Genetic variation and selection of 10-year-old Eucalyptus camaldulensis based on wind damage index and wood properties

Typhoons are becoming frequent and intense with ongoing climate change,threatening ecological security and healthy forest development in coastal areas.Eucalyptus of a predominant introduced species in southern China,faces significant growth challenges because of typhoon.Therefore,it is vital to investigate the variation of related traits and select superior breeding materials for genetic improvement.Variance,genetic parameter,and correlation analyses were carried out on wind damage indices and eight wood proper-ties in 88 families from 11 provenances of 10-year-old Euca-lyptus camaldulensis.The selection index equation was used for evaluating multiple traits and selecting superior prov-enances and family lines as future breeding material.The results show that all traits were highly significantly differ-ent at provenance and family levels,with the wind damage index having the highest coefficient of genetic variation.The heritability of each trait ranged from 0.48 to 0.87,with the wind damage index,lignin and hemicellulose contents,and microfibril angle having the highest heritabilities.The wind damage index had a positive genetic correlation with wood density,a negative correlation with lignin content,a negative phenotypic correlation and a negative genetic correlation with microfibril angle.Wind damage index and genetic progress in the selection of eight wood traits varied from 7.2%to 614.8%.Three provenances and 12 superior families were selected.The genetic gains of the wind damage index were 10.2%and 33.9%for provenances and families,and these may be starting material for genetic modification for wind resistance in eucalyptus and for their dissemination to typhoon-prone coastal areas of southern China.

Novel wood-plastic composite fabricated via modified steel slag:Preparation,mechanical and flammability properties

A novel method was developed to enhance the utilization rate of steel slag(SS).Through treatment of SS with phosphoric acid and aminopropyl triethoxysilane(KH550),we obtained modified SS(MSS),which was used to prepare MSS/wood-plastic composites(MSS/WPCs)by replacing talcum powder(TP).The composites were fabricated through melting blending and hot pressing.Their mechanical and combustion properties,which comprise heat release,smoke release,and thermal stability,were systematically investigated.MSS can improve the mechanical strength of the composites through grafting reactions between wood powder and thermoplastics.Notably,MSS/WPC#50(16wt%MSS)with an MSS-to-TP mass ratio of 1:1 exhibited optimal comprehensive performance.Compared with those of WPC#0 without MSS,the tensile,flexural,and impact strengths of MSS/WPC#50 were increased by 18.5%,12.8%,and 18.0%,respectively.Moreover,the MSS/WPC#50 sample achieved the highest limited oxygen index of 22.5%,the highest vertical burning rating at the V-1 level,and the lowest horizontal burning rate at 44.2 mm/min.The formation of a dense and stable char layer led to improved thermal stability and a considerable reduction in heat and smoke releases of MSS/WPC#50.However,the partial replacement of TP with MSS slightly compromised the mechanical and flame-retardant properties,possibly due to the weak grafting caused by SS powder agglomeration.These findings suggest the suitability of MSS/WPCs for high-value-added applications as decorative panels indoors or outdoors.

Evaluation of Mechanical Properties and Surface Quality of Wood from Bosnia and Herzegovina Exposed to Outdoor Conditions

This study investigated the mechanical properties of beech(Fagus sylvatica L.)and fir(Abies alba)wood from Bosnia and Herzegovina under outdoor exposure.Samples were exposed for 3-month exposure to assess bending strength,color changes,and surface quality.Results showed outdoor exposure negatively affected mechanical properties,particularly in samples with extended finger joints,causing significant surface cracks in uncoated samples.Beech wood exhibited notable color changes under exposure,with approximately 50%darkening without coating compared to 25%under covered conditions.Coated samples displayed minimal color changes,affirming the efficacy of surface treatment.Fir wood exhibited a roughness of 8.264μm,while beechwood average roughness increased from 6.767 to 13.916μm after exposure,with micro-pore development affecting water performance.Microscopic analysis identified prevalent fungal colonies,including Penicillium,Aureobasidium,Sclerophoma,and Chaetomium,underscoring their role in organic matter decomposition.This study highlights the importance of wood exposure and treatment selection for various applications.

