Preparation and Testing of Cementing and Coating Nano-Subnanocomposites of Slow/Controlled-Release Fertilizer

To select the cementing and coating materials of slow/controlled-release fertilizer, the natural kaoline and abandoned foam plastics were used to prepare nano-subnanocomposites through the methods of organic material intercalation, semiemulsification, and cut at high velocity techniques. Besides, two kinds of nano-subnanocomposites were tested in this study using several instruments, including the scanning electron microscope （SEM）, the X-ray diffraction （XRD）, the infrared ray spectrum （IR）, and the laser granularity. The main results were as follows： 1） The organic material was intercalated in the layers of kaoline clays, and the natural kaoline exfoliated into nanometer-sized layers. The organic agent and clays formed nanocomposites through hydrogen bond combination. 2） The SEM pictures of polystyrenestarch nano-subnanocomposites showed that many pores and rugas were present on the surface of film at sizes ranging from 10 to 20 nm. These nano-subnanocomposites were used as the cementing and coating materials of slow/controlledrelease fertilizer.

Comparing the Efficiency of Manual and Electronic Tender Document Preparation: Cost and Time Context

In Bangladesh, both manual and e-GP system is used to perform public procurement. Before tender publication, tender documents have to be prepared by the Procurement Entities (PEs). The problem is that the manual tendering system involves more cost and time in preparing tender documents. The study’s purpose is to compare now the efficiency of tender document preparation in the manual system with the e-GP system. This study tests the cost and time involved in tender document preparation, both manual and e-procurement tenders. Sample data was collected from the 11 RHD zones. Structured survey questionnaires were used to collect primary data from the PE officers of RHD. A hypothesis test was performed using the model of independent samples t-test. The test results indicated that e-Procurement tender document preparation costs and time were less than manual tendering. Academicians, researchers, PE officers, and policymakers will benefit from the study’s conclusions.

Comparing the Cost and Time of Tender Opening Committee Report Preparation for Manual and E-Procurement Tenders in the Roads and Highways Department of Bangladesh

Bangladesh’s public procurement system has been traditional, i.e., a manual tendering system, under the legislative guidance of PPA-2006 and PPR-2008. Manual tendering has long been a source of concern for public procurement agencies regarding tender opening related to cost and time. To resolve this challenge and make the dream of a Digital Bangladesh a reality, the Government of Bangladesh launched the e-Procurement system in 2011 under the flagship of e-GP Guidelines. Following the successful pilot testing conducted under the umbrella of the CPTU, all public PEs are attempting to implement electronic procurement tenders. This study aims to examine the cost and time involved in preparing Tender Opening Committee (TOC) Reports for manual and e-procurement tenders in Bangladesh’s Roads and Highways Department. A mixed-method was used to collect data from the population of 11 RHD zones, including KII and primarily survey questionnaires. The independent samples t-test was used to compare data and hypothesis tests from two groups using SPSS software. The results indicated that e-Procurement tendering, tender opening preparation costs and time were more efficient than manual tendering. Academicians, students, practitioners, researchers, and policymakers will benefit from the study’s conclusions. Additionally, the government will be urged to improve policies such as the PPA 2006, the PPR 2008, and the 2011 e-GP Guideline.

Beverage intake preference and bowel preparation laxative taste preference for colonoscopy

AIM: To examine whether non-alcoholic beverage intake preferences can guide polyethylene glycol(PEG)-based bowel laxative preparation selection for patients.METHODS: We conducted eight public taste test sessions using commercially procured(A) unflavored PEG,(B) citrus flavored PEG and(C) PEG with ascorbate(Moviprep). We collected characteristics of volunteers including their beverage intake preferences. The volunteers tasted the laxatives in randomly assigned orders and ranked the laxatives as 1st, 2nd, and 3rd based on their taste preferences. Our primary outcome is the number of 1st place rankings for each preparation. RESULTS: A total of 777 volunteers completed the study. Unflavored PEG was ranked as 1st by 70(9.0%), flavored PEG by 534(68.7%) and PEG with ascorbate by173(22.3%) volunteers. Demographic, lifestyle characteristics and beverage intake patterns for coffee, tea, and carbonated drinks did not predict PEG-based laxative preference.CONCLUSION: Beverage intake pattern was not a useful guide for PEG-based laxative preference. It is important to develop more tolerable and affordable bowel preparation laxatives for colonoscopy. Also, patients should taste their PEG solution with and without flavoring before flavoring the entire gallon as this may give them more opportunity to pick a pattern that may be more tolerable.

