仓泵技术应用于电石粉尘回收装置的探讨

根据陕西金泰氯碱化工有限公司新建的电石粉尘回收装置的运行情况,探讨了仓泵技术的应用及仓泵在运行过程中的异常情况。指出装置运行后降低了电石消耗,每年可产生约400万元的经济效益,同时也降低了企业的安全风险,改善了乙炔生产现场环境。     

煤粉锅炉脱硫系统中除尘器压差过高原因及解决方案

高倍率灰钙循环烟气脱硫技术在神东矿区的煤粉锅炉环保改造项目中已投入建设并成功运行,脱硫率可达95%以上。在NGD系统的运行调试期,布袋除尘器压差的数值及其上升速度均较改造前有大幅提高,影响了锅炉系统的正常运行并降低了布袋除尘器的运行效率。为了解决此问题,先分析滤料透气性降低而导致布袋除尘器压差上升的根本原因,再结合现场调研情况对NGD系统工况下的烟气含湿量、烟气温度、烟气灰浓度、除尘器本体的问题以及上游锅炉系统问题逐一进行对比和分析,并找出问题产生的各主要因素。NGD系统中布袋除尘器差压升高的原因包括多方面,为了使NGD系统的运行更加稳定,需要使除尘器适应NGD系统的工况并对系统中部分设备进行改造。在未来NGD系统的设计中,布袋除尘器需按高浓度烟气设计,且针对煤粉工业锅炉的运行、维护特性应加入对烟气中含水量的监测及对布袋除尘器的相应保护措施。     

Modeling and analysis of multiple access channel capacity based on hybrid energy storage and energy harvesting

Energy harvesting (EH) has been considered as a promising technology to solve the constrained energy problem in the devices of IoT with its advantages of flexible deployment and sustainable energy supply.For multiple access channel with energy harvesting,a hybrid energy storage structure model composed by super capacitor and battery was proposed for the devices of IoT.According to the peculiarities of medium access channel and energy harvesting system,an optimized energy allocation strategy with exponential-type decline (ETD) was presented,the upper and lower bounds of the average throughput were deduced,in particular,the gap of two bounds was derived to be a constant.The channel capacity was further obtained by utilizing the relationship between the average throughput and the channel capacity.In the simulations,the effect of harvested energy,storage capacity and the number of nodes on the channel capacity were analyzed respectively.Experiment results show that compared with the conventional wireless node with single battery storage,the proposed hybrid energy storage structure can improve the harvested energy value and increase the multiple access channel capacity by using adaptive modulation scheme when transmitting the signals.     

新型装配式冰场受力性能试验与模拟分析

为在2022年冬奥会期间将国家游泳中心泳池场地改造为冰壶场地,结合临时场地的新型制冰方式,提出了一种全装配式的冰壶场地及支承结构体系的构造作法.对此装配式冰场进行了现场试验测试和有限元受力性能分析,研究了装配式冰场的自振频率和振型特点,分析了冰场在使用荷载作用下的整体变形和各组件的应力水平,探讨了极端荷载作用下冰面受力、变形及开裂等关键问题.研究表明,所提装配式冰场方案具有较大刚度和承载力,能够满足冬奥会冰壶比赛对冰面的要求；此类冰场宜使用轻型浇冰车作业,大型浇冰车轮压引起的弯矩和剪力作用下冰面存在开裂的可能.     

综采工作面粉尘防治问题分析与技术改进

针对新桥煤矿2301综采工作面机载喷雾系统喷雾效果差、喷雾耗水量大造成煤质含水量超标、喷嘴雾化程度不高、喷嘴容易发生堵塞等问题,提出了高压喷雾系统设计方案,选择了1.2mm的锥形引射喷嘴和1.5mm的扇形引射喷嘴。采用固定水泵供水方式,结合工作面实际情况,计算出喷雾总用水量247.5L/min,提高了喷雾射程,提升了除尘效果。     

Effect of functionally graded structure design on durability and thermal insulation capacity of plasma-sprayed thick thermal barrier coating

This paper aimed to design and optimize the structure of a thick thermal barrier coating by adding graded layers to achieve a balance between high thermal insulation capacity and durability. To this end, conventional TBC, conventional TTBC, and functionally graded TTBCs were deposited on the superalloy substrate by air plasma spraying. To determine the quality of the bond strength of the coatings, the bonding strength was measured. The durability of coatings was evaluated by isothermal oxidation and thermal shock tests. Then, at a temperature of 1000 °C, the thermal insulation capacity of the coatings was carried out. The microstructure of the coatings was characterized by a scanning electron microscope. The results showed that the thickness of the TGO layer formed on the bond coat in the conventional TBC and TTBC under the oxidation test at 1000 °C after 150 h was 2.79 and 2.11 μm, respectively, whereas, in the functionally graded TTBC samples, no continuous TGO layer was observed as a result of internal oxidation. The functionally graded TTBC presented higher durability than conventional TTBC due to improved bonding strength, thermal shock resistance, and the lack of a TGO layer at the bond/top coat interface. Also, the thermal insulation capacity of the functionally graded TTBC (with 1000 μm thickness of YSZ coating) was better than TTBC.     

