Analytical Chemistry

Recent advancements in computing and artificial intelligence (AI) make it possible to quantitatively evaluate human movement using digital video, thereby opening the possibility of more accessible gait analysis. The Edinburgh Visual Gait Score (EVGS) is an effective tool for observational gait analysis, but human scoring of videos can take over 20 min and requires experienced observers. This research developed an algorithmic implementation of the EVGS from handheld smartphone video to enable automatic scoring. Participant walking was video recorded at 60 Hz using a smartphone, and body keypoints were identified using the OpenPose BODY25 pose estimation model. An algorithm was developed to identify foot events and strides, and EVGS parameters were determined at relevant gait events. Stride detection was accurate within two to five frames. The level of agreement between the algorithmic and human reviewer EVGS results was strong for 14 of 17 parameters, and the algorithmic EVGS results...

Condition monitoring systems generally require data acquisition (DAQ) systems. These in turn necessitate high-precision analogue-to-digital converters (ADCs) to sample and convert analogue signals from sensors into digital data, for establishing the condition of the monitored equipment. There is generally a need for high-accuracy measurement of minimally changing parameters in condition monitoring applications, indicating small changes in performance of system components. This requires DAQ systems containing high-resolution and precision ADCs, which increases the overall cost of the measurement system. This research employs chaos-based, non-linear Tent Map (TM) circuitry to perform analogue-to-digital conversion. As previous research has demonstrated TM-based ADCs, developed using low-cost components, can detect small changes in an input voltage signal over a relatively large voltage range and be incorporated with FPGAs for signal conditioning. This work investigates the potential o...

Super alloys offer excellent mechanical and chemical properties at elevated temperatures that make them an attractive choice for aerospace, automotive and chemical processing, and marine applications. These alloys are, however, difficult to machine due to their high strength at elevated temperatures, low thermal conductivity and work hardening. In this study, micro milling of Inconel 600 super alloy has been carried out and the effects of the key input parameters (cutting speed, feed rate, depth of cut) on response parameters (burr formation, surface roughness and tool wear), under various cooling conditions (dry, wet and cryogenic), have been analyzed. High speed micro milling (range up to 80,000 RPM) was carried out, while keeping the feed rate values below and above the cutting edge radius. The Taguchi design of experiments was used during this study. The results have been analyzed using SEM and 3D optical microscopy. Analysis of Variance (ANOVA) revealed that the best surface ro...

The current baseline architectures in the field of the Internet of Things (IoT) strongly recommends the use of edge computing in the design of the solution applications instead of the traditional approach which solely uses the cloud/core for analysis and data storage. This research, therefore, focuses on formulating an edge-centric IoT architecture for smartphones which are very popular electronic devices that are capable of executing complex computational tasks at the network edge. A novel smartphone IoT architecture (SMIoT) is introduced that supports data capture and preprocessing, model (i.e., machine learning models) deployment, model evaluation and model updating tasks. Moreover, a novel model evaluation and updating scheme is provided which ensures model validation in real-time. This ensures a sustainable and reliable model at the network edge that automatically adjusts to changes in the IoT data subspace. Finally, the proposed architecture is tested and evaluated using an Io...

Psychotic disorders pose a significant public health concern, and early detection of relapse is a crucial aspect of their management. In this study, we investigate the effectiveness of unsupervised learning-based anomaly detection approaches for relapse detection in psychotic disorders, using data from wearable sensors as a proposed solution for the ICASSP Signal Processing Grand Challenge e-Prevention track 2 Relapse Detection. We explore both a global scheme, where a single model is trained on data from all patients, and a personalized scheme, where a unique model is trained for each patient. To evaluate the performance of different anomaly detection models, we extract features related to sleep, heart rate, accelerometer and gyroscope data, physical activity, and percentage of time the sensor is worn. Additionally, we examine the influence of the time window size used for feature extraction. Our findings suggest that the autoencoder is the best-performing model in the global schem...

Wavelength dispersive X-ray fluorescence (WD-XRF) spectrometry has been widely used for elemental quantification of mortars and cements. In this kind of instrument, samples are usually prepared as pellets or fused beads and the whole volume of sample is measured at once. In this work, the usefulness of a dual energy dispersive X-ray fluorescence spectrometer (ED-XRF), working at two lateral resolutions (1 mm and 25 μm) for macro and microanalysis respectively, to develop quantitative methods for the elemental characterization of mortars and concretes is demonstrated. A crucial step before developing any quantitative method with this kind of spectrometers is to verify the homogeneity of the standards at these two lateral resolutions. This new ED-XRF quantitative method also demonstrated the importance of matrix effects in the accuracy of the results being necessary to use Certified Reference Materials as standards. The results obtained with the ED-XRF quantitative method were compare...

