Determining the complex refractive index of cellulose nanocrystals by combination of Beer-Lambert and immersion matching methods

Abstract Nanocelluloses have received significant interest due to their unique structural, mechanical, and optical properties. Nanocellulose refractive indices can be used to indicate many crucial characteristics, such as crystallinity, transparency, and purity. Thus, accurate measurement is important. This study describes a new method to determine the wavelength dependent complex refractive index of cellulose nanocrystals (CNCs) by the measurement of light transmittance with a spectrophotometer. The data analysis is based on a combination of the Beer-Lambert and immersion liquid matching equations. The immersion liquid method’s main advantage is that it is independent of particle shape and size. Moreover, the measurement is easy and relatively quick to perform. The present procedure is not restricted to the nanocellulose and could potentially be applied to other nanomaterials, such as hyphenate nanoparticle-based, lignin nanoparticles, nanopigments, biological entities, structural elements of dielectric metamaterials, and nanoparticle-based composites

Determination of the refractive index of particles through the immersion solid matching method

Abstract We describe a new measurement technique to determine the refractive index (RI) of solid particles by monitoring the simultaneous scattering of light from suspension with a camera and the value of the RI with a refractometer. Our immersion solid matching method is based on the solidification process of the liquid continuously changing the RI as a function of time. The principle of the determination is based on finding the RI matching point of the particle and the liquid during the solidification. The traditional liquid immersion method is based on a set of immersion liquids with different refractive indices, while the proposed method requires only a small amount of a single immersion liquid. The method was tested using calcium fluoride (CaF 2 ) particles with a varnish immersion liquid. The RI value of CaF 2 was obtained to be consistent with the literature values, thus indicating the proper functioning of the proposed procedure

Non-visual sensing of metallic pavement markers from a moving vehicle

Abstract Snow and ice covering paved surfaces cause problems for roads and other vehicles operating in cold regions. There are notable risks for road accidents and reduced performance of vehicle movements, e.g., in industrial facilities such as ports, when road markings and marked pathways are not visually observable. In this study, metallic paved surface markers identified by metal sensors are tested. The sound signals captured by a metal detector attached to the vehicle are used to detect the markings. Results indicate that the tested method for reading markings through snow is effective at lower speeds. The main advantages of the tested technology are effectiveness in snowy and icy surface conditions, low upfront cost detection technology in some environments, robust system without moving parts, high sampling rate, and low operating costs. The procedure is not restricted to specific environmental conditions, such as snow and ice; it also has the potential to detect markings through layers of mud, tree leaves or sand. The detectors have application prospects in intelligent transportation system applications at airports, logistics terminals and industrial facilities

Monitoring drying process of varnish by immersion solid matching method

Abstract The characterization of the drying process of paints and coatings on the surfaces is important for many industrial applications. We present a new optical method to study the drying process of varnish based on immersion solid matching technique. The principle of the method is to match the refractive index of dry varnish with the added particles, making the dried varnish optically transparent. The state of the drying process can be evaluated by following the transparency of the varnish by visual inspection or imaging by camera. The method has several merits since it is non-contact, fast, simple and low-cost. In addition, particles that are invisible in dry varnish can provide improved properties such as hardness, abrasion and corrosion resistance or retard flammability without sacrificing the optical appearance of the coating

Trench visualisation from a semiautonomous excavator with a base grid map using a TOF 2D profilometer

Abstract Real-time, three-dimensional (3D) visualisation technology can be used at construction sites to improve the quality of work. A 3D view of the landscape under work can be compared to a target 3D model of the landscape to conveniently show needed excavation tasks to a human excavator operator or to show the progress of an autonomous excavator. The purpose of this study was to demonstrate surface visualisation from measurements taken with a pulsed time-of-flight (TOF) 2D profilometer on-board a semiautonomous excavator. The semiautomatic excavator was implemented by recording the feedback script parameters from the work performed on the excavator by a human driver. 3D visualisation maps based on the triangle mesh technique were generated from the 3D point cloud using measurements of the trenches dug by a human and an autonomous excavator. The accuracy of the 3D maps was evaluated by comparing them to a high-resolution commercial 3D scanner. An analysis of the results shows that the 2D profilometer attached to the excavator can achieve almost the same 3D results as a high-quality on-site static commercial 3D scanner, whilst more easily providing an unobstructed view of the trench during operation (a 3D scanner placed next to a deep trench might not have a full view of the trench). The main technical advantages of our 2D profilometer are its compact size, measurement speed, lack of moving parts, robustness, low-cost technology that enables visualisations from a unique viewpoint on the boom of the excavator, and readiness for real-time control of the excavator’s system. This research is expected to encourage the efficiency of the digging process in the future, as well as to provide a remarkable view of trench work using an excavator as a moving platform to facilitate data visualisation

