HACCP在浓香菜籽油生产中的应用

为了保障浓香菜籽油的产品质量安全,采用HACCP体系对浓香菜籽油生产全过程进行生物、物理、化学的危害分析,确定关键控制点,制定预防措施,并对生产环节进行有效监控,制定纠偏措施,做好记录管理,为浓香菜籽油的安全生产提供借鉴。     

平原地区城市湖泊防洪与景观功能协调研究——以枝江市金湖为例

为了使城市湖泊尽可能滞蓄雨洪、发挥景观功能、打造良好的居民"亲水空间",以枝江市金湖为例,根据金湖主要泄洪渠道的实际情况,利用Mike 21模型模拟计算汛限水位值,按照景观水位确定大、小洪水工况下合理的水位。在此基础上,提出传统的静态景观水位与改进的动态景观水位两种方案。结果表明:以50年一遇、30年一遇为代表的大洪水工况下合理景观水位为40.7 m,以20年一遇、10年一遇为代表的小洪水工况合理景观水位为41.3 m;静态方案采用50年一遇洪水计算结果为标准执行,将40.7 m作为金湖固定的景观水位;动态方案水位可在41.3~40.7 m之间波动;金湖适宜采用动态景观水位运行方案,水位可在40.7~41.3 m之间波动;根据短期预报及历史监测资料分析后合理调度,将41.3 m作为金湖常水位,确定预测洪水大小后调整水位迎战洪水。据此,可在充分利用水资源的同时有效协调景观高水位需求与防洪之间的矛盾。     

Scheduling distributed flowshops with flexible assembly and set-up time to minimise makespan

The scheduling problems under distributed production or flexible assembly settings have achieved increasing attention in recent years. This paper considers scheduling the integration of these two environments and proposes an original distributed flowshop scheduling problem with flexible assembly and set-up time. Distributed production stage is deployed several homogeneous flowshop factories that process the jobs to be assembled into final products in the flexible assembly stage. The objective is to find a schedule, including a production subschedule for jobs and an assembly subschedule for products, to minimise the makespan. Such a scheduling problem involves four successive decisions: assigning jobs to production factories, sequencing jobs at every factory, designating an assembly machine for each product and sequencing products on each assembly machine. The computational model is first established, and then a constructive heuristic (TPHS) and two hybrid metaheuristics (HVNS and HPSO) are proposed. Numerical experiments have been carried out and results validate the algorithmic feasibility and effectiveness. TPHS can obtain reasonable solutions in a shorter time, while metaheuristics can report better solutions using more yet acceptable time. HPSO is statistically comparable yet less robust compared with HVNS for small-scale instances. For the large-scale case, HPSO outperforms HVNS on both effectiveness and robustness.     

Use of nets treated with food-grade coatings on dry-cured ham to control Tyrophagus putrescentiae infestations without impacting sensory properties

Dry-cured hams may become infested with the ham mite Tyrophagus putrescentiae during aging. Food-grade coatings have been developed to control mite infestations as a potential alternative to replace methyl bromide, but dipping or spraying these coatings requires additional labor and processing steps. Nets composed of polyester, a polyester/cotton blend and cotton were infused with coatings that consisted of propylene glycol, and either propylene glycol alginate and carrageenan or xanthan gum. Results indicated that the polyester/cotton blend and cotton nets that contained propylene glycol were effective at controlling mite infestations in assays with ham cubes covered in nets. The polyester nets slowed mite growth but were not effective at controlling mite reproduction due to low absorbance of the coatings. Polyester/cotton blend nets treated with coatings on whole hams were not different from control hams with respect to flavor, texture and moistness. Mite infestation tests on whole hams indicated that coated nets with greater stitch densities were effective at controlling mite growth. Future research will include the optimization of coating formulations and scaled-up testing in dry-cured ham plants.     

The effect of TiO2 nanotube morphological engineering and ZnS quantum dots on the water splitting reaction: A theoretical and experimental study

Ordered arrays of TiO₂ nanotubes with smooth and rippled morphologies were prepared by one-step titanium oxidation in NH₄F and ethylene glycol solution. The samples were then decorated with ZnS using a microwave-assisted solvothermal method. The experiments under constant or pulsed applied voltage resulted in smooth and rippled TiO₂material morphologies, respectively. Field emission scanning electron microscopy, incident photon-to-current efficiency, linear sweep voltammetry and electrochemical impedance spectroscopy were used to investigate the structure and morphology of the TiO₂ nanotubes, along with their photoelectrochemical activity in the water splitting reaction. An envelope function was proposed to correlate the anisotropic morphologies and broad distribution of mobility due to the random nature of charge carrier transport. The smooth and rippled morphologies were evaluated using the transmission line model. First-principles quantum mechanical calculations based on the density functional theory at the B3LYP level are conducted to obtain a better understanding of optical properties of TiO₂.     

移动物料信息分布式传输方法及应用

在流程工业生产中,移动物料计量信息的传输普遍采用电台和无线模块。接收电台周围环境严重影响计量信息的传输效果,尤其是钢结构厂房、电磁干扰区内,数据传输过程中的丢包率、误码率相当严重。本文提出一种多节点分布式传输方法,根据各个生产作业区环境条件设置相应的WIFI节点数,实现对作业区的无线信号覆盖。网络覆盖区内无线模块、PDA终端(PDA)、终端查询设备通过节点工作频段和阵列天线自适应调节,实现数据传输最佳化。铜熔炼生产现场测试表明,此种传输方法可以有效消除周围环境的电磁干扰,数据丢包率低于0.1%。     

Reinforcing cycles involving inter- and intraorganizational paradoxical tensions when managing large construction projects

In recent years, scholars have shown a growing interest in combining control and flexibility when organizing and managing large construction projects, in contrast with the traditional focus on control. Prior research recognizes that there is a paradoxical tension between control and flexibility, meaning that, while both approaches make sense individually, they appear impossible to combine. Large construction projects are interorganizational, which means that tensions between interorganizational control/flexibility coexist with tensions between intraorganizational direction/empowerment, but the interplay and possible reinforcing cycles involving the two tensions have rarely been investigated in prior research. A multiple case study of four large construction projects with three rounds of interviews show how intraorganizational direction/empowerment can influence interorganizational control/flexibility and vice versa, and demonstrate both vicious and virtuous reinforcing cycles that involve the two types of tensions. Therefore, contributing to the project management and construction management literature, it is argued that employing a systemic approach when studying interorganizational projects is essential. A systemic paradox perspective can reveal interdependencies between tensions at different organizational interfaces, improve the understanding of how individuals in all managerial positions interplay, and explain how reinforcing cycles emerge and develop; this is important to recognize when organizing, staffing and managing large construction projects.     

水电站大型竖井施工安全风险控制措施研究

竖井是大型水电工程中广泛采用的重要建筑物,但竖井的传统施工方法存在施工程序复杂、人工劳动强度大、施工效率不高等特点,同时还存在较大的安全风险。通过对杨房沟水电站大型竖井施工过程的研究,总结出精细化控制爆破、小溜渣井施工方式,同时也设计了一套用于运输的综合提升系统。采用上述创新方法不仅减少了繁琐的施工程序,降低了安全施工风险,而且大量采用机械化手段进一步提高了施工效率,确保了该工程竖井施工的安全风险可控。相关措施可为类似工程的竖井施工提供较好的借鉴作用。     

无人机控制站通用软件平台设计

针对无人机控制站难以与多型无人机互联互通的问题，从通用控制软件的角度开展研究，分析了设计需求，提出了一种采用平台+插件的软件架构，并分析了软件架构、基于XML技术的帧格式信号和参数信息描述、动态报文解析和组包、软件界面定制等关键技术。在车载控制站和便携控制站的工程验证表明，所提解决方案实现了对多型无人机的控制，具有良好的通用性、扩展性，并支持用户自定义对外通信协议和人机交互功能、界面。     

焦炉前反馈热工控制系统运行实践

焦炉生产是典型的大惯性、非线性、时变快的复杂系统，以“火落温度”为基础的焦炉前反馈热工控制系统，通过立火道温度自动测量与人工测温相关性分析、粗煤气温度测量与火落判断、标准温度的优化等运行实践，达到了自动火落时间判断、标准温度指导、加热和燃烧优化、高低温炉号判别等目的，对于稳定炉温、降低回炉煤气消耗、提高焦炭质量以及推进焦化企业技术进步具有重要意义。