90 research outputs found
Determination of early warning signs for photocatalytic degradation of titanium white oil paints by means of surface analysis
No full textTitanium white (TiO2) has been widely used as a pigment in the 20th century. However, its most photocatalytic form (anatase) can cause severe degradation of the oil paint in which it is contained. UV light initiates TiO2-photocatalyzed processes in the paint film, degrading the oil binder into volatile components resulting in chalking of the paint. This will eventually lead to severe changes in the appearance of a painting. To date, limited examples of degraded works of art containing titanium white are known due to the relatively short existence of the paintings in question and the slow progress of the degradation process. However, UV light will inevitably cause degradation of paint in works of art containing photocatalytic titanium white.In this work, a method to detect early warning signs of photocatalytic degradation of unvarnished oil paint is proposed, using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Consequently, a four-stage degradation model was developed through in-depth study of TiO2-containing paint films in various stages of degradation. The XPS surface analysis proved very valuable for detecting early warning signs of paint degradation, whereas the AFM results provide additional confirmation and are in good agreement with bulk gloss reduction.Accepted Author Manuscript(OLD) MSE-4ChemE/Catalysis Engineerin
The impact of Arizona Highways Magazine on tourism
Get PDFabstract: The purpose of this study was to: 1) examine the effect of Arizona Highways Magazine (AHM) on tourism, 2) determine trip characteristics of AHM subscribers traveling in Arizona, and 3) calculate a benefit/cost ratio for AHM based on the magazine’s cost and revenues as well as the value-added economic impact.Includes bibliographical references (p. 51-57)
Sistem Penunjang Keputusan Berbasis Importance Performance Analysis Untuk Membantu Menentukan Peningkatan Fasilitas (Studi Kasus Fakultas Ilmu Komputer Universitas Bandadar Lampung)
No full textUniversity of Bandar Lampung in particular computer science faculty is the faculty that stood since 2000 and have two departments of technique informatics and information systems. FIK UBL always try to satisfy students, especially in providing facilities. Because the facility is one of the important priorities that must be Atfilled in order to satisfy students.In determining the facility is very difficult decisions in the analysis. Importance Performance Analysis has beengenerally accepted and used in various fields of study because of the ease to apply and display the results of analysis that facilitates performance improvement proposals.Importance Performance Analysis has the main function to display information related to service factors which greatly affect consumer satisfaction and their loyalty, and service factors that consumers need to be improved because according to current conditions have not been satisfactory
The white of the 20th century: an explorative survey into Dutch modern art collections
Get PDFWhite pigments were abundantly used in 20th century paintings, and relate to several degradation risks such as titanium white mediated photocatalytic binder degradation or zinc soap formation. Knowledge about the white pigments that were used is essential for risk assessments of 20th century collections. In this study, a representative set of 179 paintings in Dutch modern art collections were analyzed by portable X-ray fluorescence spectrometry. Subsequent explorative data analysis was performed, supported by qualitative findings from 140 home-made reference samples. Micro-samples were further investigated by X-ray diffraction and scanning transmission electron microscopy to gain information about crystal structure and surface coating. This study reveals that Dutch 20th century artists were hesitant to use titanium white. In the Netherlands, the use of this pigment is observed convincingly from the 1970s onward and initially mostly in non-oil binders. Additionally, lead white was used until late in the 20th century for paints and grounds but rarely mixed with titanium white in paints. The study also indicated that many CoBrA artists used zinc white, underlining the risk of degradation due to soap formation. Furthermore, this study highlights the different production processes of titanium white. Through the association of titanium with niobium, an impurity only present for sulfate processed pigments, the production process can be identified. The absence of niobium indicates the presence of rutile and is thus a sign of paint stability, as well as a ‘post 1959’ dating. This explorative study illustrates the value of a combination of data analysis approaches, which includes assessment of spectra as well as descriptive, bivariate and multivariate analysis, for medium-sized datasets gathered at similar conditions.(OLD) MSE-
Determining the presence of photocatalytic titanium white pigments via embedded paint sample staining: A proof of principle
Get PDFTwentieth century paints often contain titanium dioxide and zinc oxide based white pigments that can range from photostable to highly photocatalytic. Photocatalytic pigments can cause the degradation of paint upon UV exposure, whereas photostable pigments may be benign or can protect paintings from degradation. Hence, knowing whether or not a pigment is photocatalytic is of high importance for risk assessment and the subsequent decision making process concerning storage and exposure conditions of objects. Here we present a proof of principle, focused on titanium white paints, for an easy-to-use and low-tech application of a commercial photocatalytic activity indicator ink (PAII) on embedded paint samples or cross sections. This test determines, qualitatively, if a photocatalytic pigment is present in a white paint sample. The PAII paint sample staining application shows an obvious color change, within five minutes of UV irradiation, for paint samples containing photocatalytic pigments. A microscope with a camera and a UV source are the only necessary equipment for the application of this method. A quantitative image processing protocol is also proposed as an extension of the staining method by applying open source software analysis to measure the color change using photographs. The test was evaluated on reference paints with well-characterized pigments and applied on samples from modern paintings by Piet Mondriaan, Robert Ryman, and Lucebert, indicating the presence of harmful photocatalytic pigments in these cases. The novel application of a commercial ink on paint samples offers a simple test, not just for assessment of photocatalytic activity of titanium white pigments, but which may in future be applied for the detection of photoactive forms of zinc white and other potentially harmful semiconductor pigments in art objects.(OLD) MSE-
Simplified Madymo Seated Human Body Model for Motion Comfort Evaluation
