16,565 research outputs found
Recent Results From the EU POF-PLUS Project: Multi-Gigabit Transmission Over 1 mm Core Diameter Plastic Optical Fibers
No full textRecent activity to achieve multi-gigabit transmission over 1 mm core diameter graded-index and step-index plastic optical fibers for distances up to 50 meters is reported in this paper. By employing a simple intensity-modulated direct-detection system with pulse amplitude or digital multi-tone modulation techniques, low-cost transceivers and easy to install large-core POFs, it is demonstrated that multi-gigabit transmission up to 10 Gbit/s over 1-mm core diameter POF infrastructure is feasible. The results presented in this paper were obtained in the EU FP7 POF-PLUS project, which focused on applications in different scenarios, such as in next-generation in-building residential networks and in datacom applications
Tomato marchitez virus, a new plant picorna-like virus from tomato related to tomato torrado virus
No full textA new virus was isolated from a tomato plant from the state of Sinaloa in Mexico. This plant showed symptoms locally known as `marchitez disease¿: severe leaf necrosis, beginning at the base of the leaflets, and necrotic rings on the fruits. A virus was isolated from the infected plant consisting of isometric particles with a diameter of approximately 28¿nm. The viral genome consists of two (+)ssRNA molecules of 7221 (RNA1) and 4898¿nts (RNA2). The viral capsid contains three coat proteins of 35, 26 and 24¿kDa, respectively. The abovementioned characteristics: symptoms, morphology, number and size of coat proteins, and number of RNAs are similar to those of the previously described tomato torrado virus (ToTV). Sequence analysis of the entire viral genome shows that this new virus is related to, but distinct from, ToTV and that these members of two obviously new virus species belong to the recently proposed plant virus genus Torradovirus. For this new virus, the name tomato marchitez virus (ToMarV) is proposed
Employing M1 direct calibration/de-embedding approaches for large signal model validation at mm-wave frequencies
No full textIn this contribution, we employ direct calibration/de-embedding approaches to validate the large signal device model of state-of-the-art HBTs and CMOS technologies operating in the mm-wave frequency band WR6. The capability of placing the first tier calibration reference plane in close proximity to the DUT allows the large signal metric to be directly compared with foundry models.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic
Dynamic Estimation of Vital Signs with mm-wave FMCW Radar
No full textIn this paper, we propose a method for continuous monitoring of vital signs-in particular, respiration frequency-with a commercial mm-wave radar. The nearly constant frequency (NCF) model is adopted to represent chest displacement due to respiration and simulate radar response. Based on this model, an extended Kalman filter (EKF) based estimator is developed to track the breathing frequency of a person. The impact of dynamic model parameters is investigated in numerical simulation. The possibility to track breathing frequency with the proposed method is demonstrated by experimental data processing. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microwave Sensing, Signals & System
Single screw extruder performance characteristics during processing of corn protein blends
No full textDuring the last decade, the global biofuels industry has experienced exponential growth. By-products such as distillers dried grains with solubles (DDGS) have grown in parallel. DDGS is primarily an animal feed, but it has also been shown to be suitable as a biopolymer. In this study, the extrusion processing behaviour of DDGS was evaluated. Prior to processing, water was added to DDGS at a level of 3 kg DDGS to 1.5 kg water (water at 50 parts per hundred (pph)). Additionally, a DDGS/water blend with 50 pph CaCO₃ was used as a tracer to determine residence time during processing. The blends were processed in a single screw autogenous extruder, which relied solely upon friction for dissipative heating. Two die plates were used: one consisted of 6 orifices equally spaced, 2 mm diameter each, with a total opening area of 18.85 mm²; the other consisted of multiple orifices (960 in total) arranged concentrically around the plate, with a diameter of 2.30 mm each, for a total opening area of 3988.45 mm². Processing began with DDGS blends without tracer; after reaching steady state, the tracer blend was introduced. Samples were collected every 5 sec during processing to determine extrudate changes over time. Extruder power consumption, mass flow rate, and temperature profile were determined during processing. Extrudates were analysed for Hunter colour (L-a-b) changes over time. Extrusion processing characteristics were highly influenced by the die opening area. Die exit temperatures ranged from room temperature (25°C) to more than 100°C, purely due to increased friction for the smaller die opening. Future work should characterize the mechanical properties of these extrudates to assess their suitability as either bioplastic feedstocks or pelletized animal feeds
A 23-to-29GHz Receiver with mm-Wave N-Input-N-Output Spatial Notch Filtering and Autonomous Notch-Steering Achieving 20-to-40dB mm-Wave Spatial Rejection and -14dBm In-Notch IP1 dB
No full textDigital beamforming receivers (RXs) support MIMO operation and offer great flexibility and accuracy in multi-beam formation and calibration. However, compared with analog phased-array and hybrid systems, due to the absence of any rejection for spatial in-band blockers, the RX/ADC dynamic range and linearity should be high enough to prevent array saturation. Therefore, the use of self-steering spatial notch filters (SNFs) is necessary to aid the digital beamformers and reduce RX/ADC power consumption while strong blockers exist. To address that, the sub-6GHz RXs in [1], [2] synthesize a baseband spatial notch impedance and translate it to RF by passive mixers. However, this technique cannot be directly applied at mm-wave frequencies as the impedance translational performance of the passive mixers degrades significantly. Hence, the mm-wave beamformer in [3] realizes a cascadable SNF at an intermediate frequency (IF). However, the front-end mm-wave components like mixers and phase shifters have to tolerate strong blockers, thus degrading RX linearity. Besides, it uses multiple IF buffers and VGAs for signal scaling and combining, which could be power-hungry if a similar method is adopted to realize a mm-wave SNF. To improve on those limitations, we propose a scalable SNF structure, which (1) suppresses the strongest in-band blocker at mm-wave frequencies, (2) supports N-input-N-output MIMOs, and (3) requires no active blocks except the phase shifters. A two-step autonomous notch-steering technique is also developed to adjust the SNF notch direction power-efficiently and accurately.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic
Monitoring foundations
