Wood specific gravity of some tree species in the Garhwal Himalayas, India

Estimation of terrestrial biomass depends critically on reliable information about wood specific gravity of forest trees. In recent years, wood specific gravity has become more important when exploring the universality of functional traits of plants and estimating their global carbon stocks. To estimate their specific gravity, wood samples were collected from a total of 34 tree species, 30 from lower elevations and 4 from upper elevations in the Garhwal Himalayas, India. The results show that the average wood specific gravity was 0.631 （ranging between 0.275 ± 0.01 and 0.845 ± 0.03） for the species at lower elevations and 0.727 （ranging between 0.628 ± 0.02 and 0.865 ± 0.02） for the upper elevations. The average wood specific gravity for the upper elevation species was 9.6% greater than that for the species at lower elevations. Aegle marmelos among the lower elevation species and Quercus leucotrichophora among the upper elevation species had the highest wood specific gravity, which were 0.845 ± 0.03 and 0.865 ± 0.02, respectively.

Forest aboveground biomass estimates in a tropical rainforest in Madagascar: new insights from the use of wood specific gravity data

To generate carbon credits under the Reducing Emissions from Deforestation and forest Degradation program（REDD＋）, accurate estimates of forest carbon stocks are needed. Carbon accounting efforts have focused on carbon stocks in aboveground biomass（AGB）.Although wood specific gravity（WSG） is known to be an important variable in AGB estimates, there is currently a lack of data on WSG for Malagasy tree species. This study aimed to determine whether estimates of carbon stocks calculated from literature-based WSG values differed from those based on WSG values measured on wood core samples. Carbon stocks in forest biomass were assessed using two WSG data sets：（i） values measured from 303 wood core samples extracted in the study area,（ii） values derived from international databases. Results suggested that there is difference between the field and literaturebased WSG at the 0.05 level. The latter data set was on average 16 % higher than the former. However, carbon stocks calculated from the two data sets did not differ significantly at the 0.05 level. Such findings could be attributed to the form of the allometric equation used which gives more weight to tree diameter and tree height than to WSG. The choice of dataset should depend on the level of accuracy（Tier II or III） desired by REDD＋. As higher levels of accuracy are rewarded by higher prices, speciesspecific WSG data would be highly desirable.

Variations in wood anatomical properties and specific gravity of half sib progenies of Populus deltoides

We studied radial and inter-progeny variations in the dimen- sions of the wood elements and specific gravity of 21 half sib progenies of Populus deltoides Bartr. ex Marsh. The female parents of half sib progenies were G48 and $7C13 clones. Variance ratio （F） test indicated that inter-progeny variations in the dimensions of wood elements and specific gravity were significant for all wood traits while variations were significant for radial location for specific gravity only. Hierarchical clus- ter analysis was done by Squared Euclidean Distance for all of 21 proge- nies considering six wood traits. 21 progenies were grouped into 4 clus- ters. Cluster 1 was the largest cluster with 11 progenies, whereas cluster 3 had only one progeny. Selected progenies in clusters 3 （progeny 155, male） and 4 （progeny 108, 196, both female） were highly divergent from the other progenies so they were used in combinations as parents of hybrids to develop new clones with desired characters. Progeny 155 showed higher growth, fiber dimensions, and specific gravity, thus, should be used for the development of new clones.

Specific gravity of some woody species in the Srinagar Valley of the Garhwal Himalayas, India

In this study, we investigated the specific gravity of wood samples collected from a total of 31 woody spe- cies, consisting of 20 trees, 10 shrubs and one species of bamboo from sub-tropical regions of Garhwal Himalayas, In- dia. Results show that among these woody species, the specific gravity of trees ranged from 0.34 for Erythrina suberosa to 0.83 for Albizia procera. For shrub species the specific gravity of Ricinus communis was 0.39 and that of Dodonaea viscosa 0.93. The average specific gravity of trees was 0.58 and of shrubs 0.66.

