SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

INTRODUCTIONIn papermaking, it is very often that more than one type (or grade) of pulps are used to develop paper sheet properties necessary for both machine runnability and requirement from the end users. In many high end paper grades (e.g., various high brightness printing/writing papers), long fiber from softwood bleached kraft pulp traditionally is often used in combination with short fiber from hardwood bleached kraft pulp (HBKP). In this combination, the long fiber component provi…     

ENZYME-ASSISTED DEINKING AND FIBER MODIFICATION OF MIXED OFFICE WASTE

INTRODUCTIONIn the past 20 years, more and more waste papers were recycled because of the shortage of raw materials and increasing pressure of environment protection. Among those recycled waste paper, MOW, which contains xerographic and laser printed pape…     

OPTIMIZING EUCALYPTUS PULP REFINING

This paper discusses the refining of bleached eucalyptus kraft pulp (BEKP).Pilot plant tests were carried out in to optimize the refining process and to identify the effects of refining variables on final paper quality and process costs.The following parameters are discussed: pulp consistency, disk pattern design, refiner speed,energy input, refiner configuration (parallel or serial)and refining intensity.The effects of refining on pulp fibers were evaluated against the pulp quality properties, such as physical strengths, bulk, opacity and porosity, as well as the interactions with papermaking process, such as paper machine runnability, paper breaks and refining control.The results showed that process optimization,considering pulp quality and refining costs, were obtained when eucalyptus pulp is refined under the lowest intensity and the highest pulp consistency possible. Changes on the operational refining conditions will have the highest impact on total energy requirements (costs) without any significant effect on final paper properties.It was also observed that classical ways to control the industrial operation, such as those based on drainage measurements, do not represent the best alternative to maximize the final paper properties neither the paper machine runability.     

全亚麻卷烟纸的研制与开发

对亚麻纤维进行打浆、抄片,检测物理指标,根据抄片指标,制定出适合生产全亚麻卷烟纸的打浆工艺,根据生产车间工艺设备配置,对盘磨磨齿进行选择、对打浆功率进行调整,对打浆浓度、打浆度、湿质量进行控制,成功开发出预期目标的全亚麻卷烟纸.     

PREPARATION AND CHARACTERIZATION OF MODIFIED STARCH-BASED BIODEGRADABLE MATERIALS EINFORCED WITH PULP FIBER

Native com starch and hydroxypropyl starch (HPS)based plastic films were prepared using the short pulp fiber as reinforcement and the glycerol as the plasticizer. The results of tensile test showed that the tensile strength and the elongation at break increased with the pulp contents. With the glycerol contents,the elongation at break increased considerably, but the tensile strength decreased. The water uptake of the films decreased with the pulp contents and hydroxypropylation, but increased with the glycerol contents. So it is concluded that the films was reinforced by pulp fiber and hydroxypropylation.     

PREPARATION AND CHARACTERIZATION OF MODIFIED STARCH-BASED BIODEGRADABLE MATERIALS REINFORCED WITH PULP FIBER

INTRODUCTIONThe developments of environmentally friendly polymeric are classified into two categories: the degradable synthetic polymers (PCL [1- 2], PLA and PVA [3], etc.) and the renewable natural polymers (chitin, pectin, cellulose [4-7] and starch [8], etc.) Among these, starch has been considered for many years as a polymer with a high potential for packaging application because of low cost, renewability and biodegradability. It usually has two major components and appears as a mi…     

混凝土结构加固中植筋深度的试验研究

通过在混凝土中植筋的拉拔试验,研究了不同条件下植筋的破坏形态,分析了混凝土强度、钢筋直径和植筋的强度等级对植筋深度的影响,给出了粘结破坏、锥形破坏、钢筋屈服和应力传递破坏等4种破坏形态的计算模型,推导出了相应的植筋深度计算公式,并通过多组试验证明了计算公式的正确性并给出了避免粘结破坏和锥形破坏的植筋深度计算公式．     

思茅松硫酸盐浆粮食包装袋纸的打浆工艺研究

针对粮食包装袋的特殊要求,研究了思茅松硫酸盐浆抄造粮食包装袋纸的打浆工艺.实验结果表明,打浆时间和打浆浓度对纸张的抗张强度、抗张能量吸收、伸长率、耐破度等都有一定程度的影响;思茅松硫酸盐浆在打浆浓度为16%时利用PFI磨打浆5,min时所抄纸页可以满足粮食包装袋纸的性能要求.以20%与5%的浓度组合进行组合打浆,更可取得较好的纸张韧性发展,同时获得良好的纸张撕裂强度和透气度性能,所制粮食包装袋纸具有较好的使用性能.     

