Energy and nutrient recovery for municipal wastewater treatment: How to design a feasible plant layout?

Activated sludge systems are commonly used for robust and efficient treatment of municipal wastewater. However, these systems cannot achieve their maximum potential to recover valuable resources from wastewater. This study demonstrates a procedure to design a feasible novel configuration for maximizing energy and nutrient recovery. A simulation model was developed based on literature data and recent experimental research using steady-state energy and mass balances with conversions. The analysis showed that in the Netherlands, proposed configuration consists of four technologies: bioflocculation, cold partial nitritation/Anammox, P recovery, and anaerobic digestion. Results indicate the possibility to increase net energy yield up to 0.24 kWh/m³ of wastewater, while reducing carbon emissions by 35%. Moreover, sensitivity analysis points out the dominant influence of wastewater organic matter on energy production and consumption. This study provides a good starting point for the design of promising layouts that will improve sustainability of municipal wastewater management in the future.     

山东省肥料施用与养分平衡状况研究

对山东省1952年以来肥料的施用情况和养分平衡状况进行了分析,结果表明:山东省自1952年以来,化学肥料用量逐步增加,有机肥用量逐渐减少;2002年有机肥用量仅占肥料施用总量的35.50%,其中有机氮肥、磷肥和钾肥分别占氮、磷、钾肥用量的26.09%、34.55%和57.60%,而化学肥料用量占肥料施用总量的64.50%,其中无机氮、磷、肥占氮、磷、钾肥的比例分别为73.91%、65.45%和42.68%,化学肥料用量明显高于有机肥;而且全省137个县市之间养分分配极不平衡,单位耕地面积化肥用量相差数千倍。进一步对全省氮、磷、钾投入产出状况进行分析发现,氮素从1982年开始盈余,每年盈余的氮素在30万吨左右;磷素从1972年开始盈余,2002年盈余高达134.64万吨;自1952年以来,钾素一直处于亏缺状态,目前每年亏缺60万吨左右。     

源路由控制的研究与实现

源路由是由信源向路由器提供路由信息,以控制信息转发的路由方式。科研信息化进程中发现,网络环境中同时存在线路拥塞和闲置,从而认识到源路由控制对于大数据量传输的重要价值,通过源路由控制,可以更有效地利用网络资源,为此提出了源路由控制(SRM),并在fedora下实现了原型系统。给出了SRM适用于IPv4、IPv6和各种主流平台的解决方案。     

End conditions for interpolatory septic splines

In this paper, septic spline is defined for interpolation at equally spaced knots along with the end conditions required to complete the definition of spline. These conditions are in terms of given functional values at the knots and lead to uniform convergence of O(h ⁸), throughout the interval of interpolation. The main objective of defining the end conditions for septic spline is to use the septic spline for the solutions of sixth-order boundary value problems, being discussed in the subsequent paper.     

植物根系对养分缺乏和毒害的适应及其与养分吸收效率的关系

根系是植物对养分最敏感的部位,直接与养分接触,参与养分的吸收过程,在养分胁迫(缺乏或毒害)下最先引起反应。植物在低氮、低磷、低钾和元素中毒胁迫下,其形态和生理上都发生一定的变化。综述了养分缺乏和元素毒害胁迫下植物根系形态的变化、生理反应、分子生物学基础及其与养分吸收效率和对元素毒害的抗性的关系。     

电压源和电流源在等效变换中的合理匹配分析

电压源电流源是电气测量和精密计量中经常使用的基本部件或仪器,例如在电能表检定中就离不开由电压源和电流源组成的功率源,在其设计和制作中或在使用和操作中也经常遇到,对于各种负载应该如何确保源与负载之间处于最佳匹配状况的问题,是学者们经常探讨的问题。针对电压源和电流源匹配的问题,比较突出的电源在大功率阻性负载有功功率输出和感性容性负载无功功率输出条件下,所遇到的匹配状况问题进行一些初步探讨。     

静压力储罐自动化计量系统

本文介绍了一种新型静压力储罐自动化计量系统,给出了其中质量、液位、容积和密度的实时计量算法。文中还涉及了采用HTG系统原理的一个实际应用,通过特别设计的投入式液位传感器,解决了在役罐的自动化计量难题。     

