Large Frame Research Articles

Insulator filth monitoring and situation awareness based on ultraviolet pulse and least square method

To monitor the filth state of insulators in time, a method based on ultraviolet pulse method is proposed to monitor the filth status of insulators, which can detect the early corona discharge of insulators by detecting UV signals and determine the degree of insulator filth. On this basis, the response characteristics of spot area to electrical pulse signal are studied and theoretical analysis is carried out, the relationship between spot area and electrical pulse signal amplitude is studied, and the correlation curve is obtained. By observing the change law of image size with the observation distance in ultraviolet image. the experiment found that the image size of UV channel and the image size of visible light channel increased or decreased in approximate proportion with the observation distance and proposed a new method to estimate the “discharge imaging area ” of discharge on the surface of the insulator by using the image information of the visible light channel. According to the discharge “relative spot area mean”, one minute time “number of large spot area image frames” two ultraviolet imaging parameters used to characterize the filth discharge characteristics, combined with the ambient humidity to establish a fuzzy logic reasoning model of the filth state, to achieve the assessment of the filth state of the insulator. By using the proposed UV image processing method, the accuracy of insulator filth detection is improved.

Thinking Europe’s “Muslim Question”: On Trojan Horses and the Problematization of Muslims

Understanding the ways in which Muslims are turned into “a problem” requires an analytic incorporating the insights gained through the concepts of Islamophobia and anti-Muslim racism into a larger frame. The “Muslim Question” can provide such a frame by attending to the systematic character of this form of racism, explored here through biopolitics. This article develops a conceptualization of Europe’s “Muslim Question” along three lines. First, the “Muslim Question” emerges as an accusation of being an “ alien body” to the nation, often expressed through the Trojan horse legend. Second, the “Muslim Question” is elaborated through demands of integration and assimilation, in which the production of difference entangles with calls and measures to regulate Muslims. And third, the “Muslim Question” is brought to life upon the terrain of gender and sexuality, as the imaginary of threat at the heart of the “Muslim Question” is a replacement conspiracy centered on birthrates.

Research on TCP Performance Model and Transport Agent Architecture in Broadband Wireless Network

The problems of Internet stability, heterogeneity, fairness of bandwidth sharing among streams, efficiency of use and congestion control have been solved in this article. This paper proposes an improved scheme of TCP proxy acknowledgement based on Automatic Repeat Request (ARQ), which improves throughput, reduces delay and saves uplink bandwidth of wireless link, and is more suitable for future asymmetric networks. The substantial improvement is observed during the experimentation as processing efficiency of protocol. The observed results revealed that overall processing time for each packet is approximately equals to one fourth of the transfer control protocol and the reduction of 59% is also observed in the utility of resources. The protocol also incorporates various simple techniques for the recovery of loss to improve the throughput in noisy wireless conditions. The results show that the adoption of the average diversity combining technology is helpful to improve the throughput and effective factor performance, and can reduce the requirement of radio link protocol (RLP) maximum retransmission times. As nearly 90% of uplink acknowledgement frames are filtered, the uplink bandwidth utilization rate is significantly improved. Decomposing large data frames into small data frames is also helpful to improve system performance.

Bounded delay scheduling with packet dependencies

A common situation occurring when dealing with multimedia traffic is having large data frames fragmented into smaller IP packets, and having these packets sent independently through the network. For real-time multimedia traffic, dropping even few packets of a frame may render the entire frame useless. Such traffic is usually modeled as having inter-packet dependencies. We study the problem of scheduling traffic with such dependencies, where each packet has a deadline by which it should arrive at its destination. Such deadlines are common for real-time multimedia applications, and are derived from stringent delay constraints posed by the application. The figure of merit in such environments is maximizing the system’s goodput, namely, the number of frames successfully delivered.We study online algorithms for the problem of maximizing goodput of delay-bounded traffic with inter-packet dependencies, and use competitive analysis to evaluate their performance. We present competitive algorithms for the problem, as well as matching lower bounds that are tight up to a constant factor. We further present the results of a simulation study which further validates our algorithmic approach and shows that insights arising from our analysis are indeed manifested in practice.