漆酶和漆酶/介体体系对AOCC浆的改性和纤维表面变化

利用NS51003漆酶对美国旧瓦愣纸箱（AOCC）浆进行生物酶改性，研究了漆酶用量对AOCC浆强度性能的影响。研究结果表明，在最佳酶促反应条件下，即：浆料浓度5％；pH7；反应温度室温；反应时间1h；通空气时，漆酶最佳用量为16U／g。同时还发现，漆酶处理过程中加入介体（丁香酸甲酯MS）后，与单独用漆酶处理相比，AOCC浆的湿抗张强度和湿环压强度均得到进一步的明显提高，这说明介体MS对促进漆酶处理AOCC浆有显著的效果。对漆酶处理和空白的浆样与手抄片进行扫描电镜分析的结果表明，经过漆酶处理后，纤维表面状况发生了明显的变化。     

基于Midas FEA的箱涵套管加固效果分析

以湖北省某农村公路提档升级项目中箱涵套管加固为工程背景,考虑混凝土的材料非线性,简化填土与箱涵之间的接触非线性,利用Midas FEA建立箱涵套管加固的精细化有限元模型,对比分析了箱涵套管加固前后的受力性能。计算分析表明:箱涵加固后其水平变形、竖向变形分别下降98.21%、96.53%,混凝土的第一主拉应力、第一主压应力最大值分别下降82.09%、94.95%,钢筋的拉应力、压应力最大值分别下降93.26%、85.00%,裂缝宽度最大值一定程度降低,箱涵采用套管加固效果明显;套管加固后,套管内钢筋以及填充区混凝土应力较小,考虑工程经济性,可在规范允许范围内适当降低套管配筋率、选取低强度钢筋、降低填充区混凝土标号,建议在石料充裕时采用片石混凝土代替混凝土。     

REFINING BEHAVIOUR OF BAMBOO LONG FIBRE FRACTION PULP

The strength properties of a sheet of paper depend on the original qualities and strength of the fibres and to the extent of bonding between the fibres that make up the sheet. A paper sheet made from virgin pulp without beating/refining is characterized by low strength, bulkiness and rough surface. These undesirable characteristics can be changed to a large extent by treating the pulp mechanically. This mechanical treatment of fibres in water is termed beating/refining. The refining of any fib…     

REFINING BEHAVIOR OF BAMBOO LONG FIBER FRACTION PULP

Refining of pulp significantly contributes to papermaking process by affecting the runnability of the stock and quality of end product. The greater the production rates of a paper, the greater are the effects of machine downtime through breaks. A correct approach towards refining treatment is very essential for energy savings and product with desired properties. Papermakers are being encouraged to use non-wood fibres for a variety of reasons - the environment, changing agricultural policy and long-term fibre supply. Compared with wood fibres,there is less knowledge on how to treat non-wood fibres for optimum performance. Laboratory studies aimed at understanding the behaviour of unbleached bamboo long fibre fraction pulp on refining in Escher Wyss Laborefiner under simulated process conditions included investigations of the important parameters like wet web tensile, wet web elongation, water retention value and paper strength properties. The paper describes the influence of two specific edge loads, 1000 and 1500 Ws/km on refining of pulp.Bamboo long fibre fraction pulp responds better to lower intensity refining to develop pulp strength.     

薄型粘合法非织造布的结构与性能

本文应用扫描电镜实验手段,结合气流成网机理,通过粘合剂对纤维的润湿效果,纤维网中纤维杂乱分布程度,以及非织造布断裂强度的分析,对 SW-63型气流成网机和 K 12气流成网机两种成网形式形成的纤维网,经粘合剂加固制成的非织造布结构与性能进行了研讨,得到的结论是:K12气流成网机中的纤维在网中的杂乱程度,比 SW-63型气流成网机好.纤维在网中的相对位置分布影响粘合剂对它的润湿,即粘附。粘合剂种类和纤维强力对非织造布的断裂强度有较大的影响.     

AN INVESTIGATION ON THE ELECTROLYTIC SURFACE TREATMENT OF CARBON FABRICS

The composites obtained from carbon fibers have poor interlaminar shear strength beacuse ofthe few active polar groups on the carbon fiber surface and the weak bonding between the carbonfiber and the resin matrix. An electrolysis study to increase the surface acidic groups of the carbonfiber was investigated in this paper. Experimental results showed that the surface acidic groups,tensile strength, peeling strength of the carbon fabrics increased under certain electrolytic condi-tions, but the breaking elongations decreased. When the electrolytic conditions were too strong,tensile strength and peeling strength dropped down. Electronic scanning micrographs showed theengraved surfaces of carbon fibers after electrolysis.     

THE DEINKING OF NON-IMPACT PRINTED PAPER BY COMBINING ENZYME WITH MECHANICAL ACTION

We studied an enzymatic deinking process of non-impact printed paper which was carried out in batch equipment, similar to Valley beater. The equipment can provide suitable forces to cause toner separation from fiber rather than fiber damage. The factors that influenced the deinking efficiency included beating time, pressure between rotating bars and bottom bars, enzyme properties such as dosage,cellulase activity, temperature, pH, etc. Beating time and enzyme type and enzyme dosage was investigated in detail. The deinked pulp was brighter and cleaner. The drainage property also can be controlled by adjusting enzyme dosage and mechanical action strength. Combining enzyme with mechanical action provides the best deinking effects,not enzyme alone. In the meantime, mechanism of enzymatic deinking was discussed depending on the deinked pulp properties.     

