Fluorinated semi-interpenetrating polymer networks for enhancing the mechanical performance and storage stability of polymer-bonded explosives by controlling curing and phase separation rates

Herein, the effect of fluoropolymer binders on the properties of polymer-bonded explosives(PBXs) was comprehensively investigated. To this end, fluorinated semi-interpenetrating polymer networks(semiIPNs) were prepared using different catalyst amounts(denoted as F23-CLF-30-D). The involved curing and phase separation processes were monitored using Fourier-transform infrared spectroscopy, differential scanning calorimetry, a haze meter and a rheometer. Curing rate constant and activation energy were calculated using a theoretical model and numerical method, respectively. Results revealed that owing to its co-continuous micro-phase separation structure, the F23-CLF-30-D3 semi-IPN exhibited considerably higher tensile strength and elongation at break than pure fluororubber F2314 and the F23-CLF-30-D0 semi-IPN because the phase separation and curing rates matched in the initial stage of curing.An arc Brazilian test revealed that F23-CLF-30-D-based composites used as mock materials for PBXs exhibited excellent mechanical performance and storage stability. Thus, the matched curing and phase separation rates play a crucial role during the fabrication of high-performance semi-IPNs;these factors can be feasibly controlled using an appropriate catalyst amount.

Effect of montmorillonite on hydrate-based methane separation from mine gas

Three types of mine gas samples were used in the solutions of tetrahydrofuran(THF),sodium dodecyl sulfate(SDS)and THF-SDS with/without MMT respectively to investigate the effect of montmorillonite(MMT)on separation characteristics of methane recovered from mine gas based on hydrate method.The partition coefficient,separation factor and recovery rate were used to evaluate the effects of MMT,and the selection factor was primarily proposed to define the selectivity of mine gas hydrate in the relative target gases.The experimental results indicate that MMT could improve the following factors including hydration separation factor,the selection factor,the partition coefficient,and the recovery rate.Furthermore,the effect of SDS on the function of MMT is analyzed in the process of hydration separation.Finally,due to the results of the experiment,it is concluded that MMT hydration mechanism explores the effect of MMT enrichment methane from mine gas.

Phase separation in solvent extraction of cobalt from acidic sulfate solution using synergistic mixture containing dinonylnaphthalene sulfonic acid and 2-ethylhexyl 4-pyridinecarboxylate ester

Phase separation rate is a critical character in determining the usefulness of a solvent extraction system in hydrometallurgy. A survey of the synergistic mixture containing dinonylnaphthalene sulfonic acid (HDNNS) and 2-ethylhexly 4-pyridinecarboxylate ester (4PC) for the extraction of cobalt from acidic single metal sulfate solution was carried out to suggest how the physicochemical properties and the morphology of the reverse micelles in the loaded organic phase affect the phase separation. The results show that effective parameters affecting the phase separation are the viscosity and the excess water uptake of the loaded organic phase. It is obvious that the specific settling rate (SSR) decreases with the apparent increase of these two parameters. The measurement of small angle X-ray scattering (SAXS) proves that the morphology of the reversed micelles in the loaded organic phase changes evidently with the change of the specific settling rate (SSR).

Relative floatability as a criterion for evaluating the separation performance of phosphate from iron

This work was aimed to study the relative floatability of phosphate flotation by means of kinetic analysis.The relative floatability is important to determine how selectively the phosphate is separated from its impurities. The effects of pulp pH, solid content, reagents dosage(depressant, collector and co-collector) and conditioning time were investigated on the ratio of the modified rate constant of phosphate to the modified rate constant of iron(relative floatability). The results showed that a large dosage of depressant associated with a low value of collector resulted in a better relative floatability. Increasing the co-collector dosage, conditioning time and pH increased the relative floatability up to a certain value and thereafter resulted in diminishing the relative floatability. Meanwhile, the results indicated that increment of solid concentration increased the relative floatability in range investigated. It was also found that that maximum relative floatability(16.05) could be obtained in pulp pH, 9.32, solid percentage, 30,depressant dosage, 440 g/t, collector dosage, 560 g/t, co-collector dosage, 84.63 g/t and conditioning time,9.43 min.

