26 research outputs found
Successional Allelopathic Interactions of Amaranthus palmeri S. Wats. and Cereals
No full textPlant allelochemicals can affect the germination and growth of other plant species. Petri and pot experiments were conducted to detect the interaction of Amaranthus palmeri with cereals (barley, oat, wheat, and triticale). Aqueous extracts of different tissues of A. palmeri and cereals at several concentrations were used to measure the inhibitory effects on the germination of other plants in the Petri experiments. A. palmeri plants and cereals grown at two different densities were incorporated into a potting mix at two different growing stages to determine the inhibitory effects on the germination and growth of other plants in pot experiments. The relative germination inhibition of A. palmeri was present in the following order: barley > oat > triticale > wheat. The relative germination inhibition of cereals was present in the following order: oat > triticale > barley > wheat. The above-ground parts of the plants were more effective than the roots. The germination of A. palmeri was only affected by wheat, while barley was better at reducing the dry weight in pot experiments. Wheat was found to be the only cereal affected by A. palmeri. Despite the prevailing hypothesis that these plants do not affect each other’s germination and development in nature, it was concluded that using wheat and barley as a cover crop can support A. palmeri management, and delaying wheat planting in the presence of A. palmeri can protect cereals from allelopathic interference
Momentary emotion differentiation: The derivation and validation of an index to study within-person fluctuations in emotion differentiation.
No full textEmotion differentiation refers to the tendency to label emotions in a granular way. While differentiation is an important individual difference in the context of psychological well-being, it is unknown how it fluctuates within individuals. Such a within-person measure is important, since it would allow the study of how changes in differentiation predict subsequent levels of other variables of interest. Here, we present a framework to study emotion differentiation at the within-person level by introducing a momentary emotion differentiation index. This index is directly derived from the classical emotion differentiation index, the intraclass correlation. We first give a theoretical derivation of this index. Next, using data from two experience sampling studies, we show how this new momentary index is related to other momentary indicators of well-being, and take the first steps in building its nomological network. A better understanding of within-person fluctuations in emotion differentiation will allow us to identify the causes and consequences of these fluctuations, and search for ways to teach individuals to increase their level of emotion differentiation.sponsorship: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was supported by the KU Leuven Research Council (grant GOA/15/003) and a grant from the Research Foundation Flanders (FWO) awarded to Eva Ceulemans (grant G074319N). Yasemin Erbas is supported by a postdoctoral fellowship of the Research Foundation Flanders (FWO). Elise K. Kalokerinos is supported by an Australian Research Council Discovery Early Career Researcher Award (DE180100352). (KU Leuven Research Council|GOA/15/003, Research Foundation Flanders (FWO)|G074319N, Research Foundation Flanders (FWO), Australian Research Council|DE180100352, Australian Research Council|DE180100352)status: Publishe
pCOLAD: Online sharing of parameters for collaborative architectural design
No full textproject faces challenges in properly sharing information across disciplines. This research developed a method and related digital tool to improve collaborative design and aimed at making selected information to be shared faster and more transparently. The method consists of developing alternative parametric solutions for different parts of the design in such a way that crucial parameters form a link between these parts. The digital tool has been developed for Grasshopper and permits synchronic (real-time over the Internet) and a-synchronic sharing of these parameters. The design alternatives are evaluated with specific criteria, pros and cons in an Internet Forum and discussed via a video-conferencing tool. Decisions are then taken in a collaborative manner through voting. The paper describes the method based on a case studyArchitecture Engineering and TechnologyArchitecture and The Built Environmen
Future direction for effective sustainable design: A preliminary study on utilisation of existing tools in the architectural practice
No full textArchitects need continuous support in their sustainability choices for building design because of the excessive amount and dispersal of information on sustainability. Currently architects utilize BSA tools that provide them general information with a checklist of sustainability measures. However, it is observed that these tools do not fully support a design process; they are mainly developed for assessing a finished design. In that respect, improvements of the existing tools or developing new ones become inevitable to supply architects with more sufficient design support. In this paper, as a part of a diptych, we discuss issues involving the architect’s needs for support in designing a high-performance green building, such as the current support tool, the interconnectedness of performance criteria and the architectural design process. Furthermore, it presents a method for a survey, from which the results are presented in our second paper.Architectural Engineering +TechnologyArchitecture and The Built Environmen
Future direction for effective sustainable design: A survey on the extent and the format of a decision support tool