Mechanical Property and Microstructure of Cement Mortar with Carbonated Recycled Powder

Carbonated recycled powder as cementitious auxiliary material can reduce carbon emissions and realize high-quality recycling of recycled concrete.In this paper,microscopic property of recycled powder with three carbonation methods was tested through XRD and SEM,the mechanical property and microstructure of recycled powder mortar with three replacement rates were studied by ISO method and SEM,and the strengthening mechanism was analyzed.The results showed that the mechanical property of recycled powder mortar decreased with the increasing of replacement rate.It is suggested that the replacement rate of recycled powder should not exceed 20%.The strength index and activity index of carbonated recycled powder mortar were improved,in which the flexural strength was increased by 27.85%and compressive strength was increased by 20%at the maximum.Recycled powder can be quickly and completely carbonated,and the improvement effect of CH pre-soaking carbonation was the best.The activity index of carbonated recycled powder can meet the requirements of Grade II technical standard for recycled powder.Microscopic results revealed the activation mechanism of carbonated recycled powder such as surplus calcium source effect,alkaline polycondensation effect and carbonation enhancement effect.

Effects of site conditions on growth and wood properties of Populus×euramericana cv.'74/76'

The growth and wood properties of 240 individual Populus×euramericana cv.’74/76’(hereafter poplar 107)trees planted in Hebei Plain,China was evaluated.Mean annual increments in height,breast height diameter and volume,as well as cellulose,hemicellulose and lignin contents,shrinkage,density,bending strength and modulus of elasticity in the heart wood and sap wood.Environmental factors influencing growth and wood properties were analyzed using correlation and stepwise regres sion.The results show that the coefficients of variation(CVs)of growth traits ranged from 10.6 to 22.4%.The CVs of the chemical properties of heartwood ranged from 4.3 to 30.2%,and for sap wood from 3.2 to 27.5%.The CVs of the physical and mechanical properties of heartwood ranged from 8.6 to 31.7%,and for sapwood from 6.4 to 29.9%.The results of one-way ANOVA showed that there were significant differences in growth traits and wood properties among sites.Soil pH,total and available phosphorus,total potassium,and soil organic matter were key soil factors affecting growth and wood properties of poplar 107,whereas mean annual ground temperatures and precipitation were the main climatic factors.To better cultivate poplar 107,area with less annual rainfall,slightly higher temperature and soil pH value close to neutral should be selected.

A Conceptual Framework for Commercial Property Price Indexes

The paper studies the problems associated with the construction of price indexes for commercial properties that could be used in the System of National Accounts. Property price indexes are required for the stocks of commercial properties in the Balance Sheets of the country and related price indexes for the land and structure components of a commercial property are required in the Income Accounts of the country if the Multifactor Productivity of the Commercial Property Industry is calculated as part of the System of National accounts. The paper suggests a variant of the capitalization of the Net Operating Income approach to the construction of property price indexes and uses the one hoss shay or light bulb model of depreciation as a model of depreciation for the structure component of a commercial property.

Optimizing Methylene Blue Removal from Textile Effluents: Comparative Study of Adsorption Efficiency Using Raw and Activated Carbon Derived from Gmelina Wood Wastes