Effect of preparation conditions on the electrochemical properties of spherical Ni(OH)_2

Spherical nickel hydroxide is used as the active material of the positive electrode in alkaline recharged batteries,it determines the most important properties of the battery. Spherical nickel hydroxide made in China meets less than half of total demand of the Chinese batteries industry. Most of the spherical nickel hydroxide used for high performance MH/Ni batteries is imported because the Chinese one cannot reach the requirements of "fine crystal grain, high density and high-activity". In this thesis, the spherical nickel hydroxide with fine crystal grain high-density and high-activity was prepared with complexation-precipitation method. The effects of the preparation conditions on the electrochemical activity of the products were investigated by means of orthogonal test, comprehensive range analysis on all the used factors. And theirs levels showed that the optimum process parameters of preparation the fine crystal grain high-density and high- activity spherical nickel hydroxide is specified as reaction temperature 60℃, pH value 11.0, stronger stirring intensity, the mole ratio of ammonia and nickel 0.3,desiccation temperature 100℃. Furthermore, the relative influence degree of those technology factors is stirring intensity>pH value>reaction temperature>desiccation temperature>mole ratio of ammonia and nickel. The spherical nickel hydroxide made at those optimum process parameters is characterized as with high bulk density(1.78 g/cm^3), larger specific surface(11.9 m^2/g), higher discharged specific capacity (281 mAh/g), and fine crystal grain (15.8 nm). The full width of half maximum intensity(FWHM) of XRD patterns of samples in (101) lines can reach as high as 0.983°. All of these merits make it completely meet the requirements of spherical nickel hydroxide used for high performance MH/Ni batteries.

Improved Control Strategy for Carbonized Cable Preparation in Low-voltage Arc Fault Test

Outdated testing methods hinder the success rate of carbonized cable preparation in low-voltage arc fault tests,leading to incomplete tests and high failure rates.To address this issue,we finely categorized the preparation results of carbonized cable specimens by analyzing the experimental phenomena during the carbonization process and assessing the impact of high-voltage energization time on the outcomes,presenting a process control strategy aimed at optimizing the preparation results of carbonized cable specimens.This method utilizes three periodic moving algorithms(root-mean-square,average,and shoulder percentage)to classify the cable specimens into four preparation categories:open-circuit carbonization,under-carbonization,short-circuit carbonization,and successful carbonization.The high-voltage energization time during carbonization or secondary carbonization was adjusted to optimize the preparation of the carbonized cables by considering different discrimination outcomes.Finally,the proposed method was tested on a purpose-built carbonized cable experimental platform,which confirmed its effectiveness in differentiating the preparation outcomes of the carbonized cable specimens and improving the success rate of the carbonized cable preparation.The proposed method has significant potential for application in low-voltage arc fault test systems.

Preparation Technology of Wuwei Xiaoke Granules

[Objectives]To optimize the extraction and preparation technology of Wuwei Xiaoke granules.[Methods]Taking the extraction rate of extract as the scoring standard,the water extraction technology was optimized by orthogonal test.The influence of the proportion of pharmaceutical excipients on the molding conditions of Wuwei Xiaoke granules was investigated using granule molding rate,solubility,moisture,granularity,water-soluble extract and microorganism examination as evaluation indicators,and the optimal molding technology was optimized.[Results]The extraction technology was soaking in water for 0.5 h and heat extraction twice for 1 h each time:adding 10 times the amount of water in the first time,and adding 8 times the amount of water in the second time.The best molding technology was:extract density 1.13-1.16(55-60℃),extract:soluble starch=1:2,and 0.15%stevioside.[Conclusions]The water extraction technology and granule molding technology optimized by orthogonal test are reliable and stable,with good granular characteristics,easy oral administration and good solubility,which can maximize the comprehensive quality of Wuwei Xiaoke granules,and provide an effective reference for the preparation and production of Wuwei Xiaoke granules.

