Characterization of Pure and Modified TiO_{2} Layer on Glass and Aluminum Support by Beam Deflection Spectrometry

\(\mathrm {TiO}_{2}\) thin films used as photocatalysts in environmental applications were studied by beam deflection spectroscopy (BDS) and by atomic force microscopy. A novel multiparameter theoretical model was developed in order to explain BDS experimental data. The fundamental parameters of examined films: thermal diffusivity, thermal conductivity, and charge transport properties such as the value of the energy bandgap, carrier lifetime, concentration, and type of dopants, were obtained as results of the modeling of BDS data. With BDS, we observed that the material’s thermal conductivity and thermal diffusivity depend also on the porosity and the surface roughness of films. Consequently, the photocatalytic performance can be estimated by measuring the thermal diffusivity of films. Furthermore, we found that surface roughness is prone to changes when the film is used as photocatalysts in water purification processes. During the purification process, the roughness decreases and the photocatalytical performance drops. Moreover, it was discovered that the thermal, electrical, and morphological properties of photocatalysts films depend on the support to which the \(\mathrm {TiO}_{2}\) layer is deposited. These complex relations demonstrate that knowledge of fundamental physical parameters is required in order to improve the photocatalytic performance of \(\mathrm {TiO}_{2}\) films. In this view, the BDS measurements offer a tool for noncontact and nondestructive evaluation of thermal and electronic parameters of thin film \(\mathrm {TiO}_{2}\) photocatalysts as demonstrated in this work.     

Key stakeholders’ perspectives on the ideal partnering culture in construction projects

This paper examines the current state of project cultures in the German turnkey construction industry and the ideal project cultures in terms of partnering from the perspective of various key stakeholders (i.e., Investors, General Contractors, (Sub-)Contractors and Designers). To investigate the current and ideal cultures, data were gathered among the key stakeholders by means of a survey study with 72 respondents divided over 12 companies. The respondents rated the current and desired cultures by using the Organizational Culture Assessment Instrument, which belongs to the Competing Values Framework. The investigations show many similarities and differences between the stakeholder perspectives of the current and the idealized partnering project cultures. Mainly, the General Contractors desire more cooperative behaviors than the (Sub-)Contractors, and the Investors desire more pronounced flexibility than the General Contractors. All stakeholders desire a cultural change from highly competitive behaviors toward more cooperation. Changes in terms of clear procedures or more flexibility are only desired by the Designers. Defining both the current and an ideal partnering project culture enables academics and project managers to compare their actual project cultures to an ideal situation. With such an approach, academics and project managers could measure whether new tools or changes in resources affect their project cultures toward a partnering project culture.     

Depolarization current of novolac phenol-formaldehyde resins doped with 1,4-diazabicyclo [2.2.2] octane

Mixtures of novolac phenol-formaldehyde (NPF) resins and 1,4-diazabicyclo [2.2.2] octane (DABCO) were polarized at different temperatures applying different d. c. electric fields. Thermally stimulated depolarization current (TSDC) measurements performed from 298 to 373 K showed a dipolar α peak and a space charge α peak as in pure NPF. The addition of DABCO decreases the magnitude of the α peak and the activation energy of the dipolar relaxation but increases the background current and the magnitude of the α peak significantly. The maximum of the α peak is only slightly shifted towards higher temperatures. New aspects in the analysis of the background current by consecutive heating and cooling experiments are considered. The results obtained show an increase in concentration of trapping sites due to the heterogeneity of the mixed systems. The proposed interactions between nitrogen from DABCO and hydroxy groups from NPF are discussed.     

On the structure‐properties relationship in montmorillonite‐filled polyamide 6 nanocomposites

Polyamide 6/montmorillonite (MMT) nanocomposites were prepared by melt compounding method comprising 1–7.5 wt % of Nanomer I.24 TL or 5 and 10 wt % of Cloisite 15A organically modified nanoclays. The composite samples were characterized by synchrotron X‐ray, thermal and FT‐IR spectroscopy methods looking for changes in the micro‐ and nanostructure of both PA6 matrix and MMT reinforcement as a function of the clay content and type. These data were discussed in conjunction with the mechanical properties of the respective nanocomposites. Generally, the Young's modulus was found to increase proportionally to the clay content being the highest in samples with strong aggregation of MMT at micron length scale. The tensile strength passed through a maximum at 2.5 wt % clay load presenting a homogeneous microstructure with almost no agglomeration. Increasing the amount of MMT produced less crystalline PA6 matrices, richer in γ‐PA6 polymorph and resulted in larger long spacings of PA6 due to expansion of both crystalline and amorphous domains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Effect of thermal oxidative ageing on the morphology of natural rubber networks as viewed by ESR