Vibrational Spectroscopic Analysis of Borates in Mother Liquid of Brine after Potassium Separated

It is well known that boron exists as polyborate anions in aqueous solution.Boron atom can coordinates to three or four oxygen atoms and borate can exist as not only the monomer but also the polymer.The polymerization

DOUBLE LOOP ACTIVE VIBRATION CONTROL OF PNEUMATIC ISOLATOR WITH TWO SEPARATE CHAMBERS

A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation： ① The low frequency resonances introduced into the system; ② Conflict between lower isolation frequency and stiffness high enough to limit quasi-static stroke;③ Inconsistent isolation level with different force load. The design of two separate chambers is for the purpose of tuning support frequency and force independently and each chamber is controlled by a different valve. The inner one of double-loop structure is pressure control, and in order to obtain good performance, nonlinearities compensation and motion flow rate compensation （MFRC） are added besides the basic cascade compensation, and the influence of tube length is studied. The outer loop has two functions： one is to eliminate the resonance caused by isolation support and to broaden the isolation frequency band by payload velocity feedback and base velocity feed forward, and the other is to tune support force and support stiffness simultaneously and independently, which means the support force will have no effect on support stiffness. Theoretical analysis and experiment results show that the three drawbacks are overcome simultaneously.

Fe3C-N-doped carbon modified separator for high performance lithium-sulfur batteries

A new Fe3C-N-doped reduced graphene oxide(Fe3C-N-rGO)prepared by a facile method is used as a separator for high performance lithium-sulfur(Li-S)batteries.The Fe3C-N-rGO is coated on the surface of commercial polypropylene separator(Celgard 2400)close to the sulfur cathode.The special nanotubes are in-situ catalyzed by Fe3C nanoparticles.They could entrap lithium polysulfides(Li PSs)to restrain the shuttle effect and reduce the loss of active material.The battery with the modified separator and sulfur cathode shows an excellent cycle performance.It has a high rate performance,580.5 mAh/g at the high current rate of 4 C relative to 1075 mAh/g at 0.1 C.It also has an initial discharge capacity of 774.8 m Ah/g measured at 0.5 C and remains 721.8 mAh/g after 100 cycles with a high capacity retention of 93.2%.The outstanding performances are notable in recently reports with modified separator.

Physical simulation and theoretical analysis of migrating rate of inclusions in aluminum melt in electromagnetic field

Simulation law and physical simulation were used to study the kinematic behavior of inclusions in electromagnetic separation. It was found that velocity of spherical non metallic particles shares different functions in different Reynolds number range. The function of spherical particle’s velocity has been got by confirming the relationship between Reynolds number and resistance coefficient when Reynolds number is 0.2 ～10. For non spherical particles, the moving behavior is influenced by shape and orientation while spherical coefficient has nothing to do with the velocity of irregular particles. The influence of orientation of cuboid particle on the electromagnetic expulsive force has been indicated by numerical computation. [

Enrichment of carbon recovery of high ash coal fines using air fluidized vibratory deck separator

Coal is primarily beneficiated by wet gravity methods. The wet processing of coal is an efficient practice. However, it introduces the moisture in the range of 6%-15%, depending upon the size of coal which is as detrimental as ash content to the heating value of coal. Dry beneficiation of coal fines was carried out using an air fluidized vibrating table in which the coal particles get separated from the heavier mineral particles as a result of horizontal and vertical stratification. Two level factorial design matrix was used to optimize and assess the interactive effects of the operational parameters of a pneumatic table viz. deck eccentric, side tilt and air flow rate on the clean coal yield and its ash content. Double stage processing was found to be more effective for reducing the ash content of the clean coal. Initial stage of processing at a higher ash level generates a reject of high ash with low combustibles. Cleaning of the rougher concentrate at 34%-35% ash level shows significant improvement in the organic efficiency （88.6%） and useful heat value of clean coal （15690 kJ/kg）. The performance of air fluidized vibrating deck was measured by Ep value which is 0.18.

