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The cancer diagnosis is currently experiencing an alteration of molecular biomarkers using a paradigm for the diagnostic panel. One of the most important genomic datasets showing genetic sequences is the classification of lung cancer. Many research studies have been conducted in this area, but none of them yields satisfied outcomes on account of lower classification accuracy. At first, the data are collected through the lung cancer dataset. Afterward, data are fed into pre-processing. The pre-processing segment removes the noise and enhances the input images utilising Dynamic Context-Sensitive Filtering. The pre-processing output is fed to the feature extraction segment. Here, four statistical features are extracted based on the Force Invariant Improved Feature Extraction Model.The extracting features are fed to the feature segmentation segment. Lung cancer images can segment the ROI region using Adaptive Density-Based Spatial Clustering. After that, the segmentation features are given to ACWGAN for effectively categorizing cancer and non-cancer of the lung cancer Hence, the Hunter–prey optimisation algorithm is employed to optimise the ACWGAN classifier. It classifies the lung cancer images accurately. The LCC-ACWGAN-HPOA-CTI algorithm is activated in MATLAB under the lung cancer database. The performance of the LCC-ACWGAN-HPOA-CTI approach shows higher accuracy and lower computation time than those of the existing methods.

Real-time automatic detection of multiple cracks from a video stream of a concrete surface is addressed in this paper. Robust principal component analysis is used to detect multiple cracks forming at different instances of time in an unsupervised manner using the Gini index as a metric to quantify the presence of an observable crack. The relative positions of the relevant pixels around the crack are monitored using the Kanade Lucas Tomasi feature tracking algorithm. Further, Hu's invariant moments of those pixel positions are computed which acts as a robust damage indicator even for breathing cracks under time-varying service loads. The proposed method is experimentally validated using two small scale under-reinforced beams undergoing three-point bending tests. The method successfully detects the onset of multiple cracks, at varied locations, at different time instants and further tracks their propagations.

Background: Consumption of unhealthy processed foods viz., refined wheat flour based bakery products such as biscuits, muffins, etc. is a key causative factor underlying nutrition transition giving rise to overweight and obesity. The underutilized coarse grain, proso millet (Panicum miliaceum) can find potential application in bakery products. Objective: The objective of the present study was to prepare healthy muffins by partial replacement of refined flour with Proso Millet Flour (PMF), Carrot Preserve (CP) and Beetroot Preserve (BP). Methods: Standardized methods were used to analyze the products for nutritional composition, antioxidant activity and sensory properties. Results: Results showed that the protein and dietary fiber contents of products ranged from 5.49- 5.95g and 3.60-4.15g/100g respectively. Total phenolic content was high in aqueous extract of muffin with PMF+BP i.e. 125±1.41mg tannic acid equivalent/100g. β-carotene content was high in muffin with PMF+CP (155±3.5µg/100g). Antioxidant activity determined by four methods showed that products with PMF+CP and PMF+BP had higher activity compared to control samples. The sensory quality of muffin was unaffected by the incorporation PMF, having scores equal to control muffins. Conclusion: To conclude PMF, CP and BP can be used as functional food ingredients in bakery products to improve the nutritional quality without affecting sensorial palatability.

Each year, the growth of cities across developing economies in Asia, Africa, and Latin America drives demand for concrete to house and serve their burgeoning populations. Since 1950, the number of people living in urban areas has quadrupled to 4.2 billion, with another predicted 2.5 billion expected to join them in the next three decades. The largest component of concrete by volume is aggregates, such as sand and rocks, with sand as the most mined material in the world. However, the extraction rate of sand currently exceeds its natural replenishment rate, meaning that a global concrete-suitable sand shortage is extremely likely. As such, replacements for fine aggregates, such as sand, are in demand. Here, flash Joule heating (FJH) is used to convert coal-derived metallurgical coke (MC) into flash graphene aggregate (FGA), a blend of MC-derived flash graphene (MCFG), which mimics a natural aggregate (NA) in size. While graphene and graphene oxide have previously been used as reinforcing additives to concrete, in this contribution, FGA is used as a total aggregate replacement for NA, resulting in 25% lighter concrete with increases in toughness, peak strain, and specific compressive strength of 32, 33, and 21%, respectively, with a small reduction in specific Young’s modulus of 11%. FJH can potentially enable the replacement of fine NA with FGA, resulting in lighter, stronger concrete.

