Pelleting and particle size reduction of corn increase net energy and digestibility of fiber,protein,and fat in corn-soybean meal diets fed to group-housed pigs

Background Reduction of the particle size of corn increases energy digestibility and concentrations of digestible and metabolizable energy.Pelleting may also reduce particle size of grain,but it is not known if there are interactions between particle size reduction and pelleting.The objective of this experiment was to test the hypothesis that particle size reduction and pelleting,separately or in combination,increase N balance,apparent total tract digestibility(ATTD)of fiber and fat,and net energy(NE)in corn-soybean meal diets fed to group-housed pigs.Methods Six corn-soybean meal-based diets were used in a 3×2 factorial design with 3 particle sizes of corn(i.e.,700,500,or 300μm)and 2 diet forms(i.e.,meal or pelleted).Pigs were allowed ad libitum access to feed and water.Twenty-four castrated male pigs(initial weight:29.52 kg;standard diviation:1.40)were allotted to the 6 diets using a 6×6 Latin square design with 6 calorimeter chambers(i.e.,4 pigs/chamber)and 6 periods.Oxygen consumption and CO_(2)and CH_(4)productions were measured during fed and fasting states and fecal and urine samples were collected.Results Regardless of particle size of corn,the ATTD of gross energy(GE),N,and acid-hydrolyzed ether extract(AEE),and the concentration of NE were greater(P<0.05)in pelleted diets than in meal diets.Regardless of diet form,the ATTD of GE,N,and AEE,and the concentration of NE were increased(linear;P<0.05)by reducing the particle size of corn,but the increase was greater in meal diets than in pelleted diets(interaction;P<0.05).Conclusions Both pelleting and reduction of corn particle size increased nutrient digestibility and NE,but increases were greater in meal diets than in pelleted diets.

Effects of fumaric acid supplementation on methane production and rumen fermentation in goats fed diets varying in forage and concentrate particle size

Background: In rumen fermentation, fumaric acid(FA) could competitively utilize hydrogen with methanogenesis to enhance propionate production and suppress methane emission, but both effects were diet-dependent. This study aimed to explore the effects of FA supplementation on methanogenesis and rumen fermentation in goats fed diets varying in forage and concentrate particle size.Methods: Four rumen-cannulated goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments: low or high ratio of forage particle size: concentrate particle size(Fps:Cps), without or with FA supplementation(24 g/d). Fps:Cps was higher in the diet with chopped alfalfa hay plus ground corn than in that with ground alfalfa hay plus crushed corn.Results: Both increasing dietary Fps:Cps and FA supplementation shifted ruminal volatile fatty acid(VFA) patterns toward more propionate and less acetate in goats. An interaction between dietary Fps:Cps and FA supplementation was observed for the ratio of acetate to propionate(A:P), which was more predominant when FA was supplemented in the low-Fps:Cps diet. Methane production was reduced by FA, and the reduction was larger in the low-Fps:Cps diet(31.72%) than in the high-Fps:Cps diet(17.91%). Fumaric acid decreased ruminal total VFA concentration and increased ruminal p H. No difference was found in ruminal DM degradation of concentrate or alfalfa hay by dietary Fps:Cps or FA. Goats presented a lower ruminal methanogen abundance with FA supplementation and a higher B. fibrisolvens abundance with high dietary Fps:Cps.Conclusions: Adjusting dietary Fps:Cps is an alternative dietary model for studying diet-dependent effects without changing dietary chemical composition. Fumaric acid supplementation in the low-Fps:Cps diet showed greater responses in methane mitigation and propionate increase.

Preparation of CNT/AlS i10Mg composite powders by high-energy ball milling and their physical properties

This study investigated the effects of carbon nanotube （CNT） concentration on the micro-morphologies and laser absorption proper- ties of CNT/AlSi10Mg composite powders produced by high-energy ball milling. A scanning electron microscope, X-ray diffractometer, laser particle size analyzer, high-temperature synchronous thermal analyzer, and UV/VIS/NIR spectrophotometer were used for the analysis of micro- graphs, phases, granulometric parameters, thermal properties, and laser absorption properties of the composite powders, respectively. The results showed that the powders gradually changed from flake- to granule-like morphology and the average particle size sharply decreased with in- creases in milling rotational speed and milling time. Moreover, a uniform dispersion of CNTs in AlSi10Mg powders was achieved only for a CNT content of 1.5wt%. Laser absorption values of the composite powders were also observed to gradually increase with the increase of CNT concentration, and different spectra displayed characteristic absorption peaks at a wavelength of approximately 826 nm.

