Improve regression-based models for prediction of internal-bond strength of particleboard using Buckingham's pi-theorem

Internal bond （IB） strength is one of the most important me- chanical properties that indicate particleboard quality. The aim of this study was to find a simple regression model that considers the most important parameters that can influence on IB strength. In this study, IB strength was predicted by three kinds of equations （linear, quadratic, and exponential） that were based on the percentage of adhesive （8%, 9.5%, and 11%）, particle size （＋5, -5 ＋8, -8 12, and -12 mesh）, and density （0.65, 0.7, and 0.75 g/cm3）. Our analysis of the results （using SHAZAM 9 software） showed that the exponential function best fitted the experi- mental data and predicted the IB strength with 18~,/0 error. In order de- crease the error percentage, the Buckingham Pi theorem was used to build regression models for predicting IB strength based on particle size,

Surface Characterization of Metallic Particles in Printed Circuit Board Comminution Fines and the Processing Implication

From the background of poor responses of metallic particles in printed circuit board comminution fines to chemical conditioning froth flotation schemes, contrary to expectations based on native metal flotation, surface studies were carried out on samples of these metallic particles in quest for the probable causatives. Auger electron spectroscopy combined with argon beam depth profiling was employed in studying the surface make-up of the metal particles. The composition profiles down to 340 nm surface depth obtained showed that the supposed metallic particles consist of organics, oxides, and various trace alloys different from the bulk material of the particles. The profiles reveal the peculiar surfaces of the particles and the matrix from which the particles were liberated. The study provides insight for better appraisal of the flotation system the sample presents. Implementing chemical conditioning flotation scheme on this sample must carefully consider the peculiar surface make up in contrast to native metal occurrences.

Development and Characterization of Particle Boards Based on Sorghum Husk

This study tackles current environmental challenges by developing innovative and eco-friendly particle boards utilizing sorghum husk, combined with recycled expanded polystyrene (EPS). This dual eco-responsible approach valorizes sorghum husk, often deemed agricultural waste, and repurposes EPS, a plastic waste, thus contributing to CO2 emission reduction and effective waste management. The manufacturing process involves dissolving recycled polystyrene within a solvent to create a binder, which is then mixed with sorghum husk and cold-pressed into composite boards. The study explores the impact of two particle sizes (fine and coarse) and two different concentrations of the recycled EPS binder. Results demonstrate significant variations in the boards’ mechanical properties, displaying a range of Modulus of Rupture (MOR) from 0.84 MPa to 3.85 MPa, and Modulus of Elasticity (MOE) spanning from 658.13 MPa to 1313.25 MPa, influenced by the binder concentration and particle size. These characteristics suggest that the boards can be effectively used in various construction applications, including interior decoration, false ceilings, and potentially for furniture and door manufacturing when combined with appropriate coatings. This study not only exemplifies the valorization of plastic and agricultural wastes but also offers a practical, localized solution to global climate change challenges by promoting sustainable construction materials.

基于AI的刀具磨损对刨花质量和刨花板性能影响的评估

为推动人造板智能制造的发展,本文建立了一种基于AI计算机视觉技术的刨花尺寸与形状的检测方法,能自动识别刨花尺寸大小并区分出杆状、类矩形、类三角形和其他型4种刨花形状。在此基础上,对在不同切削时间的刨花形态变化、刨片机刀具磨损程度和工作电流进行了监测和诊断。同时,用这些刨花分组制备了相应的刨花板,并对其物理力学性能进行测试,建立了刨片机刀具磨损程度、电流消耗量、刨花形态与刨花板性能的数学关系模型,并找到刨片机优化换刀时间。结果表明:基于AI的刨花形态检测不但能够监测刀具磨损过程中刨花形态的变化,还可以有效预测刨花板的产品性能。在给定的生产条件下,刨片机开机运行2~4 h内切削出的刨花所制造的刨花板综合性能最好。

我国刨花板工业技术进步回顾与展望

回顾总结我国刨花板工业发展与技术进步历程,分析当前我国刨花板工业现状和发展机遇,剖析刨花板产业发展存在的问题和面临的挑战,探讨我国刨花板产业发展趋势,旨在为我国刨花板产业技术创新和产业健康可持续发展提供思路,并为其他人造板技术改造和产业升级提供参考与借鉴。