Progress is reported in an emerging non-contact strain sensing technology based on optical properties of single-walled carbon nanotubes (SWCNTs). In this strain-sensing smart skin ("S4") method, nanotubes are dilutely embedded in a thin polymer film applied to a substrate of interest. Subsequent strain in the substrate is transferred to the nanotubes, causing systematic spectral shifts in their characteristic short-wave infrared fluorescence peaks. A small diode laser excites a spot on the coated surface, and the resulting emission is captured and spectrally analyzed to deduce local strain. To advance performance of the method, we prepare S4 films with structurally selected SWCNTs. These give less congested emission spectra that can be analyzed precisely. However, quenching interactions with the polymer host reduce SWCNT emission intensity by an order of magnitude. The instrumentation that captures SWCNT fluorescence has been made lighter and smaller for hand-held use or mounting onto a positioning mechanism that makes efficient automated strain scans of laboratory test specimens. Statistical analysis of large S4 data sets exposes uncertainties in measurements at single positions plus spatial variations in deduced baseline strain levels. Future refinements to S4 film formulation and processing should provide improved strain sensing performance suitable for industrial application.

The implementation of a mechanical negative stiffness device (NSD) within a reduced-scale highway bridge model and its performance under seismic loading conditions is evaluated via shaking table tests. Four different isolation system configurations are considered: isolated bridge (IB), IB with viscous dampers, IB with NSDs, and IB with viscous dampers and NSDs. In addition, two bridge pier configurations were considered: one with flexible piers (mimicking a middle span of a multi-span bridge) and one with braced piers (mimicking a single span bridge supported on abutments). The main feature of the NSD is a large pre-compressed spring, which can push the structure away from its initial undeformed position and thus induce negative stiffness behavior. The experimental results clearly demonstrate the effectiveness of the NSDs in limiting the seismic response of the bridge and provide validation of numerical simulation results wherein numerical models of the bridge model components were calibrated via system identification testing.

Progress is reported in the development of a novel non-contact strain measurement technology in which the sensors are single-walled carbon nanotubes. This approach exploits the characteristic short-wave infrared fluorescence signatures of semiconducting single-walled carbon nanotubes and the systematic shifts of their fluorescence wavelengths when the nanotubes are axially strained. A strain-sensing smart skin is prepared by coating the surface to be monitored with a thin film of a composite containing well-dispersed single-walled carbon nanotubes embedded in a urethane varnish host. Strain in the surface transfers through the host polymer to the embedded nanotubes. The nanotube strains are then quantitatively monitored by exciting the region of interest with a visible laser beam and capturing and analyzing the resulting single-walled carbon nanotube fluorescence spectrum. High-quality spectra are shown for strain-sensing smart skin films in which the nanotubes were pre-processed by selective extraction with the organic polymer poly(9,9-dioctylfluorenyl-2,7-diyl) and purification by centrifugation. The design of a compact, field-portable optical system for exciting, collecting, and interpreting strain-sensing smart skin spectral data is also described. This system is used to validate the linear dependence of peak shifts with strain in test specimens subjected to multiple tension cycles inducing strains from 0 to 5000 µε. Adequate linearity is found up to 1500 µε; however, minor hysteresis is observed above this level. The gage length for these measurements can be as small as several micrometers, and the strain resolution is currently between 10 and 100 µε (depending on strain magnitude). Cyclic reversible strain measurements are demonstrated, with minor hysteresis being attributed to imperfect adhesion between nanotube sidewalls and the surrounding polymer host.

