Time consumption, productivity, and cost analysis of the motor manual tree felling and processing in the Hyrcanian Forest in Iran

An empirical time study was cohducted to evaluate the performance of the current felling and tree processing methods used in Northern Iran＇s Hyrcanian forest. Motor-manual felling is done mostly in winter, while tree processing starts when the felling season ends. We identified the elements of felling and processing work phases, and 142 cycles and 110 cycles were respectively recorded for felling and processing. On the basis of data analysis （time study）, we developed statistical models of effective time consumption in the respective work phase and for its total productivity. The production rate of felling with and without delay time was 9.7 and 11.65 trees per hour （0.17 USD.m^-3 and 0.21 USD-m^-3）, and the average production cost with and without delay was 1.21 USD and 1.45 USD per tree, respectively. The average productivity of processing was 35 m^3 per effective hour and the average unit cost of processing was 0.92 USD.m^-3.

Diagonal Invariant Ideals of Topologically Graded C~*-algebras

We study diagonal invariant ideals of topologically graded C*-algebras over discrete groups. Since all Toeplitz algebras defined on discrete groups are topologically graded, the results in this paper have improved the first author's previous works on this topic.

STUDY ON ERGONOMICS AND ITS USE IN THE HARVESTING SYSTEM

This paper describes the researching aim and content of Ergonomics.Some prob-lems existing in modern harvesting system,such as machinery availability,cabin design,occupational accident,noise and vibration are discussed from the viewpoint of Ergonomics.Furthermore,some improving ways and suggestions are presented.

Effect of selective cutting type on the chainsaw productivity in Caspian Forests

Time and motion studies were conducted to evaluate the impact of selective cutting type on Chainsaw productivity in Caspian forests, the selective cutting performed as single and group selection cutting in the region. The selective cutting was performed on a 42-ha tract with an average slope of 30%. The results indicate that felling time for per tree is most affected by diameter at breast height, the distance among harvested trees in single-tree selection method and diameter at breast height in group selection method. The production rate in single and group selection cutting were 21.2 m^3·h^-1 and 28.4 m^3·h^-1 for one person, respectively. Considering the gross and net production rate in single and group selection cutting, the unit cost was 1.11 USD.m^-3 and 0.88 USD.m^-3, respectively. The results indicate that group selection cutting can be more profitable than single-tree selection method.

An evaluation of harvesting costs in present and planned operations: case study—Waston District of Mazandaran Wood and Paper Industries

Amongst all forest utilization phases, harvesting plays a key role as the beginning phase of the utilization cycle and has a significant effect on the following phases.In this research, in order to examine the reduction of costs with respect to present and planned operations, the starting time of the harvesting or cutting phase and work flow were recorded. The starting time of each phase of the entire operation was recorded as well. Before harvesting the marked tree, the appropriate felling direction was determined and the azimuth of the correct direction was taken.The results indicate that there was not a meaningful relationship between the differences in direction of a leaning tree compared with the felling direction. However, there was a significant relationship between the difference of the defined and felling direction and the difference in tree leaning and defined direction. The same trend was observed between tree leaning and felling directions and tree leaning and defined directions. On the other hand,there was no significant relationship between tree leaning and felling directions and the defined and tree felling directions. In addition, this research shows that with an increase in tree volume, the time for tree cutting rose.Furthermore, when the difference of tree leaning and felling direction decreased, the time to cut the tree declined.The regression equation is Y = 168.9–0.14（the difference between tree leaning and felling direction） ＋ 0.7（volume）.

Productivity and energy balance of forest plantation harvesting in Uganda

The study evaluated the productivity and energy balance of the harvesting and the extraction of wood in plantation of exotic tree species, i.e., Pinus patula （Schiede ex Schlectendahl et Chamisso） and Cupressus lusitanica （Mill.）. The harvesting and extraction operations concerned clear-cut felling on two different types of terrain （gentle and steep terrain） and two levels of prun- ing. The results show that cutting is not affected by the terrain gradient whereas the pruning condition shows a significant effect on the delimbing operation. The productivity of cutting is evaluated at 28.1 m3.d-1 for unpruned trees and at 30.2 m3.d t for pruned trees. For the extraction phase, rolling was significantly affected by terrain conditions. On steep terrain, the gross productivity can be evaluated at 22.5 m3.d 1 for an extraction distance of 40 m, while for the same distance on gentle terrain the productivity decreases to 14.1 m3.d~. As a result, the steep terrain condition showed higher energy efficiency, suggesting that it is the more efficient system of extraction. The productivity model and the energy balance resulting from the study provide a better understanding of the variables af- fecting motor-manual cutting and rolling extraction in exotic plantations in Uganda.

