模拟防尘网控制物料堆起尘的基本要求

介绍了防尘网一种多孔板,在模拟防尘网控制物料起尘时,为了能够更好地实现对低层大气湍流的模拟所应采用的一些基本要求。同时介绍了工程中防尘网在控制物料起尘时所采用的一些具体参数和造成起尘的起动风速。     

Production and application of a novel bioflocculant by multiple-microorganism consortia using brewery wastewater as carbon source

The flocculating activity of a novel bioflocculant MMF1 produced by multiple-microorganism consortia MM1 was investigated. MM1 was composed of strain BAFRT4 identified as Staphylococcus sp. and strain CYGS1 identified as Pseudomonas sp. The flocculating activity of MMF1 isolated from the screening medium was 82.9%, which is remarkably higher than that of the bioflocculant produced by either of the strains under the same condition. Brewery wastewater was also used as the carbon source for MM1, and the cost-effective production medium for MM1 mainly comprised 1.0 L brewery water （chemical oxygen demand （COD） 5000 mg/L）, 0.5 g/L urea, 0.5 g/L yeast extract, and 0.2 g/L （NH4）2SO4. The optimal conditions for the production of MMF1 was inoculum size 2%, initial pH 6.0, cultivating temperature 30℃, and shaking speed 160 r/min, under which the flocculating activity of the MMF1 reached 96.8%. Fifteen grams of purified bioflocculant could be recovered from 1.0 L of fermentation broth. MMF1 was identified as a macromolecular substance containing both protein and polysaccharide. It showed good flocculating performance in treating indigotin printing and dyeing wastewater, and the maximal removal efficiencies of COD and chroma were 79.2% and 86.5%, respectively.     

成都市2015—2019年臭氧浓度夜间变化及成因分析

利用2015—2019年成都市每日逐时地面O₃监测资料和同期气象数据,通过模拟和计算区域水平、铅直流场和大气静力稳定度支配参数(R_i),对成都市夜间O₃浓度第二峰值的反常现象进行统计分析和原因追踪。研究结果表明:成都市2015—2019年夜间O₃浓度第二峰值出现频率为17%,造成O₃浓度夜间反常现象的原因是雅安市山风将高空O₃输送至地面,而后平流至成都市,或本地高空湍流破坏夜间稳定层,将上层残留层储存的白天高浓度O₃送至近地面,加之夜晚绝大部分污染源停止排放,消耗O₃的物质大幅减少,造成地面O₃浓度的夜间反常变化。引起高空湍流的方式有2种:一是风向切变,且至少切变45°,风向切变角度越大,湍流强度越大,引起残留层向下增长的幅度越大;二是风速切变,且切变层风速要大于上、下层风速2 m/s,切变风速越大,湍流强度就越大,残留层向下增长的幅度就越大,低空急流是风速切变的极端表现。     

矸石脱介筛降噪治理

矸石脱介筛担负着排矸及回收磁铁矿粉的作用，原振动筛因噪声指标严重超标造成诸多问题，通过降低电机转速、采用激振装置，使用新型耐磨材料筛板等降噪措施，满足生产需求，工作环境改善，维修工作量降低，具有明显的经济效益和社会效益。     

打印式旋浆测流仪的简化改装

改变打印式旋浆测流仪浅路，去除复杂的电路控制、数据处理及打印功能，改为仪器自动报警，人工记数记时，手工计算，使测流更简单方便，工作更可靠，更适应野外工作的需要。     

我国机动车排放标准及检测方法简述

根据"新车新标准,老车老标准"的原则,双怠速法将是汽油车基本检测方法,简易工况法在全国范围内分步实施,柴油车将逐步采用不透光烟度计的测量方法.同时介绍了国外相关标准及检测方法.     