This research investigates the efficacy of activated Gmelina Wood Sawdust (GWS) as an adsorbent for the removal of methylene blue (MB) dye from aqueous solutions, in comparison with raw GWS. The study employs laboratory experiments to assess the percentage of dye removal across various temperature and pH conditions. The adsorption process is scrutinized under different parameters, encompassing contact time, initial dye concentration, adsorbent dosage, temperature, and pH. Results demonstrate that activated GWS surpasses its raw counterpart, showcasing superior MB dye removal percentages. Extended contact times increased initial dye concentrations, and higher adsorbent dosages contribute positively to removal efficiency, while temperature exhibits an inverse relationship with dye removal. Optimal adsorption occurs at a pH of 7.0, aligning with the adsorbent’s zero-point charge (pHzpc), underscoring the role of surface charge in the adsorption process. This study underscores the potential of activated GWS as an economical and promising adsorbent material for addressing pollutants. Furthermore, the utilization of activated carbon derived from abundant agricultural waste underscores an environmentally conscious approach to adsorption applications. The ability to tailor the size and properties of activated carbon particles opens avenues for optimizing adsorption capabilities, thereby presenting opportunities for enhanced water treatment solutions.

Classification of Principal Wood Species in China Based on the Physiomechanical Properties

Many tree species are planted in China with variable properties and usage.Toward exploring the structure-properties relationships of wood and classifying the species more reasonably,the physiomechanical properties of the domestic wood species in China were analyzed statistically.According to the correlation analysis,the mechanical properties were closely related to the wood density.Except impact toughness and cleavage strength,the correlation coefficients between mechanical properties and densities were more than 0.8.However,shrinkage properties showed fewer correlations with densities,and the coefficient was no more than 0.7.Primary component analysis was proved to be feasible to explore the information of the physiomechanical properties.Two principal components(PC1 and PC2)could account for most of the information.PC1 and PC2 were designated as density-dominated and shrinkage-associated factors,respectively.The domestic wood species in China could be classified into 4 clusters based on their physiomechanical properties.According to the cluster results,reasonable grading was proposed for air-dried density,volume shrinkage,modulus of rupture,compression strength parallel to grain and hardness in cross section.The statistical results brought insights into analyzing the physiomechanical properties of domestic Chinese wood species,which was helpful for developing strategies of tree breeding and technologies of wood processing.

APP/ZB协效阻燃发泡木塑复合材料性能研究

为了拓宽发泡木塑复合材料(FWPC)的功能性,以沙柳木粉、高密度聚乙烯(PE-HD)为主要原料,纳米炭黑(Nano-CB)为导电填料,聚磷酸铵(APP)和硼酸锌(ZB)作为阻燃剂和抑烟成分进行复配,采用发泡工艺和模压法制备阻燃抗静电型发泡木塑复合材料。研究APP/ZB协效阻燃剂质量比对FWPC力学性能、阻燃抑烟性能及热稳定性能的影响。结果表明:当APP/ZB总加入量为20%,质量比为4∶1时,FWPC的各项性能相对较优,静曲强度、弹性模量、拉伸强度和冲击强度分别为30.11MPa、2636MPa、14.65MPa和3.72kJ/m^(2),氧指数达27.3%,属难燃级别;与单独加APP时相比,力学性能降低,烟释放速总量降低11.93%,CO产率峰值和平均CO产率分别降低80.6%和49.3%,总失重率从63.53%降至61.42%,热稳定性能提高;FWPC燃烧后炭层表面凹凸不平,复合材料的阻燃和抑烟性能得到提升。

基于实验型和工业型近红外光谱仪的木片材性预测建模对比研究

本研究探讨了采用工业型光谱仪和实验型光谱仪建立近红外模型用于快速预测木片材性的可行性,分析对比不同光谱仪的建模效果。针对不同材性指标分析特点,通过光谱信号校正和特征波长筛选算法优化模型预测性能,建立适宜的建模方法。结果表明,基于工业型光谱仪建立的近红外模型对木片水分、基本密度、纤维形态等物理性能指标表现出更高的预测精度,而化学组分含量的预测精度与实验型光谱仪无显著差异。工业型光谱仪木片理化材性近红外模型适用于制浆原料品质评价和工业过程分析。