Spatial Feature-Based Prioritization for Transmission of Point Cloud Data in 3D-Image Sensor Networks

A sensor network that connects multiple 3D image sensor devices using light detection and ranging (LIDAR) is effective for collecting spatial information to detect potential risks associated with people’s movements. However, due to the large volume and high frame rate of point cloud data obtained by LIDAR devices, under the condition of strictly limited bandwidth, some part of the data can go missing when detection is performed from point cloud data, causing a degradation of the accuracy. As the communication traffic volume of other applications increases, the communication available bandwidth for spatial information applications becomes insufficient. This paper proposes a scheme of spatial feature-based prioritization for the transmission of point cloud data with strictly limited communication bandwidth. It estimates how much each piece of point cloud data contributes to the accuracy improvement of a machine learning task for spatial prediction and assigns a higher score to those with a larger contribution. These scores prioritize the control for the transmission of point cloud data from sensor devices to an edge server. Feature selection with machine learning is helpful for estimating data importance. To improve the estimation accuracy, the proposed scheme complements missing entries when performing feature selection. We developed an indoor experimental environment and found that the prediction accuracy was sufficiently maintained compared to two benchmark schemes, random and heuristic, with limited communication bandwidth. Comparison with the perturbation method, which is a conventional method of feature selection, demonstrated the effectiveness to complement missing values in the proposed scheme.

272 Effect of Frame Size and Supplementation on Performance and Carcass Characteristics of Beef Cattle Finished on Novel Endophyte-infected Tall Fescue Pastures

Abstract Objectives were to investigate the effects of frame score (FS) and supplementation on performance and carcass characteristics of cattle finished on novel endophyte-infected fescue pastures. This 2-yr experiment used 80 Angus-sired, crossbred steers and heifers bred for divergent FS. Cattle were allotted to 5 treatments: 1) non-supplemented small frame (S-NON; FS = 3.0 ± 0.9), 2) supplemented small frame (S-SUPP), 3) non-supplemented large frame (L-NON; FS = 4.7 ± 0.6), 4) supplemented large frame (L-SUPP), and 5) grain-based control feedlot ration (CON; FS = 4.2 ± 0.6; target ADG = 1.36 kg/day). Daily rations were delivered individually using Calan gates. Pasture supplement contained corn gluten feed, a commercially available rumen-protected prilled vegetable fat, and dried molasses fed at 0.5% of BW. Treatments started on 7/8/2019 and 5/21/2020, and ended in November of each yr when cattle were slaughtered at a commercial abattoir. Results were analyzed using PROC MIXED of SAS with main effects of treatment, sire, sex, yr, and yr x treatment, with contrast statements comparing large vs. small frame, pasture supplemented vs. non-supplemented, and control vs. pasture groups. As expected, CON had greater (P < 0.001) growth performance (final BW and ADG) and carcass characteristics (HCW, subcutaneous fat, marbling, dressing percentage (DRESS%) than pasture groups, and tended to have greater (P=0.053) REA. Relative to pasture groups, CON had greater (P < 0.001) Minolta L* and a* lean tissue values, and decreased (P < 0.001) b* values for fat tissue. While non-supplemented cattle had decreased (P = 0.016) yield grades (YG), supplemented cattle had greater (P < 0.050) final BW, ADG, subcutaneous fat, HCW, marbling, and DRESS% compared to non-supplemented cattle. Small framed cattle tender to have decreased (P = 0.056) YG; but, large framed cattle had greater (P = 0.006) HCW, and tended (P = 0.060) to have greater ultrasound subcutaneous fat. Results support low-level supplementation in pasture-finishing systems to improve carcass value.