Specific Gravity of the Tonsil and the Adenoid

Purpose: When considering about adeno-tonsillar hypertrophies it is important to know their weights as well as their specific gravities. Subjects and methods: Specific gravities of 344 tonsils and 117 adenoids were measured. Results: Average specific gravities of tonsils and adenoids were 1.08 (SD: 0.0411), 1.12 (SD: 0.574) respectively. Significant difference was observed between two (p 0.002). Discussion: The palatine tonsils and pharyngeal tonsil or adenoid are in a Waldeyer’s ring. They are thought that they work for lymphatic immune systems. However, there are several differences between tonsil and adenoid. The former has capsule, and increases their weight by growth;on the contrary the latter has no capsule, shrinks by growth. Tonsils are relatively hard mass but adenoids are very soft and easily bleed by touching with cotton swabs via nose. Conclusion: At this study, specific gravity of the adenoid was heavier than that of tonsils. These results suggest that tonsil and adenoid are physiologically different.

Between-Tree and Within-Tree Variation in Specific Gravity and Extractive Content in the Wood of Stercufia setigera Del. Grown in Nigeria

Variations of wood specific gravity and extractive contents from pith to bark and from base to the top of tree were investigated in a 14-year-old commercial pulpwood species Sterculia setigera Del. Growing in savanna zone in Nigeria. Tree mean specific gravity averaged 0.37; wood at the base had significant higher specific gravity than those at the top while it increased from pith to bark. For extractive content mean value was 1.20% for wood and 1.72% for bark; i[t varied significantly between trees and from base of the tree to the top and from pith to the bark. Extractive content at the butt and breast height is more than double of the value at the top of the tree. The high extractive content at the base is similar to high specific gravity observed for wood samples from the base. Extractive content of the bast was significantly higher than that of the wood. The low specific gravity show possible suitability of the species for paper making in Nigerian paper mills. The wood of Sterculia setigera showed a significant variation between- and within-trees in the two properties considered, though the wood is light with low extractive content; it is however a potential raw material for large scale pulpwood production in Nigeria.

Evaluation of Light Specific Gravity Ropivacaine Combined with Sufentanil in Hip Arthroplasty at An Advanced Age

combined with sufentanil in elderly patients undergoing hip replacement.Methods:89 elderly patients with hip arthroplasty from July 2019 to September 2020 were randomly divided into experimental group and control group.The experimental group was anesthetized with light specific gravity ropivacaine combined with sufentanil.The control group was anesthetized with equal specific gravity ropivacaine to compare the effect of anesthesia and the incidence of adverse reactions.Results:there was no significant difference in sensory recovery time and motor recovery time between the experimental group and the control group(P>0.05),and the incidence of adverse reactions between the two groups was low.The sensory block time in the experimental group was shorter than that in the control group(PP>0.05).Conclusion:ropivacaine combined with sufentanil subarachnoid anesthesia is more effective in elderly patients undergoing hip arthroplasty,and the safety of the anesthesia scheme is higher,which will not lead to serious adverse reactions during operation.Moreover,the application of the anesthesia scheme can effectively improve the analgesic effect during and after operation,and the clinical application value is high.

排岩机履带行走装置接地比压分布规律研究

针对目前接地比压分布不均匀问题,本文以排岩机为例,建立了履带行走装置接地比压计算数学模型。基于Solidworks、MATLAB软件,对排岩机重心空间坐标值与其受料臂旋转角度、排料臂上仰角度及车体回转支承旋转角度进行了拟合。进一步通过ANSYS Workbench仿真软件,证明了所建接地比压计算模型的正确性。研究分析了接地比压随受料臂旋转角度、排料臂上仰角度、排岩机车体回转支承旋转角度的变化趋势。这里研究成果可为各种履带行走设备整机的设计及其工作地基的处理提供一定的参考。

钻井法凿井壁后充填大比重水泥浆研制及其耐久性能

为提升西部地区深大钻井井筒第一段高壁后充填置换效果,提出采用大比重水泥浆作为新型壁后充填材料。首先,通过对比试验,优选重晶石粉作为加重剂、硅酸镁铝为悬浮剂。然后,采用正交试验和极差分析法,分析了水灰比、重晶石粉、硅酸镁铝和膨胀剂掺量对大比重水泥浆的密度、初凝时间、流动度、3 d及28 d抗压强度的影响,采用综合平衡法确定了大比重壁后充填材料的最优配合比为水泥∶水∶重晶石粉∶硅酸镁铝∶膨胀剂∶减水剂=1∶0.55∶0.5∶0.03∶0.025∶0.015。硫酸盐溶液侵蚀对比试验表明,与常用的水泥浆充填材料相比,大比重水泥浆充填材料具有可靠的耐久性能。最后,通过XRD和SEM分析了优选组加重水泥浆在3 d和28 d的水化产物和微观结构,揭示其优异抗渗性和耐久性能的机理。研究结果可为西部地区深大钻井井筒壁后充填提供大比重、高强度、低渗透以及耐久性好的新型壁后充填材料。