Robustness self-testing of states and measurements in the prepare-and-measure scenario with 3 → 1 random access code

Recently, Tavakoli et al.proposed a self-testing scheme in the prepare-and-measure scenario, showing that self-testing is not necessarily based on entanglement and violation of a Bell inequality [Phys.Rev.A 98 062307(2018)].They realized the self-testing of preparations and measurements in an N → 1(N ≥ 2) random access code(RAC), and provided robustness bounds in a 2 → 1 RAC.Since all N → 1 RACs with shared randomness are combinations of 2 → 1 and 3 → 1 RACs, the3 → 1 RAC is just as important as the 2 → 1 RAC.In this paper, we find a set of preparations and measurements in the3 → 1 RAC, and use them to complete the robustness self-testing analysis in the prepare-and-measure scenario.The method is robust to small but inevitable experimental errors.

Preparation and Properties of PBXs Based on FOX-7 in Controlled Fragmentation Warhead Application

Polymer bonded explosive(PBX)formulations were successfully prepared in the laboratory scale containing 1,1-diamino-2,2-dinitroethene(FOX-7)and hexogen(RDX)as brisant high explosives and different binder types of polyurethane(PU)based on glycidyl azide polymer(GAP) and hydroxyl-terminated polybutadiene(HTPB) as an energetic and inert polymeric binder respectively.Casting technique was used for the preparation of different PBX formulations based on FOX-7/RDX and PU(GAP/HTPB)with 14% binder.The sensitivity to different initial impulses and performance characteristics of the explosive and lethal zone of the tested controlled fragmentation warhead by the fragmentation warhead assessment test(arena test)were studied,in which the arena test was carried out with a controlled fragmentation warhead made from Ck45 steel,with dimensions(100 mm length,30 mm outer diameter and 3 mm thickness).Results show that PBXGF4 has lower sensitivity to impact and heat than those of PBXGR4 by 188.4% and 3.2% respectively.Its friction sensitivity is the same as that of PBXGR4.It has better performance,in which detonation velocity increases by 2.1% and brisance increases by 0.5% when compared with those of PBXGR4.It was concluded that PBXGF4 which based on FOX-7 bonded with PU/GAP matrix has good characteristics as PBX,specially in the sensitivity to impact and can be applied for replacing PBXs based on RDX in the advanced PBXs for low sensitive fragmentation warheads.

Preparation of Compound Ban Huang Oral Liquid

[Objectives] To determine the optimal preparation process of compound Ban Huang oral liquid. [Methods] Orthogonal test and other methods were used to optimize the preparation conditions of compound Ban Huang oral liquid. [Results] The optimal conditions determined were as follows: soaking for 12 h,decocting twice with 2 h per time,concentrating filtrate to 1. 18-1. 25 g/m L at 80 ℃,ethanol precipitating twice with ethanol contents of 600 and 750 ml/L,standing for 24 h. [Conclusions] The optimized preparation process is simple,feasible and stable,and can be used for preparing compound Ban Huang oral liquid.

