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Mode I fracture toughness is an important material parameter of rock. To date, a number of laboratory methods have been developed to measure the mode I fracture toughness. Although the fracture toughness values measured by different methods have been compared in many previous studies, the effect of the specimen configuration and pre-existing notch shape on the fracture toughness value and the associated cracking characteristics have not been comprehensively studied. In the present study, the failure modes and mode I fracture toughness of Kowloon granite, a major type of granite in Hong Kong, are studied experimentally based on the chevron bend (CB), semi-circular bend (SCB) and cracked chevron notched semi-circular bend (CCNSCB) methods. The fracture toughness measured by the SCB test is much lower (56.5% lower) than that measured with the CCNSCB test. The measured CB fracture toughness is between the SCB and CCNSCB results. The failure modes of specimens containing the chevron notch (CB and CCNSCB specimens) are found to differ from those containing the straight-through notch (SCB specimens), especially with respect to the post-failure behavior. The cracking mechanism of the SCB and CCNSCB is studied macroscopically and microscopically. The results show that the straight-through notch and chevron notch, which are the most commonly used notch shapes adopted in various mode I fracture toughness tests, have significant effects on the cracking behavior and crack characteristics. Further investigation on the thin sections prepared from the specimens after the mode I fracture toughness tests provides us with new insights into the microscopic characteristics of tensile cracks in granite under mode I loading condition.

Industries that rely on additive manufacturing of metallic parts, especially biomedical companies, require material science-based knowledge of how process parameters and methods affect the properties of manufactured elements, but such phenomena are incompletely understood. In this study, we investigated the influence of selective laser melting (SLM) process parameters and additional heat treatment on mechanical properties. The research included structural analysis of residual stress, microstructure, and scleronomic hardness in low-depth measurements. Tensile tests with specimen deformation analysis using digital image correlation (DIC) were performed as well. Experiment results showed it was possible to observe the porosity growth mechanism and its influence on the material strength. Specimens manufactured with 20% lower energy density had almost half the elongation, which was directly connected with the porosity growth during energy density reduction. Hot isostatic pressing (HIP) treatment allowed for a significant reduction of porosity and helped achieve properties similar to specimens manufactured using different levels of energy density.

Polymers based on 2-(acetoacetoxy)ethyl methacrylate, charged with iron or sodium, were thermally heated at 150 °C. Both polymers were studied and characterized by SEM, TEM, STEM microscopy and SAEDF techniques. The morphological investigation revealed that, upon heating, both polymers were endowed with microholes, sometimes perfectly ordered, whose dimensions varied from 4–5 nm to approximately 500 nm. In the case of an Fe-containing copolymer, unexpectedly, iron did not fill in the cavities, thus implying that it was “dispersed” in the polymeric matrix. Electronic microdiffraction documented that both polymers exhibited a proto-crystallinity, likely induced by thermal heating.

This paper presents the results of a microscopic investigation of fractured Storz type fire hose couplings. It is part of the authors’ previous investigations on the failure mechanisms of this type of couplings. The investigations were performed using optical and scanning electron microscopy with Field Emission Gun (FED) and X-ray Energy Dispersive Spectrometer (EDS). It is shown that the AlSi5Cu1Mg casting alloy, used for the fabrication of these couplings, presents a normal microstructure. Thus, the nucleation and growth of micro-cracks in the investigated couplings are not related to the alloy’s microstructural defects and must be generated by a different process.

Arjunolic acid (AA) is a potent phytochemical with wider pharmacological activities. Despite potential medicinal properties on various in vitro and in vivo studies, there is still a dearth of scientific data related to its safety profile and toxicological parameters. The current study aimed to investigate acute toxicity of AA in normal female Sprague Dawley rats. In this study, AA was administered orally at an individual dose of 300 and 2000 mg/kg body weight to group 1 and 2 respectively, while group 3 served as normal control. All the animals were observed for 2 weeks to determine any behavioral and physical changes. On day 15, blood was collected for hematological and biochemical investigation, later animals from all the three groups were euthanized to harvest and store essential organs for histopathological analysis. Four different staining techniques; hematoxylin and eosin, Masson trichrome, Periodic acid Schiff and Oil O Red were used to investigate any alterations in different tissues through microscopical observation. The results of the study showed no morbidity and mortality at two different dosage of AA treatment. Daily food & water intake, body weight, relative organ weight, hematological and biochemical parameters were detected to be normal with no severe alteration seen through microscopical investigation in the structure of harvested tissues. Our findings support the safety profile of AA, which was well tolerated at higher dose. Thus, an in-detail study on the subacute disease model is warranted.