Construction of AlF3 layer to improve Na3.12Fe2.44(P2O7)2 interfacial stability for high temperature stable cycling

Sodium ion batteries (SIBs) are applied to the field of energy storage due to their unique advantages, however, large scale energy storage equipment, also requires low cost, good cycling performance, safety performance and good environmental adaptation performance, in order to cope with various climatic conditions. The polyanionic material Na3.12Fe2.44(P2O7)2(NFPO) is considered to be an excellent cathode material for SIBs due to its unique large frame work structure and good thermal stability, leading to good cycle stability and a wide working temperature. Nevertheless, poor intrinsic conductivity of the material brings about large polarization, resulting in low electrochemical reversibility. Especially in high temperature environment, the electrolyte aggravates the erosion of the material and increases the side reactions, making the cycle stability worse. In this study, nanoscale NFPO composites are synthesized by an optimized sol–gel method, while the interface is modified using AlF3, to achieve resistance to surface oxidation and corrosion. Impressively, these modified materials exhibit high-temperature electrochemical properties due to the thermal stability and interfacial protection of AlF3. At 60 °C, it provides a discharge capacity of 130 mAh g−1 at 0.1C, still has a discharge capacity of 100.4 mAh g−1 at 10C, a capacity retention rate of 96.3% after 400 cycles, and has excellent long-term cycling performance (70% capacity retention rate after 6000 cycles at 50C). This work demonstrates the effectiveness of the interfacial modification and provides an impactful strategy for the design of batteries at high temperatures.

Demystifying frame aggregation in 802.11 networks: Understanding and approximating optimality

MAC-layer frame aggregation has significantly improved the efficiency of IEEE 802.11n and 802.11ac networks by placing multiple MAC-layer data units in a large PHY-layer frame. In this paper, we focus on finding the optimal length of an Aggregated MAC Protocol Data Unit (A-MPDU) in order to maximize throughput. In theory, larger A-MPDUs amortize overheads over more bits and therefore increase throughput. However in practice, throughput can be negatively impacted if too many frames are aggregated, due to higher error rates at the end of A-MPDUs. Determining the optimal number of subframes is challenging because error rates can be higher in the later part of the A-MPDU which change with factors such as mobility, speed and transmission rate. Additionally, there are dependencies between consecutive A-MPDUs due to software retransmissions.We develop a model of A-MPDU frame aggregation and use it to design a statistically optimal algorithm. Using our understanding of that algorithm we develop a standard compliant, Practical, Near-Optimal Frame Aggregation algorithm (PNOFA). Our trace-based evaluation shows that across a variety of devices and scenarios PNOFA outperforms existing state-of-the-art algorithms and obtains throughputs that are within 97% of those obtained using the statistically optimal algorithm. Furthermore, we implement PNOFA as a user-space process on an 802.11ac Wave 2, Google Wifi access point. We find that when compared with the frame aggregation algorithm provided in the device’s Qualcomm IPQ 4019 chipset’s firmware, PNOFA increases average throughput by 17% and 13% for UDP and TCP traffic on the scenarios tested.

Optimizing Fog Harps.

It has recently been demonstrated that harps harvest substantively more fog water than conventional mesh nets, but the optimal design for fog harps remains unknown. Here, we systematically vary key parameters of a scale-model fog harp, the wire material, wire pitch, and wire length, to find the optimal combination. We found stainless steel to not only be the best hydrophilic wire material but also nearly be as effective as Teflon-coated wires. The best choice for the wire pitch was coupled to the wire length, as the smallest pitch collected the most water for short harps but was hampered by tangling for taller harps. Accordingly, we use an elastocapillary wire tangling model to successfully predict the onset of tangling beyond a critical length for any given wire pitch. Combining what we learned, we achieved a water harvesting efficiency of 17% with an optimized stainless-steel harp, over three times higher than that of the current standard of a Raschel mesh. These results suggest that an optimal fog harp should feature high-tension, uncoated wires within a large aspect ratio frame to avoid tangling and promote efficient and reliable fog harvesting.