Elemental analysis of different sediment cores originating from the Cartagena–La Union mining district in Spain was carried out by means of a programmable small-spot energy-dispersive X-ray fluorescence (EDXRF) spectrometer to study the distribution of heavy metals along soil profiles. Cores were obtained from upstream sediments of a mining creek, from the lowland sedimentation plain, and from a mining landfill dump (tailings pile). A programmable two-dimensional (2D) stage and a focal spot resolution of 600 μm allow us to obtain complete core mapping. Geochemical results were verified using a more powerful wavelength-dispersion X-ray fluorescence (WDXRF) technique. The data obtained was processed in order to study the statistical correlations within the elemental compositions. The results obtained allow us to observe the differential in-depth distribution of heavy metals among the sampled zones. Dump site cores exhibit a homogeneous distribution of heavy metals, whereas the alluvia...

The remote management of equipment is part of the functionalities granted by the design principles of Industry 4.0. However, some critical operations are managed by operators, machine setup and initialization serve as a significant illustration. Since the initialization is a repetitive task, industrial robots with a smart vision system can undertake these duties, enhancing the autonomy and flexibility of the manufacturing process. The smart vision system is considered essential for the implementation of several characteristics of Industry 4.0. This paper introduces a novel solution for controlling manufacturing machines using an embedded camera on the robot. This implementation requires the development of an interactive interface, designed in accordance with the supervision system known as Manufacturing Execution System. The framework is implemented inside a manufacturing cell, demonstrating a quick response time and an improvement between the cameras.

Dengue has long been a serious health burden to the global community, especially for those living in the tropics. In spite of the availability of vaccines, effective treatment for the infection is still needed and currently remained absent. In the present study, antiviral properties of the KSF 103 ME which consisted of a number of potential antiviral compounds were investigated against DENV-2. The effects of this extract against DENV-2 replication were determined using the qRT-PCR. Findings from the study suggested that the KSF 103 ME showed maximum inhibitory properties toward the virus during the virus entry stage at concentrations of more than 12.5 µg/mL. Minimal antiviral activities were observed at other virus replication stages; adsorption (42% reduction at 50 µg/mL), post-adsorption (67.6% reduction at 50 µg/mL), prophylactic treatment (68.4% and 87.7% reductions at 50 µg/mL and 25 µg/mL, respectively) and direct virucidal assay (48% and 56.8% reductions at 50 µg/mL and 25 µg...

At present, fabric-based triboelectric nanogenerator (TENG) has been paid attention and developed for self-power generation systems with wearability for E-textiles, especially cotton. However, there are many commercial cellulose-based fabrics with different fiber characteristics and fabric structures that gain possibility to effect on TENG performance and has been underreported. This work presents the fabrication of the textile TENG by using four types of commercial cellulose-based fabrics as friction layer and compare the electrical output efficiency relating their molecular structure, fabric structure and surface morphology characteristics. As shown by the electrical output, though all fabrics can generate electricity for TENG device, nevertheless, the output signal is different because of their different total surface area of the fabric, affecting by different microstructure. The rayon fabric contains the smallest size fiber with highest surface area at the same woven structure. ...

Model-Driven Engineering (MDE) is widely applied in the industry to develop new software functions and integrate them into the existing run-time environment of a Cyber-Physical System (CPS). The design of a software component involves designers from various viewpoints such as control theory, software engineering, safety, etc. In practice, while a designer from one discipline focuses on the core aspects of his field (for instance, a control engineer concentrates on designing a stable controller), he neglects or considers less importantly the other engineering aspects (for instance, real-time software engineering or energy efficiency). This may cause some of the functional and non-functional requirements not to be met satisfactorily. In this work, we present a co-design framework based on timing tolerance contract to address such design gaps between control and real-time software engineering. The framework consists of three steps: controller design, verified by jitter margin analysis ...