The change of network morphology of unfilled sulfur crosslinked natural rubber exposed to thermal oxidative ageing has been studied. Three model networks with different sulfur contents (efficient network, semi‐efficient and conventional vulcanizate) have been analysed by applying spin probe ESR, equilibrium swelling measurements and mechanical measurements. By combining the density distribution deduced from the complex ESR spectra and the equilibrium swelling density, it is shown that the major network changes occur in the networks with predominantly polysulfidic bonds (conventional network) after 96 h of ageing at 373 K. The effect of ageing on the network with predominantly monosulfidic bonds is much less pronounced. Both effects (main chain scission and additional local crosslinking) have been analysed in the course of prolonged ageing up to 240 h. A correlation between network structure and its mechanical performance is established. © 2000 Society of Chemical Industry     

Molecular Insights in Uterine Leiomyosarcoma: A Systematic Review

Uterine fibroids (UFs) are the most common benign tumors of female genital diseases, unlike uterine leiomyosarcoma (LMS), a rare and aggressive uterine cancer. This narrative review aims to discuss the biology and diagnosis of LMS and, at the same time, their differential diagnosis, in order to distinguish the biological and molecular origins. The authors performed a Medline and PubMed search for the years 1990–2022 using a combination of keywords on the topics to highlight the many genes and proteins involved in the pathogenesis of LMS. The mutation of these genes, in addition to the altered expression and functions of their enzymes, are potentially biomarkers of uterine LMS. Thus, the use of this molecular and protein information could favor differential diagnosis and personalized therapy based on the molecular characteristics of LMS tissue, leading to timely diagnoses and potential better outcomes for patients.     

Thermal Lens Spectrometry: Still a Technique on the Horizon?

In this article, the historical development of thermal lens spectrometry (TLS) is briefly reviewed as an introduction. In continuation, the emphasis is on the recent progresses of TLS for measurements in ensembled sample cells and in microfluidic flow injection systems. Novel theories, instrumentation and their applications for high sample throughput for environmental, chemical and biomedical analysis, as well as thermal characterization and imaging, particularly in microspace, are presented. Discussion is given on the limitations of present TLS systems that open new horizons for future progress of this technique, which has already found place among routine techniques for chemical analysis. In the final section, proposals for the future development of TLS towards advanced applications in new research fields are presented.     

Numerically assisted analysis of flat and corrugated plate solar collectors thermal performances

The paper presents the results of experimentally supported numerical analysis performed in order to investigate the possibilities to improve the thermal efficiency of plate solar collectors. Different numerical models were developed in order to asses the influence of design and operating parameters such as bond conductance between absorber plate and tube, tube diameter, glass cover to absorber plate distance, optical properties of absorber and flow rate on thermal efficiency of collectors. Following the results, two designs of collector without tubes, with parallel flat and corrugated absorber plates of chevron type, is further considered and shown to be an effective way to increase the thermal efficiency of solar energy conversion beyond that of commercial glazed and unglazed solar water heaters. Based on the results, the guidelines for design of a new collector prototype consisting of chevron type corrugated plates normally used in plate heat exchangers are provided.     

Multifidelity component interface reduction and modal truncation augmentation

A Hurty-Craig-Bampton (HCB) reduced order component can have unnecessarily large dimension if it contains many interface degrees of freedom. This is often the case for high spatial resolution models. Furthermore, for such high-fidelity models, their static constraint modes can be expensive to compute. To overcome these problems, a component mode synthesis method with interface reduction is developed using multifidelity models. The interface reduction basis is computed from the assembled system by coarsening each substructure's mesh, but keeping the model resolution at the interface intact. It is shown that such a mesh coarsening has a small effect on the interface reduction basis quality. Using this reduction basis, the dimension of the static constraint modes problem can be reduced and the modes computed at a low cost. When few interface modes can be used without significant loss of accuracy, it is possible to enrich the HCB basis with modal truncation augmentation (MTA) vectors to increase accuracy at a small extra cost. The accuracy of a procedure that utilises MTA vectors together with the multifidelity interface reduction is investigated. The method's performance and accuracy are illustrated on a planar problem and a more complex problem from industry.