Explicit Analytical Solutions of Radial Permeable Power Rate Flow

The research of different kinds of permeable non-Newtonian fluid flow is increasing day by day owing to the development of science,technology and production modes.It is most common to use power rate equation to describe such flows.However,this equation is nonlinear and very difficult to derive explicit exact analytical solutions.Generally,people can only derive approximate solutions with numerical methods.Recently,an advanced separating variables method which can derive exact analytical solutions easier is developed by Academician CAI Ruixian（the method of separating variables with addition）.It is assumed that the unknown variable may be indicated as the sum of one-dimensional functions rather than the product in the common method of separating variables.Such method is used to solve the radial permeable power rate flow unsteady nonlinear equations on account of making the process simple.Four concise（no special functions and infinite series） exact analytical solutions is derived with the new method about this flow to develop the theory of non-Newtonian permeable fluid,which are exponential solution,two-dimensional function with time and radius,logarithmic solution,and double logarithmic solution,respectively.In addition,the method of separating variables with addition is developed and applied instead of the conventional multiplication one.It is proven to be promising and encouraging by the deducing.The solutions yielded will be valuable to the theory of the permeable power rate flow and can be used as standard solutions to check numerical methods and their differencing schemes,grid generation ways,etc.They also can be used to verify the accuracy,convergency and stability of the numerical solutions and to develop the numerical computational approaches.

Non-invasive foetal heartbeat rate extraction from an underdetermined single signal

Extraction of foetal heartbeat rate from a single passive sound sensor on the mother’s abdomen is demonstrated. The extraction is based on the assumption that a disjoint band of frequencies exist and foetal signal is concentrated in this band, and further that it can be represented conveniently as a set of wavelet coefficients. The algorithm has been applied to each stream of data obtained from six different channels and the detection performance is elaborated. The algorithm has also been tested on signals from non-pregnant abdomens to show successful rejection of adult heartbeat. The extraction of the desired signal is done in two stages so as to eliminate components from the maternal heart-beat.

MSSTNet:Multi-scale facial videos pulse extraction network based on separable spatiotemporal convolution and dimension separable attention

Background The use of remote photoplethysmography(rPPG)to estimate blood volume pulse in a noncontact manner has been an active research topic in recent years.Existing methods are primarily based on a singlescale region of interest(ROI).However,some noise signals that are not easily separated in a single-scale space can be easily separated in a multi-scale space.Also,existing spatiotemporal networks mainly focus on local spatiotemporal information and do not emphasize temporal information,which is crucial in pulse extraction problems,resulting in insufficient spatiotemporal feature modelling.Methods Here,we propose a multi-scale facial video pulse extraction network based on separable spatiotemporal convolution(SSTC)and dimension separable attention(DSAT).First,to solve the problem of a single-scale ROI,we constructed a multi-scale feature space for initial signal separation.Second,SSTC and DSAT were designed for efficient spatiotemporal correlation modeling,which increased the information interaction between the long-span time and space dimensions;this placed more emphasis on temporal features.Results The signal-to-noise ratio(SNR)of the proposed network reached 9.58dB on the PURE dataset and 6.77dB on the UBFC-rPPG dataset,outperforming state-of-the-art algorithms.Conclusions The results showed that fusing multi-scale signals yielded better results than methods based on only single-scale signals.The proposed SSTC and dimension-separable attention mechanism will contribute to more accurate pulse signal extraction.

分离禽蛋壳膜粉碎装置刀片的设计与试验

为高效分离回收蛋壳膜,设计了一款采用剪切和碾压的粉碎方式专用于分离禽蛋壳膜的粉碎装置。采用干燥的蛋壳膜进行试验,通过理论分析和预试验确定刀片类型、刀片间隙、转子转速、筛网目数为主要影响因素,根据实际生产情况确定各因素的试验水平,以分离率和损耗率为评价指标进行四因素三水平响应面试验;利用Design-Expert 12.0对试验结果进行响应面分析,研究不同影响因素对评价指标的影响规律。验证试验结果表明:当调整转子转速为1374r/min、安装2目筛网、刀片间隙为1mm的50°剪切式刀片时,分离率为86.72%,损耗率为3.71%,大粒径蛋膜较多。试验装置有效提高了粉碎蛋壳膜后蛋膜的分离效果,降低了损耗率,具有极大的优越性。