No full textPeople need to have a comfortable experience in vehicles nowadays. However, they are continuously exposed to vibrations from the vehicle. Madymo active human models (AHM) can be used for comfort analysis and to learn how vibrations influence the human body in several aspects. However, existing AHM are very time-consuming due to their complexity, and the correspondence with human comfort data is only reasonable. In order to more effectively analyze motion comfort, a computationally efficient simplified human model (SHM) is developed and validated. The human body model has 36 degrees of freedom (DoF) considering the following segments: pelvis, two thighs, two lower legs, two feet, lower torso, upper torso and head. The model is validated in fore-aft, lateral and vertical vibrations. The model's postural stabilization parameters are tuned manually, by gradient search and grid search in sequence. Manually tuning gives a group of initial values of parameters for further optimization. According to the results, failure of the gradient search illustrates that this optimization problem is non-smooth. At the same time, grid search gives a relatively better result but also shows that the current cost function does not perfectly represent a good fit and needs improvement. A comparison between AHM and the SHM shows that the SHM has a similar or even better fit for most signals while being a largest factor 116 faster. A comparison of parameters between SHM and multibody human models in the literature shows that the structure of models affects the values of the same parameters. A comparison of different time steps illustrates that shorter time step does not necessarily give higher accuracy for this SHM. Suggestions such as adding muscles and changing body shapes are given for further improvement.Mechanical Engineerin
Impact of Arizona highways magazine's facebook page
Get PDFabstract: Arizona Highways magazine is a powerful tool in highlighting, and presumably attracting tourists to, Arizona, and is particularly renowned for its photography. The publication currently has over one million readers and circulates in all 50 states and in two‐thirds of the world’s countries. In addition to the print publication, AHM utilizes electronic media, namely a website and Facebook Page, to reach customers and potential tourists. The Facebook Page enables users to engage in dialogue and interaction with each other—uploading photographs, sharing accounts of personal travel experiences, and reacting to specific AHM content—thereby personalizing their connection with the magazine and fellow users.Includes bibliographical references (p. 101-102)
Computationally Efficient Human Body Modelling for Real Time Motion Comfort Assessment
No full textDue to the complexity of the human body and its neuromuscular stabilization, it has been challenging to efficiently and accurately predict human motion and capture posture while being driven. Existing simple models of the seated human body are mostly two-dimensional and developed in the mid-sagittal plane exposed to in-plane excitation. Such models capture fore-aft and vertical motion but not the more complex 3D motions due to lateral loading. Advanced 3D full body active human models (AHMs), such as in MADYMO, can be used for comfort analysis and to investigate how vibrations influence the human body while being driven. However, such AHMs are very time-consuming due to their complexity. To effectively analyze motion comfort, a computationally efficient and accurate three dimensional (3D) human model, which runs faster than real time, is presented. The model's postural stabilization parameters are tuned using available 3D vibration data for head, trunk and pelvis translation and rotation. A comparison between AHM and EHM is conducted regarding human body kinematics. According to the results, the EHM model configuration with two neck joints, two torso bending joints, and a spinal compression joint accurately predicts body kinematics.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Intelligent Vehicle
Data Assimilation under Geological Constraints
No full textAn important key in reservoirs engineering is the development of reliable reservoir models with high predictive capacity of production behavior in the existing and new drilled wells. The reservoir predictability is the starting point for guiding the production plan to an optimum. In order to achieve this, the internal geological description of the reservoir plays a crucial role. When referring to the internal geological description of the reservoir, one may think of a description of the spatial distribution of the petrophysical properties (permeability and/or porosity) or more natural, on a description of the spatial distribution of the geological deposit formations (facies). The prior modeling of the facies distribution is carried out using geostatistical tools in specialized modules, defining thus, the geological simulation model and its uncertainty. The choice of the geological simulation model for facies field simulation takes into account the geological particularities of the reservoir. Irrespective of the geological simulation model used, the poorly knowledge of geology leads to an initial reservoir model whose parameters are uncertain. This prior uncertainty is usually so large that the predictive capacity is limited. To improve the predictive capacity, the prior uncertainty is reduced in an Assisted History Matching (AHM) process. To be able to couple the geological simulation model with an AHM method, a parameterization of the facies fields is needed. The research objective of this thesis was to elaborate reliable parameterizations of the facies fields in a such manner that, introduced in an AHM process, the updates to be able to: match the past data within the model and measurement uncertainties; incorporate all types of information (different measurement types) and preserve geological realism (consistent with the initial geomodel).Mathematical PhysicsElectrical Engineering, Mathematics and Computer Scienc
Investigating the Photocatalytic Degradation of Oil Paint using ATR-IR and AFM-IR
Get PDFAs linseed oil has a longstanding and continuing history of use as a binder in artistic paints, developing an understanding of its degradation mechanism is critical to conservation efforts. At present, little can be done to detect the early stages of oil paint deterioration due to the complex chemical composition of degrading paints. In this work, we use advanced infrared analysis techniques to investigate the UV-induced deterioration of model linseed oil paints in detail. Subdiffraction limit infrared analysis (AFM-IR) is applied to identify and map accelerated degradation in the presence of two different grades of titanium white pigment particles (rutile or anatase TiO2). Differentiation between the degradation of these two formulations demonstrates the sensitivity of this approach. The identification of characteristic peaks and transient species residing at the paint surface allows infrared absorbance peaks related to degradation deeper in the film to be extricated from conventional ATR-FTIR spectra, potentially opening up a new approach to degradation monitoring.<br/
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