Effect of ultrasonic irradiation on particle size,reagents consumption,and feed ash content in coal flotation

Ultrasonic waves have a lot of use in the particle surface cleaning.As flotation is one of the methods associated with surface properties,this paper investigates the effect of these waves on performance,particle size,reagents,and feed ash content in coal flotation.To accomplish this goal,coal samples in three size fractions,including coarse(-800 to+400μm),medium(-400 to+100 μm)and fine(-100μm)with various feed ash content.The flotation experiments were evaluated by process indexes such as yield,combustible recovery,and selectivity index.The results indicated the increasing of yield.The increasing was significant in medium size.Furthermore,the results showed that in presence of ultrasonic waves,the collector and frother consumption decreased.And also,applying ultrasonic waves would result more combustible recovery and selectivity index.The ash selectivity index had the highest impact for high feed ash content.

Fabrication of Lead Zirconate Titanate Powder Using Ultrasonic Ball Milling Technique

In this research,the ultrasonic ball milling technique has been used to fabricate lead zirconate titanate(PZT)ceramics.PZT with the composition nearly the morphotropic phase boundary(MPB):Pb(Zr_ 0.52Ti_ 0.48)O_3 was studied.The effect of milling time on phase formation of sample powder was examined by X-ray diffraction technique(XRD).Moreover,the physical,dielectric,piezoelectric properties and microstructure of PZT ceramics were investigated.The present results reveal that the ultrasonic ball milling technique results the homogeneous and small size of PZT powder.Furthermore,there is a significantly change occurs in the size of the particles with the short time of milling process.

Refinement of TiB_(2)Powders with High-speed Planetary Mill and Its Effect on TiB_(2)Sinterability

Titanium diboride ceramic was produced via spark plasma sintering(SPS)using finer TiB_(2)powder made by high-speed planetary ball milling.The effects of ball milling parameters on the composites and particle size of TiB_(2)powder were investigated.It was shown that the average particle size of TiB_(2)powder decreased from 5.8 to 1.59μm and the wear rate of WC balls was 1.58 wt%,when the ball-to-powder weight ratio(BPR),the rotary speed and milling time and were 10:1,600 rpm and 20 min,respectively.The content of WC in TiB_(2)powder can be limited below 4.58 vol%by optimizing the milling conditions.The sintering temperature of TiB_(2)powder milled can be decreased obviously,and the mechanical properties are evidently improved and the microstructure becomes more homogeneous when the powder of TiB_(2)becomes finer.The relative density,hardness,bending strength,and fracture toughness of the TiB_(2)ceramic fabricated at 1700℃reach the optimal values,which are 98.13%,19.14 GPa,756 MPa,and 5.71 MPa·m~(1/2),respectively.The decrease of TiB_(2)particle size and the introduction of WC are the potential reasons for the improvement of TiB_(2)ceramic performance.

不同粒径硬颗粒饲料养殖克氏原螯虾的投饲策略研究

为探究不同粒径硬颗粒饲料投饲策略对克氏原螯虾(Procambarus clarkii)生长性能、消化酶活性和免疫的影响,本实验采用两种粒径饲料(2 mm和3 mm),进行4种不同组合,分别为FS1组(3 mm粒径饲料投喂60 d)、FS2组(2 mm粒径饲料投喂10 d和3 mm粒径饲料投喂50 d)、FS3组(2 mm粒径饲料投喂20 d和3 mm粒径饲料投喂40 d)和FS4组(2 mm粒径饲料投喂30 d和3 mm粒径饲料投喂30 d),对克氏原螯虾幼虾(7.73±0.05)g进行为期60 d的养殖试验。结果显示,各组间存活率、肝体比、肥满度和腹部含肉率均无显著差异。克氏原螯虾增重率和特定生长率均呈现先升高后降低,且在FS2组达到最大值。FS2组和FS3组的饲料系数显著低于其他处理组。各组间肝胰腺淀粉酶和脂肪酶活性均无显著性差异,而胰蛋白酶活性先升高后降低且在FS2组达到最高水平。不同粒径硬颗粒饲料投饲策略对血清非特异性免疫酶活性(碱性磷酸酶、酸性磷酸酶)、超氧化物歧化酶、总抗氧化能力以及丙二醛含量均无显著影响。与单一粒径组(FS1组)相比,FS3组克氏原螯虾肝胰腺超氧化物歧化酶活性显著提高,FS2组和FS4组丙二醛含量显著降低。综上所述,单一粒径饲料(3 mm)投喂无法满足克氏原螯虾幼虾生长需求,适宜饲料粒径组合投喂提高了克氏原螯虾的消化酶活性和抗氧化能力,促进了生长,降低了饲料系数,其中以2 mm粒径饲料投喂10 d和3 mm粒径饲料投喂50 d的组合投饲策略最佳。