No full textIt is estimated that about 400.000 houses in the Netherlands – both shallow and wooden pile foundations – could be facing problems with their foundations. Although, house owners are becoming increasingly aware of the fact that problems (and thereby costs) can be prevented if remedial measures are taken in time. Monitoring of the foundation can possibly give insights in the remaining capacity of the foundation. In this thesis, research is performed into monitoring of foundations. The main research question is: Which methods can be used to monitor a foundation and to what extent are these useful and adequate? To answer this question, five different monitoring methods have been investigated: InSAR (Interferometric Synthetic-Aperture Radar), measurement bolts, a subsidence sensor, a groundwater level sensor and a tilt sensor. Other methods have not been considered and are beyond the scope of this research.First, InSAR data has been compared to subsidence data gathered by measurement bolts in two different cases, one in Zaandam (Netherlands) and Amsterdam (Netherlands). Measurement bolts are used as golden standard in this comparison. The comparison of measurement bolts with INSAR data resulted in a maximum error margin of ± 0,86 mm/year for Case Study Block A and ± 1,31 mm/year for all measurements for the testcase in the Case Study Block B within a 95% confidence interval. Secondly, the measurement bolts method has been qualitatively compared to InSAR data. Also, the pros and cons have been discussed. Measurement bolts have a better precision (0,3-0,5 mm) than InSAR data (2-3 mm) for individual measurements. Possible errors that can influence the accuracy of this method are: personal errors, instrumental errors and natural errors. InSAR and measurement bolts both have their strengths and weaknesses. Prescreening is an easier application for InSAR but highly accurate measurements in a specific location is more reliable if measurement bolts are used. In a way, these methods complement each other rather than measuring the same way. The datasets collected by the subsidence, groundwater level and tilt sensors is made available for this research project by KennisCentrum Aanpak Funderingsproblematiek (KCAF) which is an independent knowledge and network organization funded by the government of the Netherlands. Generally, several factors can add noise to the signal. It is unknown if the signal of the sensors is calibrated to measure the right quantity. This research project has shown that the data showed a similar trend of the groundwater level as local monitoring wells. Therefore, it can be concluded that the sensors are adequate to measure the groundwater level if they are calibrated and referenced to NAP. Moreover, the groundwater level sensor can possibly be used to measure how long dry periods are and how much wood is exposed to air, in order apply measures well in time.Tilt sensors are currently not used for monitoring of foundations. The factors that can be considered when a tilt sensor is used to monitor a foundation are investigated with a literature study and with expert opinion. As the results show the measured rotation can be related to the stiffness of the wall where the sensor is mounted on. As for all sensors, it has to be made sure if they are calibrated to actually measure what they observe. Further research could usefully explore how viable a system of sensors is. In general, classification or a prediction of the remaining service life of a foundation can be challenging. Further research might explore how useful it is when big dataset are combined to be able to give better judgement.Civil Engineering | Building Engineerin
Experiencing the armed struggle : the Soweto generation and after
No full textIncludes bibliographical references (p. 354-369).This study explores the experiences of the rank-and-file soldiers of Umkhonto we Sizwe and the Azanian People's Liberation Anny. Extensive interviews by the author and other researchers reveal the voices of the soldiers themselves. The African National Congress and Pan African Congress archives at the University of the Western Cape and the University of Fort Hare supplement and verify these oral testimonies, as do some published sources. Most previously published materials about the armed struggle against apartheid have already focused on diplomacy, strategy and tactics, operations, leadership, and human rights abuses to the neglect of the soldiers' actual experiences. This study complements these with significant new oral history materials from the Soweto generation of soldiers and their successors. When dealing with MK, many authors have documented issues of the camp structure in Angola, and operations inside South Africa, so much of this detail is only addressed briefly, leaving space to explore the soldiers' experiences. In the case of APLA, very little has been written on its history, and more detail is provided on these subjects. This study therefore deals with the soldiers' politicisation and motivation for joining the armed struggle, their experiences in leaving South Africa and training in exile, the crises in exile which limited their effectiveness for a time, their return to fight in South Africa, and their difficulties in the "new" South Africa. These materials reveal that vast problems remain facing these veterans of the struggle against apartheid, and that they have the potential, if properly supported and employed, to contribute substantially to the development of present day South Africa. Conversely, if their neglect continues, they also have the potential to bring vast harm to the country. Further use of the investigative tools of oral history, especially if extended to the former soldiers' vernacular languages, is necessary to augment the history of South Africa, and these soldiers' contributions
Grouped People Counting Using mm-wave FMCW MIMO Radar
No full textThe problem of radar-based counting of multiple individuals moving as a single group is addressed using an mm-wave multiple-input-multiple-output (MIMO) frequency-modulated continuous wave (FMCW) radar. This problem is challenging because the different individuals are closer to each other than the range/azimuth resolution, and their bulk Doppler signatures are difficult to distinguish, as they tend to move together. A processing pipeline is proposed, based on the combination of a multiple target tracking algorithm with a classifier to track each group and count the number of people within. Specific salient features are defined for the classifier and extracted from range-azimuth maps and cadence velocity diagrams (CVDs). The proposed pipeline has been experimentally validated in several outdoor scenarios with grouped people. The results show that the combination of tracking algorithm and classifier in the proposed pipeline outperforms alternative methods from the literature as well as a commercial toolbox for people counting.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microwave Sensing, Signals & System
MM Recital
No full textMM RecitalEmbargo status: Restricted until 06/2172. To request the author grant access, click on the PDF link to the left
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