干旱地区砂质土壤棉花苗床土层构建装置的研制

针对新疆南部砂质土壤“干播湿出”棉花种植模式下,春季耕整地连续作业存在作业阻力大、苗床整不平、压不实,严重影响棉花出苗率的问题,该研究设计了一种适合砂质土壤的苗床整备装置,可一次完成碎土、平土、灭茬、镇压、耱地等作业。采用分段平土装置代替耙组进行联合整备作业,分段平土装置为两段式,首段刮土板呈“W”型对称分布,通过刮土板角度对土壤流动性、平整度和作业阻力的运动分析,确定当刮土板倾斜角为45°时碎土和平土效果最好;台架试验结果表明,镇压辊直径400 mm、碎土辊直径400 mm时综合评分最高。样机性能对比试验结果表明:较耙片式联合整地机综合工作阻力降低8.67%,作业效率提升6.6%;地表平整度标准差为11 mm;耕深稳定性变异系数为9.2%,碎土率为92.3%,表面未见秸秆残膜,分段平土装置能有效碎土、平土、灭茬;二次整备后浮动式土层构建装置能有效压实土壤构建出“上虚下实”土层结构,0~5cm播种土层平均土壤紧实度为169 kPa,适合砂质土壤精量铺膜播种作业和棉花生长,较对比机型种膜错位率下降62.5%,出苗率高于对比机型4.8%。研究结果可为砂质土壤苗床整地机研发与改进提供参考。

黑木耳超微颗粒混悬液制备工艺研究

采用高压均质法制备黑木耳超微颗粒混悬液,并对制备工艺进行优化。结果表明,采用高压均质法可制备黑木耳超微颗粒混悬液,优化后的工艺参数为均质压力10 Mpa,均质固液比1∶5,均质次数4次,制备后的混悬液平均粒度为5.31μm。

五味痛风丸提取及制备工艺研究

目的:将五味痛风汤开发为五味痛风丸。方法:以加水倍数、煎煮时间、煎煮次数为考察因素,以秦皮乙素转移率和干浸膏率为评价指标,采用正交设计优化五味痛风丸的提取工艺,并进行丸剂成型工艺研究。结果:最佳提取工艺为加12倍水、煎煮1.5小时、煎煮3次;最佳成型工艺为提取液减压浓缩至相对密度为1.30~1.40,吴茱萸和红曲粉碎过100目筛,混匀后制丸,70℃干燥24小时。结论:该提取、制备工艺稳定可行。

松软破碎煤体取制样与剪切试验系统研制及应用

研究松软破碎煤体力学性质对巷道支护和煤与瓦斯突出预测等工作具有重要意义,但当前缺乏有效的松软破碎煤体取样、制样及力学特性分析装置。为此,研发了一套松软破碎煤体取制样与剪切试验系统,主要由取样装置、制样装置和力学特性参数测试系统组成,各部分具有以下主要功能与特点:①取样装置中的单动三管取芯器包含脑袋总成、外管总成及内管总成3部分,内外管间设置稳定环,保证内外管同心,内管总成腔体内部设置衬管用于储存煤心,取芯钻进时内管不随外管旋转;当钻取的煤心充满衬管后,退出取芯器,拆卸取出衬管,将煤心连同衬管一并取出并进行封装。取样装置灵活、轻便、易拆装携带。②制样装置包含脱模仪、切割机、冰箱、热风枪4部分,脱膜仪用于脱去煤心外层衬管,切割机、冰箱和热风枪用于对煤心进行切割、冷冻和热缩;制作标准煤心试件分为打孔润湿、冷冻切割和热缩脱模3个步骤,采用端头局部冷冻切割、脱模与热缩均匀同步等技术,实现多种标准尺寸试件制备,制样方法完善、成功率高。③力学特性参数测试系统包含主体结构、伺服油源控制装置和软件系统3部分,能实现限制性及非限制性直剪试验功能,主要用于开展松软破碎煤体标准试件不同法向应力下直剪试验、不同围压下三轴压缩试验。整体设计结构简单、操作方便。研究利用单动三管取芯器获取松软破碎煤体,利用脱模仪等制样装置将其制备成标准试件,进而在力学特性参数测试系统上分别开展松软破碎煤体标准试件在0.04、0.05、0.06、0.07、0.08、0.09 MPa法向应力下的直剪试验和0.2、0.3、0.4 MPa围压下的三轴压缩试验,并求得两种试验条件下松软破碎煤体的黏聚力和内摩擦角等抗剪强度参数,其中直剪试验求得的黏聚力和内摩擦角为0.125 kPa和37.2°,三轴压缩试验求得的黏聚力和内摩擦角为0.121 kPa和36.4°。结果表明,该套系统具有较好的实用性和可靠性,为研究松软破碎煤体力学特性提供了较好的试验平台和方法。