高强度竹材定向刨花板刨花参数优化

以毛竹材刨花为原料,探究了刨花厚度、宽度、搭接长度、竹青占比等因素对竹材定向刨花板力学性能的影响。结果表明:1)0.7~0.9 mm厚度的刨花制备的板材性能较优;2)1/3刨花搭接长度有助于提高板材韧性;3)宽度为10~30 mm的长条形刨花可获得更高强度的板材;4)竹青刨花的存在会大幅降低板材力学性能。研究结果可为竹材定向刨花板的工程应用提供参考依据和理论支持。

多种群变异非线性动态粒子群算法求解机场登机口分配问题

针对机场登机口分配不均造成航班拥堵和资源浪费的问题,提出多种群变异非线性动态粒子群算法。该算法设立了多个粒子种群进化并变异,将每次变异迭代后的全局最优个体纳入一个优质种群,而后结合非线性策略和动态策略对优质群的进化公式做出了改进,优质种群通过此进化公式迭代得到问题的最优解。该算法明显加大了前期的搜索范围和种群多样性,并有效避免了算法陷入局部最优的早熟问题。为了证明改进策略的有效性,将改进策略分步加进传统PSO并用四种经典测试函数测试改进效果,结果证明了改进策略的有效性。最后将PSO、GA、FA以及提出新算法对机场登机口问题进行求解。结果证明,该算法的精确度相对于FA、GA、PSO提高了23.13%、14.94%、8.01%,对于机场登机口有着更好的适应性。

人造板工业生命周期评价研究进展

随着国家环境保护政策要求的日益严格和消费者健康、环保意识的快速提升,定量评估人造板生产过程的环境负荷,可为人造板行业实现清洁生产和绿色消费提供科学指导,并对人造板行业实现高质量发展具有重要意义。作为一种权威的环境管理工具,生命周期评价(life cycle assessment,LCA)已广泛应用于各个领域。国内外学者将生命周期评价理念和方法引入人造板工业,开展了一系列研究,取得了卓有成效的成果。本研究系统总结了近年来胶合板、纤维板和刨花板等主要人造板产品生命周期评价的研究进展。在此基础上,提出了人造板生命周期评价未来的研究方向和发展趋势。

改性豆粕胶黏剂压制低密度秸秆刨花板工艺优化

在聚合MDI固化剂(聚合二苯甲烷二异氰酸酯)占总量5%的条件下,使用尿素、溴化锂和醋丙乳液对豆粕进行改性;利用改性豆粕胶黏剂压制低密度耐水型秸秆板,针对秸秆板防水性低的缺点,优化豆粕、醋丙乳液和防水剂用量;测定胶黏剂性能指标及秸秆板吸水膨胀率、静曲强度.由正交试验获得最佳工艺参数:热压时间1 500 s,热压温度175℃,豆粕与醋丙乳液质量比为1∶9,防水剂占秸秆刨花板质量的7%,在此条件下压制的秸秆板静曲强度为1.47 MPa,符合LY/T 1718—2007轻质纤维板标准.

基于改进粒子群算法的电路板测试路径规划

针对飞针测试机检测电路板时检测时间长、测试效率低、单针检测容易撞针等问题,提出了一种基于改进粒子群算法的测试路径规划算法.首先,使用分区检测的方式解决两针相撞问题;其次,提出一种改进的粒子群算法,在粒子群算法的基础上加入混沌初始化公式用于约束和更新搜索的最大速度,引入遗传算法的交叉、变异的思想,改进粒子群算法易于趋于局部最优的缺陷,提升了算法的全局搜索能力.与粒子群算法、遗传算法进行有效性的对比分析与实机测试.结果表明:此算法可以有效解决测试时两针相撞问题;比起其他两种算法改进粒子群算法在更少的迭代数的同时全局搜索能力更强,可以减少30%算法运算时间、降低10%的测试距离,具有一定的工程应用价值.