高温后冷却方式对玄武岩纤维混凝土力学性能的影响

高温处理后混凝土力学性能是工程建设中评价混凝土结构安全性能的重要指标之一。对不同玄武岩纤维(BF)掺量混凝土的力学性能进行了测试,将最优掺量的玄武岩纤维混凝土(BFRC)与普通混凝土(OC)进行高温处理(200、400、600、800℃),研究不同冷却方式(自然冷却和喷水冷却)对高温后BFRC性能劣化的影响,分析BFRC在不同温度和冷却方式下的力学性能变化规律。结果表明,当BF掺量为0.05%(体积分数)时,BFRC抗压强度、劈裂抗拉强度达到最大值,分别为50.2、3.5 MPa,较OC分别提高了14.87%、34.62%。BF的掺入能够有效增加混凝土的韧性以及抵抗开裂变形的能力。随着温度增加,BFRC试件的弹性模量减小但始终大于OC试件。同一冷却方式下OC的峰值应变均大于BFRC,不同冷却方式下的延性指数较常温均有所提高。

南方型黑杨生长性状和木材材性与湿心材形成的相关性

为了分析南方型黑杨生长性状、木材性状对其湿心材形成的影响程度,于2023年11月份,在岳阳市君山区丁字堤南方型黑杨试验林,选取13年生的8个南方型黑杨无性系为研究对象,每个无性系选取6株样株,用9 mm生长锥在树高1.3 m处钻取木样,分别测量木芯长度、湿心材长度,并称量质量;依据试验设计,测定样木的胸径、树高、材积、树液pH、生材含水量、气干材含水量、木材基本密度;运用相关分析法、通径分析法,计算各性状对湿心材比例的直接影响、间接影响、决定系数,分析南方型黑杨无性系生长性状、木材性状的7个性状指标对湿心材比例的影响。结果表明:8个无性系间,湿心材比例、胸径、树高、材积、生材含水量存在极显著差异。树液pH和生材含水量,与湿心材比例存在极显著正相关,气干材含水量与湿心材比例存在显著正相关。通径分析表明,生材含水量(W r)、树液pH、气干材含水量(W a)是影响湿心材比例(R(wh))的重要因子,通过多元回归分析建立3个性状与湿心材比例的多元回归方程R(wh)=-0.995+0.006pH+0.075 W r+0.005 W a;其中,生材含水量对湿心材比例的直接影响(0.522)和单独决定系数大小表明,生材含水量对湿心材比例影响最大。因此,生材含水量大小可以作为选育南方型黑杨低湿心材选育时的评定指标。

聚丙烯/木粉复合材料的制备及性能

分别采用聚丙烯的固相接枝共聚物和熔融接枝共聚物作为聚丙烯/木粉复合材料的界面改性剂,研究两种多单体接枝共聚物用量对复合材料界面结构、拉伸性能、弯曲性能、抗冲击性能等的影响,并根据拉伸性能数据计算复合材料的界面黏结强度。结果表明:两种多单体接枝共聚物均能有效地提高复合材料的力学性能,并维持良好的热稳定性;随多单体接枝共聚物用量的增加,复合材料的力学性能提高,当多单体接枝共聚物用量为5 phr时,复合材料的界面相容性较稳定,力学性能最佳,界面黏结强度参数从2.56升至3.50以上,表明复合材料具有较强的界面黏结强度。

海南椰子木维管束形态特征及其与物理力学性能的关系

维管束是椰子木组织构造的重要组成部分,作为承重单元,维管束的形态特征影响椰子木的宏观物理力学性能。以树龄40 a的海南高种椰子木(Cocos nucifera)为材料,以径向和高度方向为考察因素,分析维管束的分布密度、直径、横切面面积和总面积占比在株内的变异规律,并探究维管束总面积占比与密度、顺纹抗压强度等物理力学性能指标的相关性。结果表明:不同树株间,除了维管束总面积占比、抗弯强度有显著差异外,维管束其他形态特征和物理力学性能指标差异均不显著。在径向从内部向外部,椰子木维管束的分布密度、直径、横切面面积和总面积占比逐渐增大,与径向位置呈高度线性正相关;椰子木的密度和顺纹抗压强度等物理力学性能亦逐渐增大,与维管束总面积占比呈高度线性正相关。在高度方向从底部向上,维管束的直径和横切面面积逐渐减小,分布密度和总面积占比先增加后减少,与高度位置呈显著或高度相关。基于维管束总面积占比指标建立椰子木物理力学性能的模型,模型预测结果可为椰子木下锯方法和锯材质量分等提供依据。