TWAIN协议标准与图像输入

本文介绍了TWAIN图像输入协议标准以及利用该标准设计、开发Windows环境下的图像输入程序的方法．     

A stability-based distributed routing mechanism to support unicast and multicast routing in ad hoc wireless network

An ad hoc network can be envisioned as a collection of mobile routers, each equipped with a wireless transceiver, which are free to move about arbitrarily. In ad hoc wireless networks, even if two nodes are outside the wireless transmission range of each other, they may still be able to communicate in multiple hops using other intermediate nodes. However, the dynamics of these networks, as a consequence of mobility and disconnection of mobile hosts, pose a number of problems in designing routing schemes for effective communication between any pair of source and destination. In this paper, a stability-based unicast routing mechanism, that considers both link affinity and path stability in order to find out a stable route from source to destination, is proposed. It is then extended to support multicast routing as well where only local state information (at source) is utilized for constructing a multicast tree. The performance of the proposed scheme is evaluated on a simulated environment to show that the stability-based scheme provides a unified framework for both unicast and multicast routing and reduces the probability of route error drastically in both the cases.     

Microsoft,Open Source and the software ecosystem: of predators and prey—the leopard can change its spots

Over the past few years, Microsoft has promoted a project called ‘Shared Source Initiative’, which allows certain customers (e.g., research institutions and independent software vendors) access to its source code on a restricted basis. As part of this initiative, Microsoft introduced some licences that appear to give unrestricted access to source code and closely resemble ‘traditional’ Open Source licences. In July 2007, two of these ‘shared source’ licenses (the Microsoft Community Licence and the Microsoft Permissive Licence) were submitted to the Open Source Initiative (OSI) and subsequently approved by the OSI as certified Open Source licences. Thus Microsoft's Shared Source Initiative and its partial embrace of Open Source appear to be a significant step towards closing the ideological rift between developers of proprietary software and the Free/Open Source software movement, and more than just another attempt to appease consumers and/or critics in terms of software transparency. By analysing the ‘evolution’ of Microsoft's Shared Source licences, this article aims to shed some light on the question what is needed for a ‘predator’ (i.e., proprietary, software developer) such as Microsoft to become ‘prey’ (i.e., be part of the Open Source community). This article concludes that, although Microsoft's efforts are to be lauded, it is highly unlikely that the company will embrace fully the Open Source philosophy in the near future.     

基于单片机的卷烟机质量检测信号源系统

介绍了一种基于单片机(MCU)的PASSIM卷烟机质量检测系统调试用信号源,给出了该信号源的硬件设计及系统框图。该信号源具有较高的灵活性与通用性,结构简单、操作方便,可以应用于PASSIM70/80机型。     

用磁场极值信号定位磁源的方法与实验

通过数字仿真和实验的方法研究了一种基于等磁场图板值信号的等效磁偶板子（Equivalent Magnetic Dipole,EMD）源重构方法,给出了磁偶板子源位置坐标的计算公式.用磁偶极子源模型产生的磁场数据检验了该方法的源定位精度.结果表明：当阵列测点间距为1mm,令方向磁矩为0时,单磁偶极子源定位的误差小于1mm;双磁偶板子定位误差在,,方向的均值分别为4.6mm,7.8mm,5.3mm.分析了双磁源定位的误差问题,还对用9通道低磁场强度检测实验系统采集的单和双磁偶板子实验数据的源定位结果进行了分析与比较.     