基于MatLab的颗粒饲料休止角试验研究

颗粒饲料休止角对饲料储料箱设计、自动化饲喂站、投料装置设计等工程实践有重要指导意义。为实现休止角的快速准确测量,探究颗粒饲料休止角与粒径、表面能之间的关系,利用物理试验与离散元仿真相结合的方法对颗粒饲料堆进行基于MatLab图像处理的休止角测定。由于传统休止角的测量存在系统误差和测量精度低的问题,本文提出一种基于MatLab图像处理方法的休止角测定,利用傅里叶级数对堆积图像进行轮廓拟合,利用拟合曲线的单边斜率求出休止角大小,操作便捷,可提高测量精度。基于这种方法,对颗粒饲料堆进行分析,探究了颗粒粒径对休止角的影响并进行仿真试验,利用EDEM以物理试验得到的休止角为目标值进行仿真试验,以休止角作为参照,标定接触模型JKR表面能。试验结果表明:6.5mm颗粒饲料实际休止角为34.992°,仿真休止角为34.9535°;5mm颗粒饲料实际休止角为36.9797°,仿真休止角为35.2603°;3.2mm颗粒饲料实际休止角为37.9186°,仿真休止角为36.092°。休止角仿真结果与实际试验结果较为接近,两者的绝对误差分别为:6.5mm对应0.11%,5mm对应4.65%,3.2mm对应4.82%,表明颗粒饲料的休止角随着粒径的增大而减小,根据颗粒饲料参数建立的离散元模型,3种粒径的颗粒饲料其对应表面能分别为:3.2mm对应0.15J/m^(2),5mm对应0.22J/m^(2),6.5mm对应0.22J/m^(2)。

球磨对细鳞片石墨破坏程度的影响研究

以东北某细鳞片石墨矿为研究对象,考察球磨时间、球磨质量分数和介质填充率等因素对石墨鳞片破坏程度的影响,分析磨矿产物累计产率和颗粒中石墨鳞片平均粒径,探索石墨鳞片破坏机理。结果表明,磨矿过程中,粗粒石墨颗粒最先被破坏,球磨时间越长石墨鳞片破坏程度越高,当球磨时间为30 min时破坏程度最高,达到68.17%;球磨质量分数改变对连生体中石墨颗粒粒径变化影响较大,+300μm和-300+180μm区间粒级中连生体颗粒中石墨鳞片平均粒径下降幅度分别为6.69%和12.79%;介质填充率对石墨颗粒粒径影响较小。石墨矿物颗粒表面裂纹发育特征表明,颗粒越大,表面裂纹越多,越容易被破坏,石墨单体颗粒中的穿晶裂纹和连生体中的晶内裂纹是影响石墨鳞片破坏的主要因素。