中国葵花籽出口贸易及潜力——基于贸易引力模型的实证

中国是世界最大的食用葵花籽生产国与出口国,把握其贸易特征及出口潜力对中国葵花籽产业发展具有重要意义。在对中国葵花籽贸易现状及特点分析的基础上,基于2001—2021年中国与19个出口去向国的面板数据,通过构建扩展的引力模型对中国葵花籽出口潜力进行了实证分析。结果显示:中国葵花籽出口具有高竞争优势,出口价格劣势情况逐渐得到缓解;出口去向国国内生产总值(GDP)、经济自由指数与农产品外贸依存度的提高,双边贸易距离的增加,两国人均GDP差异的缩小促进了中国葵花籽的出口;当前东南亚一些国家贸易潜力发挥不足,中东一些国家贸易潜力超标实现。基于此认为:中国应与国际农产品质量标准接轨,强化品牌推广与营养知识科普,开拓国内外食用葵花籽高端消费市场。同时,巩固加强与中东国家的贸易伙伴关系,借助《区域全面经济伙伴关系协定》(RCEP)政策优势改善贸易环境,推动与周边国家小宗农产品的贸易往来。

Old-growth mixed dipterocarp forests show variable losses and gains in aboveground biomass and standing carbon over forty years

Background:No studies have documented long-term trends in aboveground biomass(AGB)for mixed-dipterocarp forests(MDF),the dominant rain forest type in tropical wet equatorial Asia.In our study,we sought to document such trends over forty years across three sites representing lowland to lower montane elevations.Methods:To do this,we established fifty 100 m×25 m plots in 1978 across three sites sampled along an elevation gradient,identified as mature old-growth forest.We measured trees for diameter at breast height that we identified to species and tagged.We took wood samples to calculate species wood-specific gravity.We re-measured plots in 1998 and again in 2018.Results:We show standing AGB for all sites combined to be 517.52 Mg·ha^(-1)in 1978,but this declined by 17%over 40 years to 430.11 Mg·ha^(-1).No differences exist among sites in AGB primarily because of considerable within site variation;but interactions of time with site show declines across sites were not uniform,one remained about the same.Relatively few species represented a high proportion of the AGB with the top five species comprising between 34%and 65%,depending upon site and year sampled.One species,Mesua nagassarium,represented a disproportionately large amount of AGB and decline over time,particularly at the low elevation site.Conclusions:Our results are directly relevant to estimating AGB and standing carbon sequestered in MDF.Our study is the first to demonstrate varying but overall,declining trends in amounts of AGB among forests making predictions of biomass and standing carbon in MDF difficult over wide regions.

低剂量轻比重椎管内麻醉及神经阻滞麻醉用于髋关节置换术的临床研究

目的 评价低剂量轻比重椎管内麻醉及神经阻滞麻醉用于髋关节置换术的临床效果。方法 选取择期行骨科髋关节置换手术患者130例,采用随机数字表法分为神经阻滞麻醉组(N组)和低剂量轻比重椎管内麻醉组(C组),每组65例。N组术中行神经阻滞麻醉, C组术中行低剂量轻比重椎管内麻醉。比较两组患者麻醉效果指标和并发症发生情况、血流动力学指标。结果 C组麻醉起效时间、感觉阻滞持续时间和运动阻滞持续时间分别为(3.56±1.03)、(24.86±5.58)、(76.85±20.24)min,较N组的(16.58±2.54)、(435.29±50.68)、(298.67±50.62)min明显缩短,差异有统计学意义(P<0.05);两组并发症发生率相比无明显差异(P>0.05)。两组麻醉前、术后30 min平均动脉压(MAP)、心率(HR)水平相比无明显差异(P>0.05);N组术毕MAP、HR分别为(89.25±10.76)mm Hg(1 mm Hg=0.133 kPa)、(76.34±5.64)次/min,与C组的(93.45±11.02)mm Hg、(78.91±5.82)次/min相比明显降低,差异有统计学意义(P<0.05)。结论 髋关节置换术中行低剂量轻比重椎管内麻醉的效果比神经阻滞麻醉好,患者的血流动力学较平稳,且不会增加围术期并发症的发生,值得临床推广应用。