Optical properties of cellulose nanofibre films at high temperatures

Abstract Nanocelluloses and their different designs, such as films and nanopapers, have gained considerable interest in many application areas due to their unique properties. For many purposes, such as packaging and electronics, the thermal stability and optical properties of nanocellulose materials are crucial characteristics. In this study, the effects of heat treatment (100 ºC, 150 ºC and 200 ºC) on the optical and mechanical properties of 2,2,6,6-tetramethylpiperidinyl-1-oxy radical-oxidised cellulose nanofibre (TO-CNF) films were investigated, especially the alteration of the colour, complex refractive index and birefringence. Exposing TO-CNF films to high temperatures (> 150 ºC) induced permanent transformations in the CNF structure, leading to an increase in the refractive index, decreases in the birefringence and crystallinity index, colour darkening and significant deterioration of the mechanical properties

4D modeling of soil surface during excavation using a solid-state profilometer mounted on the arm of an excavator

Abstract The aim of this research is to create a 4D point cloud map from a trench through a solid-state 2D profilometer. The profilometer is integrated with an 8.5-ton medium-size excavator’s machine control system with pose calculation. Accordingly, the point cloud was transformed to a work coordinate system. We used a recently developed pulsed time-of-flight laser light detection and ranging profilometer, which makes possible simultaneous depth measurements to 256 directions in an angle range of ±20° and measurement range from 1 m to 8 m with a frame rate of 25 frames per second under sunlight conditions (≈50 Klux). The analysis is based on a 4D map, which consists of 3D data (XYZ) and intensity information. The XYZ coordinates give the position of an object, and the intensity data can be used to roughly identify materials and recognise surface markings, such as texts. An analysis of the results shows that the detection accuracy of the profilometer is better than ±10 mm. The main advantages of our method are accuracy, high update rate, compact size, real-time measurement and a construction without moving parts. Our technique has a great potential in construction applications, where accurate measurements of a surface shape are needed

Characteristics of Secondary, Primary, and Compensated Hypogonadism in Aging Men: Evidence from the European Male Ageing Study

Context: The diagnosis of late-onset hypogonadism (LOH) in older men with age-related declines in testosterone (T) is currently not well characterized. Objective: Our objective was to investigate whether different forms of hypogonadism can be distinguished among aging men. Design: The study was a cross-sectional survey on 3369 community-dwelling men aged 40-79 yr in eight European centers. Methods: Four groups of subjects were defined: eugonadal (normal T and normal LH), secondary (low T and low/normal LH), primary (low T and elevated LH), and compensated (normal T and elevated LH) hypogonadism. Relationships between the defined gonadal status with potential risk factors and clinical symptoms were investigated by multilevel regression models. Results: Among the men, 11.8, 2.0, and 9.5% were classified into the secondary, primary, and compensated hypogonadism categories, respectively. Older men were more likely to have primary [relative risk ratio (RRR) = 3.04; P < 0.001] and compensated (RRR = 2.41; P < 0.001) hypogonadism. Body mass index of 30 kg/m(2) or higher was associated with secondary hypogonadism (RRR = 8.74; P < 0.001). Comorbidity was associated with both secondary and primary hypogonadism. Sexual symptoms were more prevalent in secondary and primary hypogonadism, whereas physical symptoms were more likely in compensated hypogonadism. Conclusions: Symptomatic elderly men considered to have LOH can be differentiated on the basis of endocrine and clinical features and predisposing risk factors. Secondary hypogonadism is associated with obesity and primary hypogonadism predominately with age. Compensated hypogonadism can be considered a distinct clinical state associated with aging. Classification of LOH into different categories by combining LH with T may improve the diagnosis and management of LOH. (J Clin Endocrinol Metab 95: 1810-1818, 2010