Salient research dimensions across STEM

The Open Research Knowledge Graph (ORKG) represents a next-generation platform designed to structure scholarly contributions as a knowledge graph, enhancing the readability for both machines and humans. This thesis investigates the structured representation of research, particularly identifying universally applicable dimensions across various fields to facilitate comparisons on similar research issues. By analyzing comparison tables from selected survey articles across ten STEM domains—including Agriculture, Astronomy, Biology, Chemistry, Earth Science, Engineering, Materials Science, Mathematics, and Medicine—the research delineates both domain-independent and domain-dependent dimensions. Furthermore, this study explores the capability of generative AI technologies, like ChatGPT, to predict these dimensions, paralleling human annotation. The findings contribute to the development of advanced generative-AI-powered search systems like ORKG Ask, which could standardize research comparison dimensions across specific problems while accommodating domain specificity elsewhere. The thesis culminates in the creation of multiple ORKG templates, comparisons, and reviews, laying groundwork for future developments in scholarly communication

Investigation of Innovative Means to Enhance Mist Cooling in Gas Turbines

One of the most common techniques to increase the thermal efficiency and output power of gas turbines is to increase the turbine inlet temperature with increased pressure ratio. The current turbine cooling schemes have almost reached a plateau with most of cooling advancements being incremental. Since the main challenge is to cool the turbine airfoils without using more cooling air, application of mist cooling is a very promising scheme that can provide significant cooling enhancement. In this study, mist (tiny water droplets 10-20 µm) is added to the conventional cooling air technique to improve the cooling performance. Computational studies have been performed to investigate employment of mist cooling a) in a complete, current gas turbine airfoils design under real gas turbine operating conditions including conjugate gas-solid heat transfer with internal passage cooling, impinging jet cooling, trailing edge cooling, and external film cooling and tip cooling in a rotating blade. b) in the first stator-rotor stage under complicated interactions of passing wakes and shock waves in a transonic gas turbine. c) through a row of novel sweeping jet design via fluidic oscillators without moving parts in the applications of impinging jet cooling and film cooling. Furthermore, an experimental study has been performed to investigate mist film cooling through the sweeping jet film cooling design in a wind tunnel. A Phase Doppler Particle Analyzer (PDPA) system was used to investigate the water droplet behavior with such a sweeping jet in conjunction with the temperature field using thermocouples and Infrared Thermography. The results show that using mist can achieve an average cooling enhancement of 20% to 80% with the local maximum enhancement up to 350%. For sweeping flow studies, due to the sweeping and feed-back flow behavior inside the fluidic oscillator, tiny droplets coalesce into bigger droplets, resulting in a phase lag between the air and mist flow, which makes cooling more uniform. The non-steady flow simulation has identified the fundamental vortex dynamics that explains the reason why the sweeping jet film cooling flow produces a time-averaged inward counter-rotating vortex pair (CRVP) against the outward CRVP presents in traditional steady jet film cooling flow

Experimental Study and Modeling of Smart Loss Circulation Materials; Advantages and Promises

Lost circulation occurs when mud or cement is lost to the formation while drilling. Lost circulation has been a huge problem and may cause heavy financial costs in the form of lost rig time, mud fluid and in severe cases, well blowout with serious environmental and safety consequences. Despite extensive advances in the last couple of decades, lost circulation materials used today still have disadvantages such as damaging production zones, plugging drilling tools or failing to seal the fractures. Here, we propose a new class of smart expandable lost circulation material (LCM) to remotely control the expanding force and functionality of injected LCM. The utilized smart LCM is made out of anionic shape memory polymers and becomes activated by formation natural heat; hence it can effectively seal fractures’ width without damaging production zones and strengthen the wellbore. The activation temperature of the LCMs can be adjusted based on the formation temperature. In this work, a series of experiments were conducted using a HPHT permeability-plugging apparatus (PPA) to measure the sealing efficiency of the smart LCMs as a proof of concept. Various slot disc sizes were used to mimic different size fractures in the formation. The API RP 13 B-1&2 have been followed as standard test methods to evaluate fluid loss in water based muds. In addition, a fully coupled CFD-DEM model is developed to further study the effectiveness of different size distribution of smart LCMs and to calculate compressional stresses acting on the wellbore from their expansion. These tests will then allow us to improve the design of the smart LCM and also allow us to see if the smart LCM can be implemented in the field

Acquired Port-Wine Stain: Not a simple stain!