Nurses play a significant role in identifying and securing potential organ donors in the clinical environment. Research among Indian nurses related to organ donation is sparse. The present study aimed to investigate nurses' attitudes towards organ donation. A cross-sectional descriptive survey was carried out among nurses (n=184) at a tertiary care centre. Data were collected through a self-report questionnaire. A majority (81%) of the respondents were ‘willing to sign the card’ for organ donation; however, only 3.8% (n=7) of them actually ‘signed the organ donation card’. There were significant associations found between intentions to sign the organ donation card and gender (x2=5.852; p<0.054), religion (x2=40.175; p<0.000), and experience caring for brain-dead patients (x2=22.790; p<0.001). The researchers strongly suggest continuing education for nurses to enhance skills and knowledge, as well as sensitivity to cultural, ethical, social, and religious issues, and advocacy in the area of organ donation. Furthermore, nurse administrators must take the initiative to develop guidelines clarifying the role of nurses in the organ donation and transplantation process to promote organ donation and improve rates.

Nurses play a significant role in identifying and securing potential organ donors in the clinical environment. Research among Indian nurses related to organ donation is sparse. The present study aimed to investigate nurses' attitudes towards organ donation. A cross-sectional descriptive survey was carried out among nurses (n=184) at a tertiary care centre. Data were collected through self-report questionnaire. A majority (81%) of the respondents were ‘willing to sign the card’ for organ donation; however, only 3.8% (n=7) of them actually ‘signed the organ donation card’. There were significant associations found between intentions to sign the organ donation card and gender (x2=5.852; p<0.054), religion (x2=40.175; p<0.000), and experience caring for brain-dead patients (x2=22.790; p<0.001). The researchers strongly suggest continuing education for nurses to enhance skills and knowledge, as well as sensitivity to cultural, ethical, social, and religious issues, and advocacy in the area of organ donation. Furthermore, nurse administrators must take the initiative to develop guidelines clarifying the role of nurses in the organ donation and transplantation process to promote organ donation and improve rates.

The lateraltorsional response of baseisolated structures, with sliding isolation system due to bidirectional lateral ground motion, is studied. The objective of the study is to identify the key system parameters that lead to significant torsional coupling in sliding baseisolated structures. The analysis procedure adopted can capture the highly nonlinear behavior of sliding systems in plane motion. The nonlinear biaxial stickslip characteristics of sliding bearings and the velocity dependence of coefficient of friction are accounted for. The study considers multistoried structures with variable number of bearings subjected to the effects of earthquakes with various frequency content and different peak ground accelerations. It is shown that, although the total superstructure response is reduced significantly due to the effects of sliding base isolation, torsional coupling can be significant depending on the superstructure eccentricity and the lateraltorsional flexibility of the superstructure and the base.

An experimental study, performed to evaluate the feasibility of using a sliding isolation system with uplift restraint devices for mediumrise buildings subject to column uplift, is presented. A Teflondisc sliding bearing with builtin uplift restraint devices is described. A quarterscale, 52kip 231kN model of a sixstory structure was isolated using the sliding isolation system with uplift restraint devices. The model had a slender configuration with ratio of height to width of 4.5. The slender configuration was chosen to ensure column uplift. Shaketable tests, involving strong motions with different frequency contents and peak table accelerations as high as 0.6 g, were performed. The shaketable test results show that the sliding isolation system is effective in reducing the structural response and uplift forces, by reducing the lateral floor accelerations and overturning moments, and that the uplift restraint system is effective in resisting uplift forces. An analytical model for predicting the response is developed. Comparisons between the predicted and observed responses are presented.