振动台试验饱和机制砂模型土动力特性研究

根据饱和砂土-结构相互作用振动台试验的相似性要求,对饱和砂土的相似性要求进行探讨,提出以机制砂作为通用的饱和砂土模型材料。通过动力三轴分级循环加载试验,研究饱和机制砂模型土的最大动剪切模量Gmax、动剪切模量比G/Gmax-γ曲线、阻尼比λ-γ曲线、孔压比ru-ΔW曲线的变化范围,得到其动力本构模型参数随有效粒径d10、不均匀系数Cu、曲率系数Cc和相对密度Dr的变化规律和拟合公式,并根据相似要求和拟合公式分不同情况给出饱和机制砂模型土的配制方法。与文献中多种原型砂土的相似性分析表明,饱和机制砂模型土可以对大部分原型砂土有效实现动力特性相似和液化特性相似,证明其广泛适用性。

进行CTOD试验的焊接工艺评定试板制备要点分析

文中对双面焊的大厚试板焊接工艺评定试板的制备过程制定了指导说明。针对大厚试板的制备过程的各个环节提出了合理做法,并结合作业特点,设定了合理的作业顺序,提高试板制备效率。针对热影响区CTOD试样容易出现无效试样的情况,明确了在试板焊接时应关注的操作要点,提高获取热影响区CTOD试样的有效率。

油菜直播组合式埋茬防堵装置设计与试验

针对长江中下游地区油菜机械化种植时土壤黏重板结、前茬秸秆留茬高、残留量大,致使油菜直播机旋耕及深施肥部件易出现秸秆缠绕、壅土堵塞等问题,导致秸秆埋覆率低、种床厢面起伏不平,影响种床质量的生产现状,该研究设计了一种适用于高茬黏重稻茬田的油菜直播机组合式埋茬防堵装置。该装置主要包括埋茬弯刀和双刃旋耕刀,刀片在筒状刀轴上整体呈人字型排布,通过埋茬弯刀和双刃旋耕刀配合作业,可防止旋耕及深施肥部件秸秆缠绕和黏附堵塞,实现黏重土壤细碎、高茬秸秆埋覆和厢面平整。开展理论分析与EDEM仿真,确定了埋茬弯刀回转半径为245 mm,正切面弯折线角为27°、弯折角为125°,作业幅宽为75 mm,防堵直刀回转半径为275 mm,刃磨角为15°。田间对比试验结果表明:装有组合式埋茬防堵装置的油菜直播机在高茬黏重地表作业通过性好,未出现秸秆缠绕和黏土堵塞,厢面平整度为19.19~22.14 mm,相较于普通旋耕装置,秸秆埋覆率至少提高27.19个百分点,埋茬防堵性能良好,种床质量满足油菜直播农艺要求。研究结果可为高茬黏重工况下的种床整备装置开发提供参考。

基于正交设计优化新鲜川芎中挥发油提取工艺

为优化川芎挥发油提取工艺,建立以新鲜川芎为原料提取制备挥发油的新方法,采用正交试验设计对乙醇回流提取工艺条件进行优化,并进一步考察优选回收浓缩、油水分离等关键工艺参数。以藁本内酯和洋川芎内酯A作为指标成分,应用HPLC一测多评法进行含量测定。以提取量、油收率、油含量为评价指标,最终确定川芎挥发油提取制备新方法为:鲜川芎切片,加8倍量70%乙醇回流提取2次(以干药材计,第一次需测定鲜川芎水分,调节乙醇浓度为70%),每次1.5 h,滤液回收浓缩至2.0~3.0 g生药/mL,静置过夜,弃去水层,上层乳化层加热至60℃离心,分取油层,余下乳化层再加氯化钠至饱和并加热至60℃离心,合并油层,即得川芎挥发油。新方法所得川芎挥发油收率约为3%,藁本内酯和洋川芎内酯A含量达70%。该研究所建立的新方法生产设备要求低、操作简便易行,可实现川芎挥发油的高效制备,且含量高、品质优,为川芎挥发油的工业化生产提供了新思路和新方法。