The View From Here: Contemporary Perspectives from Senegal

The View From Here: Contemporary Perspectives from Senegal

Strengthening of vulnerable RC moment resisting frames using direct internal connection of X-steel bracing

Non-ductile reinforced concrete frames are commonly found in older buildings in many parts of the world. These structures designed for gravity loads, have limited lateral strength and ductility, are prone to excessive one-way lateral movement and soft-story mechanism. This paper focuses on the retrofit of an existing reinforced concrete frame, using steel X-braces by direct internal connection method. The main purpose is the analytical study of general behavior and response of large scale vulnerable frames. An experimental study was used to validate the numerical modeling performed in ABAQUS. Next the base samples were retrofitted with X-braces and four proposed direct internal connection methods. Furthermore, in a separate parametric studies, the effect of frame type, bracing cross-section dimensions and gusset plate shape were investigated. The results indicated that the stiffness, bearing capacity and absorbed energy of the reinforced concrete frame by using steel X-braces increases up to 4, 2.3 and 1.5 times, respectively. Moreover, bracing acts like the first defense system against lateral loads, such as structural fuse with its yield, increases the amount of energy dissipation. It also removes the plastic hinges by reducing the ultimate displacement and stress of lateral load in the panel zone.

Implications of Protest and Reform for Domestic Governance in Ethiopia

The nexus between protest–transition–reform situated in a larger frame of Ethiopia’s political dynamics anchored in historical narratives and theoretical debates are presented in this paper. Moreover, the genesis and the dynamics surrounding the rolling out of the post-2018 Ethiopia’s transition are examined from the vantage point of prospects for entrenching a stable democratic dispensation in the country. To this end, the political economy approach, along with presenting ethnographic narratives that are pertinent to the subject under study, is used as an analytical lens. Also, document review of journal articles, official and academic reports, internet blogs, and newspaper and other media posts was undertaken to substantiate findings from primary sources. The paper concludes that the ongoing Ethiopian transition unfolded by paving avenues for opening up space for negotiating unsettled issues surrounding state-society relations in a context of a relatively liberalized political economy. However, the envisioned model of transition is constrained by different factors characterized by a split in the ranks of the ruling coalition, intergroup conflicts, and rising unmet expectations that resulted in the absence of peace and stability. Besides, the prevailing weakness of democratic institutions and polarized inter-ethnic relations, the recent outbreak of the COVID-19 pandemic stalled the progress of the transition process.

Basic aspects of the metal–insulator transition in vanadium dioxide VO2: a critical review

Vanadium dioxide exhibits a first order metal to insulator transition (MIT) at 340 K (T MI ) from a rutile (R) structure to a monoclinic (M 1 ) structure. The mechanism of this transition interpreted as due either to a Peierls instability or to a Mott–Hubbard instability is controversial since half a century. However, in the last twenty years the study of chemical and physical properties of VO 2 and of its alloys, benefits of a renewed interest due to possible applications coming from the realization of devices made of thin films. We describe in this review the structural, electronic and magnetic properties of the different metallic (R) and insulating (M 1 , T, M 2 ) phases of VO 2 , of its solid solutions and under constraint. We present in a synthetic manner the various phase diagrams and their symmetry analysis. This work allows us to revisit older interpretation and to emphasize in particular the combined role of electron–electron interactions in the various phase of VO 2 and of structural fluctuations in the MIT mechanism. In this framework we show that the phase transition is surprisingly announced by anisotropic one-dimensional (1D) structural fluctuations revealing chain like correlations between the V due to an incipient instability of the rutile structure. This leads to an unexpected critical dynamics of the order–disorder (or relaxation) type. We describe how the two-dimensional (2D) coupling between these 1D fluctuations, locally forming uniform V 4+ zig-zag chains and V–V pairs, stabilizes the M 2 and M 1 insulating phases. These phases exhibit a 1D electronic anisotropy where substantial electron–electron correlations conduct to a spin–charge decoupling. The spin-Peierls ground state of M 1 is analyzed via a mechanism of dimerization, in the T phase, of the spin 1/2 V 4+ zig-zag Heisenberg chains formed in the M 2 phase. This review summarizes in a critical manner the main results of the large literature on fundamental aspects of the MIT of VO 2 . It is completed by unpublished old results. Interpretations are also placed in a large conceptual frame which is also relevant to interpret physical properties of other classes of materials.

