Laser-induced graphene (LIG) presents a promising route toward next-generation smart textiles by enabling direct patterning of conductive materials onto textiles through a single-step laser writing process. In particular, femtosecond laser-based fabrication offers high-resolution processing without damaging substrates. This review summarizes LIG formation mechanisms, laser manufacturing parameters, physical/chemical characteristics, electrical, thermal, and optical properties of LIG. Furthermore, it categorizes representative applications including biosignal monitoring, energy storage, thermal regulation, optical absorber, and extraterrestrial adaptability, all based on textile-integrated LIG. With its porous morphology, high conductivity, and structural versatility, LIG offers outstanding multifunctionality for smart textile applications. Future research should explore precise functional tuning of LIG through laser parameter optimization, accurate characterization of LIG, and advanced smart textile applications.
Physical fundamentals of ultrashort femtosecond lasers are addressed along with emerging applications for precision manufacturing and metrology. Femtosecond lasers emit short pulses whose temporal width is in the range of less than a picosecond to a few femtoseconds, thereby enabling extremely high peak-power machining with less thermal damages. Besides, the broad spectral bandwidth of femtosecond lasers constructed in the form of frequency comb permits absolute distance measurements leading to ultraprecision positioning control and dimensional metrology.
During the last two decades, many researchers investigated influences of stress triaxiality on ductile fracture for various specimens and structures. With respect to a transferability issue, the local approach reflecting micro-mechanical specifics is one of effective methods to predict constraint effects. In this paper, the applicability of the local approach was examined through a series of finite element analyses incorporating modified GTN (Gurson-Tvergaard-Needleman) and Rousselier models as well as fracture toughness tests. To achieve this goal, fracture resistance (J-R) curves of several types of compact tension (CT) specimens with various crack length, with various thickness and with/without 20% side¬grooves were estimated. Then, the constraint effects were examined by comparing the numerically estimated J-R curves with experimentally determined ones. The assessment results showed that the damage models might be used as useful tool for fracture toughness estimation and both the crack length and thickness effects should be considered for realistic structural integrity evaluation.
Single-walled carbon nanotubes (SWNT) exhibit strong Raman signals as well as fluorescence emissions in the near infrared regions where most biomolccules arc transparent. Such signals do not blink or photoblcach under prolonged excitation, which is advantageous to optical nano-bio marker applications. In this paper, single walled carbon nanotubes are conjugated with specific types of single-stranded DNA in order to detect oligonucleotides of corresponding complimentary sequences. Dot blotting experiments and comparative Raman spectroscopy observations demonstrated excellent sensitivity and specificity of carbon nanotube-DNA probes. The results show the possibility of using SWNT as generic nano-bio markers for the precise detection of specific kinds of genes.
Pressurized gas pipeline is subject to harmful effects both of the surrounding environment and of the materials transmitted in them. In order to maintain the integrity, reliable assessment procedures including fracture mechanics analysis etc are required. Up to now, the integrity assessment has been performed using conventional deterministic approaches even though there are many uncertainties to hinder a rational evaluation. In this respect, probabilistic approach is considered as an appropriate method for gas pipeline evaluation. The objectives of this paper are to estimate the failure probability of corroded pipeline in gas and oil plants and to propose limited operating conditions under different types of loadings. To do this, a probabilistic assessment program using reliability index and simulation techniques was developed and applied to evaluate failure probabilities of corroded API-5L-X52/X60 gas pipelines subjected to internal pressure, bending moment and combined loading. The evaluation results showed a promising applicability of the probabilistic integrity assessment program.
Anti-shock performance is one of the most important design specifications of TFT -LCD modules. Since they are adopted for major display units of many mobile applications such as lap-top PCs, cellular phones, and palm pilots, they are able to accommodate and endure high level transient mechanical energy inputs. For the reasons, not only the LCD unit manufacturers but their customers like PC makers perform a series of strict impact/drop test on the units. Currently, designers are mostly relying on their own trial-error based experience for the anti-shock design. Thus those designs depending on only experience may result in disqualification from the drop/impact test during final product evaluation. Those shock failures of any new designs are prohibitive for both LCD and PC manufacturers. In order to avoid this problem, many designers are focusing on the development of computer-aided design tools that is directly connected to shock simulation capabilities and then shock-proof design cycle time could be significantly reduced. Development of an integrated CAE system for the shock-proof design is presented in this article. At every stages of the development of present work, practical industrial applicability and mass production feasibility are seriously considered and tested so that the system is to be used in the LCD design engineering field.