Nozzles are used in a wide range of applications. Nevertheless, the geometric of non-circular orifices have not been widely studied. This project has examined fluid jets exiting through a non-circular orifice, in the gravitational direction. Furthermore, its transformation to a circular cross-section due to a surface tension forces. How the length to a circular cross-section changes with the nozzles geometry and bath depth of the tundish was the main focus of this studied. A water model and high-speed camera was used to capture the profile of the fluid jet. Four different nozzles were attached one by one to five different tundishes with different bath depths. The result showed that with deeper bath depths the circular cross-section occurred further down from the nozzles orifice. The length to the circular cross-section also depended on the orifice area, a larger area gave a longer distance than a smaller area. It was shown that the length to circular cross-section followed a quadratic function, when the measured values were analyzed based on the Weber number. The profile of the fluid jet was dependent on the material of the nozzle, the geometries of the orifice, the bath depth and the surface tension.

The purpose of our thesis is to determine to what extent the cow milk and oat drink industries can implement a circular economy according to Ellen MacArthur Foundation’s definition. In addition, we will discuss the impact on the overall sustainability.  31% of the anthropogenic emissions stem from processes related to food production and in Sweden, a significant portion of these stem from the dairy industry– which has also been noticed by some oat drink companies. The problem is further amplified by the fact that a third of the food produced for human consumption ends up lost or wasted. Multiple laws and policies have been introduced to combat this, and new solutions are needed. A term that has gained popularity lately is the circular economy, which focuses on closing the loop and thus eliminating waste. That way, if would be possible to see the environmental impact from the oat drink and cow milk industries in a bigger perspective.  We have conducted a qualitative study using primary and secondary data. The primary data stems from 11 semi-structured interviews and the secondary data comes from relevant documents by the companies. An inductive approach was used.  The results showed that it is not possible for these industries to implement an entirely circular food supply chain because of the inevitable food waste. Overall, there is also a lack of terminology and measuring methods in both areas related to the CE. Yet, the work with food waste has come far within the individual companies but the coordination between companies that will allow them to cooperate requires further attention. The efforts should be aimed at the consumer level and seek to clarify the question of responsibility. Furthermore, the difficulties in profitability must be solved, and an improved compensation system is needed. Finally, we noted that a circular economy is not by definition perfectly sustainable, and that changes in the oat drink can lead to other implications of a study like this one.

The purpose of the study was to evaluate the merits of the DiscRotor concept that combine the features of a retractable rotor system for vertical take-off and landing (VTOL) with an integral, circular wing for high-speed flight. Tests were conducted to generate basic aerodynamic characteristics of the DiscRotor in hover and in fixed-wing flight. To assess the DiscRotor during hover, small scale tests were conducted on a 3ft diameter rotor without the presence of a fuselage. A "hover rig" was constructed capable of rotating the model rotor at speeds up to 3,500 RPM to reach tip speeds of 500fps. Thrust and torque generated by the rotating model were measured via a two-component load cell, and time averaged values were obtained for various speeds and pitch angles. It has been shown that the DiscRotor will perform well in hover. Ground Effects in hover were examined by simulating the ground with a movable, solid wall. The thrust was found to increase by 50% compared to the ground-independent case. Pressure distributions were measured on the ground and disc surfaces. Velocity measurements examined the flow field downstream of the rotor by traversing a seven hole velocity probe. A wake behind the rotor was shown to contract due to a low pressure region that develops downstream of the disc. Wind tunnel experimentation was also performed to examine the fixed wing flight of the DiscRotor. These experiments were performed in the VA Tech 6â X6â Stability Tunnel. A model of the fuselage and a circular wing was fabricated based upon an initial sizing study completed by our partners at Boeing. Forces were directly measured via a six degree of freedom load cell, or balance, for free stream velocities up to 200fps. Reynolds numbers of 2 and 0.5 million have been investigated for multiple angles of attack. Low lift-to-drag ratios were found placing high power requirements for the DiscRotor during fixed-wing flight. By traversing a seven-hole velocity probe, velocities in a 2-D grid perpendicular to the flow were measured on the model. The strengths of shed vortices from the model were calculated. A method to improve fixed-wing performance was considered where two blades were extended from the disc. An increase of 0.17 in the CL was measured due to the interaction between the disc and blades. This research utilized a wide range of experiments, with the aim of generating basic aerodynamic characteristics of the DiscRotor. A substantial amount of quantitative data was collected that could not be included in this document. Results aided in the initial designs of this aircraft for the purpose of evaluating the merit of the DiscRotor concept. / Master of Science