The quality control of discretely manufactured parts typically involves defect recognition activities, which are time-consuming, repetitive tasks that must be performed by highly trained and/or experienced personnel. However, in the context of the fourth industrial revolution, the pertinent goal is to automate such procedures in order to improve their accuracy and consistency, while at the same time enabling their application in near real-time. In this light, the present paper examines the applicability of popular deep neural network types, which are widely employed for object detection tasks, in recognizing surface defects of parts that are produced through a die-casting process. The data used to train the networks belong to two different datasets consisting of images that contain various types of surface defects and for two different types of parts. The first dataset is freely available and concerns pump impellers, while the second dataset has been created during the present study...

Twenty-four substances, mainly NIAS, have been tentatively identified in food contact polycarbonate through the application a new, fast, and automated analytical strategy for the investigation of unknowns in food contact materials. Most of the identified compounds were plasticizers, slip agents, antioxidants, and ultraviolet stabilizers and fragrances, and the majority of them have not been previously identified in PC food contact materials. The workflow setup includes an intelligent data acquisition applied using LC-Orbitrap Tribrid-HRMS (MS3), with an automated data processing using Compound DiscovererTM. To obtain a high confidence identification of unknown substances, a very strict criterion has been established, which comprises exact mass, isotopic profile, MS2 match, retention time, and MS3 match. To check for the safety of the migration from the food contact polycarbonate, a risk assessment was achieved using the threshold of the toxicological concern (TTC) approach. Except f...

Data-independent acquisition (DIA) based strategies have been explored in recent years for improving quantitative analysis of metabolites. However, the data analysis is challenging for DIA methods as the resulting spectra are highly multiplexed. Thus, the DIA mode requires advanced software analysis to facilitate the data deconvolution process. We proposed a pipeline for quantitative profiling of pharmaceutical drugs and serum metabolites in DIA mode after comparing the results obtained from full-scan, Data-dependent acquisition (DDA) and DIA modes. using open-access software. Pharmaceutical drugs (10) were pooled in healthy human serum and analysed by LC-ESI-QTOF-MS. MS1 full-scan and Data-dependent (MS2) results were used for identification using MS-DIAL software while deconvolution of MS1/MS2 spectra in DIA mode was achieved by using Skyline software. The results of acquisition methods for quantitative analysis validated the remarkable analytical performance of the constructed wo...

Background: A validated high performance planar chromatographic analysis for a combination medication of corticosteroids mometasone furoate and bronchodilators formoterol fumarate available as Evocort®: inhaler in market was developed. It is used for treating asthma, a reversible obstructive airways disease. Materials and Methods: The HPTLC chromatographic condition was optimised using aluminium sheets formerly coated with silica gel 60F254 as stationary phase and toluene: methyl alcohol: methanoic acid (12.5:4:0.3 v/v/v) as mobile phase. Results: Formoterol fumarate and mometasone furoate concentration was found to be directly proportional to peak area in the range of 120-720 ng/band and 3996-23976 ng/band, respectively. Results of precision studies were between 0.77-1.274 stated in %RSD and recovery studies ranged from 99101% indicating very low inter day variability and good reproducibility of the method. Fractional factor design was applied to five factors i.e. volume of mobile ...

A nonlinear MEMS multimass sensor is investigated. The MEMS design consists of an array of nonlinear microcantilevers clamped to a shuttle mass which, in turn, is attached to a linear spring and a dashpot. The microcantilevers are made of a polymeric hosting matrix reinforced by aligned carbon nanotubes (CNT) with different CNT volume fractions in each cantilever so as to suitably tune the frequency bandwidth of the device. The advantages of a single input-single output (SISO) system are here exploited for the design, actuation and detection principles as in previous literature.

膠體粒子(colloid)在溶液中的穩 定性一直是食品工業與清淨程序操作中 的重要影響因素。近年來，由於耐米粒子 (nano-sized particle)在各式新興工業 的潛在應用價值，其合成與製造已在學術 領域中引起廣泛的研究興趣。然而在其製 造程序中，耐米粒子懸浮液的熱力學或動 力學穩定性更是扮演決定性的角色。 一般而言，耐米粒子之間具有長距 離的凡得瓦引力，它會導致粒子之間凝絮 而產生不穩定的沉降現象。本研究之目的 在探討添加高分子至耐米粒子懸浮液中 對其穩定性之影響。高分子種類包含非吸 附性高分子(nonadsorbing polymer)、吸附性高分子、雙塊區間共聚合高分子(di-block copolymer)。我們採用類似分子模擬的蒙地卡羅 法(Monte Carlo method)，從微觀層次來 研究(a)耐米粒子之間，及(b)耐米粒子與 高分子之間的作用和結構;該系統穩定性 可反應於徑向分佈函數(radial dis- tribution function)。我們將比較未添 加高分子、添加非吸附性高分子、吸附性 高分子、及共聚合高分子的徑向分佈函 數。另外，我們也將討論耐米粒子濃度、 高分子濃度、及其鏈長對懸浮液穩定性的影響。The addition of polymers to a col-loidal dispersion creates a change in the phase behavior and the local structure of the colloidal component. This effect is of great importance in dealing with treatment of colloidal suspensions. For example, it has been known that upon adding enough nonadsorbing polymer to the system, the colloidal particles tend to cluster. The presence of the polymers induces an en-tropic- originated attraction between the colloidal particles...