In baseisolated structures specially designed isolation systems provide the needed flexibility and energy dissipation capacity. The isolation systems, which can be either elastomeric or sliding systems, exhibit highly nonlinear behavior. The existing algorithms cannot analyze baseisolated structures with sliding isolation systems accurately. This paper presents an analytical model and a solution algorithm developed for nonlinear dynamic analysis of threedimensionalbaseisolated structures with elastomeric andor sliding isolation systems. The novelty of the analytical model and solution algorithm is its capability to capture the highly nonlinear frictional behavior of sliding isolation systems in plane motion. Nonlinear behavior is restricted to the base and the superstructure is considered to be elastic at all times. Biaxial and uniaxial models, which can represent both elastomeric and sliding isolation bearings, are presented. The solution algorithm consisting of the pseudoforce method with iteration is presented. Comparison of computed results with experimental results is presented for verification. A sixstoryreinforcedconcretebaseisolated structure is analyzed.

Torsion in baseisolated structures with inelastic elastomeric isolation systems due to bidirectional lateral ground motion is studied. In a companion paper by the writers, torsional coupling in sliding baseisolated structures was investigated. In this paper, which is the second part of the sequence, torsional coupling in elastomeric baseisolated structures is investigated. Various multistoried structural systems with elastomeric isolation systems are investigated, with the objective of studying the influence of: (1) The flexibility of the superstructure; (2) the ratio of uncoupled torsional to lateral frequencies; (3) stiffness eccentricity in the superstructure; (4) eccentricity in the isolation system; (5) higher mode effects; and (6) number of bearings in the isolation system. Response to different ground motions is also studied. The results are used to explain: (1) The behavior of actual buildings; and (2) some inconsistencies in the conclusions of previous studies. It is shown that, although the total superstructure response is reduced significantly due to the effects of elastomeric base isolation, torsional amplification can be significant depending on the isolation and superstructure eccentricity and the lateral and torsional flexibility.

Euthanasia provokes controversies in various domains, such as the moral, ethical, legal, religious, scientific, and economic. India legalised passive euthanasia (withdrawal of life support) for patients with brain death or who are in a permanent vegetative state in 2011, but research on perceptions of euthanasia among people in India is limited. This study aimed to examine Nurses' perceptions of the practice of euthanasia as well as factors influencing those perceptions. A non-probability quantitative, cross-sectional design was adopted for a sample of 214 nurses working at a tertiary care centre. Data was collected through self-reported questionnaires at the Nurses' workplace. The findings revealed mixed opinions on euthanasia among the nurses. However, the majority of the participants did not agree with the practice of euthanasia. Nonetheless, further research is needed on this issue across the country among various health professionals in the context of current legislation.

Yielding can be emulated in a structural system by adding an adaptive “negative stiffness device” (NSD) and shifting the “yielding” away from the main structural system-leading to the new idea of “apparent weakening” that occurs ensuring structural stability at all displacement amplitudes. This is achieved through an adaptive negative stiffness system (ANSS), a combination of NSD and a viscous damper. By engaging the NSD at an appropriate displacement (apparent yield displacement that is well below the actual yield displacement of the structural system) the composite structure-device assembly behaves like a yielding structure. The combined NSD-structure system presented in this study has a re-centering mechanism thereby avoids permanent deformation in the composite structure-device assembly unless, the main structure itself yields. Essentially, a yielding-structure is “mimicked” without any, or with minimal permanent deformation or yielding in the main structure. As a result, the main structural system suffers less accelerations, less displacements and less base shear, while the ANSS “absorbs” them. This paper presents comprehensive details on development and study of the ANSS/NSD. Through numerical simulations, the effectiveness and the superior performance of the ANSS/NSD as compared to a structural system with supplemental passive dampers is presented. A companion paper presents the NSD and its mechanics in detail.

