Selected physical and chemical properties of mechanically extracted neem seed oil sourced as a preservative for ligno-cellulose in south-western Nigeria

Most of the seeds produced by neem （Azadirachta indica A. Juss） trees in Nigeria are currently underutilized. Hence, relevant literature provides only limited information conceming many of the seed oils from this country, especially where it concems the potential applications of these oils as preservatives for ligno-cellulose against bio-deterioration. Using standard procedures therefore, this study was carried out to evaluate and document selected physical and chemical properties of neem seed oil （NSO）, mechanically extracted using a cold press at 31.03 N-mm^-2 pressure and a room temperature of 25 ± 2℃. The results show that oil yield was 38.42% with a specific gravity of 0.91 ± 0.01. The amount of acid was 18.24 ± 1.31 mg KOH.g^-1 and that of iodine 93.12 ± 2.01 g-100 g^- 1, while saponification and peroxide values were 172.88 ± 2.06 and 1.42 ± 0.04 mg·g^-1 respectively. The implication of the values obtained, particularly those for the chemical properties, as they concern the potential application of NSO as a preservative for ligno-eellulose, is likely that it may be useful in this regard since the values may support some of the documented anti-microbial properties of the oil, although other physical and chemical properties that may affect this potential are recommended for investigations. Conclusions and other recommendations follow in line with the results of the study.

Effect of Combined Chemical Treatment on Physical, Mechanical and Chemical Properties of Posidonia Fiber

The aim of this study is to investigate the effect of chemical treatment method on the properties of Posidonia fibers. The chemical treatment which is carried out is a combined hydrogen peroxide and sodium hydroxide treatment. First, an investigation of the treatment processes was undertaken. Secondly, the physical properties (linear density, diameter and ratio length per diameter), the mechanical properties (tenacity, elongation) and chemical properties (FT-IR spectra and X ray diffraction) of posidonia fibers were investigated. The optimum operating conditions were identified using a factorial design.

Effect of Chemical Extraction on Physicochemical and Mechanical Properties of Doum Palm Fibres

The aim of this study is to investigate the effect of chemical extraction method on the properties of doum palm fibres. The method of extraction which is carried out is a soda treatment. First, an investigation of the extraction processes was undertaken. Secondly, the physical properties (surface morphology, density, linear density and diameter), the mechanical properties (tenacity, strain) and chemical properties (FT-IR spectra) of doum palm fibres were inspected. Finally, a comparison between properties of doum palm fibres and other vegetal ones has been included. Results indicates an influence of soda treatment on properties of Doum palm fibers. In fact, there is an improvement on fibers diameter and linear density while increasing soda concentration, temperature and treatment duration. Moreover, the studied fibers have a low density which does not exceed 1. The fibers tenacity achieved the maximum value of 20.86 cN/Tex when precessing in the following combination (0.75 N, 100°C and 180 mn). In the end, the FTIR spectra reveals a change in structure after this alkali treatment while increasing the cellulose amount exposed on the fiber surface and consequently the number of possible reaction sites (OH groups).

Preparation of Manganese Oxide and Its Adsorption Properties

The in-situ oxidation of manganese sulfate solution with H2O_(2),sodium hypochlorite,potassium permanganate and oxygen as oxidants was investigated by means of SEM,EDS,XRD,BET and infrared analysis,and the effects of different oxidants on the morphology,phase composition,surface properties and specific surface area of manganese oxides were investigated.The experimental results show that the diameter of manganese oxide particles prepared with H_(2)O_(2)is the smallest,about 50 nm,and the specific surface area is the largest,63.8764 m^(2)/g.It has the advantages of abundant surface hydroxyl groups,no introduction of other impurities and large adsorption potential.It is most suitable to be used as an oxidant for oxidizing manganese sulfate solution to prepare manganese oxide by in-situ oxidation.Nano manganese oxide prepard by H_(2)O_(2)in-situ oxidation method is used as adsorbent to adsorb cobalt and nickel impurities in manganese sulfate.When the reaction pH is 6,the reaction time is 30min and the amount of adsorbent is 1.0 g,the adsorption rates of cobalt and nickel impurities in 100ml manganese sulfate solution are 97.59%and 97.67%,respectively.The residual amounts of cobalt and nickel meet the industrial process standard of first-class products(Co,Ni w/%≤0.005)of high-purity manganese sulfate(Hg/t4823-2015)for batteries.The study plays a guiding role in the preparation and regulation of manganese oxide,and provides a new method with high efficiency,purity and adsorbent availability for the preparation of high-purity manganese sulfate solution.

SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

In this investigation, two different grades of birch chemical mechanical (P-RC APMP) pulps and aspen market bleached kraft pulp were compared by low consistency refining of the pulps separately and in different combinations. In addition, the separately refined pulps were also combined to compare with the pulps from the co-refined pulp blend. The results showed that in both cases there were synergistic effects between the two types of pulps: adding the birch P-RC APMP pulp to the aspen kraft pulp improved pulp properties, and the resultant pulp blends had a higher fiber bonding strength (tensile and tensile energy absorption) than the sum of weighted contributions from the individual components. Understanding this synergistic effect between chemical mechanical (P-RC APMP) and kraft pulps can help to improve their applications and performances in various papermaking processes.The results also showed that introducing, at least up to certain percentage of, the birch P-RC APMP pulp into the aspen bleached kraft pulp not only improves optical and bulk properties, but also maintains or improves tensile strength, even though the P-RC APMP pulp used has lower tensile than the kraft pulp.

A Palladium Based Alloy for Prosthetic Dentistry: Structure and Properties

Using the results of physical and chemical researches and mechanical tests of the Pd-Au-Cu-Sn system alloys, a new palladium-based alloy has been chosen and studied in detail. It has a higher plasticity and a lower hardness than the Palladent alloy, widely used in prosthetic dentistry: its hardness is lower than 300 MPa, and its specific elongation is 10%~14 %. At the same time, such important practical characteristics of the alloys as the strength of adhesion to ceramics and thermal expansion coefficient are almost similar.

Determination of microcapsule physicochemical, structural, and mechanical properties

Research into the fundamental properties of microcapsules and use of the results to develop a wide variety of products in industries such as printing, fast-moving consumer goods, construction, pharmaceuticals, and agrochemicals is a dynamic and ever-progressing field of study. For microcapsules to be effective in providing protection from harsh environments or delivering large payloads, it is essential to have a good understanding of their properties to enable quality control during formulation, storage, and applications. This review aims to outline the commonly used techniques for determining the physicochemical, struc- tural, and mechanical properties of microcapsules, and highlights the interlinked nature of these three areas with respect to the end-use industrial application. This review provides information on techniques that are well supported in the literature, and also examines microcapsule analytical techniques that will become more prevalent as a result of new technological developments or extensions from other areas of study.

侏罗系油藏油井用固体缓蚀剂适用性研究

依据相关标准及模拟工况的腐蚀速率和电化学性能测试,对固体缓蚀剂的理化性能、缓蚀效果和缓蚀作用机理进行评价分析,探讨固体缓蚀剂在长庆油田侏罗系油藏开发过程中的适用性。研究结果表明,固体缓蚀剂具有良好的理化性能,在现场水介质中溶解性良好,并且无乳化倾向,但大量油相的存在会降低固体缓蚀剂的长期有效性;添加固体缓蚀剂后,在较短释放周期内,J55钢的均匀腐蚀速率明显下降,缓蚀效率高达85.64%;固体缓蚀剂长时间释放后,缓蚀作用明显减弱,其释放60 d后的缓蚀效率仅为7.37%;综合固体缓蚀剂均匀和局部腐蚀缓蚀性能以及释放率的测试结果,其投加周期不应超过60 d;固体缓蚀剂的电化学作用机理主要表现为阴极阻滞型缓蚀,但当固体缓蚀剂长时间释放后,J55钢的阳极过程明显活化,缓蚀剂吸附膜阻急剧减小,固体缓蚀剂的缓蚀效果显著降低。