The current global waste problem presents significant challenges worldwide, and Spain is no different. Factors such as rapid urbanization, population growth, intensive agriculture, linear production models, and changing consumption patterns contribute to the upward trend in waste generation. To address these challenges and meet EU requirements, Spain developed the Law 7/2022 on Waste and Contaminated Soils for a Circular Economy (LRSC) to establish a legal framework promoting waste reduction, reuse, recycling, and proper waste management. The LRSC includes green taxes on plastic and landfill waste, incineration, and co-incineration. This qualitative policy research investigates the drivers and barriers influencing Spanish small and medium companies (SMEs) in transitioning to a circular economy (CE) and evaluates the effectiveness of the LRSC in supporting this shift reducing the scope to packaging waste. The study also aims to assess the impact of the LRSC, particularly the two green taxes within it, and address any emerging issues. Through a literature review and interviews with ten SMEs, the research reveals challenges in waste management, low recycling rates, and high landfilling rates in Spain. Barriers to circular economic models include the need for EU-wide alignment of laws, consumer education, stagnation of recycling technology, lack of economic incentives, high prices of recycled plastic, greenwashing, and cost savings. Companies face challenges such as lack of availability of recycled plastic, concerns about food contact packaging approval if produced with recycled plastics, changing company values and workforce habits, lack of legislative harmonization which increase the system complexity, capitalist marketing strategies, investment requirements, and lack of education. However, drivers for transition include consumer choices, economic incentives, and market demand. Concerns about the LRSC’s effectiveness in reducing packaging waste and facilitating the transition to a CE, include late implementation, eco-design and circular economy foundation deficiencies, selective collection challenges, and the low availability of recycled plastics. The LRSC is believed to have potential positive impact for the environment, however further efforts are needed to overcome the challenges identified in the study.

Yes / This communication presents a single-feed ultra-wideband circularly polarized (CP) antenna with high front-to-back ratio (FBR). The antenna is composed of two orthogonally placed elliptical dipoles printed on both sides of a substrate. To realize high FBR, a novel composite cavity is also proposed and integrated with the presented crossed dipoles, which effectively reduces the backlobe of the crossed dipoles. Simulation results are in good agreement with the measured results that demonstrate an impedance bandwidth from 0.9 to 2.95 GHz (106.5%) and a 3-dB axial ratio (AR) bandwidth from 1 to 2.87 GHz (96.6%). The measured FBR is about 30 dB across the whole global navigation satellite system (GNSS) band. Compared with other reported single-feed wideband CP antennas, the antenna has advantages such as a wider CP bandwidth and lower backlobe radiation.

Yes / This research article analyzed the self-preserving behaviour of wall-wake region of a circular pipe mounted horizontally over a flat rigid sand bed in a shallow flow in terms of mean velocity, RSS, and turbulence intensities. The study aims to investigate self-preservation using appropriate length and velocity scales.in addition to that wall-normal distributions of the third-order correlations along the streamwise direction in the wake region are analyzed. An ADV probe was used to record the three-dimensional instantaneous velocities for four different hydraulic and physical conditions corresponding to four cylinder Reynolds numbers. The results revealed that the streamwise velocity deficits, RSS deficits, and turbulence intensities deficits distributions displayed good collapse on a narrow band when they were non-dimensionalized by their respective maximum deficits. The wall-normal distance was non-dimensionalized by the half velocity profile width for velocity distributions, while the half RSS profile width was used in the case of the RSS deficits and turbulence intensities deficits distributions. The results indicate the self-preserving nature of streamwise velocity, RSS, and turbulence intensities in the wall-wake region of the pipe. The third-order correlations distributions indicate that sweep is the dominant bursting event in the near-bed zone. At the same time, ejection is the dominant bursting event in the region above the cylinder height.

