Automated Point Cloud Registration Approach Optimized for a Stop-and-Go Scanning System.

The latest advances in mobile platforms, such as robots, have enabled the automatic acquisition of full coverage point cloud data from large areas with terrestrial laser scanning. Despite this progress, the crucial post-processing step of registration, which aligns raw point cloud data from separate local coordinate systems into a unified coordinate system, still relies on manual intervention. To address this practical issue, this study presents an automated point cloud registration approach optimized for a stop-and-go scanning system based on a quadruped walking robot. The proposed approach comprises three main phases: perpendicular constrained wall-plane extraction; coarse registration with plane matching using point-to-point displacement calculation; and fine registration with horizontality constrained iterative closest point (ICP). Experimental results indicate that the proposed method successfully achieved automated registration with an accuracy of 0.044 m and a successful scan rate (SSR) of 100% within a time frame of 424.2 s with 18 sets of scan data acquired from the stop-and-go scanning system in a real-world indoor environment. Furthermore, it surpasses conventional approaches, ensuring reliable registration for point cloud pairs with low overlap in specific indoor environmental conditions.

Experimental and computational study of naphthalimide derivatives: Synthesis, optical, nonlinear optical and antiviral properties.

The nonlinear optical (NLO) and antiviral properties of naphthalimide Schiff base compounds (5a-c) were experimentally and computationally investigated. The synthesized compounds (5a-c) were successfully characterized via UV-Vis, FTIR, 1H NMR, fluorescence spectroscopy, and elemental analysis. The calculated average third-order NLO polarizabilities (˂γ˃) of 5a, 5b, and 5c were found to be 5, 9, and 21 times greater than the ˂γ˃ amplitude of p-NA, respectively. The computed results revealed the potential of the synthesized compounds for NLO applications. Additionally, molecular docking studies of the synthesized compounds with two crucial SARS-CoV-2 proteins were performed to examine their biochemical properties. Compound 5c exhibited a higher binding affinity with the spike protein compared to that with Mᴾᴿᴼ. The results obtained herein indicate the potential of the synthesized naphthalimide derivatives for optoelectronic and drug design applications.

Synthesis of 2,5-furandicarboxylic acid-enriched-chitosan for anti-inflammatory and metal ion uptake.

The main aim of the present study is to synthesize a hitherto unreported polymer of chitosan (CS) and 2,5-furandicarboxylic acid (FDCA) derived from renewable biomass resources. For this purpose, CS was chosen which had -NH2 groups as abundant active sites. Synthesis of 2,5-furandicarboxylic acid-enriched-chitosan polymer (CS-FDCA) was carried out by reaction involving EDC-NHS coupling reagents. The structure of CS-FDCA polymer was confirmed by various characterization techniques such as Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), X-ray powder diffraction (XRD), high resolution-field emission scanning electron microscope (HR-FESEM), and thermogravimetric analysis (TGA). Moreover, CS and CS-FDCA were scrutinized to examine their efficacies towards ameliorate inflammation via detection of lipopolysaccharide (LPS) induced nitric oxide (NO) production. As compared to CS, CS-FDCA with low concentration (1.0 µM) exhibited the better efficacy to reduce the NO production. Furthermore, CS-FDCA polymer showed high as 12.6% of Cu2+ ion uptake while CS showed 9.2% of Cu2+ ion uptake. Overall, it can be inferred that CS-FDCA polymer is expected to be used for biomedical application and for the removal of metal contaminants from industrial wastewater.

Synthesis and Application of N-methylphthalimidylazo Disperse Dyes to Cellulose Diacetate for High Wash Fastness.

Cellulose diacetate fibers were prepared from cellulosic biomass with high α-cellulose contents such as purified cotton linters and wood pulps. Cellulose diacetate fibers are sensitive to alkaline solution, which causes hydrolysis of the acetate ester to hydroxyl groups, especially at high temperatures. Thus, the low alkali-resistance of cellulose acetate fibers makes it difficult to achieve high wash fastness by restricting the application of intense after-treatment, such as reduction clearing. A series of N-methylphthalimide-based high-washable azo disperse dyes were synthesized and their dyeing and fastness properties on cellulose diacetate fabrics were investigated. From the overall results obtained in this study, N-methylphthalimidylazo disperse dyes are expected to be a desirable alternative to high value-added dyes that can be used for high color fastness dyeing of cellulose diacetate with a minimal discharge of wastewater during washing process.

Dyeing of Polyester with 4-Fluorosulfonylphenylazo-5-pyrazolone Disperse Dyes and Application of Environment-Friendly Aftertreatment for Their High Color Fastness.