基于制浆废液和麦草废渣的生物质颗粒燃料预测模型的建立及分析

以麦草制浆备料工段中产生的麦草废渣和制浆过程产生的制浆废液为原料,通过混合压缩成型工艺制备麦草废渣颗粒燃料,以期提高制浆造纸工业废弃物的利用价值。为探究制浆废液对生物质颗粒燃料成型的影响机制,参照麦草废渣组分,将粉末状商业纯纤维素和半纤维素在质量比10.17∶7.62下与制浆废液混合,制备生物质颗粒燃料模型,并通过曲线拟合建立生物质颗粒燃料预测模型,探究制浆废液中固形物含量对颗粒燃料成型性能及其物理性能的影响机制。结果表明:制浆废液可以提高燃料颗粒间的黏结力,有利于颗粒燃料成型,改善了麦草废渣颗粒燃料的物理性能。当制浆废液固形物含量为10.28%时,麦草废渣颗粒燃料显示出较好的物理性能,其抗渗水性为84.90%,压缩应力为1.45 MPa。生物质颗粒燃料预测模型对麦草废渣颗粒燃料物理性能的预测结果误差小于5%,显示出较高的预测精度。研究结果可为生物质颗粒燃料的制备技术提供理论参考,同时为制浆造纸工业废弃物的综合利用提供新思路。

沙颍河典型河段河岸带土壤理化性质对地下水氮污染的影响

以沙颍河典型河段为研究对象,通过采集果园和农田河岸带的河水、土壤以及地下水样品,并进行理化指标分析,旨在深入探讨土壤理化性质对河岸带地下水氮浓度的影响机制.结果表明:农田河岸带土壤总氮(TN)含量明显高于果园河岸带,达到其TN的1.15倍,并均在距河岸约200m处达到最高值.河岸带地下水与土壤氮含量有一定的响应关系,呈现出相似的空间分布特征.农田河岸带地下水NO_(3)--N浓度(0.56~25.17mg/L)显著高于果园河岸带(0~0.97mg/L);远岸(>200m)地下水NO_(3)--N浓度均高于近岸(<100m).土壤氮素是河岸带地下水氮污染的主要来源之一.土壤中的黏土颗粒含量和施氮量较高,使得土壤颗粒更易于吸附NO_(3)--N,增加了河岸带地下水氮污染的风险.本研究揭示了河岸带土壤理化性质对地下水氮含量的影响机制,为河岸带地下水氮污染防控提供了参考依据.这些发现有助于制定可行的土地管理策略,以减缓或防止地下水氮污染的进一步扩散.

卡托辛杂质的合成及其对卡托辛使用性能的影响

为系统分析卡托辛产品中杂质种类及添加量对其6种关键理化性能的影响,利用气质联用技术解析产品中主要杂质并合成出相对含量大于0.5%的5种杂质,分别是二茂铁(Fc)、乙基二茂铁(EFc)、1,1’-二乙基二茂铁(Di-EFc)、(2-二茂铁-2-乙基二茂铁)丙烷(Fc-(EFc))和2-2’-双(乙酰基二茂铁)丙烷(Di-(AFc));选取固化参数R为0.9和0.95,利用HTPB固化体系的力学性能研究杂质种类及添加量对卡托辛产品应用性能的影响。结果表明,5种杂质对铁含量、密度、粘度和挥发损失4种理化性能影响显著,对酸度和水分2种理化性能无显著影响;随着杂质添加量的增加,R为0.9时,Fc、Di-EFc对体系力学性能影响不显著,强度及断裂伸长率的最大变化率均小于15.0%;EFc在保证强度基本不变的情况下,断裂伸长率的最大变化率为+17.1%;Fc-(BFc)和Di-(AFc)在保证强度基本不变的情况下,断裂伸长率的最大变化率分别为-22.9%和-17.1%;R为0.95时,Fc、(Fc-(EFc))和Di-(AFc)的断裂伸长率的最大变化率分别为-31.3%、-23.5%和-17.1%;EFc强度的最大变化率为-16.5%,断裂伸长率的最大变化率为+19.0%;Di-EFc在保证强度基本不变的情况下,断裂伸长率的最大变化率为+17.3%。