茶树精油纳米乳剂的制备及其质量评价

为了制备稳定性高的茶树精油(tea tree oil, TTO)纳米乳剂,并评价制备的TTO纳米乳剂的质量,试验采用高能剪切法制备TTO纳米乳剂,根据伪三元相图确定TTO纳米乳剂的最优配方。对采用最优配方制备的TTO纳米乳剂进行外观性状观察,采用染色法进行类型鉴定,使用pH计测定pH值,通过透射电子显微镜观察表面形貌,使用激光粒度仪测定粒径和电位,并考察其稳定性,利用二倍稀释法测定TTO纳米乳剂和TTO对巴氏杆菌和沙门氏菌的最低抑菌浓度(MIC)。结果表明:TTO纳米乳剂的最优配方为12.95%蓖麻油聚氧乙烯醚(EL-40)、6.5%聚乙二醇400(PEG-400)、8.33%TTO、72.22%纯化水。采用最优配方制备的TTO纳米乳剂为水包油(O/W)型乳剂,平均pH值为8.32,平均粒径为15.7 nm,表面电位为(-4.29±0.26)mV。将TTO纳米乳剂加水按1∶20~1∶120稀释,静置24 h后观察无分层或沉淀现象;4 000,6 000,8 000,10 000 r/min分别离心20 min后,纳米乳剂的外观性状无变化,也无沉淀、分层等现象产生。在不同温度(-20℃、4℃、25℃、40℃、60℃、80℃)下处理30 min后,其外观无明显变化,且60℃加热后其外观更透明,80℃加热后出现分层现象;在4℃下放置30 d后观察,无任何异常变化。用pH值为5,6,7,8,9的水溶液将TTO纳米乳剂分别按1∶100、1∶1 000、1∶10 000稀释后静置24 h观察,无沉淀或絮状物等产生。TTO纳米乳剂对巴氏杆菌和沙门氏菌的MIC值分别为39.65 mg/mL、29.74 mg/mL,优于未纳米乳化的TTO(对巴氏杆菌和沙门氏菌的MIC值均为49.57 mg/mL)。说明TTO纳米乳剂能够解决TTO易挥发、难溶于水等问题,制备的TTO纳米乳剂具有纳米级粒径且尺寸均一,稳定性强,易于储存,易溶于水,具有良好的抑菌性。

高强度木单板/异氰酸酯复合材料制备及性能优化

通过脱除木质素的方法对木材进行前处理是制备高强度木基复合材料的一种重要手段,然而,脱除木质素过程中会产生大量废液,且不利于工业化应用。在当前“双碳”目标以及绿色发展的背景下,探究一种低碳环保、简单高效的高强度木基复合材料的制备方法对提升木材附加值显得尤为重要。基于此,以桦木单板和聚合二苯基甲烷二异氰酸酯(pMDI)为原材料,采用正交试验研究热压温度、热压时间以及pMDI添加量对高强度木单板/异氰酸酯复合材料(pMDI-WC)的力学性能、耐水性和表面颜色的影响。结果表明,热压温度、热压时间和pMDI添加量对pMDI-WC的力学性能、耐水性和表面颜色均具有显著的影响。厚度为6 mm的pMDI-WC最佳热压温度、热压时间和pMDI添加量分别为170℃、20 min和10%,在最优工艺条件下制备出具有优异力学性能的pMDI-WC,其弯曲强度和拉伸强度分别是473.59和408.56 MPa。在热压温度180℃、热压时间20 min、pMDI添加量20%的条件下,pMDI-WC的耐水性最优。pMDI-WC不仅具有轻质高强特性,而且制备工艺简单、绿色环保,这对提高木材的高附加值利用和复合材料的绿色发展具有重要意义。