Dyeing and fastness properties of a series of 4-fluorosulfonylphenylazo-5-pyrazolone dyes on polyester were investigated in this study. The 4-nitrophenylazo-5-pyrazolone dyes were also synthesized to compare their dyeing and fastness properties on polyester with those of fluorosulfonyl-substituted analogues. The substantivity of 4-arylazo-5-pyrazolone derivatives containing a p-fluorosulfonyl group in the diazo component was lower than that of their nitro analogues which have a higher extinction coefficient and higher affinity because of the polar nitro group. They showed relatively hypsochromic color and lower chroma on polyester compared with their nitro analogues because of the relatively weaker electron-accepting power of the fluorosulfonyl group compared to the nitro group. Disperse dyeing of polyester with 4-fluorosulfonylphenylazo-5-pyrazolone disperse dyes achieved high color fastness and reduces the adverse environmental impact of the dyeing process by providing the option of performing alkali clearing instead of reductive clearing, which has high biological oxygen demand when discharged into the dyeing effluent and generates carcinogenic aromatic amines.

Flexible Energy Harvester Based on Poly(vinylidene fluoride) Composite Films.

In these days, we are facing emerging energy crisis due to depletion of fossil fuels. Therefore, renewable energy which is based on wind energy, mechanical force energy, microwave energy and vibrations energy have attracted a lot of attentions. Piezoelectric energy harvesting is one of the promising renewable energy sources. As the use portable electronic devices increases, the need for portable renewable energy sources further increases. Especially, piezoelectric materials can be the best selection due to their robust properties. In this research, piezoelectric composites were prepared and investigated for piezoelectric energy harvesting applications. In this study, two types of flexible energy harvesters, 0.36BS-0.64PT-PVDF composite and PVDF film, were prepared and analyzed. Due to its high Curie temperature and low lead content, BS-PT is expected to be a substitute for PZT in the near future. The composite materials based on the PVDF and 0.36BS-0.64PT film showed higher open circuit voltage (0.73 V) than PVDF film (0.49 V). Also, the stored voltage of 0.36BS-0.64PT-PVDF composite film was 330 nJ which is 5.68 times higher than 58 nJ for PVDF films. By introducing the piezoelectric BS-PT ceramics, 0.36BS-0.64PT-PVDF composite film shows the enhanced performance such as open circuit voltage, energy and dielectric constant compared with those of PVDF materials. It seems that 0.36BS-0.64PT-PVDF composite film is more suitable for flexible energy device.

Spring-Based Active Shock Absorber Systems with Piezoelectric Energy Harvesters.

In this research, energy harvesters with different types of spring-based shock absorbers were invested for the active shock absorber applications. Two different types of spring-based shock absorbers were prepared for the comparison, coil type spring-based shock absorbers and specially designed slice type spring-based shock absorbers. Shock absorbers have been widely employed to protect the complicated main system by cancelling the applied mechanical forces from outsides. Therefore, in the classical points of view, shock absorber can be prepared by the elastic materials to store and release the applied mechanical energy with sequentially in the form of elastic energy, thermal energy, and sound energy. However, in recently, there are strong demands to replace this classical shock absorber to the energy harvesters, which can collect the wasted energy in the form of electrical energy. Therefore, in this research, alternative two different types of spring-based advanced shock absorber will be presented and discussed. To combine with the spring-based shock absorber, multilayered piezoelectric energy harvesters were attached to collect the applied mechanical energy.

Piezoelectric Energy Generators Based on Spring and Inertial Mass.

In this study, inertial mass-based piezoelectric energy generators with and without a spring were designed and tested. This energy harvesting system is based on the shock absorber, which is widely used to protect humans or products from mechanical shock. Mechanical shock energies, which were applied to the energy absorber, were converted into electrical energies. To design the energy harvester, an inertial mass was introduced to focus the energy generating position. In addition, a spring was designed and tested to increase the energy generation time by absorbing the mechanical shock energy and releasing a decreased shock energy over a longer time. Both inertial mass and the spring are the key design parameters for energy harvesters as the piezoelectric materials, Pb(Mg1/3Nb2/3)O3-PbTiO3 piezoelectric ceramics were employed to store and convert the mechanical force into electric energy. In this research, we will discuss the design and performance of the energy generator system based on shock absorbers.

Enhanced Ferroelectric and Piezoelectric Properties of (1-x)PMN-xPT Ceramics Based on a Partial Oxalate Process.