EXCEL数据的常用访问方式与简单实现

Excel是最常用的表格处理软件，因而存在大量的数据是以Excel表格形式保存的，那么如何访问这些资源并加以利用就变得很重要。     

针对网络机房ARP欺骗攻击的研究与防范

分析了ARP安全漏洞及病毒攻击原理。探讨了在局域网内的主机和网络变换设备等应多方面采取防护措施和应对策略。     

注入脉冲与局部放电UHF信号的等效性仿真研究

在进行GIS UHF传感器现场校核时注入的模拟脉冲和真实局部放电在GIS中传播衰减规律的等效性是保证传感器校核有效性的重要前提。本文通过建立与某220KV GIS尺寸一致的模型,仿真分析了注入脉冲与局部放电UHF信号的等效性,仿真过程中将信号源分别设置在GIS内部高压导杆和GIS金属法兰浇筑孔处来作为局部放电激励源和注入脉冲激励源。在仿真模型的内部设置了观测点来接收UHF电磁波信号,通过在观测点测量到的信号幅值来比较注入脉冲与局部放电UHF信号的衰减程度,同时使用FFT变换对信号波形进行了频谱分析。研究结果表明,注入脉冲UHF信号在时域和频域上均能很好地模拟局部放电UHF信号,在现场实验时可利用注入脉冲来代替局部放电来对UHF传感器进行校核。     

保护地土壤养分特点

保护地蔬菜土壤养分状况与大田露地土壤有很大差别．土壤有机质含量高于露地,一般在１５～４０ｇ／ｋｇ,土壤有酸化的趋势．土壤中有效氮的含量明显高于露地土壤,硝态氮的平均含量超过１９０ｍｇ／ｋｇ．土壤有效磷的含量１５８．８ｍｇ／ｋｇ,比露地土壤高出６倍多．土壤有效钾的平均含量２７４．５２ｍｇ／ｋｇ,比露地土壤高出２．５６倍．土壤中交换性钙和镁的含量在临界指标以上,但某些情况下作物出现缺钙和缺镁症．化肥施用量大,决定了保护地蔬菜土壤养分的特点．     

基于分布式计算的IT资源管理系统的应用研究

本文研究了基于分布式计算的IT资源管理系统,该系统实现了网络IP地址的安全管理、IT资产的自动管理、基于VLAN管理、软件的集中分发及远程桌面维护、网络的在线监控等功能。     

基于Multiwii的开源四轴飞行器

基于Multiwii的开源四轴飞行器是目前主流的开源四轴项目之一。该文介绍了四轴飞行器的概念和特性,对Multi-wii四轴飞行器的硬件组成、安装调试以及关键技术做了一定的探讨。实验结果表明,该飞行器能较好地执行飞行任务。     

长白山北坡高山冻原土壤碳和养分的分布特征

以长白山高山冻原为研究对象,对土壤碳和氮、磷、硫养分在不同海拔和不同植被类型间的变化进行研究。经试验分析和数据处理,得出以下结论:海拔和所测试的土壤理化因子都高度相关;不同植被类型下土壤理化因子差异显著(除全硫)(p<0.05);全碳和全氮在土壤表层(0~10 cm)的含量大于10~20 cm的土层,而全磷和全硫含量在10~20 cm土层明显大于土壤表层0~10 cm;长白山高山冻原(15195 hm2)土壤中(0~20 cm)全碳、全氮、全磷和全硫储存分别为3134613 t、57060.82 t、14413.35 t和23099.64 t;土壤表层(0~10 cm)储量所占的比例分别是59.3%、57.9%、47.4%和49.1%。     

A comparative study of challenges in integrating Open Source Software and Inner Source Software

Context

Several large software-developing organizations have adopted Open Source Software development (OSSD) practices to develop in-house components that are subsequently integrated into products. This phenomenon is also known as “Inner Source”. While there have been several reports of successful cases of this phenomenon, little is known about the challenges that practitioners face when integrating software that is developed in such a setting.

Objective

The objective of this study was to shed light on challenges related to building products with components that have been developed within an Inner Source development environment.

Method

Following an initial systematic literature review to generate seed category data constructs, we performed an in-depth exploratory case study in an organization that has a significant track record in the implementation of Inner Source. Data was gathered through semi-structured interviews with participants from a range of divisions across the organization. Interviews were transcribed and analyzed using qualitative data analysis techniques.

Results

We have identified a number of challenges and approaches to address them, and compared the findings to challenges related to development with OSS products reported in the literature. We found that many challenges identified in the case study could be mapped to challenges related to integration of OSS.

Conclusion

The results provide important insights into common challenges of developing with OSS and Inner Source and may help organizations to understand how to improve their software development practices by adopting certain OSSD practices. The findings also identify the areas that need further research.