应用挤塑板颗粒制备轻骨料混凝土

在生产挤塑聚苯乙烯板(XPS)的过程中会产生大量的颗粒废料,为避免产生环境问题,可将XPS颗粒废料用于制备轻骨料混凝土。采用外掺法研究聚苯颗粒掺量、XPS废料颗粒和可再分散性乳胶粉对轻骨料混凝土性能的影响。结果表明:聚苯颗粒体积掺量小于1200 mL时,与混凝土的抗压强度、抗折强度、密度呈线性关系,当聚苯颗粒体积掺量为1500 mL时在混凝土中趋向于饱和;可再分散性乳胶粉能改善聚苯颗粒与混凝土之间的界面问题,当质量掺量为6 g时,抗压强度提高了28%、抗折强度提高了48%。使用XPS颗粒等体积取代聚苯颗粒,XPS颗粒较大的空隙率导致导热系数升高;计算中去除颗粒之间空隙后,XPS颗粒等体积取代聚苯颗粒,当取代2/3的聚苯颗粒时导热系数降至0.0896 W/(m·K)。

Ultrafine particle emission characteristics of diesel engine by on-board and test bench measurement

This study investigated the emission characteristics of ultra.fine particles based on test bench and on-board measurements. The bench test results showed the ultrafine particle number concentration of the diesel engine to be in the range of （0.56-8.35）×10^8 cm^-3. The on-board measurement results illustrated that the ultra_fine particles were strongly correlated with changes in real-world driving cycles. The particle number concentration was down to 2.0 ×10^6 cm^-3 and 2.7 ×10^7 cm^-3 under decelerating and idling operations and as high as 5.0×10^8 cm^-3 under accelerating operation. It was also indicated that the particle number measured by the two methods increased with the growth of engine load at each engine speed in both cases. The particle number presented a ＂U＂ shaped distribution with changing speed at high engine load conditions, which implies that the particle number will reach its lowest level at medium engine speeds. The particle sizes of both measurements showed single mode distributions. The peak of particle size was located at about 50-80 nm in the accumulation mode particle range. Nucleation mode particles will significantly increase at low engine load operations like idling and decelerating caused by the high concentration of unburned organic compounds.

On-board measurement of particle numbers and their size distribution from a light-duty diesel vehicle:Influences of VSP and altitude

In this study,the particle size-resolved distribution from a China-3 certificated light-duty diesel vehicle was measured by using a portable emission measurement system（PEMS）.In order to examine the influences of vehicle specific power（VSP） and high-altitude operation,measurements were conducted at 8 constant speeds,which ranged from 10 to 80 km/hr at10 km/hr intervals,and two different high altitudes,namely 2200 and 3200 m.The results demonstrated that the numbers of particles in all size ranges decreased significantly as VSP increased when the test vehicle was running at lower speeds（〈 20 km/hr）,while at a moderate speed（between 30 and 60 km/hr）,the particle number was statistically insensitive to increase VSP.Under high-speed cruising conditions,the numbers of ultrafine particles and PM2.5were insensitive to changes in VSP,but the numbers of nanoparticles and PM10 surged considerably.An increase in the operational altitude of the test vehicle resulted in increased particle number emissions at low and high driving speeds;however,particle numbers obtained at moderate speeds decreased as altitude rose.When the test vehicle was running at moderate speeds,particle numbers measured at the two altitudes were very close,except for comparatively higher number concentrations of nanoparticles measured at 2200 m.

刨花板吸水厚度膨胀率检测不确定度研究

根据JJF 1059.1-2012《测量不确定度评定与表示》要求,对刨花板吸水厚度膨胀率的检测不确定度进行分析。根据刨花板吸水厚度膨胀率的数学计算模型,分析试验过程,确定影响检测结果不确定度的因素有千分尺测量误差、恒温水槽控温误差、操作人员操作误差等。对P2型刨花板进行2 h吸水厚度膨胀率检测,结果表明试验条件下P2型刨花板吸水厚度膨胀率检测结果的扩展不确定为0.1%。

不同粒径的废弃电路板粉末对水泥砂浆基本性能的影响

废弃电路板作为危险废弃物,对环境污染十分严重.为了提高废弃电路板的利用效率,将2种不同粒径的废弃电路板粉末掺入砂浆中,探究其对水泥砂浆抗压强度、抗折强度、流动度和稠度、孔隙率、保水性等性能的影响.研究结果表明:废弃电路板粉末能够提高砂浆强度,且在同一龄期、同一掺量下,细粉改性砂浆的抗压、抗折强度均高于粗粉改性砂浆;废弃电路板粉末的掺入,能够在一定范围内提升水泥砂浆的强度和保水性,有利于发展环境友好型社会.