The pyrochlore phase in ferroelectric and piezoelectric materials is the main obstacle device application due to its poor electrical properties. Especially, the pyrochlore phase is frequently observed in the perovskite-based metal-oxide materials including piezoelectric and ferroelectric ceramics, which are based on solid-state reaction methods for fabrication. To overcome these problems, advanced innovative methods such as partial oxalate process will be investigated. In this method, crystalized magnesium niobite (MN) and lead titanate (PT) powders will be coated with a certain amount of lead oxalate and, then, the calcination process can be carried out to form the PMN-PT without pyrochlore phase. In this study, (1-x)PMN-xPT ceramics near the morphotropic phase boundary (MPB), with compositions of x = 0.25⁻0.40, have been prepared employing the partial oxalate method at various temperatures. The crystalline, microstructure, and piezoelectric properties of (1-x)PMN-xPT ceramics depending on the sintering temperature were intensively investigated and discussed. By optimizing the sintering temperature and compositions from the PMN-PT ceramics, the maximum value of the piezoelectric charge coefficient (d33) of 665pC/N, planar electromechanical coupling factor (kp) of 77.8%, dielectric constant (εr) of 3230, and remanent polarization (Pr) of 31.67 µC/cm² were obtained.

Geographical variations and influential factors in prevalence of cardiometabolic diseases in South Korea.

Geographical variations and influential factors of disease prevalence are crucial information enabling optimal allocation of limited medical resources and prioritization of appropriate treatments for each regional unit. The purpose of this study was to explore the geographical variations and influential factors of cardiometabolic disease prevalence with respect to 230 administrative districts in South Korea. Global Moran's I was calculated to determine whether the standardized prevalences of cardiometabolic diseases (hypertension, stroke, and diabetes mellitus) were spatially clustered. The CART algorithm was then applied to generate decision tree models that could extract the diseases' regional influential factors from among 101 demographic, economic, and public health data variables. Finally, the accuracies of the resulting model-hypertension (67.4%), stroke (62.2%), and diabetes mellitus (56.5%)-were assessed by ten-fold cross-validation. Marriage rate was the main determinant of geographic variation in hypertension and stroke prevalence, which has the possibility that married life could have positive effects in lowering disease risks. Additionally, stress-related variables were extracted as factors positively associated with hypertension and stroke. In the opposite way, the wealth status of a region was found to have an influence on the prevalences of stroke and diabetes mellitus. This study suggested a framework for provision of novel insights into the regional characteristics of diseases and the corresponding influential factors. The results of the study are anticipated to provide valuable information for public health practitioners' cost-effective disease management and to facilitate primary intervention and mitigation efforts in response to regional disease outbreaks.

Development of kinematic 3D laser scanning system for indoor mapping and as-built BIM using constrained SLAM.

The growing interest and use of indoor mapping is driving a demand for improved data-acquisition facility, efficiency and productivity in the era of the Building Information Model (BIM). The conventional static laser scanning method suffers from some limitations on its operability in complex indoor environments, due to the presence of occlusions. Full scanning of indoor spaces without loss of information requires that surveyors change the scanner position many times, which incurs extra work for registration of each scanned point cloud. Alternatively, a kinematic 3D laser scanning system, proposed herein, uses line-feature-based Simultaneous Localization and Mapping (SLAM) technique for continuous mapping. Moreover, to reduce the uncertainty of line-feature extraction, we incorporated constrained adjustment based on an assumption made with respect to typical indoor environments: that the main structures are formed of parallel or orthogonal line features. The superiority of the proposed constrained adjustment is its reduction for uncertainties of the adjusted lines, leading to successful data association process. In the present study, kinematic scanning with and without constrained adjustment were comparatively evaluated in two test sites, and the results confirmed the effectiveness of the proposed system. The accuracy of the 3D mapping result was additionally evaluated by comparison with the reference points acquired by a total station: the Euclidean average distance error was 0.034 m for the seminar room and 0.043 m for the corridor, which satisfied the error tolerance for point cloud acquisition (0.051 m) according to the guidelines of the General Services Administration for BIM accuracy.

Bore-Sight Calibration of Multiple Laser Range Finders for Kinematic 3D Laser Scanning Systems.

The Simultaneous Localization and Mapping (SLAM) technique has been used for autonomous navigation of mobile systems; now, its applications have been extended to 3D data acquisition of indoor environments. In order to reconstruct 3D scenes of indoor space, the kinematic 3D laser scanning system, developed herein, carries three laser range finders (LRFs): one is mounted horizontally for system-position correction and the other two are mounted vertically to collect 3D point-cloud data of the surrounding environment along the system's trajectory. However, the kinematic laser scanning results can be impaired by errors resulting from sensor misalignment. In the present study, the bore-sight calibration of multiple LRF sensors was performed using a specially designed double-deck calibration facility, which is composed of two half-circle-shaped aluminum frames. Moreover, in order to automatically achieve point-to-point correspondences between a scan point and the target center, a V-shaped target was designed as well. The bore-sight calibration parameters were estimated by a constrained least squares method, which iteratively minimizes the weighted sum of squares of residuals while constraining some highly-correlated parameters. The calibration performance was analyzed by means of a correlation matrix. After calibration, the visual inspection of mapped data and residual calculation confirmed the effectiveness of the proposed calibration approach.