Yes / Recent studies and research have centred on new solutions in different elements and stages to the increasing energy and data rate demands for the fifth generation and beyond (B5G). Based on a new-efficient digital beamforming approach for 5G wireless communication networks, this work offers a compact-size circular patch antenna operating at 60 GHz and covering a 4 GHz spectrum bandwidth. Massive Multiple Input Multiple Output (M–MIMO) and beamforming technology build and simulate an active multiple beams antenna system. Thirty-two linear and sixty-four planar antenna array configurations are modelled and constructed to work as base stations for 5G mobile communication networks. Furthermore, a new beamforming approach called Projection Noise Correlation Matrix (PNCM) is presented to compute and optimise the fed weights of the array elements. The key idea of the PNCM method is to sample a portion of the measured noise correlation matrix uniformly in order to provide the best representation of the entire measured matrix. The sampled data will then be utilised to build a projected matrix using the pseudoinverse approach in order to determine the best fit solution for a system and prevent any potential singularities caused by the matrix inversion process. The PNCM is a low-complexity method since it avoids eigenvalue decomposition and computing the entire matrix inversion procedure and does not require including signal and interference correlation matrices in the weight optimisation process. The suggested approach is compared to three standard beamforming methods based on an intensive Monte Carlo simulation to demonstrate its advantage. The experiment results reveal that the proposed method delivers the best Signal to Interference Ratio (SIR) augmentation among the compared beamformers

Yes / Construction and demolition waste (CDW) management and recycling practices are crucial for transitioning to a circular economy. This study focuses on the detailed characterization of CDWs, including hollow brick (HB), red clay brick (RCB), roof tile (RT), concrete (C), and glass (G), collected from seven different sites. The CDWs were characterized based on particle size distribution, chemical composition, and crystalline nature. Pozzolanic activity was evaluated through compressive strength measurements of cement mortars with 20% cement replacement by CDWs at 7, 28, and 90 days. The results showed that clayey CDWs exhibited similar physical/chemical properties and crystalline structures. Compositions of Cs varied significantly based on their original materials. CDWs satisfied the minimum strength activity index for supplementary cementitious materials, with pozzolanic activity influenced by fineness and SiO2+Al2O3 contents. The average strength activity indexes for HB, RCB, RT, C, and G were 84.5%, 86.3%, 83.4%, 80.7%, and 75.8%, respectively. Clayey CDWs contributed to mechanical strength development, while Cs' contribution was related to hydration of unreacted cementitious particles. G exhibited the weakest pozzolanic activity due to its coarser particle size. Overall, CDWs demonstrated suitable properties for use as supplementary cementitious materials in PC-based systems.

Among the most critical elements at signalized intersections are the design of vehicle detection equipment and the timing of change and clearance intervals. Improperly timed clearance intervals or improperly placed detection equipment can potentially place drivers in a Type I dilemma zone, where approaching motorists can neither proceed through the intersection before opposing traffic is released nor safely stop in advance of the stop bar. Type II dilemma zones are not necessarily tied to failures in design, but are more readily tied to difficulties in driver decision making associated with comprehension and behavior. The Type II dilemma zone issues become even more prevalent at high-speed intersections where there is greater potential for serious crashes and more variability in vehicle operating speeds. This research initiative attempts to further describe the impact of driver behavior and comprehension on dilemma zones. To address this notion several experiments are proposed. First, a large empirical observation of high-speed signalized intersections is undertaken at 10 intersection approaches in Vermont. This resulted in the collection of video and speed data as well as full intersection inventories and signal timings. These observations are reduced and analyzed for the purpose of reexamining the boundaries of a Type II dilemma zone. Second, a comparison of point and space sensors for the purpose of dilemma zone mitigation was conducted. This experiment provides evidence supporting the notion that space sensors have the potential for providing superior dilemma zone protection. Third, a computer based survey is conducted to identify if drivers comprehend the correct meaning of the solid yellow indication and how this relates to their predicted behavior. Lastly, a regression model is developed drawing on the data collected from the field observation as well as the static survey to determine how characteristics such as the speed and position of the vehicle as well as driver age and experience influence driver behavior in the Type II dilemma zone. Cumulatively, these experiments will shed additional light on the influence of driver behavior and comprehension on the Type II dilemma zone.

This  exploratory research  identifies  how  can  clothing companies  implement  textile recyclingtechnologies that help transition them to a sustainable circular economy business model, given the challenges of eco-innovation diffusion. The study is exploratory in nature, employs a literature review and a case study of Patagonia, the outdoor equipment and clothing company that pioneered the use of recycled fibers in the outdoor clothing industry and continues to have today several initiatives for diverting textile waste away from landfills.To implement textile recycling technologies, the company created the Worn Wear Program, the Common Threads Recycling Program and the possibility to return a worn-out garment to Patagonia’s distribution center by mail or from any store or local authorized dealer of Patagonia’s products. To make the recycling (or repurposing) of worn-out garments work, the company also established a repair department at its distribution center which receives all worn-out clothes sent for recycling or repurposing.