An Analysis and Prevention of Stop Marks in Weaving

The cause of stop marks of fabrics in weaving is introduced, and the floating displacement of the cloth fell during loom stoppage is a primary cause of stop marks. The stop marks caused by fabric system are analyzed. A new method to eliminate stop marks by using the electronic let-off system is presented. This new method needn't any special detecting equipment, it can control the fell position by the powerful control program,so the cost is decreased greatly. The method is so flexible that can be applied to weaving all kinds of fabrics.

Modelling Stand Dynamics after Selective Logging： Implications for REDD and Carbon Pools Estimations from Forest Degradation

Forest degradation and biomass damage resulting from logging is currently difficult to evaluate with satellite images, but contributes substantially to carbon emissions in the tropics. To address this situation, we modelled how changes in the minimum felling diameter affect stem density, basal area and the related carbon biomass at the end of the felling cycle （30 years） in a semi-deciduous natural forest in Cameroon. With new MFDs estimates, at 7% logging damage rate, we found that the stem density of initially harvestable trees reduces from 12.3 （50.4 MgC·ha^-1） to 6.7 （32.5 MgC·ha^-1） trees per ha and the number of initial residual trees increases from 80 （18.9MgC·ha^-1） to 85.7 （36.8 MgC·ha^-1） trees per ha. This corresponds to an avoided damage estimated at 17.9 MgC·ha^-1. We also found that increasing mortality and damage intensity also increases the damage on carbon biomass estimated to be 8.9 MgC·ha^-1 at 10% or to be 17.4 MgC.hal at 15% logging damage. Overall, our study shows that proper determination of MFD of logged species taking into consideration their capacity of reconstitution and the Reduced Impact Logging can avoid the loss of up to 35 MgC·ha^-1.

Ten Years Dedication Blossom on the Delicate Piece——Ordifen Cup 2014 China Lingerie Design ContestLaunches in Beijing

In the afternoon of October 29th,2014,Ordifen Cup 2014 China Lingerie Design Contest unveiled during China Fashion Week.Jointly held by China Fashion Association and Ordifen International Group,the contest presented us a grand feast with the essence of Ordifen’s ten years dedication.Tiny but delicate,the lingerie condenses the charisma of both culture and fashion in the small piece of cloth.Time goes so fast all in the blink of an eye.

Hooked Online

China ramps up its efforts to safeguard juveniles from the Internet gaming addiction Just before this year’s national college entrance exam,or the gaokao,on June 7-8,a letter from a despairing mother of student made a big splash on Weibo,a Chinese Twitter-like microblogging platform.The mother described how her son,who used to be an outstanding learner,failed the exam

Fell丛上的拓扑分次Toeplitz交错代数(英文)

设B=(Bt)t∈Γ为离散群Γ上的一个Fell丛.任取Γ的一个非空子集E,定义了一个Toeplitz交错代数T E.证明了若给定的Fell丛B=(Bt)t∈Γ关于E是正则的,则相应的Toeplitz交错代数T E是拓扑分次的.

Fell拓扑,Choquet容量和遍历的Choquet容量系统（英文）

本文描述了Fell拓扑的结构与收敛条件,重新确立了关于随机集的Choquet定理在概率论中的重要作用,并提出了不变Choquet容量的概念.此外,利用环面上的双曲自同构和随机映射,具体构造了一个遍历的Choquet容量系统,且进一步探讨了这种系统的动力性态.

带干扰的双险种cox风险模型

基于保险公司在实际经营中收益所具有的不确定性,在现有文献模型的基础上建立了一个更现实的风险模型即带干扰的双险种cox风险模型.运用鞅论对该模型破产概率进行了研究,得到了它的lundberg上界,并给出特殊情况下破产概率的Fell表示,可合理地估计保险公司的破产概率.

上半连续映射的下方图形

令X是Hausdorff空间,I=[0,1]为单位区间,用↓USC(X)表示从X到I所有的上半连续映射的下方图形构成的集族.利用Torunczyk刻画定理研究了带有Fell拓扑的空间↓USC(X)的拓扑结构,证明了↓USC(X)同胚于Hilbert方体Q=[-1,1]ω当且仅当X为无限的局部紧第二可数空间.