氯代烃污染场地微生物修复技术研究进展

氯代烃(CAHs)是工农业生产中广泛应用的重要化工原料,其处置不当或意外泄漏使其成为土壤和地下水中最常检测出的有毒有害污染物之一,对人体和生态环境危害巨大。生物修复技术因具有绿色、经济、高效和无二次污染等优势,是氯代烃污染治理的理想技术手段。文章在分析CAHs的理化性质、在环境中的迁移特征和生物降解机制的基础上,对实验室小试、中试等不同规模的微生物修复研究实例、联合修复的进展和降解转化机制进行梳理,同时对CAHs污染生物修复技术的影响因素进行概述,最后,对CAHs污染微生物修复技术的研究进行展望,未来应在采用微孔芯片与极限稀释技术开展低丰度降解菌的挖掘与解析、研发太阳能加热生物原位修复等高效联合修复技术并分析修复效果影响因素等方面开展研究,以期为CAHs污染的高效、绿色治理提供技术支持。

复合活化对废弃混凝土再生微粉活性的影响及机理研究

再生微粉具有潜在活性,可作为辅助性胶凝材料取代水泥,但活性低限制了其应用。采用物理-化学复合活化方法激发再生微粉的活性,研究了活化再生微粉的活性指数、力学性能和微观形貌。结果表明:随着研磨时间的延长,胶砂的抗压、抗折强度先提高后降低;当研磨时间为4 h时胶砂试块的28 d抗压强度为28.6 MPa,28 d活性指数为64.3%。采用物理-化学复合活化时,当研磨4 h且掺加1%Na2SO4+1%Ca(OH)2激发剂时,胶砂28 d抗压强度为35.2 MPa,28 d活性指数达到79.1%,再生微粉的活性显著提高。

聚合物微球在油田应用中的机理分析及前景展望

本文针对聚合物微球现场实际应用情况,结合聚合物微球的理化性质,综合分析了聚合物微球在油田上的作用机理,研究了聚合物微球作用影响因素,指出了聚合物微球的油藏适应性及存在的不足,并对聚合物微球的发展方向提出了展望,为油田深部调驱提供了参考性建议。

锂渣对水性环氧砂浆性能的影响研究

为了探索锂渣资源化利用的新路径,测试分析了锂渣的物化性能,并研究了锂渣替代率对水性环氧砂浆凝结时间、力学性能、尺寸稳定性的影响。结果表明,锂渣的重金属浸出毒性、放射性符合相关标准要求,且机械研磨可以较好地激发锂渣的火山灰活性;当锂渣替代0~12%水泥时,随着锂渣替代率的增加,水性环氧砂浆的凝结时间不断延长,抗压、抗折及拉伸粘结强度均先提高后降低,收缩率先减小后增大。当锂渣替代率为6%时,水性环氧砂浆的抗压、抗折及拉伸粘结强度分别为58.8、14.3、1.96 MPa,收缩率为0.036%,其力学性能和尺寸稳定性改善最明显。

川南纸浆竹林土壤养分特征及其影响因子

对川南纸浆竹林土壤理化性质进行调查和测定,分析绵竹、慈竹、硬头黄竹林在不同区域和不同土壤深度的土壤养分特征及其影响因子。结果表明:随着土层深度的增加,土壤容重呈现增大的趋势,土壤pH值呈深层酸化加重趋势。不同养分指标随着土层深度的增加,变化趋势不同,总体表现为表层土壤养分含量高于下层土壤,全氮、有机质、速效氮含量随土层深度增加而递减的规律尤其明显,而全磷、全钾、速效磷、速效钾含量则随着土壤深度的增加变化不明显。根据全国第2次土壤普查养分分级标准,土壤中除速效磷含量处于“丰富”状态外,其余养分含量呈“适中”至“很缺”状态;土壤中全磷、全钾和速效磷含量严重缺乏;全氮和速效氮含量呈“适中”状态,尤其是表层土壤的速效氮含量呈“很丰”状态。同一区域不同竹种间土壤养分差异明显,宜宾的土壤全氮、全磷和有机质含量在3个竹种之间分别表现出较显著(P<0.05)、显著(P<0.01)、极显著(P<0.001)差异;硬头黄竹林土壤速效磷、速效钾含量在不同区域间差异明显,其中宜宾与泸州、乐山与泸州呈现极显著性差异(P<0.001)。环境因子对表层土壤养分的影响较为明显,随着土壤深度增加,海拔、土壤容重、坡度和土壤含水率对土壤养分的影响逐渐减弱。因此,在人工干预和经营纸浆竹林时,应根据土壤养分分布规律、丰缺状态、酸化情况合理搭配施用钾肥、有机肥和石灰,以补充林地营养和调节土壤酸化状况,促进纸浆竹林的生长。