CharlesKennyThe Plague Cycle: The Unending War Between Humanity and Infectious DiseaseScribner, 2021, 320 p., $28.00

Charles Kenny, senior fellow at the Center for Global Development, begins his history of infectious disease with a two-century old quote from An Essay on the Principle of Population (1798): “Premature death must in some shape or other visit the human race.” Malthus reasoned that the power of population was so superior to the power of the earth to produce subsistence that periodic outbreaks of “misery”—either war, pestilence, or famine—were inevitable. Kenny begins his story circa 1800 on purpose. It was an inflection point in the history of infectious disease. Two hundred years ago half of all people born in the world died before their fifth birthday; today it is one in twenty-five. Life expectancy at birth was below 30 in 1870; now it is above 70. Only recently has our ability to control infectious disease made premature death the exception and not the given that Malthus believed it to be. In chapters 2 and 3, Kenny updates Malthus's story of misery's past by noting that infectious disease actually played a relatively minor role when humans lived in hunting and gathering groups and while they gradually spread from Africa across the globe. It assumed a central role, more important than war and famine combined, only with the rise of farming and “civilization,” when humans and animals began clustering together in villages and cities. The virulence of infectious disease rose dramatically with increased density, social interaction, and trade. With over half the world's population now living in cities, and trade and travel at record levels, our current containment of infectious disease is historically unprecedented. In fact, Kenny believes, these levels of globalization and urbanization cannot exist without this containment. On this larger frame, Kenny appends specific narratives of major pandemics, strategies of containment, public health innovations, vaccines, and responses to new infections. Chapter 4 tells of the massive die-offs that happened when European explorers with their Eurasian diseases of “civilization” arrived in long isolated regions. Chapter 5 tells of the “exclusion instinct” that people repeatedly exposed to deadly outbreaks developed: treating the infected with disgust and quarantine, and fleeing them when possible. Chapter 6 examines various “cleaning up” attempts: cooking food, reducing bad odors, sequestering excrement. By tracing responses to cholera, a fecal-oral bacterial infection which first appeared as a global pandemic in 1817, Kenny documents the trial and error attempts to reduce contamination in water supplies that finally produced tangible infection control. Chapter 7 examines the similar trial and error process that produced beneficial vaccines. Chapter 8 reports the good news that arrived by the mid-twentieth century with the completion of the first stage of the sanitation and medical revolutions: city living being more healthy than rural, life becoming healthier and longer, families becoming smaller and better educated, and trade and travel making the world more interconnected and prosperous. The concluding chapters examine the vulnerability of our urban and globalized world to new outbreaks of infection. We have lost tens of millions of lives to HIV/AIDS, and face a continual emergence of new threats: avian influenza, Nipah virus, Hendra virus, Ebola, Marburg fever, Lassa fever, cryptosporidiosis, cyclosporiasis, Zika, and hantavirus. Our response often has been too late and too uncoordinated. We have allowed older foes like tuberculosis and malaria to developed multidrug resistance due to our misuse of antibiotics. Covid-19 is proving just how difficult it is to contain and control an emerging viral threat in a world like ours. Kenny argues that we need consistently good sanitation and health systems throughout the world, and better systems of surveillance, screening, isolation, and research. Our modern world simply cannot exist without it.

Cubic Manganese Potassium Hexacyanoferrate Regulated by Controlling of the Water and Defects as a High-Capacity and Stable Cathode Material for Rechargeable Aqueous Zinc-Ion Batteries.