沙粒粒径分布对高尔夫球在沙坑中球位的影响

【目的】探索沙坑沙粒粒径特征对沙坑中高尔夫球位的影响。【方法】选取兰州市高尔夫球场常用的3种沙坑沙进行粒径分布分析,确定粒径大小、级配指数、不均匀系数、曲率系数、静止角和沙面硬度;采用模拟高尔夫球坠入沙坑的方法,以不同沙与粒径组分组合为处理,研究沙坑中球坑的大小和深度,推导不同沙粒组成对高尔夫球球位的影响以及可获得较为理想球位的沙坑沙应具备的粒径特征。【结果】选取的3种沙坑沙中,河沙质地较粗、粒径分布连续广泛且均匀、级配好、硬度大、稳定性强。从1 m高度模拟坠球,河沙球坑内径和深度显著小于土沙和山沙(P<0.05),不易产生“荷包蛋”球位。另外,通过对中粗粒径(0.25~20)mm组分和不同单一粒径组分进行1 m高度模拟坠球发现,0.25~2 mm粒径的河沙不容易产生埋嵌的“荷包蛋”球位。【结论】质地较粗、粒径分布广且均匀、级配好、细小沙粒少且粒径最佳在0.25~2 mm范围的沙能更好地形成较为理想的球位;粒径分布窄、级配差、中位粒径<0.5 mm的沙极容易形成“荷包蛋”球位。

不同生产工艺和赖氨酸、蛋氨酸添加水平对饲料中晶体氨基酸在水中溶失率的影响研究

本试验旨在研究不同生产工艺(饲料料型、饲料粒径)和赖氨酸(Lys)、蛋氨酸(Met)添加水平对饲料中晶体氨基酸在水中溶失率的影响。研究结果表明:(1)饲料料型对虾料中晶体赖氨酸在水中的溶失率有影响。浸泡30 min后,膨化浮性虾料的晶体赖氨酸溶失率最高(73.85%),显著大于膨化沉性虾料(66.05%)和非膨化颗粒虾料(50.84%)。(2)在浸泡(5、15 min)前期,饲料粒径对膨化沉性蟹料中晶体赖氨酸的溶失率影响不显著;但浸泡30 min后,饲料中晶体赖氨酸的溶失率会随着饲料粒径的减小而显著提高。(3)Lys和Met添加水平对膨化料中晶体赖氨酸、晶体蛋氨酸在水中的溶失率没有影响。(4)饲料经过浸泡后,其晶体赖氨酸的溶失率显著低于晶体蛋氨酸溶失率。因此,在虾蟹饲料的实际生产过程中,配方中晶体氨基酸的添加量需考虑晶体氨基酸的溶失情况;同时,在符合动物摄食习性的条件下,选择生产粒径较大的非膨化颗粒饲料可能会明显降低晶体氨基酸在水中的溶失率,进而提高晶体氨基酸的利用率。

球磨法制备芡实超微粉及其理化功能性质分析

芡实淀粉属小颗粒淀粉,且以超聚合的复粒形式存在。为了解超微粉碎对淀粉复粒结构及其中功效组分溶出的影响,文中采用球磨法制备超微芡实粉,分析了不同球磨参数对芡实粉理化功能性质的影响。研究显示,芡实粉的适宜球磨参数为:转速200 r/min,m(用料量)∶m(研磨球)=1∶30,研磨球直径4 mm,研磨时间30 min。与对照相比,所得超微芡实粉中超细粉末(粒径0~1μm)占比达到85.04%,其中总黄酮溶出量增加不显著,但总酚溶出量有明显增加(P≤0.05)。所得超微芡实粉吸水性和吸油性显著提高,分别达到3.88、2.46 g/g,分别增加了3.26、1.34倍。X-衍射图谱和扫描电子显微镜照片显示,超微芡实粉中淀粉的复粒结构发生碎裂,淀粉颗粒完整性及其晶体结构也被严重破坏,印证了超微芡实粉理化功能性质改变的内在原因。研究结果表明,球磨处理不仅改善了芡实粉的理化功能性质,也有利于其中功效组分的溶出。

基于液体射流破碎法制备粒径可控的聚乙烯醇微球

在工业生产中,聚乙烯醇(polyvinyl alcohol,PVA)微球多采用机械搅拌法制备,得到的微球粒径不可控、粒径分布宽、小粒径(100~300μm)微球产率低。为改善上述问题,本研究将液体射流破碎法应用于油包水(W/O)微球制备体系,制备了粒径可控、粒径分布窄的PVA水凝胶微球。本研究系统研究了分散相流速、PVA浓度、加料装置内径及稳定剂浓度对微球粒径和粒径分布的影响。最终,采用分散相流速为40 mL/min、PVA浓度为7.0%、加料装置内径为400μm及稳定剂浓度为11.5%的条件,制备了平均粒径为146.00μm,粒径分布为1.63的PVA微球。该方法得到的小粒径微球产率高、批次间重复性良好、装置简单,可实现微球的规模化生产。