轻比重罗哌卡因复合芬太尼腰麻在老年髋部手术麻醉中的应用分析

目的探究对老年髋部手术患者采取轻比重罗哌卡因复合芬太尼在腰麻中的效果。方法非随机选取泗阳康达医院于2022年3月—2023年6月收治的62例老年髋部手术患者为研究对象,依据麻醉方案不同分为对照组和观察组,每组31例。对照组实施10%葡萄糖注射液+布比卡因,观察组实施轻比重罗哌卡因复合芬太尼,比较两组麻醉各项指标、心率(heart rate,HR)、平均动脉压(mean arterial pressure,MAP)。结果两组运动阻滞起效时间、感觉阻滞起效时间对比,差异无统计学意义(P均>0.05)。与T0时比,T1~T3时两组患者HR、MAP均先降低后升高,并且麻醉后在T1~T3观察组HR以及MAP波动幅度均较小,差异有统计学意义(P均<0.05)。结论在对老年髋部手术患者麻醉时,给予轻比重罗哌卡因复合芬太尼在腰麻中,效果较好,对循环系统影响较小。

5XZ-10型比重式种子分选机气流孔板布置优化

种子的好坏,直接影响粮食产量,优良种子的筛选对于国家粮食安全问题具有重大意义。针对5XZ-10型比重式种子分选机筛面气流分布不均的问题进行单因素试验。利用Fluent软件,采用数值模拟与试验相结合的方法对比重式分选机气室流场进行了求解。为了简化计算量,引入多孔介质模型代替气流孔板。利用数值拟合求解了多孔介质模型参数,建立气室几何模型并验证了模型的可行性。将气流孔板布置高度比例系数α作为单因素变量,得到分选机空气流场及空气动力场的分布特点。为获得合理的筛面气流,讨论了不同的气流孔板高度对气室出口界面气流稳定性、均匀性的影响,发现当α=0.84时,气室出口界面气流稳定性、均匀性较好。确定气流孔板合理的安装高度530 mm,为比重式种子分选机优化设计提供了试验数据及理论依据。

全回路CFB中一级燃料配比对异重燃料分级燃烧影响的模拟

循环流化床以其燃料适用范围广的优势,被作为低热值固体废物热利用的优选设备。为解决循环流化床燃烧异重混合燃料时出现燃料配比不当而导致的污染物控制困难问题,本文将软质煤矸石(soft coal gangue,SCG)颗粒和垃圾衍生物(refuse derived fuel,RDF)颗粒作为异重燃料,采用分级燃烧技术,应用欧拉双流体模型模拟研究了3种不同一级燃料配比在循环流化床锅炉中分级燃烧过程的流动、温度和气体组分分布情况,以获得其在循环流化床中分级燃烧的最佳一级燃料配比。结果表明:SCG/RDF为5/2的配比可促进颗粒与流体之间的碰撞频率和提高煤矸石中挥发分的热解反应强度,此配比下挥发分在密相区的反应速率较SCG/RDF为6/1和3/4时分别提高0.025和0.010。同时,该比例下的炉膛整体温度较SCG/RDF为6/1和3/4时分别提升175 K、25 K,达到了燃料协同燃烧的最佳效果,该比例下O_(2)消耗量较SCG/RDF为6/1和3/4时分别增加0.08和0.01。另外,RDF比例的升高会使污染物NO和SO_(2)的含量下降。因此,选用SCG/RDF为5/2的配比可达到异重燃料分级燃烧的最优运行状态,此时异重燃料的循环流化床燃烧效果最佳。