配方施肥技术研究进展

过量施用化肥、农业生产者施肥方式粗放等都会造成肥料浪费,配方施肥技术是通过合理施用有机肥并调节氮、磷、钾等关键养分的比例和施肥方法,以提高作物产量和品质。该文综述配方施肥技术在提高土壤有机质、改善土壤理化性质、增加根周土壤和根际土壤微生物多样性及促进植物营养元素吸收等方面的作用,并从配方施肥对植物转录组、代谢组的影响阐明配方施肥对植物生长代谢的影响机理。综述为配方施肥技术在作物栽培上应用与推广提供参考。

不同树龄日本落叶松的化学组成与制浆特性

对不同树龄日本落叶松的化学组成和硫酸盐法制浆特性进行研究与比较。结果表明:随着树龄的增大,原料中碳水化合物含量逐渐降低;冷水抽出物、热水抽出物和1%NaOH抽出物含量增加。碳水化合物组成中,随树龄增大,葡萄糖和木糖含量降低,半乳糖含量增加。通过对日本落叶松硫酸盐法制浆工艺参数的优化研究,确定最佳蒸煮条件为:用碱量(Na2O计)21%、硫化度25%、液比1∶4、最高温度170℃、保温时间2.5h。随着树龄的增大,蒸煮耗碱量增加,纸浆硬度增高。树龄较小的12年生日本落叶松纸浆的物理强度性能较好。综合对不同树龄日本落叶松化学组成和硫酸盐法制浆特性研究结果认为:12年生日本落叶松的硫酸盐法制浆性能优于树龄较大的日本落叶松,23年生日本落叶松的制浆性能相对较差。

中国南方喀斯特石漠化演替过程中土壤理化性质的响应

以中国西南典型喀斯特石漠化生态系统土壤为研究对象,运用野外定点取样和实验室分析检测方法,研究不同等级石漠化环境土壤理化性质特征;运用空间代替时间方法,探讨石漠化演替过程中土壤理化性质的响应及其机制,旨在为中国西南喀斯特森林生态保护和石漠化生态系统恢复重建提供理论支撑。结果表明:1)不同等级石漠化环境土壤理化性质存在显著差异,土壤容重、毛管孔隙度、总孔隙度、田间含水量、毛管含水量、pH值、有机质、水解氮、有效磷和全钾均在不同等级石漠化环境间具有显著差异。但这些指标并不是随着石漠化程度增加而一直退化,而是一个先退化后改善的趋势;2)土壤有机质、氮素、毛管持水量、容重和孔隙度与土壤其它绝大多数理化因子具有明显的相关性,是土壤理化性质的关键因子,在改善土壤理化性质和促进养分循环方面起着关键作用;3)主成分分析也表明,土壤有机质、氮素、钾素、容重、持水状况、孔隙度等是基于土壤理化性质评价石漠化程度的关键指标。作者提出了强度石漠化环境裸岩对土壤养分的聚集效应学说和喀斯特石漠化演替过程中土壤理化性质的响应及其机制。研究结果对中国西南喀斯特森林生态保护和石漠化生态系统恢复重建具有重要的理论意义和实践指导价值。

稻米储藏期间陈化机制研究

稻米的陈化是一个复杂的过程,包括物理化学特性变化。稻米中主要成分有淀粉、蛋白质、脂肪,这些成分影响稻米的蒸煮和食用品质。在稻米储藏期间尽管淀粉、蛋白质、脂肪的总量基本上不发生变化,但它们的结构却发生了变化,这些变化影响到米饭的凝胶、糊化特性、风味和质地。本文综述了稻米的物理、化学特性以及储藏期间物理、化学特性的变化及其变化对稻米食用品质的影响。