The Marine Polysaccharide Ulvan Confers Potent Osteoinductive Capacity to PCL-Based Scaffolds for Bone Tissue Engineering Applications

Hybrid composites of synthetic and natural polymers represent materials of choice for bone tissue engineering. Ulvan, a biologically active marine sulfated polysaccharide, is attracting great interest in the development of novel biomedical scaffolds due to recent reports on its osteoinductive properties. Herein, a series of hybrid polycaprolactone scaffolds containing ulvan either alone or in blends with κ-carrageenan and chondroitin sulfate was prepared and characterized. The impact of the preparation methodology and the polysaccharide composition on their morphology, as well as on their mechanical, thermal, water uptake and porosity properties was determined, while their osteoinductive potential was investigated through the evaluation of cell adhesion, viability, and osteogenic differentiation of seeded human adipose-derived mesenchymal stem cells. The results verified the osteoinductive ability of ulvan, showing that its incorporation into the polycaprolactone matrix efficiently promoted cell attachment and viability, thus confirming its potential in the development of biomedical scaffolds for bone tissue regeneration applications.     

Investigations on hydrogen storage performances and mechanisms of as-cast TiFe0.8-mNi0.2Com (m=0, 0.03, 0.05 and 0.1) alloys

In order to improve the hydrogen storage performances of TiFe-based alloys, a new type of TiFe_0.8-mNi_0.2Co_m (m = 0, 0.03, 0.05 and 0.1) alloys were prepared through vacuum medium-frequency induction melting. XPS results showed that the composition of surface oxide film contains TiO₂, FeO and NiO for the cobalt-free alloy, and it also includes CoO and Co₃O₄ besides the above oxides for the cobalt-containing alloys. The activation temperature is 523, 403, 383 and 373 K for the TiFe_0.8-mNi_0.2Co_m (m = 0, 0.03, 0.05 and 0.1) alloys, respectively. The changes of the composition and microstructure of the surface oxide film are the root causes of the reduction of the activation temperature. XRD and SEM analyses showed that all the alloys are composed of the majority phase of TiFe phase and non-hydrogenated phase of Ti₂Fe phase. Adding appropriate amount of cobalt is beneficial to inhibiting the generation of Ti₂Fe phase and increasing the cell volume of TiFe phase. The hydrogenation capacity is proportional to the content of TiFe phase, which is 1.11, 1.48, 1.54 and 1.29 wt% for the TiFe_0.8-mNi_0.2Co_m (m = 0, 0.03, 0.05 and 0.1) alloys at 313 K, respectively. The hydrogenation plateau performance also is improved correspondingly.     

Nutritional and functional characterisation of hydrolysates from quinoa flour (Chenopodium quinoa) using two proteases

The objective was to study the nutritional and functional properties of hydrolysates from quinoa (Chenopodium quinoa) obtained by enzymatic hydrolysis of defatted quinoa flour (DQF). The commercial enzymes alcalase and flavourzyme were used to obtain the hydrolysates defatted quinoa flour hydrolysate with alcalase (DQFA) and defatted quinoa flour hydrolysate with flavourzyme (DQFF), respectively, after 3 h of digestion at 50°C and pH 8. The degree of hydrolysis (47.32%), yield (31.05%) and protein recovery (88.80%) values were higher in DQFA; however, its protein content (48.34%) was lower compared to that of DQFF (55.06%). Also, DQFA had a solubility greater than 57% over a wide pH range (2–10) and good foam stability (70–90%). On the other hand, DQFF presented adequate emulsifying activity (61.30 m²/g), emulsifying stability (158.62 min) and foaming capacity (131%). Due to the high content of macro- and micronutrients and adequate emulsifying and foaming properties, DQFA and DQFF could be used as ingredients in various processed food products and protein supplements.     

钢筋UHPC梁正截面抗弯承载力计算方法

超高性能混凝土(ultra-high-performance concrete，UHPC)是一种高强、高韧性和高耐久性的新型水泥基复合材料，具有广阔的应用前景。由于UHPC内的钢纤维能有效控制裂缝开展并提高UHPC的抗拉强度，因此，UHPC构件抗弯承载力分析时，一般计入截面受拉区UHPC的抗拉作用，但对于如何考虑受拉区UHPC的抗弯贡献，国内外相关研究结果间存在较大分歧，因此值得进一步研究。首先，编制钢筋UHPC梁正截面抗弯承载力分析程序，分析不同设计参数对截面受拉区UHPC抗弯贡献的影响。结果表明：配筋率、梁高、钢纤维长度、截面形状和预应力水平是影响受拉区UHPC抗弯贡献的主要参数。基于参数分析结果的回归分析，提出截面受拉区UHPC的均匀分布应力折减系数k的计算公式；通过引入受拉翼缘面积折减系数kf，考虑不同截面形状的影响。在此基础上，提出不同弯曲破坏模式下钢筋UHPC梁抗弯承载力的简化计算方法，并以国内外115根钢筋UHPC梁抗弯承载力试验结果验证所提方法的适用性。