尿量仪校准方法的研究

在尿量仪质量控制方面,目前国内并没有相应的国家标准和计量标准。本文主要介绍了尿量仪的组成和用途,针对目前临床在用设备,研究了尿量仪的校准方法,并进行了验证实验。依据此方法制定了《尿量仪国家校准规范》,已通过全国临床医学计量技术委员会专家评审,即将颁布。此规范的实施将为开展相应的质量控制工作提供技术依据,希望通过质量控制,确保尿量仪设备良好运行,有效提高医疗安全。

小剂量轻比重腰-硬联合麻醉和股神经及坐骨神经阻滞麻醉在老年创伤性下肢骨折患者内固定术中的应用对比

目的探究小剂量轻比重腰-硬联合麻醉和股神经及坐骨神经阻滞麻醉在老年创伤性下肢骨折(TLEF)患者内固定术中的应用效果。方法随机选取南阳市中心医院在2020年5月至2022年5月收治的80例老年TLEF患者作为本次研究对象,用随机数字法将其分为对照组(40例)和研究组(40例)。两组患者均行内固定术治疗,对照组术中行小剂量轻比重腰-硬联合麻醉;研究组术中行股神经及坐骨神经阻滞麻醉。比较两组麻醉效果、生命体征变化、凝血功能、术后不良反应、术后恢复情况。结果两组麻醉起效时间、完全麻醉时间、感觉神经完全麻醉时间、运动神经完全麻醉时间比较,差异无统计学意义(P>0.05)。麻醉后,两组心率(HR)和平均动脉压(MAP)水平均低于麻醉前(P<0.05),两组麻醉后HR和MPA水平比较,差异无统计学意义(P>0.05)。术后,两组凝血酶时间(TT)、凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)水平均高于术前,研究组高于对照组(P<0.05),两组纤维蛋白原(FIB)水平低于术前,研究组低于对照组(P<0.05)。两组术后不良反应差异无统计学意义(P>0.05)。研究组术后苏醒时间、拔管时间、下肢运动恢复时间及排尿恢复时间均低于对照组(P<0.05)。结论老年TLEF患者内固定术中接受小剂量轻比重腰-硬联合麻醉和股神经及坐骨神经阻滞麻醉均有较好麻醉效果,但股神经及坐骨神经阻滞麻醉可明显减轻血液高凝状态,减少麻醉不良反应,有效促进患者术后恢复。

草乌甲素柱层析三元体系回收洗脱液快速调节及二次利用

目的:提供一种草乌甲素柱层析三元体系回收洗脱液快速调节的方法,适用于草乌甲素回收洗脱液的二次利用。方法:通过酸碱滴定法和密度比重法的联合运用,推导出简便的计算公式,按照操作方法测定未知量带入公式,即可准确调节草乌甲素柱层析回收液中三元溶剂的比例关系。结果:通过回收洗脱液(调节后)各组分比例关系验证及洗脱效果验证,说明按照上述方法调节后的回收液能达到新配制的水平,可进行二次利用。结论:所提供的方法原理清晰,操作简单,实用性强,并且将数学计算运用到原料药研发工艺上,使过程控制更精确且可数字化,降低废液排放和生产成本。

一种基于结构面密度的岩体结构均质区划分方法

根据结构面发育的主要特点以及工程实际需要,合理选择划分岩体结构均质区的岩体参数是必要的。在某些特殊情况下,选择结构面密度作为划分均质区的依据更为合适。为此,提出了一种基于结构面密度的岩体结构均质区划分方法,即密度分区方法,并通过对西南某大型水电站工程侧裂结构面的密度分区,证明了该方法的可行性。该方法简单、直观、易于操作,有很强的推广实用价值。

特高重力坝考虑高压水劈裂影响的初步研究

本文设计了混凝土试件高压水劈裂模拟试验,可近似模拟无拉、压应力作用下混凝土结构的水力劈裂问题。用试验结果和断裂力学分析校正了有限元分析程序。通过对比分析和有限元计算,研究了大狄克逊重力坝(坝高285m)和假定的坝高216.5m重力坝考虑高压水劈裂的安全问题,结果表明,200m以上的特高重力坝除按无拉应力和抗滑稳定准则设计外,还应考虑高压水的劈裂影响。