保持底空间度量的Fell拓扑的相容度量

对于任意的局部紧可分(完备)度量空间(X,d),令Cld(X)为赋予了Fell拓扑的X上的非空闭集族.证明存在Cld(X)上一个相容(完备)度量D使得其保持X上的度量d.对于n维度欧式空间R^(n),可以构建这样的度量D.不幸的是,这个具体构造的度量D不是完备的.所以,寻找一个满足上面条件的完备度量是一个有意义的问题.而如果限制在R^(n)的非空凸闭集族Conv(R^(n)),则可以重新具体构造一个相容的具体的完备度量D_(Conv)使得其保持R^(n)上的度量.

Rare earth market analysis in December 2016

(1) Rare earth price index Rare earth price index increased at first but fell during the end of December 2016. It grew from 115.3 to the highest of 118.5 and then fell to 116.8 at the month end. (2) Yttrium-medium and europium-rich mineral Listed price of yttrium-medium and europium-rich minerals averaged 195,000 yuan/ton in November, maintaining flat since the beginning of 2016. However, the real deal price was far lower than the listed one.

Brief news

China’s rare earth export volume fell in January Analysis of customs statistics showed that China’s rare earth export volume continued to fall in January2019.Compared with January 2018, export volume fell by 1.7 percent to 3752.9 tons, while average export prices rose by 6.0percent to$9.8/kg.

The Hyperspace of the Regions below Continuous Maps with the Fell Topology

For a Tychonoff space X, we use ↓USCF（X） and↓CF（X） to denote the families of the hypographs of all semi-continuous maps and of all continuous maps from X to I = [0, 1] with the subspace topologies of the hyperspace Cldf（X × I） consisting of all non-empty closed sets in X × I endowed with the Fell topology. In this paper, we shall show that there exists a homeomorphism h： ↓USCF（X） → Q = [-1, 1]^∞ such that h（↓ CF（X）） ： co ： {（Xn） E Q ｜ limn→ ∞ xn = O} if and only if X is a locally compact separable metrizable space and the set of isolated points is not dense in X.

Variable retention forestry in European boreal forests in Russia

We explored whether,and to what extent,variable retention(VR)forestry has been applied in European boreal forests in northwestern Russia.Our survey revealed VR since 1910.Between 1910 and the 1960s,the statistics showing how much was retained are largely missing.However,for example,in the 1950s,on a large scale in the Republic of Karelia,up to 200-ha-sized harvesting areas,18–33%,were retention patches with a mean growing stock of 30–40m3 ha−1.In the fellings defined as“incomplete clear fellings,”which were the most common final felling type at that time,11–40%of the growing stock was left.Between the 1960s and the early 1990s,with more efficient harvesting and skidding techniques,conventional clear fellings with a much lower amount of retention were practiced.Concern about the regeneration of harvested areas gradually led to smaller(maximum 50 ha)harvesting areas and the increase of silvicultural activities.Until now,to ensure natural regeneration,patches of understory and 20–25 seed trees(i.e.,ca.15–25m3)per ha have been left permanently in harvesting areas.Landscape-scale retention for protecting ecosystem functions and biodiversity was legislated in 1978 by preserving key biotopes up to 1000 ha in size.Since 2001,promoted by forest certification,the key biotopes,such as paludified forest patches,buffers around water bodies,and habitats of red-listed species,have also been retained in harvesting areas,together with a dispersed retention of different elements.Quantitative estimates of the amount of key biotopes are largely missing.However,estimates of 1–13%in harvesting areas and 23%in whole managed landscapes have been given.VR applied during the last century has emulated natural disturbances and created diverse uneven-aged forest structures with high amounts of diverse coarse woody debris.We conclude that an analysis of past and current retention practices is essential for estimating the global role of Russian forestry.Further decisions on the general direction of Russian forestry and,specifically,retention practices are important to address the global challenges of biodiversity loss and climate change.

Klippel—Feil综合征的X线表现

目的结合文献报道，综合分析Klippel—Feil综合征的X线表现，提高对此病的认识。资料和方法：收集我院2000年，2005年间共计16例患者，采用平片，部份结合CT，综合分析Klippel—Feil综合征的X线表现。结果：本组16例患者均表现为Klippel—Feil综合征Ⅱ型——单纯颈椎融合，其中颈1、2椎融合1例，颈2、3椎融合12例，颈5、6椎融合3例。结论：Klippel—Feil综合征的特点是不同平面的颈椎融合，以颈2、3椎融合最多见；常伴有颈部短缩、运动障碍等临床症状。X线检查不仅能明确诊断，而且能明确病变的范围和程度。