基于RRB方程探究粉磨工艺对熟料粒径的影响

为研究粉磨工艺对熟料粒径分布的影响,采用行星式球磨机探究了不同钢球级配和粉磨时间下熟料粒径分布情况,结合RRB(Rosin-Rammler-Bennet)方程计算了熟料的均匀性指数和特征粒径,建立了激光粒度分析法和勃氏法两种不同测试比表面积方法的关联关系。结果表明,粉磨30 min之前,熟料粒径随着粉磨时间的延长逐渐减小,均匀性指数逐渐提高,特征粒径逐渐减小,比表面积增长显著。但是,粉磨时间超过30 min后,熟料粒径变化不明显,均匀性指数略微减少,特征粒径基本无变化,比表面积增长幅度不大。综合考虑熟料粒径分布和能源消耗情况,应选取合适的粉磨时间。钢球直径对熟料粒径分布具有重要影响。随着直径为10 mm钢球数量的减少,大于80μm的熟料颗粒含量大幅度增多,5~45μm的熟料颗粒含量显著减少,熟料均匀性逐渐变差,特征粒径增大。激光粒度分析法能够较好地反映熟料的细度,其测试的比表面积和勃氏法测试的比表面积具有较好的线性相关性。

某锌锡铜铁硫多金属矿应用陶瓷球工业试验

为了提高云南某锌锡铜铁硫多金属矿选矿技术指标,推动绿色低碳发展,针对钢锻磨矿过程能耗高,同时伴随磨矿产品易过磨等问题,进行了纳米复合陶瓷球替换钢锻的二段磨矿工业应用研究。研究结果表明:纳米复合陶瓷球磨矿可以改善磨矿产品粒度分布特性,易选粒级含量明显增加,其溢流产品中过细粒级-0.010 mm产率降低1.30个百分点,有效减轻了过粉碎,使得锡粗精矿理论回收率提高了0.60个百分点;磨矿单位电耗降低43.32%,单位球耗降低10.34%,综合磨矿成本降低31.00%,节能降耗效果显著。

Solvent-free synthesis of alumina supported cobalt catalysts for Fischer–Tropsch synthesis

A novel mechano-synthesis method has been elaborated in this work for the design of efficient cobalt-based Fischer–Tropsch catalysts. The process aims to reduce the total number of steps involved in the synthesis of solid catalysts and thus to avoid relevant toxic solutions generated during the catalyst preparation. The mechano-synthesis of the Co/Al2O3catalyst was processed in a low-energy vibratory micro mill and high energy planetary ball mill. Porous spherical γ-aluminas (1860 µm and 71 µm mean particle diameter) were used in this work as host compounds. Co3O4(3 µm mean particle diameter) has provided guest particles for mechano-synthesis. The catalysts were characterized by textural (surface area, porosity and particle size) and structural analyses (X-ray diffraction, TPR, SEM-EDX and microprobe). The microprobe images show deposition of Co3O4on the surface of the alumina and indicated no Co3O4diffusion inside the alumina pores. SEM-EDX mapping illustrated that cobalt coating tended to occur on surface of rounded shape of cracked alumina fragments. After milling, the crystallite size of Co3O4decreased to 15 nm from 30 to 50 nm. The TPR profiles indicated very low concentrations of inactive cobalt aluminate mixed compounds which are usually produced during the catalyst preparation by impregnation. In Fischer–Tropsch synthesis, the catalysts prepared using mechano-synthesis methods showed catalytic performance comparable to the catalysts prepared by impregnation. © 2016 Science Press

Prediction and Analysis of Deposition Efficiency of Plasma Spray Coating Using Artificial Intelligence Method

Modern industrial technologies call for the development of novel materials with improved surface properties, lower costs and environmentally suitable processes. Plasma spray coating process has become a subject of intense research which attempts to create functional layers on the surface is obviously the most economical way to provide high per- formance to machinery and industrial equipments. The present work aims at developing and studying the industrial wastes (Flay-ash, Quartz and illmenite composite mixture) as the coating material, which is to be deposited on Mild Steel and Copper substrates. To study and evaluate Coating deposition efficiency, artificial neural network analysis (ANN) technique is used. By this quality control technique, it is sufficient to describe approximation complex of in- ter-relationships of operating parameters in atmospheric plasma spray process. ANN technique helps in saving time and resources for experimental trials. The aim of this work is to outline a procedure for selecting an appropriate input vec- tors in ANN coating efficiency models, based on statistical pre-processing of the experimental data set. This methodology can provide deep understanding of various co-relationships across multiple scales of length and time, which could be essential for improvement of product and process performance. The deposition efficiency of coatings has a strong dependence on input power level, particle size of the feed material, powder feed rate and torch to substrate distance. ANN experimental results indicate that the projection network has good generalization capability to optimize the deposition efficiency, when an appropriate size of training set and network is utilized.