To examine whether birthweight and head circumference at birth are associated with childhood cognitive ability in South India, cognitive function was assessed using three core tests from the Kaufman Assessment Battery for children and additional tests measuring long-term retrieval/storage, attention and concentration, and visuospatial and verbal abilities among 505 full-term born children (mean age 9.7 y). In multiple linear regression adjusted for age, sex, gestation, socioeconomic status, parent's education, maternal age, parity, body mass index, height, rural/urban residence, and time of testing, Atlantis score (learning ability/long-term storage and retrieval) rose by 0.1 SD per SD increase in newborn weight and head circumference, respectively (p < 0.05 for all), and Kohs' block design score (visuospatial ability) increased by 0.1 SD per SD increase in birthweight (p < 0.05). The associations were reduced after further adjustment for current head circumference. There were no associations of birthweight and/or head circumference with measures of short-term memory, fluid reasoning, verbal abilities, and attention and concentration. In conclusion, higher birthweight and larger head circumference at birth are associated with better childhood cognitive ability. The effect may be specific to learning, long-term storage and retrieval, and visuospatial abilities, but this requires confirmation by further research.

To examine whether birthweight and head circumference at birth are associated with childhood cognitive ability in South India, cognitive function was assessed using three core tests from the Kaufman Assessment Battery for children and additional tests measuring long-term retrieval/storage, attention and concentration, and visuospatial and verbal abilities among 505 full-term born children (mean age 9.7 y). In multiple linear regression adjusted for age, sex, gestation, socioeconomic status, parent's education, maternal age, parity, body mass index, height, rural/urban residence, and time of testing, Atlantis score (learning ability/long-term storage and retrieval) rose by 0.1 SD per SD increase in newborn weight and head circumference, respectively (p< 0.05 for all), and Kohs' block design score (visuospatial ability) increased by 0.1 SD per SD increase in birthweight (p< 0.05). The associations were reduced after further adjustment for current head circumference. There were no associations of birthweight and/or head circumference with measures of short-term memory, fluid reasoning, verbal abilities, and attention and concentration. In conclusion, higher birthweight and larger head circumference at birth are associated with better childhood cognitive ability. The effect may be specific to learning, long-term storage and retrieval, and visuospatial abilities, but this requires confirmation by further research.

A novel series of benzimidazole-based molecules mimicking biological receptors, which exhibit selective coordination with zinc ions, were designed and synthesized. The photochromic behavior of these derivatives with various metal ions suggests a selective interaction of one of the receptors 2-(pyridin-2-yl)-4,7-di(thiophen-2-yl)-3H-benzo[d]imidazole (2c) with zinc ion. The lower limit of detection by photoluminescence quenching was determined to be 16 nM. The mechanism of selective complexation was elucidated by 1H nuclear magnetic resonance titrations and dynamic light scattering analysis. The stoichiometry of the formation of the Zn(2c)2complex was evaluated by single-crystal X-ray diffraction and mass spectral techniques and calculated to be 2:1 (L:M). A change in the electronic energy levels on the sensor analyte interaction was observed by both ultraviolet photoelectron spectroscopy analysis and by density functional theory calculations, suggesting an electroactive semiconductor behavior. A symmetric Schottky structured sensor device was fabricated using the receptor 2cas the active sensing layer. A distinct change in current–voltage characteristics between the receptor and the complex suggests that the fabricated device could be used as a solid-state sensor for detecting zinc ion.

This study validates an adaptive control algorithm capable of compensating for online sensor failure. Online failure is a relevant problem when considering actively damped, multi-story smart buildings experiencing a disturbance event. In recent years, Artificial Neural Networks (ANNs) have proven very efficient in pattern classification and control applications. In this study, the unique application of ANNs involving Radial Basis Functions (RBFs) combined with H∞ optimal control has demonstrated three significant characteristic advantages: (1) real time adaptability, (2) optimal convergence and computation time, and (3) most importantly, no offline training. The novelty of the proposed controller is elucidated by performing disturbance rejection tests involving a scaled two degree of freedom shear frame subjected to a combined H∞ and ANN control. A bench scale structural model is instrumented with piezoelectric sensors and actuators. After the onset of a first mode disturbance, the structural frame is subjected to a complete sensor failure. The proposed controller is shown to enhance the performance of a baseline H∞ controller in the presence of sensor failure.