模糊数学综合评价结合响应面法优化竹笋汁饮品发酵工艺

该研究以清水竹笋罐头生产过程中产生的清水为原料,以发酵乳杆菌(Lactobacillus fermentium)与红茶菌为菌种复合发酵制备竹笋汁饮品。利用单因素试验、模糊数学综合评价结合响应面法对其发酵工艺进行优化,并对其理化指标、微生物指标及抗氧化性进行检测分析。结果表明,竹笋汁饮品的最佳发酵工艺为:红茶菌添加量6%、发酵温度25℃、发酵时间2.5 d。在此优化条件下,竹笋汁饮品的色泽均匀,呈浅黄色的基底液,其感官评分为85.24分,固形物含量为6.13 g/L,pH为3.38,总糖含量为0.16 g/L,总酸含量为41.33 g/L,总酚含量为7.74 mg/L,总黄酮含量为0.066 mg/m L;益生菌活菌数为3.5×107CFU/g,大肠菌群、沙门氏菌及霉菌未检出,说明其理化指标及微生物指标均符合T/CASME 435—2023《益生菌发酵植物饮料》。竹笋汁饮品对1,1-二苯基-2-苦基肼(DPPH)自由基清除率为64.03%,羟自由基(·OH)清除率为46.62%,说明其具有一定的抗氧化能力。

不同配比基质对草莓扦插苗生长的影响

为筛选适合培育草莓扦插苗的基质配方,本研究以草莓品种天使8号为试验材料,通过测定不同配比基质的理化指标及草莓扦插苗的生长指标,分析不同基质对草莓扦插苗生长的影响。结果表明,不同配比基质的总孔隙度、持水孔隙度、通气孔隙度存在差异,并且不同配比基质对草莓扦插苗生长的影响不同。其中椰糠∶草炭∶珍珠岩=4∶1∶1(重量比)为最佳基质配比,该配比基质的容重、总孔隙度、持水孔隙度较高。使用该基质培育的草莓扦插苗的叶柄粗、株高、茎粗、叶柄长、叶长和叶宽较大,地下部鲜重和地下部干重较大,同时草莓扦插苗气孔导度、胞间CO 2浓度、蒸腾速率较高。本研究结果为草莓穴盘扦插育苗的基质配置提供了参考。

微胶囊释香饰面板的制备及其香气缓释性能评价

【目的】制备稳定、持久释香的饰面板,并建立缓释性能评价方法,实现规模化生产。【方法】采用微胶囊和树脂复合包覆方法制备释香型浸渍胶膜纸饰面板;采用固相微萃取-气相-质谱联用技术(solid-phase microextraction-gas chromatography-mass spectrometry,SPME-GC-MS),通过人工嗅闻直测法和气味分级法分析了释香饰面板在50℃下480 h的加速释香过程,揭示其香气释放机制,并建立香气缓释性能的快速评价方法。【结果】添加0.75%释香微胶囊的饰面板释香效果最优;微胶囊经热压后仍能均匀分布在胶层的表面和内部,壁材和胶层起到协同缓释香气的作用,且香气主成分(芳樟醇)的释放与温度、时间呈正相关。【结论】制备了持久、稳定释香的饰面板,并通过香气加速释放和干燥器富集法建立了香气缓释性能快速评测方法。