Discriminant Analysis of the Linear Separable Data - Japanese 44 Cars

There are four serious problems in the discriminant analysis. We developed an optimal linear discriminant function （optimal LDF） based on the minimum number of misclassification （minimum NM） using integer programming （IP）. We call this LDF as Revised IP-OLDF. Only this LDF can discriminate the cases on the discriminant hyperplane （Probleml）. This LDF and a hard-margin SVM （H-SVM） can discriminate the lineary separable data （LSD） exactly. Another LDFs may not discriminate the LSD theoretically （Problem2）. When Revised IP-OLDF discriminate the Swiss banknote data with six variables, we find MNM of two-variables model such as （X4, X6） is zero. Because MNMk decreases monotounusly （MNMk 〉= MNM（k＋1））, sixteen MNMs including （X4, X6） are zero. Until now, because there is no research of the LSD, we surveyed another three linear separable data sets such as： 18 exam scores data sets, the Japanese 44 cars data and six microarray datasets. When we discriminate the exam scores with MNM=0, we find the generalized inverse matrix technique causes the serious Problem3 and confirmed this fact by the cars data. At last, we claim the discriminant analysis is not the inferential statistics because there is no standard errors （SEs） of error rates and discriminant coefficients （Problem4）. Therefore, we poroposed the ＂100-fold cross validation for the small sample＂ method （the method）. By this break-through, we can choose the best model having minimum mean of error rate （M2） in the validation sample and obtaine two 95% confidence intervals （CIs） of error rate and discriminant coefficients. When we discriminate the exam scores by this new method, we obtaine the surprising results seven LDFs except for Fisher＇s LDF are almost the same as the trivial LDFs. In this research, we discriminate the Japanese 44 cars data because we can discuss four problems. There are six independent variables to discriminate 29 regular cars and 15 small cars. This data is linear separable by the emission rate （X1） and the number of seats （X3）. We examine the validity of the new model selection procedure of the discriminant analysis. We proposed the model with minimum mean of error rates （M2） in the validation samples is the best model. We had examined this procedure by the exam scores, and we obtain good results. Moreover, the 95% CI of eight LDFs offers us real perception of the discriminant theory. However, the exam scores are different from the ordinal data. Therefore, we apply our theory and procedure to the Japanese 44 cars data and confirmed the same conclution.

进液量对气举式同向出流旋流器分离特性影响

为了提高旋流器的分离效率,提出一种气举式同向出流水力旋流器结构,通过注气的方式将旋流器轴心的油核举升至溢流口,加速油核向溢流口方向运动,进而提升旋流器的分离性能。基于雷诺应力模型(Reynolds Stress Model,RSM)与多相流模型(Mixture),模拟计算了入口进液量对气举式同向出流旋流器分离性能的影响,分析了进液量对旋流器内气核形态、速度场分布以及分离性能的影响规律。数值模拟结果表明:进液量分布在(3.6~8.4)m^(3)/h范围内时,随着进液量的增加,注气口处压力逐渐增大,混合液内各相介质的轴向速度与径向速度均有显著提高,旋流器轴心处的油相体积分数明显增大,旋流器的分离效率从64%增至77.9%。

