1,924 research outputs found
Slope Stability Monitoring Using Remote Sensing Techniques
During the past six years the Arkansas State Highway and Transportation Department (AHTD) has spent over nine million dollars repairing slope failures that have occurred in the state of Arkansas. Specifically, higher than average precipitation in 2004 and 2008 led to large quantities of slides, all of which were repaired. Two highways, within the state of Arkansas, with known historical movements along or across the highways are being monitored using traditional surveying techniques and advanced remote sensing techniques. These slides, both of which are located in fill slopes. One a 500-foot long slide located north of Chester, Arkansas, within the median of Interstate I-540. The other site is a 1200-foot long slide located east of Malvern, Arkansas, cutting across all four-lanes of Interstate I-30, have visible evidence of movement (tension cracks, traverse cracks, head scarps, flank displacement, etc.)
A ground portable RADAR interferometer (GPRI-II) constructed by Gamma Remote Sensing is the first device in the United States being used to remotely monitor slopes. Surveying monuments (2.5-inch diameter aluminum monuments placed on 24-inch long, œ-inch diameter rebar encased in 6-inches of concrete) were installed inside and outside of the sliding mass at each site (29 monuments at the calibration site in Chester, Arkansas site and 54 monuments at the validation site in Malvern, Arkansas), and are being monitored using traditional surveying techniques (using a Nikon DTM-520 total station) to identify the movement of each monument as detected from two observation points. The GPRI-II and a Leica C-10 LIDAR are also being used to identify the movement of the slopes. Inclinometers have been also installed at the validation site near Malvern, Arkansas to compare the displacements obtained by remote sensing techniques with standard borehole slope monitoring methods. The results of the movements observed using in-situ instrumentation, total station, RADAR, and LIDAR are discussed.
A full geotechnical subsurface investigation was perform at the validation site in Malvern, Arkansas during the summer of 2011. The drilling and sampling investigation provided the necessary soil and rock samples for laboratory testing. The results from the laboratory tests permitted the displacement rates to be inspected in the light of the shear strength of the soil strata and the depth to the shear failure plane. Since December 2010, site visits have been conducted every two weeks for the Chester site and every month for the Malvern site. During each visit total station, RADAR, and LIDAR observations were conducted
Novelle italiane antiche nella tradizione manoscritta: contenuto, struttura e genealogia del cod. Firenze, BNCF II III 343
Un significativo corpo di novelle due-trecentesche ha circolato per iscritto nei primi secoli della letteratura in volgare in forme diverse, prima di essere recuperato e sistemato nel Cinquecento su iniziativa di Pietro Bembo e Carlo Gualteruzzi, a cui si deve lâedizione antologica intitolata per lâoccasione Le cento novelle antiche, ormai nota come Novellino. Lâarticolo verte su uno dei testimoni delle novelle, il quattrocentesco codice II III 343 della Biblioteca Nazionale Centrale di Firenze: una compilazione contenente una serie di Vite di filosafi, una cinquantina di novelle del Novellino e infine dieci novellette non attestate altrove. Si dimostra qui lâimportanza del ms. sia sul piano ecdotico, tra i testimoni del Novellino, sia in seÌ come antologia di copista. Anche se eÌ un codice relativamente tardo e ha solo alcune delle novelle antiche, alla luce dello stemma codicum si rivela prezioso per ricostruire la complessa storia della loro circolazione nelle raccolte: esso conserva significative tracce della prima redazione di unâantologia trecentesca perduta â a sua volta cavata da un antico Libro di novelle dâautore, o Ur-Novellino â e nello stesso tempo mostra lâintraprendenza di un copista che ha assemblato una sua personale silloge sulla base di altre compilazioni. Si ha unâul- teriore conferma sia del ruolo attivo avuto dai copisti-compilatori nel tramandare lâantico patrimonio novellistico in volgare, sia del fatto che la novella si sia andata codificando come genere letterario nelle antologie, fino alla monumentale collezione «bembiana-gualteruzziana».A rich corpus of Italian novelle is transmitted by a few codexes from the 14th to the 16th century, including the first printed edition published in 1525 under the apocryphal title of Le cento novelle antiche (The One Hundred Ancient Tales, namely the Vulgate Novellino), but they differ from each other in order and number of pieces. The article mainly focuses on the ms. II III 343 of the National Central Library of Florence, containing a series of Vite di filosofi (Lives of Eminent Philosophers), about fifty novelle of the Novellino and ten more short stories not attested elsewhere. The importance of this narrative collection from the 15th century is highlighted here: the ms. contains the fragment of an early version of the Novellino, but is also a remarkable anthology that assembles different collections composed by different authors and collected by the same copyst. The comparison of its sections with each other, and with the other codexes that partially share the corpus, spreads light on the laboratory of the novella, on some aspects of its written circulation in the first centuries, its definition and its developments since the ancient Libro di novelle e di bel parlar gentile (Book of Tales and of Lovely Gentle Speech) or Ur-Novellino
Development of geopolymer composites reinforced with fiber felts using an industrial approach
Geopolymers are synthetic inorganic alumino-silicate materials generally formed by reaction of an aluminosilicate with an alkali (Na,K) silicate solution. The reaction occurs at room temperature, so geopolymer can be considered as a type of bi-component inorganic resin.
