Helipad on the building roof design features

The following items are considered: requirements, constructive decisions for helipads; covering plate design of the helipad located on the building roof; helipad modeling in LIRA CAD SP; calculation of a multi-storey building with a helipad on the roof, check for strength and rigidity; characteristics of the helipad on the building roof.

Light Scattering in Glass Ceramic X-ray Imaging Plates

<p>Glass ceramic materials have been suggested as a possible high resolution replacement for current commercial storage phosphor imaging plates. The low spatial frequency of the current plates is caused by strong scattering of the laser light incident on the plate during the read-out process. Glass ceramic materials show very small scattering due to their transparent nature, which should lead to a higher resolution. However, a competing argument is the small amount of scattering that does occur travels a much greater distance in the plate, limiting the resolution. The aim of this thesis was to simulate the scattering of light in imaging plates and use this to optimise the trade-off between resolution, sensitivity and transparency which is implicit in plate design. Additionally, experiments were performed to determine the resolution of glass ceramic and commercial imaging plates. Simulations show that high resolution can be achieved in both the strong and weak scattering limits, corresponding to opaque and transparent materials. Increasing the absorption of the laser light increases the resolution, as does decreasing the laser beam diameter and power. An increase in the resolution almost always comes at a cost of a decrease in the sensitivity. The resolutions of an Agfa MD30 and glass ceramic imaging plate were found to be 4:5 line pairs/mm and 6:5 - 8:0 line pairs/mm respectively for an MTF equal to 0:2.</p>

Light Scattering in Glass Ceramic X-ray Imaging Plates

<p>Glass ceramic materials have been suggested as a possible high resolution replacement for current commercial storage phosphor imaging plates. The low spatial frequency of the current plates is caused by strong scattering of the laser light incident on the plate during the read-out process. Glass ceramic materials show very small scattering due to their transparent nature, which should lead to a higher resolution. However, a competing argument is the small amount of scattering that does occur travels a much greater distance in the plate, limiting the resolution. The aim of this thesis was to simulate the scattering of light in imaging plates and use this to optimise the trade-off between resolution, sensitivity and transparency which is implicit in plate design. Additionally, experiments were performed to determine the resolution of glass ceramic and commercial imaging plates. Simulations show that high resolution can be achieved in both the strong and weak scattering limits, corresponding to opaque and transparent materials. Increasing the absorption of the laser light increases the resolution, as does decreasing the laser beam diameter and power. An increase in the resolution almost always comes at a cost of a decrease in the sensitivity. The resolutions of an Agfa MD30 and glass ceramic imaging plate were found to be 4:5 line pairs/mm and 6:5 - 8:0 line pairs/mm respectively for an MTF equal to 0:2.</p>

Desain Underwater Rotor Untuk Memanfaatkan Laju Aliran Sungai Sebagai Pembangkit Listrik Tenaga Air

<p><em>This study aims to design an underwater rotor to utilize the flow rate of the river as a hydroelectric power plant. In this study, an underwater rotor design model will be made with three variations in the number of blades, namely three, six, nine blades. The test parameter observed in this study is the turbine performance through the value of the power coefficient (cp) and the moment coefficient (cm). The method used in this research is an experimental method, namely by making a turbine model with a laboratory scale. The results show that the underwater rotor designed with aspect ratio = 2.0, overlap ratio = 0, end-plate diameter = 1.1d then the barrier plate design with L/D ratio = 1.2 60º provides the highest power coefficient and moment coefficient, namely respectively 0.15 and 0.27 in the design with the number of blades 3 (three)</em></p>

Time to revisit the endpoint dilution assay and to replace the TCID50 as a measure of a virus sample’s infection concentration

The endpoint dilution assay’s output, the 50% infectious dose (ID50), is calculated using the Reed-Muench or Spearman-Kärber mathematical approximations, which are biased and often miscalculated. We introduce a replacement for the ID50 that we call Specific INfection (SIN) along with a free and open-source web-application, midSIN (https://midsin.physics.ryerson.ca) to calculate it. midSIN computes a virus sample’s SIN concentration using Bayesian inference based on the results of a standard endpoint dilution assay, and requires no changes to current experimental protocols. We analyzed influenza and respiratory syncytial virus samples using midSIN and demonstrated that the SIN/mL reliably corresponds to the number of infections a sample will cause per mL. It can therefore be used directly to achieve a desired multiplicity of infection, similarly to how plaque or focus forming units (PFU, FFU) are used. midSIN’s estimates are shown to be more accurate and robust than the Reed-Muench and Spearman-Kärber approximations. The impact of endpoint dilution plate design choices (dilution factor, replicates per dilution) on measurement accuracy is also explored. The simplicity of SIN as a measure and the greater accuracy provided by midSIN make them an easy and superior replacement for the TCID50 and other in vitro culture ID50 measures. We hope to see their universal adoption to measure the infectivity of virus samples.

