Global Challenges最新文献

With wooden balls, a visualization of the hydrothermal carbonization to show the progress of the conversion to char is presented. In the present study, the balls represent the particles of biomass to investigate the differences in conversion outside and inside of biomass particles, during hydrothermal carbonization. A special focus is on hydrochar and pyrochar formation. The wooden balls are treated in subcritical water at 220 °C for holding times between 0 and 960 min. Even after 960 min, hydrolysis of the original biomass is incomplete as cellulose and hemicellulose are linked by lignin, inhibiting the reaction with water. Moreover, two different pathways of char production can be observed. Inside of the wooden ball pyrochar is formed as any water got that deep in, on the surface hydrochar is fixed, originated from the surrounding liquid. On the ground of the HTC reactor, a thin, brittle precipitate of likely hydrochar or humins can be found either from the precipitation of loosely attached compounds on the surface of the biomass or direct precipitation from the liquid.

In the present study, a novel combined power cycle for solar power tower (SPT) system consisting of helium Brayton cycle (HBC) and transcritical CO₂ (TCO₂) for waste heat recovery is being studied for carbon-free generation. The performance of the proposed SPT based combined cycle (SPT-HBC-TCO₂ cycle) is compared with SPT based basic cycle (SPT-HBC) based on exergoeconomic and thermodynamic analyses. It is concluded that the SPT-based combined cycle (SPT-HBC-TCO₂ cycle) produces a thermal efficiency of 32.39% and exergy efficiency of 34.68% with an electricity cost of 1.613 UScent kWh⁻¹. The exergy and thermal efficiency of the SPT-based combined cycle are enhanced by 13.18% and 13.21% respectively, while electricity cost is reduced by around 2% as compared to the SPT-based basic cycle (SPT-HBC) configuration at base conditions. A notable finding is that, despite the additional expenditures related to the bottoming cycle, the cost of electricity is lesser for the proposed combined cycle. Additionally, a comparison with the related prior published research exhibits that the performance of the current novel system is superior to that of the systems based on steam rankine cycle and supercritical CO₂ cycles.

The negative environmental effects of global civil aviation growth since the 19th century lead to the emergence of the “sustainable aviation” concept. This study aims to determine the current status of sustainability discussions in developing Turkish civil aviation and its alignment with global sustainable aviation policies. The research data are collected through document analysis and key expert interviews. Document analysis is to review reports on sustainable aviation and to compare two cases of AirFrance-KLM and Turkish Airlines. Semi-structured interviews are conducted with key experts from airline companies, public institutions, and subsidiary services in the Turkish aviation sector. The analysis results are presented under the themes of “institutional, conceptual, Turkey's current situation, motivations, role of international organizations, cooperation and coordination, problems and obstacles.” The results show that the Turkish civil aviation industry is enthusiastic about catching up with international standards and is successful in keeping up with the latest technologies. The private sector is leading the sector by targeting global competitiveness. Current deficiencies stem from legislation, incentives, obligations, resources, and environmental awareness. The main contribution is to be the first source and guide for future studies that aim to shed light on policymaking in Turkey as an emerging country case.

Employing new therapeutic indications for drugs that are already approved for human use has obvious advantages, including reduced costs and timelines, because some routine steps of drug development and regulation are not required. This work concentrates on the redirection of artemisinins (ARTS) that already are approved for clinical use, or investigated, for malaria treatment. Several mechanisms of action are suggested for ARTS, among which only a few have been successfully examined in vivo, mainly the induction of oxidant stress and anti-inflammatory effects. Despite these seemingly contradictory effects, ARTS are proposed for repurposing in treatment of inflammatory disorders and diverse types of diseases caused by viral, bacterial, fungal, and parasitic infections. When pathogens are treated the expected outcome is diminution of the causative agents and/or their inflammatory damage. In general, repurposing ARTS is successful in only a very few cases, specifically when a valid mechanism can be targeted using an additional therapeutic agent and appropriate drug delivery. Investigation of repurposing should include optimization of drug combinations followed by examination in relevant cell lines, organoids, and animal models, before moving to clinical trials.

Printed electronics (PE) have provided new material and application opportunities for devices and systems as well as new manufacturing routes that all need to be considered for commercialization. This paper introduces a case study with universally relevant manufacturing processes and applications in the PE area, focusing on the Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) of the Personal Activity Monitor (PAM) device. In the study, the PAM device's most important costs and environmental impacts during the prototype pilot production and device use phases are identified and assessed. Additionally, the potential environmental impacts of post-consumption scenarios are considered. The LCA results indicate that the roll-to-roll (R2R) assembly of electronics and the R2R injection over-molding are generally the most prominent production process steps affecting the results. From the LCC perspective, the capitial expenditure (CAPEX) contributor is the R2R assembly pilot line, due to its high investment cost and long operating time compare to other production assets. The traditional electronic components are the major operating expenditures (OPEX), especially the microcontroller units (MCUs) and accelerometers, in contrast to the low impact from the printed electronics. There are several advantages to applying LCA and LCC since they provide explanations of the relationships between cost, environmental, design, and manufacturing characteristics.

Colorectal cancer (CRC) is the second most common malignancy in women and the third most frequent cancer in men. Evidence has revealed that the survival of patients with metastatic CRC is very low, between one and three years. Neoantigens are known proteins encoded by mutations in tumor cells. It is theorized that recognizing neoantigens by T cells leads to T cell activation and further antitumor responses. Neoantigen-reactive T cells (NRTs) are designed against the mentioned neoantigens expressed by tumor cells. NRTs selectively kill tumor cells without damage to non-cancerous cells. Identifying patient-specific and high immunogen neoantigens is important in NRT immunotherapy of patients with CRC. However, the main challenges are the side effects and preparation of NRTs, as well as the effectiveness of these cells in vivo. This review summarized the properties of neoantigens as well as the preparation and therapeutic outcomes of NRTs for the treatment of CRC.

This paper reports the Maisotsenko's cycle-based waste heat recovery system with enhanced humidification to exploit the maximum waste heat recovery potential of the gas turbine. This research uses an integrated methodology coupling thermodynamic balances with heat transfer model of air saturator. The performance of the system is deduced which are assisted with sensitivity analysis indicating the optimal mass flow rate ratio (0.7–0.8) and pressure ratio (4.5–5.0) between the topping and bottoming cycles, and the air saturator split (extraction) ratio (0.5). The net-work output, energy, and exergy efficiencies of the system are found to be ≈58.39 MW, ≈55.85%, and ≈52.79%, respectively. The maximum exergy destruction ratios are found as 68.2% for the combustion chamber, 16.0% for the topping turbine, 5.7% for topping compressor, 4.9% air saturator. The integration of Maisotsenko's cycle-based waste heat recovery system with a comprehensive thermodynamic model, as demonstrated in this research, offers valuable insights into enhancing the efficiency, cost-effectiveness, and environmental impact of gas turbines. By presenting fundamental equations related to thermodynamic balances, this work serves as an invaluable educational resource, equipping future researchers and students with the knowledge and skills needed to advance the study of thermodynamics and sustainable energy solutions.