Hasil untuk "Engineering"

T. Hall, Sarah Beecham, David Bowes et al.

S. Singer, Natalie R. Nielsen, H. Schweingruber

S. Rahman

I. El-Sherbiny, M. Yacoub

Designing of biologically active scaffolds with optimal characteristics is one of the key factors for successful tissue engineering. Recently, hydrogels have received a considerable interest as leading candidates for engineered tissue scaffolds due to their unique compositional and structural similarities to the natural extracellular matrix, in addition to their desirable framework for cellular proliferation and survival. More recently, the ability to control the shape, porosity, surface morphology, and size of hydrogel scaffolds has created new opportunities to overcome various challenges in tissue engineering such as vascularization, tissue architecture and simultaneous seeding of multiple cells. This review provides an overview of the different types of hydrogels, the approaches that can be used to fabricate hydrogel matrices with specific features and the recent applications of hydrogels in tissue engineering. Special attention was given to the various design considerations for an efficient hydrogel scaffold in tissue engineering. Also, the challenges associated with the use of hydrogel scaffolds were described.

N. Annabi, J. Nichol, Xiamei Zhong et al.

G. Nicodemus, S. Bryant

Qie He, Ling Wang

G. Desiraju

C. Schmidt, J. Leach

E. Hoek, J. Bray

E. Sachlos, J. Czernuszka

K. Deb, K. Deb, Deb Kalyanmoy

M. Shuler, F. Kargı

L. Tsoukalas, R. Uhrig

Katharina Krombholz, Heidelinde Hobel, Markus Huber et al.

Irum Inayat, S. Salim, S. Marczak et al.

Rahman Shafique, Khadija Kanwal, Venkata Chunduri et al.

Abstract Regular inspection of the health of railway tracks is crucial to maintaining reliable and safe train operations. Some factors including cracks, rail discontinuity, ballast issues, burn wheels, super-elevation, loose nuts and bolts, and misalignment developed on the railways due to pre-emptive investigations, non-maintenance, and delay in detection pose grave threats and danger to the safe operation of railway transportation. In the past, manual inspection was performed for the rail track by a rail cart which is both prone to error and inefficient due to human biases and error. Several train accidents are reported in Pakistan; it is important to automate these techniques to avoid such train accidents for the safety of countless lives. This study aims to enhance railway track fault detection using an automatic rail track fault detection technique with acoustic analysis. Moreover, the proposed method contributes to making the dataset large by using the CTGAN technique. Results show that acoustic data may help to determine the railway track faults effectively and logistic regression is used to perform the classification for railway track faults with an accuracy of 100%.

Gengyang Li, Mason Peng, Qingguo Huang et al.

Per- and polyfluoroalkyl substances (PFAS) have drawn public concern recently due to their toxic properties and persistence in the environment, making it urgent to eliminate PFAS from contaminated water. Electrochemical oxidation (EO) has shown great promise for the destructive treatment of PFAS with direct electron transfer and hydroxyl radical (⋅OH)-mediated indirect reactions. One of the most popular electrodes is Magnéli phase titanium suboxides. However, the degradation mechanisms of PFAS are still unsure and are under investigation now. The main methodology is the first-principal density functional theory (DFT) computation, which is recently used to explore the degradation mechanisms and interpret by-product formation during PFAS mineralization. From the literature review, the main applications of DFT computation for studying PFAS degradation mechanisms by EO include bond dissociation energy, absorption energy, activation energy, and overpotential η for oxygen evolution reactions. The main degradation mechanisms and pathways of PFAS in the EO process include mass transfer, direct electron transfer, decarboxylation, peroxyl radical generation, hydroxylation, intramolecular rearrangement, and hydrolysis. In the recent 4 years, 11 papers performed DFT computation to explore the possible PFAS degradation mechanisms and pathways in the EO process. This paper’s objectives are to: 1) summarize the main degradation mechanisms of PFAS degradation in EO; 2) review the application of DFT computation for studying PFAS degradation mechanisms during EO; process; 3) review the possible degradation pathways of perfluorooctane sulfonoic acid (PFOS) and per-fluorooctanoic acid (PFOA) during EO process.

Tobias Heimann, Lara-Sophie Wähling, Tomke Honkomp et al.

Bioenergy with carbon capture and storage (BECCS) is a crucial element in most modelling studies on emission pathways of the Intergovernmental Panel on Climate Change to limit global warming. BECCS can substitute fossil fuels in energy production and reduce CO _2 emissions, while using biomass for energy production can have feedback effects on land use, agricultural and forest products markets, as well as biodiversity and water resources. To assess the former pros and cons of BECCS deployment, interdisciplinary model approaches require detailed estimates of technological information related to BECCS production technologies. Current estimates of the cost structure and capture potential of BECCS vary widely due to the absence of large-scale production. To obtain more precise estimates, a global online expert survey ( N = 32) was conducted including questions on the regional development potential and biomass use of BECCS, as well as the future operating costs, capture potential, and scalability in different application sectors. In general, the experts consider the implementation of BECCS in Europe and North America to be very promising and regard BECCS application in the liquid biofuel industry and thermal power generation as very likely. The results show significant differences depending on whether the experts work in the Global North or the Global South. Thus, the findings underline the importance of including experts from the Global South in discussions on carbon dioxide removal methods. Regarding technical estimates, the operating costs of BECCS in thermal power generation were estimated in the range of 100–200 USD/tCO _2 , while the CO _2 capture potential was estimated to be 50–200 MtCO _2 yr ^−1 by 2030, with cost-efficiency gains of 20% by 2050 due to technological progress. Whereas the individuals’ experts provided more precise estimates, the overall distribution of estimates reflected the wide range of estimates found in the literature. For the cost shares within BECCS, it was difficult to obtain consistent estimates. However, due to very few current alternative estimates, the results are an important step for modelling the production sector of BECCS in interdisciplinary models that analyse cross-dimensional trade-offs and long-term sustainability.

Tao Wang, Qi Luo, Fengyuan Cui et al.

Given the recent success of metasurfaces in free-space applications, these concepts can be leveraged to an even larger extent in on-chip waveguide systems. The in-plane diffractive metasurfaces enable the manipulation of guiding waves in the multimode regime with greater parallelism than conventional single-mode or few-mode waveguides, leading to exciting opportunities in signal processing and optical computing systems. Beam focusing is one of the basic functionalities of wavefront shaping, which can be implemented using phase gradient metalenses consisting of arrays of meta-atoms. The meta-atoms are mainly realized by etched trenches with varying lengths, which are assembled into a one-dimensional transmit array with a specific phase response. However, this kind of periodic arrayed structure has significantly limited design freedom compared to its free-space counterparts. Here, we propose a digital metalens that consists of a seamless array of pixelated unit cells, which are engineered via inverse design. In contrast to conventional focusing metalenses based on transmit arrays, highly functional digital metalenses have been demonstrated: (1) achromatic focusing lens; (2) extended depth of focus (EDOF) lens; (3) Airy beam lens. These devices were fabricated on a silicon photonic platform and characterized in near-infrared. The intersection of digital structures and algorithm-driven optimizations offers greater versatility for on-chip wavefront shaping.