L6-M Al的超塑性工艺的实验研究

依拟定之正交实验方案，主要探讨工艺因素成形温度(T)，气体速度(V)，模具圆角半径(R)对铝板(L6-M)超塑性工艺性能的影响。经研究发现铝材(L6-M)在超塑性成形时，三个主要工艺因素对其影响的强弱顺序为成形温度(T)；气体速度(V)；模具圆角(R)，且都影响显著。     

Identifying crash propensity using specific traffic speed conditions

INTRODUCTION: In spite of recent advances in traffic surveillance technology and ever-growing concern over traffic safety, there have been very few research efforts establishing links between real-time traffic flow parameters and crash occurrence. This study aims at identifying patterns in the freeway loop detector data that potentially precede traffic crashes. METHOD: The proposed solution essentially involves classification of traffic speed patterns emerging from the loop detector data. Historical crash and loop detector data from the Interstate-4 corridor in the Orlando metropolitan area were used for this study. Traffic speed data from sensors embedded in the pavement (i.e., loop detector stations) to measure characteristics of the traffic flow were collected for both crash and non-crash conditions. Bayesian classifier based methodology, probabilistic neural network (PNN), was then used to classify these data as belonging to either crashes or non-crashes. PNN is a neural network implementation of well-known Bayesian-Parzen classifier. With its superb mathematical credentials, the PNN trains much faster than multilayer feed forward networks. The inputs to final classification model, selected from various candidate models, were logarithms of the coefficient of variation in speed obtained from three stations, namely, station of the crash (i.e., station nearest to the crash location) and two stations immediately preceding it in the upstream direction (measured in 5 minute time slices of 10-15 minutes prior to the crash time). RESULTS: The results showed that at least 70% of the crashes on the evaluation dataset could be identified using the classifiers developed in this paper.     

长隧道韵律型视觉环境设计研究

采用心理物理试验分析公路隧道内部视觉环境对驾驶员行车安全的影响,将E-prime 2.0软件与仿真驾驶模拟器相结合,对驾驶员在隧道内长时间行车中的速度判断准确率及反应时间两个指标进行分析,提出了利用标志标线构建公路隧道内韵律型标线系统的改善措施,以改善隧道内视觉环境,并利用数理统计方法及Logistics拟合分析对设计方案进行评价。结果表明:1)公路隧道内韵律型标线系统能提升隧道内驾驶员的速度判断准确率3.33%~11.66%;2)普通公路隧道场景中,被试者反应时间与隧道内行车时间存在显著关系,公路隧道内韵律型标线系统的场景中,反应时间与隧道内的行车时间没有显著关系,能有效缓解视觉疲劳现象;3)被试者反应时间的增加同时受隧道内视觉环境与行车时间的影响。公路隧道内韵律型标线系统能有效提高驾驶员的反应时间,适用于行驶速度为80 km/h、大于1 333 m的隧道。     

Experimental analysis of food detection in capuchin monkeys: effects of distance, travel speed, and resource size

Knowing how far away animals can detect food has important consequences for understanding their foraging and social behaviors. As part of a broader set of field experiments on primate foraging behavior, we set out artificial feeding platforms (90 × 90 cm or 50 × 50 cm) throughout the home range of one group of 22 brown capuchin monkeys, at sites where they had not seen such platforms previously. Whenever the group approached such a new platform to within 100 m, we recorded the group's direction and speed of approach, and the identity and distance from the platform of the group member that detected the platform or came closest to it without detecting it. We used logistic regression on these data to examine the effects of group movement speed, platform size and height, and focal individual age and sex on the probability of detecting the platform as a function of distance. Likelihood of detecting a platform decreased significantly at greater distances – the probability of detecting a platform reached 0.5 at 41 m from the group's center and 25.5 m from the nearest group member. These results show that detectability of platforms by the entire group (9 adults, 13 juveniles) was less than twice that for single group members. Detectability at a given distance decreased severely as the group moved faster; at their fastest speed, individuals had to approach a platform to within less than 10 m to find it. The large platforms were significantly more likely to be detected than the small ones, suggesting that increased use of larger food patches by wild primates may not necessarily reflect foraging preferences. Received: 20 May 1996 / Accepted after revision: 5 April 1997