No full textThis paper – as part of a broader research - summarizes the key findings of a survey based on an online questionnaire which has investigated existing insights, needs and expectations of architects about decision support tools (DSTs) to assess sustainability of buildings. The survey is conducted in Dutch context with architectural professionals. Furthermore, this paper underlines the major requirements for future improvement and development of support tools for architects in a sustainable design process. With the results we aimed to gather information that would help us to have an insight on current use of DSTs in several stages of the design process, preferred level of breadth and detail of information and knowledge by architects throughout the process of designing a high performance green building and the preferred format of information and knowledge presentation about sustainable design – extent and format of a possible decision support tool.Architectural Engineering + TechnologyArchitecture and The Built Environmen
Narratives #1: Eastern Mediterranean and Atlantic European Cities
No full textWe have selected seven contributions for this issue of Spool, four from the Eastern Mediterranean basin (Istanbul, Beirut, Acre and Jaffa) and three from Atlantic Europe (Bodø, Matosinhos and Gafanha da Nazaré).Roula El Khoury and Paola Ardizzola address the post-civil war reconstruction of Beirut in Lebanon and reveal how neoliberal models of development resulted in a generic city. Adem Erdem Erbas uses the Istanbul port heritage area in Turkey to showcase how GIS helps to consider underground cultural inventory from a historic landscape perspective within the framework of the conservation plans.Ana Jayone Yarza Pérez explores the potential of adaptive reuse evaluation procedure in the Old City of Acre, Israel, as a means to deal with development and gentrification in this World Heritage site.Komal Potdar explores the historical evolution of the old town, cultural geography, and the current state of exclusion and gentrification in Jaffa, Israel. She underlines the need for discourse on socio-spatial analysis and assessment for decision-making processes for urban heritage design.Diego Inglez de Souza and Ivo Pereira de Oliveira reconnect architectural history with social and industrial accounts as a strategy for understanding the relationship between infrastructure, fishing, and urbanisation by studying the emblematic case of Matosinhos, Portugal.André Tavares seeks to trace the links between fluctuations in the natural cod resources, the technologies used by fishermen to catch and process the fish, and the development of coastal landscapes and the urban form of the fishing port Gafanha da Nazaré, Portugal.And finally, Fatma Tanis uses an interview with architect Daniel Rosbottom from DHDR to provide insight into situated architecture in port cities by addressing a library and concert hall project realised in Bodø, Norway.Teachers of Practice / ASituated Architecture100% ResearchUrban Desig
Micron-Level Actuator for Thermal-Fluid Control in Microchannels
No full textEffectiveness of an actuator is investigated for thermal-flow control in microchannels. First, simulations of a single actuator in a quiescent external medium are performed in order to study the parameters characterizing the synthetic jet flow from the actuator. For this purpose, a simplified, two-dimensional configuration is considered. The membrane motion is modeled in a realistic manner as a moving boundary in order to accurately compute the flow inside the actuator cavity. The geometric and actuation parameters of the actuator are investigated to define the effectiveness of the jet flow. The study is done initially at macro scales. Then, the flow in the Knudsen number range of less than 0.1 is modeled starting with a conventional compressible Navier-Stokes solver valid for continuum approach. Its boundary conditions, however, are modified to account for the slip velocity and the temperature jump boundary conditions encountered in micron-level devices. Compressibility effects are also taken into account and modeled through the compressible flow solver. The utility of synthetic jet actuators for manipulating fluid flows has been shown for mostly macro- and mini-scale applications. To the best of the author\u27s knowledge, there have been only a few studies on micro-sized synthetic jets; also they have only been modeled assuming continuum flow regime with no-slip at the walls. Therefore, several issues must still be addressed for micron-scale synthetic jets and also their applications to micron-level problems. Thus, as the second part of the study, a micron-level synthetic jet is proposed as a flow control device to manipulate the separated flow past a backward facing step in a microchannel. First, an uncontrolled flow past a backward facing step in a channel is computed. Then, a synthetic jet actuator is placed downstream of the step where the separation occurs. A large number of test cases have been analyzed. It is observed that the size of the separation bubble and its enstrophy are functions of the geometry of the actuator cavity and the membrane oscillation parameters. Considerable reduction in separation bubble size as well as in enstrophy is achieved using the actuator. Finally, a design for thermal management of a semiconductor device using the present actuator is introduced. For this purpose, a single microchip dissipating heat is placed in a two dimensional rectangular channel. Then, the different cavity and actuation parameters are considered in order to infer some characteristics of the effect of controlled synthetic jet thermal management. Using the actuator, a circulation region is generated on the top surface of the microelectronic chip. It is found that the fluctuating jet interacts with the channel flow and increases the convection rate by transferring linear momentum to the channel flow.
