Vibration properties of Paulownia wood for Ruan sound quality using machine learning methods

As an important material for manufacturing resonant components of musical instruments,Paulownia has an important influence on the sound quality of Ruan.In this paper,a model for evaluating the sound quality of Ruan based on the vibration characteristics of wood is developed using machine learning methods.Generally,the selection of materials for Ruan manufacturing relies primarily on manually weighing,observing,striking,and listening by the instrument technician.Deficiencies in scientific theory have hindered the quality of the finished Ruan.In this study,nine Ruans were manufactured,and a prediction model of Ruan sound quality was proposed based on the raw material information of Ruans.Out of a total of 180 data sets,145 and 45 sets were chosen for training and validation,respec-tively.In this paper,typical correlation analysis was used to determine the correlation between two single indicators in two adjacent pairwise combinations of the measured objects in each stage of the production process in Ruan.The vibra-tion characteristics of the wood were tested,and a model for predicting the evaluation of Ruan’s acoustic qualities was developed by measuring the vibration characteristics of the resonating plate material.The acoustic quality of the Ruan sound board wood was evaluated and predicted using machine learning model generalized regression neural net-work.The results show that the prediction of Ruan sound quality can be achieved using Matlab simulation based on the vibration characteristics of the soundboard wood.When the model-predicted values were compared with the tradi-tional predicted results,it was found that the generalized regression neural network had good performance,achieving an accuracy of 93.8%which was highly consistent with the experimental results.It was concluded that the model can accurately predict the acoustic quality of the Ruan based on the vibration performance of the soundboards.

Estimating wood quality attributes from dense airborne LiDAR point clouds

Mapping individual tree quality parameters from high-density LiDAR point clouds is an important step towards improved forest inventories.We present a novel machine learning-based workflow that uses individual tree point clouds from drone laser scanning to predict wood quality indicators in standing trees.Unlike object reconstruction methods,our approach is based on simple metrics computed on vertical slices that summarize information on point distances,angles,and geometric attributes of the space between and around the points.Our models use these slice metrics as predictors and achieve high accuracy for predicting the diameter of the largest branch per log (DLBs) and stem diameter at different heights (DS) from survey-grade drone laser scans.We show that our models are also robust and accurate when tested on suboptimal versions of the data generated by reductions in the number of points or emulations of suboptimal single-tree segmentation scenarios.Our approach provides a simple,clear,and scalable solution that can be adapted to different situations both for research and more operational mapping.

ARTIFICIAL NEURAL NETWORK MODELLING OF A WOOD CHIP REFINER

1 INTRODUCTIONWood chip refining is the most critical step in mechanical pulping.Commercical experi-ences have been gained for years.Modelling and control of chip refiners,however,pose a challenge mainly because of the stochastic nature of the process.Some attemptshave been made to employ factor analysis technique[1]in the modelling andsimulating of refiner operation[2,3].Strand[2]used common factors as links betweenintrinsic fibre properties and pulp quality.He believed that a qualitative concept onthe physical nature of these common factors could be arrived at,and thus would helpto understand what refining variables need to be controlled or adjusted in order to im-prove pulp quality.However,the linear model used in factor analysis is based on theassumption that the interactions among the system variables are linear,which,ofcourse,is not true in practice.

RESEARCH A NEW TOOL STEEL AND ITS PROPERTIES FOR MAKING WOOD-CHIP CUTTING KNIVES

On the basis of analyses of service conditions and properties requirements of wood chip cutting knives, an alloying scheme was formulated and a kind of new tool steel was developed. Parameters for its heat treating process and mechanical properties were systematically investigated and optimized. Satisfactory results were obtained on the knives in practice.

Effect of Incorporation of Chips and Wood Dust Mahogany on Mechanical and Acoustic Behavior of Brick Clay

An experimental study was carried out on bricks using local materials in order to take into account the waste wood management to protect the environment and to reduce the cost of the habitat. Chips and sawdust were built-in clay bricks in order to study their influence on the compressive strength, Young’s modulus and the speed for soundproofing. Testings in compressive strength were made on the parallelepiped clay bricks, stabilized with different percentages of cement, with incorporation to various percentages of sawdust or wood chips (Mahogany), using a universal press. Young’s modulus was measured from the speed of sound by the ultrasonic method. The results obtained show that the incorporation of mahogany tree chips in the stabilized brick at 8% of cement, does not have much effect on the compressive strength. It was found that the incorporation of chips or sawdust on the clay brick, does not improve the compressive strength. The Young’s modulus decreases with increasing content of sawdust and practically remains constant regardless of the content of chips at 4% and 6% of cement. The clay brick mixed with 8% of mahogany sawdust can be an acoustic barrier.