竹浆纤维再回收利用及纸张强度改善

 研究了竹浆纤维的循环再利用及超声波处理对竹浆纤维和纸张特性的影响;评价了竹浆纸张的密度、抗张强度等特性,探讨了单纤维强度和纸张纤维间结合力的关系。结果表明,竹浆纸张的密度和抗张强度随着循环再利用次数的增加而降低,超声波处理纸浆纤维提高了纸张的抗张强度。Page理论表明,纸张抗张强度的提高主要是由于超声波处理增强了纸张内部的纤维间结合力。光学显微镜结果显示,超声波处理通过切断纤维、润胀纤维、细纤维化纤维的作用,有效改善了纸张的强度。研究表明,纸张的循环再利用会降低竹浆的保水值,而利用超声波处理可以有效提高纸浆的保水性能,改善纸张的抗张强度。     

Study on the Structure and Properties of Polynosic Fiber Treated by Alkali

The regenerated cellulose fibers, made from wood pulp, have excellent physical properties like cotton fiber. Especially polynosic fibers can be mercerized by alkali, but conventional Viscose fiber can not be treated or mercerized by alkali. The paper studies on behavior of polynosic fibers treated by alkali, including physical properties, such as weight loss, tensile strength and elongation, and fiber structures properties. In this paper, on the basis of study on polynosic fibers treated by alkali, the conclusions were drawn as following. Firstly, polynosic fiber is good at alkali resistance. Secondly, the changes of fiber structure and physical properties begin declining at 5 wt% NaOH concentration and reverse changes take place at 10 wt%.     

平面应力状态下混凝土强度的软化

变换施加于钢筋砼平板试件水平及垂直方向拉力与压力的比值以及钢筋的配置方向,使平板内产生不同的应力状态、用于研究砼强度的软化性能。研究表明:在二向拉压力作用下,钢筋砼平板中的砼不仅主应力方向的抗压强度降低,而且抗拉强度也降低,即存在砼强度软化现象。同一砼和配筋率情况下,砼强度的降低程度与配筋角度及施加于试件两向的拉压应力比有关,而与加載路径无关。通过分析,提出了砼抗压和抗拉的强度软化计算公式。     

UHMWPE背板铺层角度对陶瓷复合靶板抗弹性的影响

由于背板强度对陶瓷/纤维复合装甲的抗弹性能存在明显影响，采用12.7 mm穿燃弹(刚脆性)冲击实验研究了不同UHMWPE背板铺层角度对陶瓷/纤维复合装甲弹道冲击性能的影响.通过观测回收的弹芯、靶体陶瓷及纤维背板宏观破坏特征，分析了陶瓷/纤维复合装甲的耗能机理及抗弹性能.试验结果表明，陶瓷锥是陶瓷面板的主要破坏模式，其宏观裂纹主要有:径向、环向及与锥形裂纹；纤维背板变形模式为动态锥形鼓包及边界褶皱，其破坏失效模式有:剪切失效及层间剥离.并且，背板强度对陶瓷/纤维复合靶板的抗弹性能有明显影响，随着UHMWPE背板铺层角度的减小，背板强度以及陶瓷/纤维靶板整体结构刚度随之增大，靶板对弹芯的破碎作用越明显，冲击后剩余弹芯最大碎片质量减小，小碎块数量增多，弹丸碎块穿透靶板后剩余侵彻能力减弱，复合靶板整体抗弹性能增加，同时背板鼓包高度减小，锥形鼓包所形成的角度增大，纤维层合板的破坏失效模式从剪切失效向层间剥离转变.      

W1型弹条扣压力与疲劳性能的试验研究

W1型扣件弹条是高速铁路无砟轨道常用的弹条之一,高速铁路弹条在实际工作时受到反复多变的荷载作用,其强度会逐渐变化并发生疲劳破坏.以W1型弹条为列,首先,将W1型弹条的原材料60Si2 MnA弹簧钢加工成试验所需试件进行静力拉伸试验;其次,对W1型弹条进行应变电测试验测出弹条各部位的应力变化;最后,通过MTS810伺服液压试验机对W1型弹条施加三种不同的循环荷载工况,研究弹条在循环荷载作用下其扣压力和中端圆弧位移的变化规律.通过试验数据拟合出弹条中端圆弧位移和扣压力的函数方程式.结果 表明:弹簧钢的屈服强度为1600 MPa,抗拉强度为1900 MPa.弹条内侧圆弧应力值最大也是最易断裂的位置和25 kN是弹条的最佳安装预压力,随着疲劳荷载的循环次数增加,弹条扣压力与中端圆弧位移呈反相关系,弹条在5、7.5、10 kN循环荷载作用下的疲劳寿命分别为82万、19万、7万次.