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width-k Eulerian polynomials of type A and B and its Gamma-positivity

We define some generalizations of the classical descent and inversion statistics on signed permutations that arise from the work of Sack and Ulfarsson [20] and called after width-k descents and width-k inversionsof type A in Davis's work [8]. Using the aforementioned new statistics, we derive some new generalizations of Eulerian polynomials of type A, B and D. It should also be noticed that we establish the Gamma-positivity of the "width-k" Eulerian polynomials and we give a combinatorial interpretation of finite sequences associated to these new polynomials using quasisymmetric functions and P-partition in Petersen's work [18].Comment: 28 page

Dynamic Symbolic Execution for Enhanced Intermediate Representation of Data Flow Space Applications

Verifying the safety and security requirements of embedded software requires a code analysis. Many software systems are developed based on software development libraries; therefore, code specifications are known at compiling time. Hence, many source-code analyses will be excluded, and low-level intermediate representations (LLIRs) of the analyzed binaries are preferred. Improving the expressiveness of the LLIR and enhancing it with more information from the binaries will improve the tightness of the applied analyses. This work is interested in developing a lifterthat lifts binaries into an enhanced LLIR and can resolve indirect jumps. LLVM is used as the LLIR. Our proposed lifter, which we call DEL (Dynamic symbolic Execution Lifter), combines both static and dynamic symbolic execution and strives to fully recover the analyzed program’s control flow. DEL consists of an API to translate ARMv7-M assembly instructions into static single assignment LLVM instructions, an LLIR to Z3 expressions parser, a memory model, a register model, and a specialized condition flags handler. This work used a case study based on a software development library for onboard data-handling applications developed at the German Aerospace Center (DLR), which is called the Tasking Framework. DEL demonstrated high accuracy of around 93% in resolving indirect jumps in our case study

Minimally Invasive Approach in Surgical Management of Renal Neoplasms National Cancer Institute Experience

BACKGROUND: Minimally invasive nephrectomy is considered a technically challenging procedure requiring a long learning curve to reach acceptable warm ischemia time and perioperative complications. These minimally invasive techniques result in a shorter hospital stay and less post-operative pain. AIM: This study aims to demonstrate the National Cancer Institute experience regarding the benefits of laparoscopic and robot-assisted nephrectomy over open technique. METHODS: This is a retrospective descriptive cohort study including 62 patients with renal masses treated with nephrectomy whether partial, total or radical, 26 cases were treated by minimally invasive techniques (8 robotic and 18 laparoscopic), while 36 cases were treated by open technique. Inclusion criteria were patients between 20 and 70 years with renal neoplasm without renal vein thrombosis, with tumor stage T1 or T2 N0 M0. Exclusion criteria were patients with medical comorbidities that preclude surgical management or minimally invasive techniques and patients refusing surgery in general. RESULTS: Minimally invasive nephrectomy resulted in shorter hospital stay (mean hospital stay was 2.2 days for the minimally invasive group and 3.6 days for the open group) and less post-operative pain than open technique (p < 0.001 and = 0.002, respectively), while open technique resulted in shorter operation time (p = 0.039, mean operation time 147.8 min compared to 184.8 in the minimally invasive group). CONCLUSION: Minimally invasive nephrectomy (laparoscopic and robotic) resulted in less post-operative pain and shorter hospital stay compared to open technique despite consuming longer operation time which may be decreased by improving the learning curve of operating surgeons

Cellular Deformations Induced by Conical Silicon Nanowire Arrays Facilitate Gene Delivery

Engineered cell–nanostructured interfaces generated by vertically aligned silicon nanowire (SiNW) arrays have become a promising platform for orchestrating cell behavior, function, and fate. However, the underlying mechanism in SiNW-mediated intracellular access and delivery is still poorly understood. This study demonstrates the development of a gene delivery platform based on conical SiNW arrays for mechanical cell transfection, assisted by centrifugal force, for both adherent and nonadherent cells in vitro. Cells form focal adhesions on SiNWs within 6 h, and maintain high viability and motility. Such a functional and dynamic cell–SiNW interface features conformational changes in the plasma membrane and in some cases the nucleus, promoting both direct penetration and endocytosis; this synergistically facilitates SiNW-mediated delivery of nucleic acids into immortalized cell lines, and into difficult-to-transfect primary immune T cells without pre-activation. Moreover, transfected cells retrieved from SiNWs retain the capacity to proliferate—crucial to future biomedical applications. The results indicate that SiNW-mediated intracellular delivery holds great promise for developing increasingly sophisticated investigative and therapeutic tools. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei