Johnson Matthey (Germany)

Flows in square channels are common in applications, such as automotive after-treatment systems and heat exchangers. Flows with axial flow entry are well understood, but for oblique flow entry, there is no clarity on the additional pressure loss magnitude or the flow regime. Laminar flow is often assumed, even though flow separation at the channel entrance can cause a transition to turbulence. Here, the impact of oblique flow entry on the flow is investigated using LES (large eddy simulation) and RANS (Reynolds averaged Navier–Stokes) models, and their advantages and limitations are identified. The LES simulations show that the shear layer at the channel entrance produces continuous shedding of eddies that persist downstream even at moderate channel Reynolds numbers (≈ 2000). The LES predicted pressure losses mostly agree with experimental data, and the differences observed are attributed to the difficulty of accurately replicating the experimental geometry. It is shown that both LES and RANS results are sensitive to the rounding of the leading edge (present in experiments). Including edge rounding improves the pressure predictions. RANS simulations mostly agree with experimens, but unlike LES did not predict transitional flow phenomena for sharp leading edge. This study provides insight into the flow structure and sources of pressure losses in square channels, highlights the importance of understanding key flow and geometric features when using LES to predict complex flows involving flow separation and shear layers, and indicates the need to further investigate the complex instability arising from interactions between secondary flow and shear-layer roll-up.

Nafion<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> membranes are one of the most common electrolyte materials used inside proton exchange membrane fuel cells where adequate hydration is required for proton conduction. Exploiting the relatively high attenuation of terahertz (THz) radiation to liquid water, we have previously demonstrated quantitative video-imaging of hydrated Nafion<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> under ambient conditions. In this work, we build on our earlier demonstrations to investigate the feasibility for membrane liquid water imaging and quantification under controlled humidity conditions.

Mục tiêu: Đánh giá kết quả điều trị bước đầu bong thể mi sau chấn thương đụng dập nhãn cầu và một số yếu tố ảnh hưởng tới kết quả điều trị bong thể mi về mặt giải phẫu. Đối tượng và phương pháp nghiên cứu: nghiên cứu mô tả tiến cứu không có nhóm chứng trên 60 mắt bong thể mi sau chấn thương đụng dập nhãn cầu được điều trị khoa Chấn thương và phòng khám ngoại trú Bệnh viện Mắt Trung ương từ 01/2017 đến 07/2018. Kết quả: Đa số bệnh nhân là nam giới, tỷ lệ nam/nữ xấp xỉ 6/1. Độ tuổi trung bình là 39,0±12,3 tuổi, đa số trong nhóm tuổi 31 – 50 tuổi. Thị lực trung bình của nhóm bệnh nhân trong nghiên cứu trước điều trị là 0,2±0,3, sau 3 tuần là 0,08±0,16 và sau 3 tháng là 0,05±0,08. Nhãn áp trung bình trước điều trị là 14,3±4,7 mmHg. Sau điều trị 3 tháng, nhãn áp trung bình là 19,9 ± 2,9 mmHg. Tỷ lệ tăng nhãn áp sau 3 tuần điều trị là 8,3%. Tỷ lệ bệnh lý hoàng điểm nhãn áp thấp là 36,7%. Nhãn áp và mức độ sâu của khe bong thể mi khi vào viện có tương quan nghịch với nhau (r=-0,4, p=0,0015). Các yếu tố ảnh hưởng tới kết quả điều trị về mặt giải phẫu bao gồm độ sâu khe bong thể mi ban đầu, mức độ bong thể mi ban đầu phân loại theo độ rộng khe bong, bệnh hoàng điểm nhãn áp thấp và phân loại nhãn áp trước điều trị. Kết quả điều trị không phụ thuộc vào các yếu tố tuổi, giới, thời gian từ khi chấn thương tới khi điều trị và thị lực trước điều trị. Kết luận: Bong thể mi là tổn thương trầm trọng gặp trong chấn thương đụng dập nhãn cầu. Điều trị bong thể mi phụ thuộc vào mức độ bong và các tổn thương phối hợp. Một số yếu tố có thể được sử dụng để tiên lượng khả năng điều trị thành công về mặt giải phẫu.

Platinum (Pt) alloys are excellent oxygen-reduction catalysts used in proton exchange membrane fuel cells, yet their effective integration poses challenges. Through in-situ X-ray diffraction, we investigate the compositional changes during the ink preparation of PtCo and PtNi catalysts and reveal that dissolution is primarily driven by temperature. Comparisons with conventional catalyst-coated membrane (CCM) fabrication methods highlight structural transformations during hot-pressing. Paving the way for advancements in sustainable energy technologies, our findings emphasize the essential need for fundamental knowledge of ink-making and CCM fabrication to unlock Pt-alloy catalyst potential for hydrogen fuel cells. In addition to the academic community, the industry shall benefit from this precise and easy-to-employ methodology.

The platinum group metals (Pt, Pd, Rh, Ir, and Ru) are cited as critical minerals by the US Geological Survey and appear on the EU Critical Raw Materials list due to their low natural abundance and economic importance. Platinum has many uses including jewellery, medical devices and pharmaceuticals, coatings, automotive catalysts, nitric acid manufacture and other industrial catalysts, electronics, and plays a crucial role in the growing area of fuel cell and water electrolyzers.Early recognition of the need to recycle these valuable elements has led to the development of a circular economy using highly advanced processes for extracting and separating them from complex materials, returning the metals to use in a highly pure form. This presentation will give an overview of the industry up to the present day, including examples of the application of separation techniques, and will explore the potential for reduced environmental impact from recycling platinum group metals and the benefits of consideration of design for recycle in product development.

We describe a 36-year-old man with a long-standing diagnosis of ulnar fibrous dysplasia with associated fracture of the ulna. He presented with a growing and increasingly tender forearm mass and was diagnosed with adamantinoma of the ulna, for which he underwent wide resection of the ulnar diaphysis followed by reconstruction with a vascularized fibula autograft. This case serves to emphasize the importance of performing a stepwise workup for the diagnosis of osseous neoplasms even in cases with long-standing diagnoses. [Orthopedics. 2024;47(2):e102-e105.].

Join us for our online conference, where we will be asking important questions about the future of platinum group metals (pgms), their contribution to technology development and the net zero transition. The conference brings together industry and academics, professional organisations and policymakers, to discuss the critical role pgms have to play in the technologies of the future.

The reliance of proton exchange membrane water electrolysis (PEMWE) on iridium as an oxygen evolution catalyst has led to uncertainty over whether a large-scale PEMWE industry can be realised. The future PEMWE capacity growth that is sustainable in terms of iridium supply is investigated. It is found that, if optimistic improvements in iridium utilisation and high recycling rates are achieved, a global capacity of 1.3 TW could be reached by 2050, which is above the Net-Zero Emissions 2050 target, using only 20% of annual primary iridium supply. The different catalyst strategies that can improve iridium utilisation are compared using membrane electrode assembly (MEA) testing data from the literature, with the order found to be supported nanoparticles ≈ extended surface structures > mixed oxides > nanoparticles. As a main result, it is found that a terrawatt-scale PEMWE industry can avoid being constrained by iridium supply if technological development of a similar level to that seen in PEM fuel cells is realised.

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Despite the legislation targets set by several governments of a full electrification of new light-duty vehicle fleets by 2035, the development of innovative, environmental-friendly Internal Combustion Engines (ICEs) is still crucial to be on track toward the complete decarbonization of on road-mobility of the future. In such a framework, the PHOENICE (PHev towards zerO EmissioNs &amp;amp; ultimate ICE efficiency) project aims at developing a C SUV-class plug-in hybrid (P0/P4) vehicle demonstrator capable to achieve a -10% fuel consumption reduction with respect to current EU6 vehicle while complying with upcoming EU7 pollutant emissions limits.&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;Such ambitious targets will require the optimization of the whole engine system, exploiting the possible synergies among the combustion, the aftertreatment and the exhaust waste heat recovery systems. Focusing on the first aspect, the combined use of innovative in-cylinder charge motion, Miller cycle with high compression ratio, lean mixture with cooled EGR and electrified turbocharger will enable a highly diluted combustion process capable to achieve a peak indicated efficiency of 47% and, at the same time, to minimize the engine out emissions. Numerical simulations were intensively exploited to reduce the engine calibration time and to preliminary assess the benefits of the abovementioned technologies. In particular, 3D-CFD simulations highlighted the capabilities of the Swumble&lt;sup&gt;TM&lt;/sup&gt; intake ports to produce an increase of about 50% of the Turbulent Kinetic Energy (TKE), while 1D-CFD models showed possible further enhancements of the brake thermal efficiency through the use of the new turbocharger (+2%) and of an aggressive Millerization of the cycle (+1.1%).&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;Finally, a preliminary experimental campaign, performed on the first engine prototype, confirmed the encouraging results of the simulation activity. With an AFR = 1.43 and an EGR ratio close to 5%, the PHOENICE engine showed a further improvement in the BTE up to 4% and a simultaneous reduction of the NOx emissions of more than 70% in comparison with conventional stoichiometric, undiluted operation.&lt;/div&gt;&lt;/div&gt;