Qualitative and Quantitative Characterization of Wood Fibers of Shrubs and Tree Species of the Tamaulipan Thorn Scrub, Northeastern Mexico and Its Possible Relation to Wood Quality and Utilization

The present study was undertaken to determine the variability in fiber cell morphology and its length among wood species of the Tamaulipan Thorn Scrub, Northeastern Mexico, used for various uses such as timber for furniture, fence, post, firewood and sources of forage. The results reveal large variability in fiber cell morphology and fiber cell dimensions. The species are classified on the basis of its fiber cell morphology and fiber cell length and recommended for their possible utilization for different purposes. Wood having fibre cells with broad lumen and thin wall could be suitable for the manufacture of paper documented in the literature viz. Acacia farnesciana, Caesalpinia mexicana, Cordia boisiieri, Diospyros palmeri, Forestieria angustifolia, Morus celtifolia, Prosopis laevigata. This technique can be used in preliminary screening of woody species for its utilization for different purposes. Further studies are needed to confirm.

Feasibility of Using Wood Chips to Regulate Relative Humidity Inside a Building: A Numerical Study

The use of bio-based materials in buildings has become more and more significant last years.In most of the cases,their health properties and natural provenance have made them a great solution to face global climate warming and the new policies to reduce building energy consumption.In many thermal problems,biobased materials can allow to optimize the building thermal behavior according to its energy consumption and inside comfort conditions.So it is when they are used as an insulation material in the building.However,it is not the case in this paper.In fact,the bio-based matter is rather used as a desiccant wheel to control air conditioning inside the building.The aim of this paper is to numerically verify if it is possible to use a bed of wood chips as a hygroscopic material(or a desiccant matter)in order to modify the relative humidity inside the building in Reunion Island and so improve thermal comfort.A simple model of heat and mass transfer between a bed of wood chips and building inside air has been set up and implemented into a validated building simulation code named ISOLAB.Numerical simulations were set up for the four climate zones of the island regulations and a focus has been made on the low altitude one(with high,solar irradiation,temperature and relative humidity).Simulation results give the thermal behavior of the building particularly the temperature and relative humidity of inside air temperature,and temperature and moisture content of wood chips.The obtained results lead to determine if the wood chips bed is suitable for the reference building and to verify its technical feasibility(wood species,size of the bed,integration to the building,etc.).The results show that the use of a WCB help to decrease the building inside air temperature and water content up to 10°C less and 11.6 g.kg-1 less.These are the ways to improve inside comfort conditions.Indeed,comfort analysis have shown the possibility to significantly increase building users’thermal comfort when coupled with a fan and natural ventilation,like the regulation needs for low altitude climate.In this case,a gain of 68%of year time is achieved for a building equipped with WCB system compared to one without it(6308 hours of comfort over a year with the WCB against 350 hours without WCB).So the WCB seems to be able to help reducing cooling loads in tropical climate conditions.

Demarcation of juvenile and mature woods of planted Chinese fir and its wood quality prediction

According to the dara of trashed length, micro fiber angle, air density, ring width and late wood percentage, with the analysis of optimum method of classification, the boundary line of juvenile wood and maturewood of planted Chinese fir (Cunninghamia lanceolata) was determined as the 14th year. Based on the variationpattern of these parameters, the prediction equations were established. Wood quality prediction can be realizedby these equations. By error analysis between the values of measured data and the values of prediction data, it isfound that the results of wood prediction of planted Chinese fire are satisfactory.