木塑空心柱轴压力学性能试验与有限元分析

为探究木塑复合材料用作低密度装配式建筑承重柱的可行性,通过材性测试和轴压试验评估共挤出木塑空心柱的轴压力学性能,并利用ABAQUS有限元分析软件模拟探究木塑空心柱壁厚、长细比和内置薄壁圆钢管壁厚对其极限承载力、变形能力和破坏模式的影响。模拟分析结果与试验测试数据高度一致,验证了模拟方法的有效性。试验研究表明,木塑空心柱主要通过局部压溃破坏,并表现出明显的弹塑性阶段。有限元分析结果表明,增加壁厚能提高木塑空心柱的初始刚度和极限承载力,其中8 mm厚度在成本、重量及承载能力方面具有最佳性价比。随着长细比的增加,木塑空心柱的承载力和刚度逐渐降低,破坏模式也从强度破坏转向失稳破坏。内置3 mm薄壁钢管显著增强了木塑空心柱的承载力和延性,其力学性能能够满足建筑对抗压承重构件的要求。

杨木旧材高温作用后力学性能试验研究

依托新疆玉儿滚军垦旧址保护项目,采用火灾后未过火原木制作杨木旧材的标准无疵小试样,考虑温度、恒温时间两种因素高温处理试样并进行抗拉、抗压力学性能试验,探究木材顺纹和横纹方向上的主要力学性能演化规律。在试验基础上,建立了顺纹杨木旧材抗压本构模型。试验结果表明:高温处理后,顺纹木材抗压强度整体下降幅度为15%~30%,横纹木材抗压强度整体下降幅度为20%~50%;顺纹木材和横纹木材的抗拉强度均显著下降,为25%~62%。建立的本构模型曲线与试验结果相比,误差在10%以内,可适用于相应木材力学性能分析。

CT血管造影联合血清尿素、胱抑素C、甘油三酯葡萄糖乘积指数对冠心病患者冠脉狭窄程度的诊断价值和斑块性质的关系

目的探讨CT血管造影(CTA)联合血清尿酸(UA)、胱抑素C(Cys C)、甘油三酯葡萄糖乘积(TyG)指数对冠心病(CHD)患者冠状动脉(以下简称冠脉)狭窄程度诊断价值和斑块性质的关系。方法选择2021年2月至2023年2月我院收治的129例CHD患者,所有患者均接受CTA检查获得血管体积、斑块体积、重建指数(RI)、斑块负荷等参数资料,检测血清UA、Cys C、甘油三酯及空腹血糖水平,并计算TyG指数。根据冠脉狭窄程度和斑块性质将CHD患者分为中度狭窄组和重度狭窄组,钙化斑块组和非钙化斑块组。比较不同冠脉狭窄程度和斑块性质CHD患者CTA参数和血清UA、Cys C、TyG指数的差异。受试者工作特征(ROC)曲线分析CTA参数联合血清UA、Cys C、TyG指数对冠脉狭窄程度诊断价值。结果CHD组血管体积小于对照组(P<0.05),斑块负荷、血管狭窄程度、RI、CTA参数模型CTA'和血清UA、Cys C、TyG指数高于对照组(P<0.05)。重度狭窄组斑块负荷、血管狭窄程度、RI、CTA参数模型CTA'和血清UA、Cys C、TyG指数高于中度狭窄组(P<0.05),非钙化斑块组斑块负荷、RI和血清UA、Cys C、TyG指数高于钙化斑块组(P<0.05)。CTA参数(CTA')、血清UA、Cys C、TyG指数等4指标单独及联合应用时:ROC-AUC(0.95CI)分别为0.767(0.568~0.954)、0.703(0.432~0.963)、0.732(0.524~0.918)、0.741(0.560~0.914)、0.891(0.773~0.983)。联合应用诊断效能更高。结论CHD患者的血管体积减小,斑块负荷、血管狭窄程度、RI增加,血清UA、Cys-C、TyG指数均升高,与钙化斑块形成有关。CTA与血清UA、Cys C、TyG指数均可诊断冠脉狭窄程度,且联合诊断效能更高。