本文是以蒙地卡羅法研究幾近無熱效 應高分子溶液的相平衡行為。我們發現當 溫度提高時，高分子粒子與溶劑粒子間的 自由體積差異隨之加大。在到達所謂的下 臨界溫度時，因為商的效應，使得溶劑粒 子排斥高分子，而造成相分離的現象。我 們也發現較長的高分子因為它們與溶劑粒 子的自由體積差異較大，所以相分離的起 始溫度亦較低。對於等長的高分子且溫度 相同的情況下，壓力的增加會減少高分子 與溶劑粒子間自由體積的差異，故相分離 現象會較不明顯。我們亦將模擬結果與 SAFT 理論比較，發現SAFT 理論在對於高 分子溶液定性的描繪上，有很好的預測性，但在定量上尚無法有精確的結果。The Phase equilibrium behaviors of a nearly athermal polymer/solvent solution are studied by using the Monte Carlo method. It is found that as temperature increases, the free volume differences between solvent molecules and polymer chains become larger. To a certain temperature, which is the so called Lower Critical Solution Temperature (LCST) the entropic effect dominates over the enthalpic effect, thus phase separation occurs. We have also found that phase separation takes place at lower temperature for longer chain polymer solution. By comparing the phase envelope of polymer of the same chain length but at different pressure, LCST increases as pressure increases. We have also applied the SAFT theory to...

The complex wave structure of annular gas–liquid flow with disturbance waves and liquid entrainment is a result of the evolution of high-frequency initial waves, appearing at the very inlet of the flow, prior to the hydrodynamic stabilization of liquid film. This stage of flow evolution is studied experimentally, using a shadow technique, and theoretically, using a linear stability analysis of the Orr–Sommerfeld equation in both phases. The present work is focused on the comparison of earlier results obtained in air–water downward flow with the new results obtained in upward flow and with more viscous liquids. The flow orientation affects the shape of the liquid film prior to stabilization; the initial film area is thicker but shorter in upward flow. Upward flow orientation also leads to a lower frequency and the increment of growth of initial waves. The viscosity effect is found to be weak if flow rates of both phases are the same. The model is mostly able to reproduce the qualitat...

The rapid growth of the Internet of Things (IoT) and its attributes of constrained devices and a distributed environment make it difficult to manage such a huge and growing network of devices on a global scale. Existing traditional access-control systems provide security and management to the IoT system. However, these mechanisms are based on central authority management, which introduces issues such as a single point of failure, low scalability, and a lack of privacy. In order to address these problems, many researchers have proposed using blockchain technology to achieve decentralized access control. However, such models are still faced with problems such as a lack of scalability and high computational complexity. In this paper, we propose a light-weight hierarchical blockchain-based multi-chaincode access control to protect the security and privacy of IoT systems. A clustering concept with BC managers enables the extended scalability of the proposed system. The architecture of th...

Biodegradable/biocompatible microspheres have been prepared from poly(lactic acid-co-glycidyl methacrylate), P(LA-co-GMA), copolymers by a phase inversion emulsification (PIE) process. As the copolymer contains unsaturated functional groups, this can be crosslinked by employing thermo-curing reaction. Effects of co-surfactant concentrations and the aqueous phase addition rate on efficiency of the particle formation are evaluated. The addition of sodium dodecyl sulfate (SDS) co-surfactant at slow rates leads to narrow size distribution and higher stability of the microspheres, due to formation of effective structures of polyvinyl alcohol (PVA) surfactant and SDS at the oil/aqueous interface. The resulting microspheres are spherical shape with rough wrinkled surface morphology and bimodal particles size distribution at 1 and 10 μm. Curable behavior of the microspheres are also investigated. The semi-crystalline particles consist of network structure with high gel content of 50%, as th...