CHEMICAL AND PHYSICAL CHANGES OF STEAM TREATED WOOD CHIP

High dimensional stable particlcboards could be produced by usisng saturated steam treated wood chip at elevated pressures. Sample Particleboards were made from wood chip of Birch (Platyphylla). The component changes of steam treated wood chip were analysed by infrared. Infrared spectra demonstrated that the hemicelluloses in steam treated chip were less than those in untreated chip. This is one of the main reasons why steam treatment could improve particlcboard stability. The free radical concentration of steam treated chip surfaces was analysed by ESR spcctroscopy. The results showed that free radical concentration of treated chip surface was higher than that of untreated chip surface. The glueyncss of chip increased and particlcboard resin content decreased.

Tree growth performance and estimation of wood quality in plantation trials for Maesopsis eminii and Shorea spp.

Plantations of tropical species axe becoming an increasingly important source of wood. However, it is important that research trials focus not only on tree growth performance, but also on wood quality. The aims of this study were to assess the growth performance of six commercially and ecologically important tree species from separate plantation trials in Indonesia and to determine the relationships between tree growth and wood quality in terms of the dynamic modulus of elasticity （MOE） and wood density. Forty-eight 7-year Maesopsis eminii Engl. and thirty-five 9-year specimens （7 each of 5 Shorea spp.） were selected from two trials. The MOE, based on acoustic velocity, was indirectly measured to evaluate wood stiffness. Tree-growth performance was evaluated, and correlations between growth traits and acoustic velocity as well as density and wood stiffness properties were estimated. The growth performance of M. eminii in terms of tree volume was significantly different in three different cate- gories of growth （i.e. fast, medium, slow）. Of the five Shorea spp. studied, Shorea leprosula Miq. had the highest growth rate, as expected since it is known to be a fastgrowing Shorea species. Indirect measurement of wood quality by means of non-destructive ultrasonic methods showed a weak negative correlation between tree volume and acoustic velocity and dynamic MOE. Although each fast-growing tree could reach a merchantable size faster than other varieties or species, wood traits of various species tested were not significantly different based on tree growth rate performance. The findings from this study could be used to improve selection criteria in future breeding trials; indirect measurements of the dynamic modulus of elasticity can be used in mass pre-selection of genetic materials, to choose the most-promising material for in-depth evaluation.

Prediction and Analysis of Surface Quality of Northeast China Ash Wood during Water-Jet Assisted CO_(2) Laser Cutting

As a natural and environmentally friendly renewable material,Northeast China ash wood(NCAW)(Fraxinus mandshurica Rupr.)was cut by water-jet assisted CO_(2) laser(WACL),the surface quality was evaluated by surface roughness of cut section.The surface roughness was measured by three-dimensional(3D)profilometry.Furthermore,the micromorphology of machined surface was observed by scanning electronic microscopy(SEM).Carbon content changes of machined surface were measured by energy dispersive spectrometer(EDS).A relationship between surface roughness and cutting parameters was established using response surface methodology(RSM).It is concluded that the cutting speed,laser power and water pressure played an important role in surface roughness of cut section.The surface roughness increased as an increase in laser power.It decreased caused by increasing of cutting speed and water pressure.Measurements revealed that the surface quality of NCAW part was improved using the optimized combination of cutting parameters.The established quadratic mathematical model of a good prediction is helpful for matching suitable cutting parameters to obtain expected surface quality.

Metal and Composite Intermodal Containers in Comparative Cold Tests with Wood Chips

Intermodal containers have many advantages in the bulk supply chain, but idle times may cause freezing problems for containers in terminals and long-lasting deliveries, especially during the winter time in Nordic conditions. The aim of the cold tests was to study metal and composite containers’ ability to tolerate wood chips freezing into the inner surface of the container. Two of the containers were normal metal containers and one was a composite container. The loaded containers were put inside the laboratory hall, the temperature of which was -30°C, and kept there for variable times: less than 24 hours. The inner surface of one of metal containers was treated with a special coolant, EC1. After the test, the chips were unloaded, and the container walls were checked to determine whether there was any material left on them. The test results indicated the advantages of composite containers having a thermally insulated structure without freezing problems. At the same time, chips were freezing badly onto the floor of both metal containers. A frozen chip layer with a thickness of approximately 50 cm - 60 cm was stuck to the floors. As such, EC1 did not seem to prevent the freezing of the chips onto the inner surfaces. The results proved that intermodal logistics of truck and train transportation would be more suitable for composite containers than for metal containers in the winter time in Nordic conditions.