混合煤矸放落态势特征研究

传统的基于图像检测技术的放顶煤过程中煤流动态特性研究多侧重于某一特定阶段的图像分析,未结合全阶段的动态特性进行综合分析;现有研究较少将放顶煤过程中上覆岩层的松散区变化与放煤过程中的煤矸分离和煤流特性相结合,缺乏对放煤过程的全局性系统分析。针对上述问题,对放顶煤过程中的煤流动态特性、煤矸分离效果及上覆岩层松散区凹陷变化进行了系统研究。首先,提出了一种基于双光流网络的放顶煤过程动态分析方法。实验结果表明:不同放煤方案下,放煤速度不随放煤形式和规律的变化而改变,平均检测准确率随着放煤口数量的增多而提高,尤其在不同放煤步距阶段呈明显线性增长;顶煤放出率与平均检测准确率呈正相关关系,验证了该方法在放顶煤过程监测中的有效性。其次,利用OpenCV技术对上覆岩层松散区凹陷面积进行实验分析。结果表明,初始放煤阶段松散区凹陷面积急剧增长,随后随时间推移逐渐趋于稳定;通过凹陷面积的动态变化趋势,可有效判断顶煤的放出过程,实现透明化放煤监测。最后,结合称重实验数据,分析了放煤量、放出率与含矸率之间的关系。结果表明,初始放煤阶段纯煤放出量最大,周期放煤阶段纯煤放出量趋于稳定,含矸率则随着放煤口数量的增多而减少。该结果进一步揭示了放煤方式对煤矸分离和顶煤放出率的影响。

多级孔MOF的制备及其吸附分离应用研究进展

金属有机框架材料(MOF)因其具有高比表面积、丰富孔隙率、孔径可调的优点,受诸多学者关注,被认为是用于吸附分离的理想吸附剂。但是在实际应用中,大部分微孔MOF材料在吸附过程中的内在传质速率严重受限,而且构建多级孔的方法一般不具有普遍性。本文介绍了调节剂策略、模板策略、后处理策略等构建多级孔MOF的方法,制备了兼具介孔、大孔的多级孔材料,并结合应用场景评价各方法的优缺点,以获得在相对温和条件下构建孔径可调的多级孔MOF的普适性策略。针对多级孔MOF材料在气体吸附分离领域的应用问题,着重剖析了构建多级孔MOF对CO_(2)气体吸附提升的案例,发现多级孔的构建增加了孔径,提高了MOF的比表面积,提供了额外的孔通道,使气体分子的吸附容量和传质速率得到提升,表明多级孔MOF在气体吸附分离方面有优异的性能。最后讨论了多级孔MOF合成和应用存在的问题,并对多级孔MOF面临的合成过程绿色可重复等挑战进行了展望。

高强度多孔疏水亲油材料的制备及性能

将超细硅酸盐与悬浮剂、造孔剂、改性剂等外加剂复配,制得疏水亲油材料,研究了材料的孔隙率、抗压强度、油水相对渗透率以及油水分离性能。结果表明,该材料水相接触角高达152°,孔隙率在68.5%,抗压强度大于5 MPa,油相是水相渗透率的4~5倍,材料对不同黏度、不同油相状态和不同含油率的油水混合液均有明显分离效果。

巴润矿露天开采贫化控制技术研究及应用

在分析巴润矿贫化原因基础上,结合矿山生产实际,对巴润露天矿矿岩交界处的贫化率进行控制,提出了通过穿孔取样的方式精准确定矿岩边界、矿岩爆破分离、混合爆堆中矿岩石边界的精准识别及优化铲装技术等措施,有效降低了矿岩混杂情况,贫化率降到了2%以下,回采指标明显改善。

纵式轴流油莎豆脱粒分离装置设计与试验

为了解决油莎豆收获过程中破损率高、脱净率低等问题,结合现有的农作物脱粒分离装置的特点,设计了一款纵式轴流油莎豆脱粒分离装置。对该装置的脱粒滚筒、螺旋喂入头、凹版筛等关键部件进行了设计。对脱粒滚筒进行应力和模态分析,确定设计的合理性,并通过试验确定了影响脱粒性能的主要因素,利用搭建的纵式轴流油莎豆脱粒分离试验台进行单因素试验,得到了脱粒分离性能较好的滚筒转速及脱粒间隙的变化范围。以滚筒转速、脱粒间隙和脱粒元件材料为试验因素,以籽粒破损率、未脱净率为指标进行三因素三水平正交试验。结果表明:对籽粒破损率和未脱净率影响由大到小均为滚筒转速、脱粒间隙、脱粒元件材料;最优工作参数组合为转速367.55 r·min-1、脱粒间隙4.18 mm,脱粒元件为聚氨酯橡胶,此时的未脱净率为0.751%,破损率为0.906%。对该组合进行试验验证,各指标符合国家相关标准要求。