the presence or absence of BD, without or with dried chicken manure (CM) and/or oilseed rape cake (RC). We assessed the effect of compost on yields and nutrient recovery efficiencies of both crops. Results revealed that BD reduced composting duration and enriched compost with N, P and K. Composts with CM and CM plus RC increased grain yields of wheat and rice. The composts increased grains of wheat and rice nearly 5 and 1.6 times, respectively, above the control. Nitrogen, P and K recovery efficiencies were positively correlated with yields, suggesting that supplementation in composting with CM or CM plus RC enabled effective accumulation of the nutrients, resulting in higher yield. Moreover, BD increased 9.4% of wheat and 6.9% of rice grains. So, composting of PP, in the presence of BD, with CM or CM plus RC is recommend for a pea-wheat-rice cropping system to improve soil fertility and effectiveness of pea on the system.     

Effect of Rapeseed Green Manure Amendment on Soil Properties and Rice Productivity

Green manure crops can be used as alternatives to mineral fertilizers because they improve soil structure and nutrient content of soil. Here, we evaluated the effect of partial replacement of mineral nitrogen (N) fertilizer with rapeseed residue green manure on soil properties and rice productivity in a rice–rapeseed double-cropping system. The treatments were comprised of four levels of mineral N fertilizer and recommended levels of phosphate and potash fertilizers. Rice clum and panicle length did not differ between treatments. However, the proportion of ripened grains and 1,000-grain weight of rice plants were greater under rapeseed residue amendments than those under 100% conventional mineral N fertilizer treatments. Paddy soils treated with rapeseed residues had greater soil organic matter and exchangeable cations than those treated with mineral N fertilizer alone. Thus, rapeseed residues applied as green manure can serve as alternative N sources in sustainable rice–rapeseed double-cropping systems.     

DDT and HCH Residues in Basmati Rice (Oryza sativa) Cultivated in Dehradun (India)

Organochlorine pesticides were used earlier for agricultureproduction. Their residues may still be present in soil and mayaccumulate in food crops, posing potential health problems to consumers. DDT, HCH, their isomers and metabolites were analyzedin samples of soil and rice plants collected from ten differentvillages of a well-known Basmati rice growing area in Dehradun.Residues of both pesticides were found in all samples ofsoil and different parts of rice plants except for a few grainsamples. Maximum residue was observed in husk and minimum ingrains. The average concentration of DDT in soil ranged from0.013 to 0.238 ppm. p,p′-DDE was the major metabolite (>63%). Theaverage concentration of DDT in rice grain varied from 0.002 to 0.040 ppm. o,p′-DDT was the main isomer (>93%). Theaverage concentration of HCH in soil ranged from 0.122 to 0.638 ppm. β-HCH was the predominant (43%) isomerfollowed by α-HCH (21%). The average HCH concentrationin rice grain ranged between 0.013 and 0.113 ppm. All four isomers were present in grains. The levels of DDT and CHCin grains were similar in magnitude as those from differentIndian states, but well below the maximum residue limit of 0.1 ppm for DDT and 0.05 ppm for HCH prescribed by the Government ofIndia and WHO/FAO. As such, the pesticide residue levels in thisexport commodity are not of hazardous nature.     

Pulsed Nuclear Magnetic Resonance (PNMR) Study of Rice Starch Retrogradation

Although pulsed NMR (PNMR) has been used for qualitative study of starch retrogradation in selected systems, validation is necessary for its application to new systems. PNMR was used to analyze the retrogradation of rice starches in purified form, in rice flour, and in cooked rice grains. The standard curves between the relative solid content (S′, %) by PNMR and the percentage of gelatinized starch (GS, %) were determined for common rice flour, common rice starch, and waxy rice starch at different moisture contents. The coefficients of linear regression for these curves (R²) were all >0.997. Starches with different amylose contents were tested for S′ values at the stages of freshly gelatinized, retrograded (4°C, 18 days), and reheated (90°C, 20 min). The S′ of reheated starch (S′_reheat) was similar to the S′ of freshly gelatinized starch (S′₀), so we concluded that the increase in S′ during storage corresponded to amylopectin retrogradation. The effect of moisture content on retrogradation of rice starch, rice flour, and cooked rice grains was studied by PNMR, and the data were interpreted using the Avami equation. Decreasing the moisture content increased the rate of retrogradation and led to a higher parameter k and a lower parameter n. For moisture content in the range studied, PNMR can be used to follow amylopectin retrogradation of different rice starch systems.     

Decomposition of rice residue in tropical soils

Nitrogen mineralization and immobilization of rice residue in Maahas clay soil under lowland and upland conditions were investigated by using ¹⁵N-labelled rice straw. The mineralization of residue-nitrogen was taking place even though the net mineralization was depressed by incorporation of rice residue.

There were some significant differences in the pattern of nitrogen transformation between lowland and upland soil conditions. The nitrogen transformation measured by mineralization of soil nitrogen and rice-residue nitrogen and the nitrogen immobilization into rice residue were more active under lowland conditions than under upland conditions, during the earlier period of residue decomposition.