低温真空油炸柿子脆片工艺优化及其品质分析

本文以柿子为原料,开展油炸温度、油炸时间、脱油时间以及切片厚度4个单因素对低温真空油炸柿子品质影响,并根据Box-Behnken试验原理,以柿子脆片的脆度、色差为响应值对低温真空油炸柿子脆片加工工艺进行优化,进一步对最终产品理化成分、微生物指标和微观结构进行分析。结果表明,油炸温度、油炸时间、脱油时间和切片厚度都影响柿子脆片的脆度和色差,经响应面优化试验分析并根据实际修正确定低温真空油炸柿子脆片的最佳工艺为:脱油时间5 min、油炸时间50 min、油炸温度80℃、切片厚度5.5 mm。该条件下柿子脆片脆度858.97 g、色差值ΔE 17.28、水分含量2.60%、含油率为22.53%、可滴定酸0.34 g/L、V_(C)含量31.20 mg/100 g;柿子脆片产品色泽金黄、形状完整,脆片内部呈现蜂窝状多孔疏松结构,产品口感酥脆,微生物指标符合卫生要求。本研究可为柿子低温真空油炸脆片产品的开发提供技术支撑。

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。

生物菌剂与木醋液配施对温室草莓产量和品质的影响

[目的]探索通过微生物菌剂与木醋液配施,有效提高草莓产量和品质的方法。[方法]采用田间小区试验,研究生物菌剂与木醋液配施以及单独喷施等不同处理对草莓生长、产量、品质和贮藏性能的影响。[结果]复合生物菌剂和木醋液均能增加草莓产量和改善品质,两者混合喷施效果更佳。生物菌剂与木醋液配施,草莓果实膨大期叶片净光合速率提高31.3%,草莓单位面积产量提高25.7%,果实单果重提高26.3%,果重变异系数降低11.9个百分点,存放6 d的腐烂率降低18.2个百分点、硬度变化值降低56.5%、糖酸比变化值降低25.3%。[结论]复合菌剂和木醋液配施能够促进草莓生长,提高草莓产量、品质和贮藏性状指标。

木片集装箱翻转机设计与试验

木片集装箱翻转机械作为重要装卸转运机械,是木片输送链的核心设备,能够简化木片装卸工艺流程、提升装卸效率。为此,研制一款木片集装箱翻转机,能够实现集装箱转运、举升、装载和翻转等作业。阐述整机结构工作原理,对集装箱装载作业、翻转作业和关键零件进行力学分析,综合Hypermesh、ANSYS、Adams软件建立机器有限元模型和动力学仿真模型,分析机器装载作业和翻转作业得到,集装箱翻转角为γ∈[0°,85°]、支撑轴最大作用力为4331 kN、最小直径为65 mm、翻转液压缸最大负载力为59.4 kN,小于机器相关设计参数,满足设计要求。以自行研制的集装箱翻转机展开相关试验研究,计算分析试验数据与仿真结果高度拟合,利用与试验数据高度拟合的仿真模型分析机器关键零部件可缩短机器研制开发周期、降低加工制造成本。该研制的木片集装箱翻转机满足设计要求,具有一定的应用潜力。