Structural Health Monitoring (SHM) is an important and growing field in civil engineering. The goal of SHM techniques is to identify, quantify and locate damage in structures. In light of the aging infrastructure and recent failures of important bridges, long-term monitoring techniques are being increasing investigated and adopted. In addition to SHM, structural control (SC) is increasingly adopted in modern structures around the world. In the past two decades a number of SC techniques, including, passive, semi-active, and active control methods have been developed and adopted in civil engineering–particularly, in infrastructure such as important tall buildings, critical facilities, and long span bridges. Both SHM and SC technology face significant challenges due to the size and scale of civil engineering structures. In response of these challenges researchers in the U.S.A and around the world have developed new and innovative techniques.This paper summarizes some of the ongoing research in the U.S.A. in the area of monitoring, damage detection and control in civil engineering structures.

The article explores the response of Spar platforms from a model test using a system identification algorithm called the Empirical Mode Decomposition and Hilbert Transform (EMD/HT). It explains the results of the motion decay tests conducted to the platform to determine the responses of surge, heave and pitch for intact mooring condition. It cites the potential of the algorithm as a tool for assessing the fatigue damage of offshore structures in the presence of nonlinearities caused by waves and response.

Abstract: This paper presents an experimental investigation of a recently developed Kronecker Product (KP) method to determine the type, location, and intensity of structural change from an identified state-space model of the system. Although this inverse problem appears to be highly nonlinear, the system mass, stiffness, and damping matrices are identified through a series of transformations, and with the aid of the Kronecker product, only linear operations are involved in the process. Since a state-space model can be identified directly from input-output data, an initial finite element model and/or model updating is not required. The test structure is a two-degree-of-freedom torsional system in which mass and stiffness are arbitrarily adjustable to simulate various conditions of structural change or damage. This simple apparatus illustrates the potential applicability of the system identification technique for damage detection problems by not only identifying the location and the extent of the damage, but also differentiating the nature of the damage. The results are successfully confirmed by laboratory tests.

Structural Health Monitoring (SHM) is an important and growing field in civil engineering. The goal of SHM techniques is to identify, quantify and locate damage in structures. In light of the aging infrastructure and recent failures of important bridges, long-term monitoring techniques are being increasing investigated and adopted. In addition to SHM, structural control (SC) is increasingly adopted in modern structures around the world. In the past two decades a number of SC techniques, including, passive, semi-active, and active control methods have been developed and adopted in civil engineering–particularly, in infrastructure such as important tall buildings, critical facilities, and long span bridges. Both SHM and SC technology face significant challenges due to the size and scale of civil engineering structures. In response of these challenges researchers in the U.S.A and around the world have developed new and innovative techniques.This paper summarizes some of the ongoing research in the U.S.A. in the area of monitoring, damage detection and control in civil engineering structures.

This study validates an adaptive control algorithm capable of compensating for online sensor failure. Online failure is a relevant problem when considering actively damped, multi-story smart buildings experiencing a disturbance event. In recent years, Artificial Neural Networks (ANNs) have proven very efficient in pattern classification and control applications. In this study, the unique application of ANNs involving Radial Basis Functions (RBFs) combined with H∞ optimal control has demonstrated three significant characteristic advantages: (1) real time adaptability, (2) optimal convergence and computation time, and (3) most importantly, no offline training. The novelty of the proposed controller is elucidated by performing disturbance rejection tests involving a scaled two degree of freedom shear frame subjected to a combined H∞ and ANN control. A bench scale structural model is instrumented with piezoelectric sensors and actuators. After the onset of a first mode disturbance, the structural frame is subjected to a complete sensor failure. The proposed controller is shown to enhance the performance of a baseline H∞ controller in the presence of sensor failure.