Aqueous zinc ion batteries (A-ZIBs) have been used as new alternative batteries for grid-scale electrochemical energy storage because of their low cost and environmental protection. Finding a suitable and economical cathode material, which is needed to achieve high energy density and long cycle stability, is one of the most important and arduous challenges at the present stage. Potassium manganese hexacyanoferrate (KMHCF) is a kind of Prussian blue analogue. It has the advantages of a large 3D frame structure that can accommodate the insertion/extraction of zinc ions, and is nontoxic, safe, and easy to prepare. However, regularly synthesized KMHCF has higher water and crystal defects, which reduce the possibility of zinc ions' insertion/extraction, and subsequently the discharge capacity and cycling stability. In this work, a KMHCF material with less water and low defects was obtained by adding polyvinylpyrrolidone during the synthesis process to control the reaction process. The KMHCF serves as the cathode of A-ZIBs and exhibits an excellent electrochemical performance providing a specific capacity of 140 mA h g-1 for the initial cycle at a current density of 100 mA g-1 (1 C). In particular, it can maintain a reversible capacity of 85 mA h g-1, even after 400 cycles at 1 C. Moreover, unlike the traditional zinc storage mechanism of A-ZIBs, we found that the KMHCF electrode undergoes a phase transition process when the KMHCF electrode was activated by a small current density, which is attributed to part of the Mn on the lattice site being replaced by Zn, thus forming a new stable phase to participate in the subsequent electrochemical reaction.

An automatic approach for detecting building fences from high-resolution images: the case study of Makkah, Saudi Arabia

Abstract In the light of the constantly expanding technological advancements concerning high-resolution satellites and imaging techniques for investigative and information uses it is important to look at how these algorithms progress to acquire more reliable data in a much efficient manner. This study aims to (1) investigate the ability to use remote sensing and geographic information system techniques to extract the detecting building edges in the City of Makkah and (2) investigate new machine learning techniques to derive the illegal building fences in the study area. Two WorldView-3 images will be the first obtained for the City of Makkah in 2016 and 2018. Convolutional neural networks algorithm will be investigated to detect all the fences within the two images. These traits have been utilized to create automated object detection techniques, which are a core requirement of information extraction and large frame analysis of images covering large expanses of land. In high-resolution images, object detection identifies objects belonging to a class, locating them using a bounding box. Based on satellite images time series, the outputs will detect the changes that occurred during 2016 and 2018. A web map application will be designed as the primary tool to make it easier, illustrating the differences between the main changes. Evaluation of binary classifiers approach will be used to evaluate the outcomes of building fences based on several performances that measure data interpretation. Preliminary findings will illustrate the precision and accuracy of the used machine learning algorithm. The research findings can contribute to the federal/municipal authorities and act as a generic indicator for targeting building fences for urban areas and/or suburban areas.

149 An investigation into self-perception of body image in female equestrians in the United Kingdom

Body image has become widely considered in modern society and has been found to affect performance, sport participation levels, athlete self-confidence and impact subjective judging. Female body image (BI) has been investigated in a range of sports yet, in the female dominated sport of equestrianism, where several disciplines are subjectively judged, there is a paucity of BI research. This study aimed to identify self-perceptions of BI in female equestrians, identify rider perceptions of judge and coach BI bias, highlight relationships between female equestrian body image and self-consciousness and explore any effect of breast size. A 4-part, 27 question online survey (GoogleForms) was distributed for 2 mo via various equestrian social media platforms and was completed by female equestrians (n = 493), based in the United Kingdom, currently participating in horse riding activities. Participants supplied demographic information, self-perceived BI and ideal female equestrian BI (rated on a validated scale from smallest A to largest J), and self-consciousness details while horse riding. Chi-squared ( X 2 ) and Wilcoxon (W) analyses were utilized to test associations between participant responses. The second smallest body image on the scale (B) was perceived to be ideal for the female equestrian (X 2 = 352.751, P < 0.001). There was no significant effect of rider age, own BI, or level of riding commitment to this perception. There was a significant perception that judges favored riders with a smaller frame (X 2 = 54.2111, P < 0.001); and a significant association was found between riders who perceived their BI to be larger feeling self-conscious when riding (X 2 87.514, P < 0.001). Additionally, significantly more people perceived the ideal BI to be smaller than their own BI (Median = −1.5, W = 7777.00, P < 0.001), there was an association between those categorised as dissatisfied with their BI and feeling self-conscious when riding (X 2 = 83.649, P < 0.001). Consequently, perception of the ideal female equestrian frame is smaller than many riders’ own BI, and a larger BI negatively impacts rider self-confidence, potentially impacting performance, and participation, therefore, warranting further research. Female riders with a larger frame may be perceived negatively by judges, or at least feel they are, and further study is indicated to investigate the extent these influences have on the subjective judging of equestrian sport.