Genomic polymorphism in consecutive generation rice plants from seeds on board a spaceship and their relationship with space HZE particles

Dry rice seeds(Oryza sativa,subspecies indica)were sandwiched between nuclear track detectors,aboard the Chinese spaceship Shenzhou-3 for seven days.The seeds were recovered and the genomic polymorphism in 201 plants developed from these seeds was studied using random amplified polymorphism DNA analysis.When compared with plants from ground-based control seeds,the genomic polymorphic bands were amplified in 30.2%of the plants from the seeds exposed in space.The results for sequencing and SNP analyses of the polymorphic bands verified the single nucleotide variations in these plants.Genomic poly-morphisms in the consecutive generations of individual plants of the seeds from space were also discovered.Seven seeds receiving hits of HZE(high atomic number and high energy)particles from space were selected for further analyses and variable genomic polymorphisms were detected in all plants that developed from these seeds.Among them,the embryos of three seeds were hit at least once,and mutants with significant changes in agronomic traits were only found in later generations of these seeds.This result implies that the HZE particles of space are effective in inducing the changes of plant genome of inherited phenotypes.

浅谈影响半自磨磨矿效果的因素

结合云南某选矿厂SAB磨矿流程中半自磨运用实践,针对半自磨机在生产运行中存在的问题,探索影响半自磨磨矿过程的关键性因素,分析各因素对半自磨磨矿过程的影响,总结半自磨操作控制关键点控制途径,提高半自磨磨矿系统过程的稳定性,改善磨矿效果,促进半自磨磨矿在矿山生产运用中的适应性。

印刷线路板废弃物的热解及其产物分析

Pyrolysis experiments of a typical printed circuit boards has been carried out under various conditions in a laboratory installation Liquid yield of 15%～21%, gas yield of 15%～20% and solid yield of about 60% were obtained The liquid products had high gross calorific values that might be recycled as fuel oils after simple treatment CO, CO 2 and N 2 were the main constitutes of the gas products Using combustion method, organic carbon of 7% in the solid products could be removed Then the solid products, which contained high purity fiberglass and CaCO 3, could be reused as filling materials in the process of SMC production In addition, the effects of final pyrolysis temperature (FPT) and particle size on pyrolysis products had been investigated The yield of gas products will be increased under high temperature and with powder

竹席/竹碎料新型建筑模板制备工艺研究

将小径竹及竹材加工剩余物加工成一定规格的竹碎料。以竹碎料为芯层,以竹席为表层组成板坯,通过热压制备竹席/竹碎料新型建筑模板。采用正交试验,选取热压时间、热压温度和施胶量作为工艺因素,对竹席/竹碎料复合新型建筑模板制备工艺进行了研究。研究发现,施胶量对产品的各项性能指标的影响最显著,其次是热压时间和热压温度。通过分析得出优化工艺:热压时间70 s.mm-1,热压温度为170℃,施胶量为10%。

空间搭载水稻种子后代基因组多态性及其与空间重离子辐射关系的探讨

神舟三号飞船搭载带核径迹辐射探测器的水稻种子装置,回收后应用随机扩增多态性DNA(randomamplified polymorphic DNA,RAPD)技术,分析了201粒升空种子长出植株的基因组多态性。在检测的189个基因座位范围内,30.2%的植株中发现与地面对照不同的扩增带,单株的多态性座位数为1￣25。特异扩增带的测序及单核苷酸多态性(single-nucleotide polymorphism,SNP)分析进一步证明了空间搭载水稻种子确实可导致当代植株基因组发生变异。同一技术分析个别种子连续世代的基因组多态性,结果显示,当代的部分多态性可遗传至后代。7粒受空间高原子序数、高能粒子轰击的种子,在当代植株均显示不同程度的基因组多态性,从胚受粒子击中的3粒种子后代中,筛选出农艺性状明显变异的突变株系,初步暗示了空间高能重离子辐射对诱导基因组的多态性,乃至遗传性表型变异的有效性。