木屑颗粒堆积参数对液体渗流特性的影响规律

为了探究木屑颗粒堆积参数对液体渗流特性的影响规律,参照达西渗流实验,设计开发了渗流实验系统,选取颗粒床层湿度、渗流速度、床层储水量及透水率作为评价颗粒床层内液体渗流特性的指标,在对各因素进行初步筛选的基础上,实验研究木屑颗粒堆积床层的粒径分布、压缩高度比以及渗透压力(注水量)对液体渗流特性的影响.实验结果表明,相同粒径分布,注水量为1500 mL时,压缩高度比从0.80降到0.50,木屑颗粒床层湿度变化幅值为3.32%;相同粒径分布,压缩高度比为0.50,注水量从1500 mL增加到3000 mL时,木屑颗粒床层湿度变化幅值为2.30%;相同压缩高度比和注水量,全粒径分布、不同级配粒径分布及小粒径分布时木屑颗粒床层最大湿度分别为54.4%、54.0%及53.7%,变化幅值为0.7%.在本文研究范围内,压缩高度比对颗粒床层湿度影响最大,初始注水量次之,颗粒级配影响最小.相同粒径分布,注水量为2000 mL时,压缩高度比从0.80降到0.50,木屑颗粒床层渗流速度变化幅值为18.92×10^(-4) m/s;相同粒径分布,压缩高度比为0.50,注水量从1500 mL增加到3000 mL时,木屑颗粒床层渗流速度变化幅值为1.08×10^(-4) m/s;相同压缩高度比和注水量,全粒径分布、不同级配粒径分布及小粒径分布时木屑颗粒床层最大渗流速度分别为20.7×10^(-4) m/s、15.4×10^(-4) m/s及18.2×10^(-4) m/s,变化幅值为5.3×10^(-4) m/s.在本文研究范围内,压缩高度比对颗粒床层渗流速度影响最大,颗粒级配次之,初始注水量影响最小.综合各类因素考虑,不同粒径级配的木屑颗粒床层,压缩高度比为0.70、注水量为2000 mL时木屑颗粒床层中的液体渗流特性较好,此时,床层湿度为52.5%,平均渗流速度为9.86×10^(-4) m/s,床层储水量为1149 mL,床层透水率为42.56%.相关结果可为后续可压缩性颗粒堆积物的存放以及水基灭火剂开发需要关注的参数提供指导.

江苏西瓜制种产业高质量发展研究

种业是农业的“芯片”,是保障国家粮食安全的重要基础。党中央高度重视种业发展,并提出打好种业翻身仗和深入实施种业振兴行动重要战略部署。江苏省东台西瓜、潼阳西瓜、王庄西瓜、横溪西瓜、魏营西瓜获得国家地理标志农产品保护,江苏是全国西瓜重要产地,农业生产依赖种子,种子供给影响产业的稳定,探讨西瓜制种产业发展对江苏西瓜产业发展、种业振兴具有重要意义。文章梳理了江苏省西瓜制种产业发展的必要性及优势,分析了江苏西瓜制种产业发展的现状及存在的问题,并从提高农业机械化水平、培育种业企业科研创新能力、加强制种行业规范和标准的推广与实施等方面提出了推动江苏西瓜制种产业发展的建议,亦为其他制种产业提供借鉴。

甜瓜翠雪7号高质量种子生产及加工技术研究

甜瓜种子质量决定出苗率、出苗整齐度和幼苗的健壮生长,继而影响甜瓜的产量以及品质。随着甜瓜育苗向集约化和规模化方向的发展,育苗场或者种植户对高质量甜瓜种子的需求也越来越高。基于对甜瓜种植密度、授粉数量、单株坐果数和采收时间等因素的分析以及基于木酢液可破除种子休眠特性,研究甜瓜品种翠雪7号高质量种子生产和加工处理技术,以期为厚皮甜瓜高质量种子生产提供借鉴。

中国木地板产业发展现状及对策建议

2019年我国木地板产量达到阶段性历史峰值,木地板产业进入高质量发展阶段。当前产业发展形势严峻:企业效益普遍下滑;国内市场存在“逆向选择”现象;国际市场频繁遭遇贸易壁垒;科技创新增效显示度不高;制造和服务模式面临挑战。本文在对上述发展现状和问题深入分析后,借鉴产业数字化、融合式发展等传统产业转型升级路径理论,提出木地板产业高质量发展的对策建议:一是锚定国内大循环,实施需求驱动木地板产业与服务业深度融合。建议首要任务是致力于满足客户的需求,从产品导向向满足用户体验转变,实施需求驱动,将“能够让消费者在使用产品或享受服务中得到满足”作为衡量企业转型升级成功的标准。二是提升自主创新能力,实施创新驱动木地板产业与研发端深度融合。建议加强跨企业技术流动,大企业发挥主导和引领作用,中小企业向“专精特新”方向发展,协同促进生产力跃迁,逐步构筑新竞争优势,赢得发展的主动权。三是发扬工匠精神,努力提高产品质量和服务质量。建议从产品设计、工艺、原材料、销售服务、铺装服务、品牌创建等全过程下苦功,致力于提升用户体验。四是有组织地开展科学普及,努力消除与消费者间的信息不对称。建议组织开展地板相关知识的科普工作,努力消除信息不对称,避免逆向选择,引导消费者正确认知、科学消费、绿色消费。