Application and Seismic Analysis of changing masonry structure into bottom frame structure

In order to meet the requirements of people for the use of large space, the masonry structure building is underpinned, the load-bearing wall of the building is removed, and the underpinning beam is constructed to replace the original load-bearing wall to bear the upper load, the bottom masonry structure is transformed into a large space frame structure. Based on the analysis of two different underpinning methods, this paper selects the structural underpinning method according to their advantages and disadvantages, and takes an example as an example to summarize the construction of underpinning beam structure first. Then the main construction methods and matters needing attention of the underpinning technology for removing the load-bearing wall in the construction process, so as to provide a certain basis for the future construction of the structure. Through the displacement loading method, the bearing capacity of frame beam and underpinning beam is analyzed, and the data are processed, and the advantages and disadvantages of underpinning beam and frame beam under load are obtained.

Advanced full-scale laboratory dynamic load testing of a ballasted high-speed railway track

Understanding ballast layer dynamic response and long-term behavior under moving train loads is necessary for optimization of railway track performance. This paper discussed an advanced testing effort undertaken in a controlled laboratory environment for the measurement of dynamic load responses via multitude of installed sensors and the development of validated computer models and simulation tools suitable for analyzing full-scale ballasted track under dynamic loading. Constructed in a large rectangular metal frame, the laboratory model consisted of a full-scale track with eight ties, ballast, subballast, and embankment. Three different speeds and axle load configurations were applied sequentially onto the full-scale ballasted track using eight actuators, which realistically captured both slow moving freight and high-speed passenger train loads. Vibration velocities were captured at different locations on ballast surfaces and ties. Dynamic soil stresses were recorded at the bottom of the ballast and subballast layers. Both transient and permanent deformations due to repeated dynamic loads were measured in the track substructure layers and for all eight ties. “SmartRock” advanced sensors were used for the first time to track ballast particle movements under dynamic loading. Further, the test data from the experiments were compared with preliminary Discrete Element Method (DEM) simulations.

Quasi-plastic flexural behavior of adhesive-bolt hybrid connection for large scale pultruded GFRP frame

Flexural behavior of an adhesive-bolt hybrid connection for pultruded glass fiber reinforced polymer (GFRP) frame is investigated through monotonic and cyclic loading tests. It is shown that the hybrid connection fabricated using resin adhesive and steel bolts is able to exhibit a quasi-plastic behavior. Multistage damage occurred in tests, and the adhesive failed initially, followed by GFRP failure at bolt holes. Effect of shear force was investigated by variable shear-span ratios in tests. Additionally, moment and rotation curves obtained from monotonic and cyclic loading tests are found to be similar, indicating that loading schemes have little impact on structural performance of the hybrid connection. Energy dissipation is analyzed based on cyclic loading tests. Finite element model is also built, and design formulas are proposed to predict the quasi-yield moment and maximum moment. A good agreement is found between experimental results and analytical predictions. In addition, design recommendation on the use of adhesive-bolt hybrid connection is provided.