Two flour-water systems were prepared under different conditions. A mixed flour-water system (dough) was prepared by mixing and kneading, and an unmixed (Hydrated, Unmixed Flour=HUF system) flour-water system without mixing and kneading. For preparation of the systems wheat flours of different qualities were used. Characterisation of the systems was done by rheological and microscopic analyses. Rheological measurements were performed at small deformation in dynamic oscillating mode, as well as at large deformation by uniaxial extension. The dough, the HUF system and the gluten from them were also investigated by microscopic technique. The mixed and unmixed systems showed differences in structure causing different physical properties. At small deformations (dynamic oscillating measurements) as well as at large ones (uniaxial extension measurements) HUF systems were firmer than doughs having a higher resistance in uniaxial extension measurements and higher elasticity at the beginning of dynamic measurements. Differences in structure of dehydrated systems were also found by microscopic investigations.[PUBLICATION ABSTRACT]

X20CrMoV121 is a 12%Cr martensitic steel which has been used in power plants in Europe for many decades. Superheater tubes exposed for various durations up to 135,000 hours in power plants in Denmark at steam temperatures varying from 450 to 575°C were investigated. Light optical and scanning electron microscopy was used to investigate steamside oxide morphologies. At all temperatures there is a double layered oxide, however, the inner:outer oxide thickness is not always equal. At the lower steam temperature range of <500°C, there is an internal oxidation zone at the oxidation front indicating that chromium is less mobile at these temperatures. At a higher steam temperature range of 540 - 575°C the inner oxide consists of chromium rich and chromium poor oxide running parallel to the oxidation front indicating that the chromium is more mobile within the steel. Both types of morphology have been observed in the laboratory, however the internal oxidation is observed up to 600°C and the chromium rich oxide striation are observed at 700°C.

In biological wastewater treatment inorganic and organic substances are fixed and metabolized by mixed populations of microorganisms forming either activated sludge flocs or biofilms. Not only the type of wastewater but also the operational conditions promote the development of an adapted biocenosis of microorganisms with specialized enzymatic functions. Understanding the biological properties of the microorganisms, it is possible to assess the prevailing conditions in their natural environment. Regular microscopic and enzymatic investigations of activated sludge and biofilms thus improve the assessment of the stability of the processes and support troubleshooting in wastewater treatment plants. While the role of bacteria is often discussed, the importance of ciliated protozoes and metazoes for the maintenance of the stability of biofilm systems is rarely mentioned. In this paper we intend to show some new results of direct microscopic observations in different sorts of biofilm systems focussing upon ciliated protozoes and metazoes. Practical results will demonstrate the relation between enzymatic analysis, microscopic investigations and performance of biofilm systems.

Over the past decades a great deal of attention has been dedicated to the broadening and diversification of the notion of narratives, which lead to a variety of models for narrative analysis and encouraged some to speak of a \"narratological renaissance\" (e.g., CURRIE, 1998; HERMAN, 1999). However, the application of these concepts to early development has faced a major challenge--the use of narratives (as both a theoretical framework and a methodological tool) to examine psychological processes prior to the acquisition of language. The present contribution offers a systematic approach to examine early emotional development grounded on narrative traditions. I begin by briefly presenting the relevant literature and linking it with the narrative-developmental approach proposed herein. This approach, I contend, implies that narratives and development are inextricably anchored to one another as narratives evolve over time through communication processes. I then describe within the narrative analysis the steps that I have developed to investigate emotions in the context of parent-toddler relationships. Thus, the narrative-developmental approach discussed aims to provide a conceptually grounded qualitative methodology to microscopically investigate the development of emotions and to demonstrate the inherently emergent nature of narratives. URN: urn:nbn:de:0114-fqs0103147

INTRODUCTION:Microscopic colitis (MC) is an inflammatory condition of the large intestine. Primarily diagnosed in middle-aged and older adults, the incidence of the disease has increased markedly during the past few decades. While MC is associated with a reduced quality of life, large-scale studies on the association with future psychiatric disorders are lacking.METHODS:We conducted a nationwide matched cohort study in Sweden from 2006 to 2021. Through a nationwide histopathology database (the Epidemiology Strengthened by histoPathology Reports in Sweden study), we identified 5,816 patients with a colorectal biopsy consistent with MC. These patients were matched with 21,509 reference individuals from the general population all of whom with no previous record of psychiatric disorders.RESULTS:From 2006 to 2021, 519 patients with MC (median age 64.4 years [interquartile range = 49.5-73.3]) and 1,313 reference individuals were diagnosed with psychiatric disorders (9.9 vs 6.5 events per 1,000 person-years), corresponding to 1 extra case of psychiatric disorder in 29 patients with MC over 10 years. After adjustments, the hazard ratio for psychiatric disorders was 1.57 (95% confidence interval = 1.42-1.74). We found significantly elevated estimates up to 10 years after MC diagnosis and a trend toward higher risk with increasing age. Specifically, we observed increased risks for unipolar depression, anxiety disorders, stress-related disorders, substance abuse, and suicide attempts. In sibling-controlled analysis, the adjusted hazard ratio was 1.76 (95% confidence interval = 1.44-2.15).DISCUSSION:Patients with MC are at increased risk of incident psychiatric disorders compared with the general population.