智能磨矿系统半自磨机控制关键参数研究

以某选矿厂半自磨工艺智能磨矿系统生产实践为基础,总结分析了智能磨矿系统半自磨机重要控制参数的影响和运行情况。通过分析生产实践数据发现,智能磨矿系统的关键控制参数为半自磨机转速、给矿粒度、半自磨机磨矿浓度。半自磨机转速对智能磨矿系统的控制最敏感,调节效果最显著,可快速调整磨矿系统运行状态;给矿粒度次之,能起到短时调节作用;半自磨机磨矿浓度敏感性最弱,可实现微调。通过上述关键参数的协同控制,能实现磨矿系统处理能力最大化,产品粒度可调可控。

基于语义分割的炼铁球团粒径在线检测算法研究

铁矿成团过程中,对球团粒径有严格要求。为了能实时检测球团粒径,本文通过对造球机的动态区域图像进行分析,提出了前景提取加粘连分割的球团分割算法。该算法针对图像球团背景矿粉干扰问题,在Unet基础上融入可分离卷积结构,设计了轻量化的DSC-Unet前景分割网络,保证了前景分割的鲁棒性;同时针对球团相互重叠问题,使用了一种基于距离变换的分水岭分割方法,实现了前景粘连的分割,进而通过圆形拟合,获得球团直径。试验结果表明,所涉算法分割准确率达到97%,优于现有其他算法,达到了检测要求。

不同种类原料粉碎粒度对饲料品质、肉鸡能量利用的影响

试验旨在研究玉米、豆粕的粉碎粒度对饲料品质及不同日龄阶段肉鸡生长性能和能量代谢的影响。试验分为两部分,均采用单因素完全随机试验设计。试验饲粮分为玉米、豆粕型两种,玉米型日粮是将玉米分别通过1、2、3 mm粉碎筛片进行粉碎,其他大片原料通过2 mm粉碎筛片;豆粕型日粮是将豆粕分别通过1、2、3 mm粉碎筛片进行粉碎,其他大片原料通过2 mm粉碎筛片。试验选取11日龄肉鸡288只、24日龄肉鸡192只,每个日龄分为6组,前3组用于玉米粉碎粒度试验,后3组用于豆粕粉碎粒度试验,每组8个重复,每个重复4(大日龄)或6(小日龄)只鸡。试验期为6 d(预试期3 d、正试期3 d)。结果表明:(1)玉米、豆粕的几何平均粒径均随筛片孔径增加而增加;相同粉碎筛片孔径下,豆粕的几何平均粒径均大于玉米;玉米的几何平均粒径与筛片孔径存在线性关系:y=90x+359.33(P<0.001,R2=0.983),豆粕的几何平均粒径与筛片孔径存在线性关系:y=110x+359.00(P<0.001,R^(2)=0.990);颗粒饲料硬度随粉碎粒度增加而显著降低(P<0.05)。(2)玉米、豆粕不同粉碎粒度对试验鸡的能量代谢无显著影响。(3)肉鸡11~16日龄时,豆粕组在3 mm粉碎筛片孔径下平均日采食量显著高于1 mm时(P<0.05),玉米、豆粕组都是3 mm粉碎筛片孔径下料重比最低(P<0.05);肉鸡24~29日龄时,玉米及豆粕粉碎粒度对肉鸡平均日增重、平均日采食量、料重比无显著影响(P>0.05)。综上所述,粉碎粒度对饲料品质有显著影响,粉碎粒度对11~16日龄肉鸡的生长性能影响比24~29日龄更为显著,推荐粉碎筛片孔径为3 mm,即玉米、豆粕平均几何粒径分别为638、681μm。