Considering their inorganic structure, geopolymer composites have better thermal properties than organic resins, which typically decompose by oxidation starting from ~400°C.
In collaboration with Trucker Subforniture s.r.l., geopolymer based composites reinforced with different kinds of felt, have been developed as alternative to GFRP, for applications where a high thermal resistance is required. Glass and basalt fibers were considered as reinforcement; using felts based on recycled fibers it is possible to keep the cost lower than that of virgin fibers for basalt fibers. Geopolymer composites were developed using an industrial technology. In order to have a good infiltration of the felts, the composition of a potassium based geopolymer resin was optimized in terms of water and alkalinity to tune the rheology and the reactivity in function of the temperature.
Density, mechanical properties and thermal stability of the different composites were tested.
References: 1. A. Natali, S. Manzi, M.C. Bignozzi, Novel fiber-reinforced composite materials based on sustainable geopolymer matrix, Procedia Engineering, 21, pp 1124-1131, 2011
2. D. Ribero and W.M. Kriven, âProperties of Geopolymer Composites Reinforced with Basalt Chopped Strand Mat or Woven Fabricâ. J. Am. Ceram. Soc., 99, pp.1192â1199, 201
Computational Model for Delamination Growth at SMA-GFRP Interface of Hybrid Composite
AbstractA cohesive model of the new interface of the CuZnAl SMA/GFRP hybrid composite is proposed and the interfacial delamination under Mode II loading conditions, between plain CuZnAl SMA sheet insert and GFRP matrix, as well as between CuZnAl SMA sheet insert having elliptical hole pattern and GFRP matrix, are studied in detail.The results of the pull-out tests with plain sheet insert are used to calculate the interfacial parameters of the hybrid composite. With these parameters, the cohesive interaction and failure mechanism for hybrid composite with plain sheet, as well as with patterned sheet insert, is modelled. The efficacy of the laser patterned SMA sheet inserts to improve the overall interfacial strength in the new laminated SMA/GFRP hybrid composite for applications, such as light weight and high damping material under dynamic loads, is validated
Cohesive surface model for delamination and dynamic behavior of hybrid composite with SMA-GFRP interface
The interface model between CuZnAl SMA and GFRP, used in a hybrid composite, is proposed using cohesive surfaces. Using this model and derived parameters, mode-II delamination is studied between CuZnAl SMA insert and GFRP and also between laser patterned CuZnAl SMA insert and GFRP. Natural frequency and damping ratio of the hybrid composite specimen, in the shape of slender beam in a cantilever configuration, are evaluated in impulse tests. A numerical model is also presented, to calculate the aforementioned dynamic properties numerically, using Modal Strain Energy (MSE) and Modal Dynamics procedures by considering the derived interfacial parameters. Keywords: Hybrid composite, Delamination, FE analysis, Cohesive interface, Damage initiation, Modal dynamic
Real world data in the era of Immune Checkpoint Inhibitors (ICIs): Increasing evidence and future applications in lung cancer.
Immune checkpoint inhibitors (ICIs) targeting programmed death 1 (PD-1) and PD-ligand 1 (PD-L1) quickly subverted the standard of treatment in Non-Small Cell Lung Cancer (NSCLC), where they were first introduced in all comers previously treated advanced/metastatic NSCLC patients and subsequently in the first line of PD-L1 selected cases of metastatic and locally advanced disease. Treatment algorithm is an evolving landscape, where the introduction of front-line ICIs, with or without chemotherapy, unavoidably influences the following treatment lines. In this context, medical oncologists are currently facing many unclear issues, which have been not clarified so far by available data. Effectiveness and safety in special populations underrepresented in clinical trials - such as elderly, poor PS, hepatitis or human immunodeficiency virus-affected patients - are only a part of the unexplored side of ICIs in the real world. Indeed, pivotal randomized clinical trials (RCTs) often lack of external validity because eligibility criteria exclude some patient subgroups commonly treated in real-world clinical practice. Similarly, cost-effectiveness and sustainability of these innovative agents are important issues to be considered in the real-world. Though affected by several limitations, real-world evidence (RWE) studies allow to collect data regarding overall treated patients in clinical practice according to local authority regulations, overcoming the intrinsic limits of RCTs. The present review focuses on RWE about ICIs in lung cancer treatment, with particular reference to special patient populations, and discusses potential application of real-world data in a potential innovative drug development model
Zeolite-based ceramic components through hydrothermal dry synthesis
Zeolites are three-dimensional, microporous, crystalline solids with well-defined structures that contain aluminum, silicon and oxygen in their regular framework. Zeolites are generally formed in strong alkali solution (Na, K) and in hydrothermal conditions.
In this work, inorganic compacts were produced using an innovative approach, where kaolinite was directly converted into a zeolite structure through a hydrothermal synthesis without the addition of any water, and therefore in dry conditions. Zeolite-based components reinforced with fillers were also produced. XRD analyses were conducted to confirm the formation of the desired phase. Strength and microstructure were evaluated to optimize the composition of the composites.
The zeolite-based components could replace fiber reinforced plastic in terms of thermal resistance. Moreover, this class of ceramic composites can be process with the same technology of thermosetting based composites.
References: Davidovits J, Legrand J (1977). Process for agglomerating compressible mineral substances under the form of powder, particles or fibres. US4028454
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