Compression Rubber Damper Assessment Through Simulation

Rubber torsional vibration dampers are often used on mid-range engines. Usually, the geometry of a rubber torsional vibration damper is such that the rubber element in it undergoes shear. However, in the work presented, a compression rubber damper is being proposed, in which the rubber element undergoes compression rather than shear. The proposed compression rubber damper, just like the shear rubber damper, is a tuned damper. An analytical tool is being used to evaluate the stiffness of compression rubber design and thus evaluate its performance. The rubber geometry, material and plate design are selected through simulations. The analytical tool demonstrates the functionality of the compression rubber damper paper and focuses on simulation-based product development using ANSYS for FEA and an in-house tool for torsional vibration analysis.

Mechanical Evaluation of Two Hybrid Locking Plate Designs for Canine Pancarpal Arthrodesis

Hybrid locking pancarpal arthrodesis plates were designed with either a round (RH) or an oval (OH) radiocarpal hole, the latter allowing varied screw positioning. Due to concerns about potential decreased structural properties of the OH design, our aim was to compare the mechanical behavior of the contrasting plates using combined finite element analysis (FEA) and mechanical testing. Pancarpal arthrodesis plates with RH or OH design were assigned to three fixation techniques ( n = 6 ), prebent at 20°, and fixed to canine forelimb models with simulated radius and radiocarpal and 3rd metacarpal bones. OH plates were instrumented with a radiocarpal screw inserted either most proximal (OH-P) or most distal (OH-D). Specimens were axially loaded to 300 N over 10 ramped cycles at 0.5 Hz. Plate strains were measured with strain gauges placed at areas of highest deformations as predicted by FEA under identical loading conditions. FEA predicted the highest strains (μm/m) adjacent to the radiocarpal hole (2,500 [RH], 2,900 [OH-P/OH-D]) and plate bending point (2,250 [RH], 1,900 [OH-P/OH-D]). Experimentally, peak radiocarpal hole strains were not influenced by the OH screw position ( 3,329 ± 443 [OH-P], 3,222 ± 467 [OH-D]; P = 0.550 ) but were significantly higher compared to the RH design ( 2,123 ± 154 ; P < 0.001 ). Peak strains at the bending point were significantly lower for OH-P ( 1,792 ± 174 ) and OH-D ( 1,806 ± 194 ) versus RH configurations ( 2,158 ± 114 ) ( P ≤ 0.006 ). OH plates demonstrated highest peak strains next to the radiocarpal hole and were associated with more heterogenous plate strain distribution. Structural weakening associated with radiocarpal OH plate design could result in decreased fixation strength and increased risk of plate fatigue failure.

Bone morphological feature extraction for customized bone plate design

Fractures are difficult to treat because of individual differences in bone morphology and fracture types. Compared to serialized bone plates, the use of customized plates significantly improves the fracture healing process. However, designing custom plates often requires the extraction of skeletal morphology, which is a complex and time-consuming procedure. This study proposes a method for extracting bone morphological features to facilitate customized plate designs. The customized plate design involves three major steps: extracting the morphological features of the bone, representing the undersurface features of the plate, and constructing the customized plate. Among these steps, constructing the undersurface feature involves integrating a group of bone features with different anatomical morphologies into a semantic feature parameter set of the plate feature. The undersurface feature encapsulates the plate and bone features into a highly cohesive generic feature and then establishes an internal correlation between the plate and bone features. Using the femoral plate as an example, we further examined the validity and feasibility of the proposed method. The experimental results demonstrate that the proposed method improves the convenience of redesign through the intuitive editing of semantic parameters. In addition, the proposed method significantly improves the design efficiency and reduces the required design time.

Resonant metamaterial designs for a broadband mitigation of flow-induced vibrations

Resonant metamaterials have recently emerged as lightweight and performant noise and vibration solutions for the hard-to-address low-frequency ranges. These engineered materials are made by an assembly of resonant elements onto a host structure. Their interaction leads to tuneable frequency ranges, known as stop bands, in which they can outperform classical noise control measures. However, these stop bands have a limited frequency range effect. To broaden the noise and vibration performance also outside the stop band, this paper presents a design approach for a finite resonant metamaterial plate. Two regularly spaced grids of resonant elements are both added to a plate. In the first grid, the resonant elements are tuned to the same nominal frequency and stop band behaviour is achieved. In the second grid, the tuned frequency of each resonant element is found through an optimisation procedure, with the goal of minimising the dynamic response of the plate outside the stop band. To speed up the optimisation, model order reduction and a dynamic sub-structuring method are employed. The performance of this finite resonant metamaterial plate design is validated by evaluating its vibration response due to a broadband grazing flow excitation and comparing it to a plate with equivalent mass additions.