It is seen from the results of the computations that the synthetic jets can be utilized effectively to control separation in internal flow applications and that they guarantee an efficient thermal management of microelectronic devices. Therefore, the synthetic jet actuator proves itself to be an effective device for thermal-fluid control applications where low-speed flows are encountered
Seismological characterization of the Theistareykir geothermal field (Iceland)
No full textIn 2017 the National Power Company in Iceland, Landsvirkjun, started the operation of a geother- mal power plant in Theistareykir (Northeastern Iceland). The plant’s operation requires extraction, circulation, and injection of the geothermal fluids to produce energy. These processes depend on the existing fracture network of the reservoir. Therefore, geothermal energy exploitation requires knowledge of underground structures to identify potential fluid flow pathways. These are, in many cases, evidenced by the local seismicity. In this context, the GFZ German Research Center for Geo- sciences and Landsvirkjun chose this site for deploying a dense network of fifteen seismic broadband stations to monitor and characterize the field’s seismicity. The data coming from this very dense network allows us to implement and test an optimized processing scheme to perform a detailed analysis of the local seismicity. This study’s primary goal is to implement an efficient and reliable scheme to characterize the local seismicity of the Theistareykir geothermal field using the collected high-resolution seismic data from the dense network. I used several traditional earthquake seismology methods to detect, analyze, classify, and localize, repeating microseismic events. I first used a recursive STA/LTA algorithm to detect the local seismicity between January 1, 2018, until June 30, 2018. Using the detections, I manually reviewed and picked P- and S-phase arrival times. After an initial non- linear localization, I performed a correlation clustering analysis and identified two events with a high degree of waveform similarity. I corrected the picked phase arrivals using the cross-correlation coefficients of the events to a master trace. These events were relocated to improve their relative locations. Events of both clusters will be used in future studies for template-matching to detect and pick additional events within this period. The methodology applied here is meant as a guide to process upcoming seismic data of the geothermal field and efficiently perform a full seismological characterization using more massive data-sets.MicroGraviMoTiS projectApplied Geophysics | IDEA Leagu
Ambient seismic noise monitoring and imaging at the Theistareykir geothermal field (Iceland)
No full textIn autumn 2017 a network of 14 broadband seismic stations was deployed at the Theistareykir high temperature geothermal field (NE Iceland). This experiment was conducted as part of the current efforts to characterize the field's main structures, and possible short and long term stress variations due to the ongoing fluid injection and extraction operations which started in autumn 2017. In this work, we use two years of continuous seismic records (October 2017–October 2019) to compute a 3D shear wave velocity model of the geothermal field and to detect possible crustal stress changes related to the injection and production activities. From phase cross-correlations of the vertical component recordings, we measure the Rayleigh wave group velocity dispersion curves to obtain 2D group velocity maps between 1 and 5 s. Subsequently, we use a neighborhood algorithm to retrieve the 3D shear wave velocity model of Theistareykir. Mainly, two sets of elongated high and low velocity anomalies can be observed oriented in a NW/WNW direction, parallel to the lineaments of the active Tjörnes fracture zone. Velocity reductions west of Ketilfjall and at Baerjafjall could indicate the location of upflow zones of the magmatic reservoir or hydrothermal system. We analyzed the temporal evolution of phase and amplitude of phase auto-correlations using the stretching technique and discuss their behavior in relation to the geothermal field operations. We notice a slightly stronger long-term velocity decrease in the reservoir region compared to outer regions. This could be related to the mass depletion in that area (higher fluid extraction compared to the water reinjection). In summary, our findings show how a monitoring network can be set up to enable a detailed imaging and monitoring of reservoir behavior in general.Mathematical Geodesy and Positionin
Embodied imitation-enhanced reinforcement learning in multi-agent systems
No full textImitation is an example of social learning in which an individual observes and copies another's actions. This paper presents a new method for using imitation as a way of enhancing the learning speed of individual agents that employ a well-known reinforcement learning algorithm, namely Q-learning. Compared with other research that uses imitation with reinforcement learning, our method uses imitation of purely observed behaviours to enhance learning, with no internal state access or sharing of experiences between agents. The paper evaluates our imitation-enhanced reinforcement learning approach in both simulation and with real robots in continuous space. Both simulation and real robot experimental results show that the learning speed of the group is improved. © The Author(s) 2013