The kinetics approach of oxidation of torsemide (TOR) by hexacyanoferrate (III) [HCF (III)] has been identified spectrophotometrically at 420 ​nm in the alkaline medium in the presence and absence of catalyst ruthenium (III) at 25 ​°C, by keeping ionic strength (1 ​× ​10−2 ​mol ​dm−3) constant. The reaction exhibits at the stoichiometry ratio 1:2 of TOR and HCF (III), for uncatalysed and catalysed reactions. In the absence and presence of the catalyst, the order of the reactions obtained for TOR and HCF (III) was unity. However, the rate of the reactions enhanced by the increase in the concentration of catalyst, as well as the rate increases with an increase in alkaline concentration. The activation parameters for the reaction at the slow step were identified, and the effect of temperature on the rate of the reaction was analysed. A suitable mechanism has been demonstrated by considering the obtained results. The derived rate laws are reliable with analysed experimental kinetics.

This paper presents an experimental and analytical study of hybrid control of bridges using sliding bearings, with recentering springs, in parallel with servohydraulic actuators. A new control algorithm with absolute acceleration feedback, based on instantaneous optimal control laws, is developed. The developed control algorithm is implemented in a shake‐table study of an actively controlled sliding‐isolated bridge. The objective of implementing the hybrid system is to evaluate its advantages in addition to those due to the passive sliding system. The experimental system used in the shake‐table test is described and the results of the experiments are presented. It is shown that substantial reduction of response acceleration is possible, using hybrid control, while confining the sliding displacement within an acceptable range, and eliminating almost completely postearthquake permanent offsets. Comparisons of the results of hybrid system with results of passive system are presented. The advantages of hybrid control, in addition to those due to passive control, are discussed.

Torsion in base‐isolated structures with inelastic elastomeric isolation systems due to bidirectional lateral ground motion is studied. In a companion paper by the writers, torsional coupling in sliding base‐isolated structures was investigated. In this paper, which is the second part of the sequence, torsional coupling in elastomeric base‐isolated structures is investigated. Various multistoried structural systems with elastomeric isolation systems are investigated, with the objective of studying the influence of: (1) The flexibility of the superstructure; (2) the ratio of uncoupled torsional to lateral frequencies; (3) stiffness eccentricity in the superstructure; (4) eccentricity in the isolation system; (5) higher mode effects; and (6) number of bearings in the isolation system. Response to different ground motions is also studied. The results are used to explain: (1) The behavior of actual buildings; and (2) some inconsistencies in the conclusions of previous studies. It is shown that, although the total superstructure response is reduced significantly due to the effects of elastomeric base isolation, torsional amplification can be significant depending on the isolation and superstructure eccentricity and the lateral and torsional flexibility.

Progress is reported in an emerging non-contact strain sensing technology based on optical properties of single-walled carbon nanotubes (SWCNTs). In this strain-sensing smart skin (“S4”) method, nanotubes are dilutely embedded in a thin polymer film applied to a substrate of interest. Subsequent strain in the substrate is transferred to the nanotubes, causing systematic spectral shifts in their characteristic short-wave infrared fluorescence peaks. A small diode laser excites a spot on the coated surface, and the resulting emission is captured and spectrally analyzed to deduce local strain. To advance performance of the method, we prepare S4films with structurally selected SWCNTs. These give less congested emission spectra that can be analyzed precisely. However, quenching interactions with the polymer host reduce SWCNT emission intensity by an order of magnitude. The instrumentation that captures SWCNT fluorescence has been made lighter and smaller for hand-held use or mounting onto a positioning mechanism that makes efficient automated strain scans of laboratory test specimens. Statistical analysis of large S4data sets exposes uncertainties in measurements at single positions plus spatial variations in deduced baseline strain levels. Future refinements to S4film formulation and processing should provide improved strain sensing performance suitable for industrial application.