Abstract In the past two decades, Europe has witnessed a significant transition in the design codes used for assessing foundation structures, with the widespread adoption of the Eurocodes (EC). This ...shift remains a pertinent topic within the engineering community, particularly concerning the transition from traditional design methodologies to those prescribed by the Eurocodes, as well as the potential for fully probabilistic design. While the Eurocodes’ methodology is described as probabilistic, it is crucial to recognize that the achievement of the target reliability level is predominantly facilitated through a system of partial safety factors. These factors are integrated into the calculation algorithm as fixed values, rendering the process essentially deterministic. To refine these calculations for more accurate reliability estimates—expressed in terms of failure probability—a genuinely probabilistic framework is required, termed as fully probabilistic computation. This paper aims to elucidate the fully probabilistic calculation approach for the broader professional community, using the geotechnical application of shallow foundations as an illustrative example. We present a comparative analysis of this advanced approach with the standard foundation design according to EC7 and ČSN 731001, the latter being a precursor in Europe for implementing the partial safety factor method. The discussion extends to a practical demonstration of full probabilistic design juxtaposed against the conventional partial safety factor method, using a shallow foundation case study. Furthermore, the paper delves into the impact of the tail behavior of uncertain or spatially varying soil parameters on the theoretical probability of failure, underscoring its significance in foundation design.
The article is focused on the medium-term negative effect of groundwater on the underground grout elements. This is the physical-mechanical effect of groundwater, which is known as erosion. We ...conduct a laboratory verification of the erosional resistance of grout mixtures. A new test apparatus was designed and developed, since there is no standardized method for testing at present. An erosion stability test of grout mixtures and the technical solutions of the apparatus for the test's implementation are described. This apparatus was subsequently used for the experimental evaluation of the erosional stability of silicate grout mixtures. Grout mixtures with activated and non-activated bentonite are tested. The stabilizing effect of cellulose relative to erosion stability has been also investigated. The specimens of grout mixtures are exposed to flowing water stress for a certain period of time. The erosional stabilities of the grout mixtures are assessed on the basis of weight loss (WL) as a percentage of initial specimen weight. The lower the grout mixture weight loss, the higher its erosional stability and vice versa.
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•Evaluation of material without and with coarse aggregates is performed.•Basic equations for the early age digital concrete are established.•3D construction printing technology is ...evaluated.
This experimental study analyses coarse aggregate-containing and coarse aggregate-free materials from the perspective of additive manufacturing. The primary objective is to identify, through a series of experiments, the fundamental equations that characterise material behaviour at early ages in order to formulate a digital material model. During the research, a previously unreported phenomenon, namely the contradictory development of Young's modulus and cohesion, was observed. In addition, the sensitivity of buildability to changes in material properties was discussed and demonstrated with a motivating example using a spatiotemporal simulation of 3D-printed concrete.
This thesis deals with the design and subsequent realization of laser diode control devices. The circuit will be able to control the diode with using a laser driver, via a computer network or via the ...display for control current values, setting of initial values and more. The device will be connected also with a SD card for saving of settings. In the theoretical part there are described individual components that are needed for functionality of the device. The practical part contains a block diagram, in which is described complete feature of the device, then a draft scheme with a description of all integrated circuits and important components. At the end of this work is described the software that controls the entire designed device.
Erosion of underground grout element resulting from the physical-mechanical effect of groundwater is a crucial problem, therefore the erosion resistance of grout element should be addressed in more ...detail. This paper aims to experimentally define the erosion resistance of underground grout element subjected to water flow-induced hydraulic forces. Laboratory tests were performed to investigate the resistance of geo-composites that practically form the grout element when applying the jet grouting technology. Erosion resistance of the geo-composite is investigated for (1) different composition of the grout suspension and (2) different concentration of the grout suspension within the geo-composite. The specimen of geo-composite was subjected to shear stress resulting from water flow for a certain period. The erosion resistance of the geo-composite specimens is defined depending on the so-called erosion rate which is the weight loss as a percentage of the original weight of the specimen. Final discussion on the experiments and their results is presented.
Anaerobic bacteria, such as Bacteroides fragilis or Clostridium perfringens, are part of indigenous human flora. However, Clostridium difficile represents also an important causative agent of ...nosocomial infectious antibiotic‐associated diarrhoea. Treatment of C. difficile infection is problematic, making it imperative to search for new compounds with antimicrobial properties. Hops (Humulus lupulus L.) contain substances with antibacterial properties. We tested antimicrobial activity of purified hop constituents humulone, lupulone and xanthohumol against anaerobic bacteria. The antimicrobial activity was established against B. fragilis, C. perfringens and C. difficile strains according to standard testing protocols (CLSI, EUCAST), and the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBC) were calculated. All C. difficile strains were toxigenic and clinically relevant, as they were isolated from patients with diarrhoea. Strongest antimicrobial effects were observed with xanthohumol showing MIC and MBC values of 15–107 μg/mL, which are close to those of conventional antibiotics in the strains of bacteria with increased resistance. Slightly higher MIC and MBC values were obtained with lupulone followed by higher values of humulone. Our study, thus, shows a potential of purified hop compounds, especially xanthohumol, as alternatives for treatment of infections caused by select anaerobic bacteria, namely nosocomial diarrhoea caused by resistant strains.
Macrophages play an important role in the immune system. They also participate in multiple processes including angiogenesis and triggering of inflammation. The present study summarizes pieces of ...knowledge on the importance of macrophages in disease, especially the inflammation. Special attention is paid to the cholinergic anti-inflammatory pathway (CAP) associated with the nicotinic acetylcholine receptor (nAChR) and the parasympathetic nervous system. The current pharmacological effectiveness in suppressing the inflammation in general and the septic shock in particular, is limited. CAP was discovered recently and it seems to be a suitable target for the development of new drugs. Moreover, available drugs binding to either nAChR or acetylcholinesterase (AChE) are candidates for either an inhibition or enhancement of CAP. Though the current scientific databases do not include all necessary data on the association of CAP with body functions and the research is quite intensive, the objective of the present review is to introduce the current trends and to critically evaluate CAP and macrophage-associated pathways.
Staphylococcus (S.) aureus is an important causative agent of wound infections with increasing incidence in the past decades. Specifically, the emergence of methicillin-resistant S. aureus (MRSA) ...causes serious problems, especially in nosocomial infections. Therefore, there is an urgent need to develop of alternative or supportive antimicrobial therapeutic modalities to meet these challenges. Purified compounds from hops have previously shown promising antimicrobial effects against MRSA isolates in vitro. In this study, purified beta-acids from hops were tested for their potential antimicrobial and healing properties using a porcine model of wounds infected by MRSA. The results show highly significant antimicrobial effects of the active substance in both the powder and Ambiderman-based application forms compared to both no-treatment control and treatment with Framycoin. Moreover, the macroscopic evaluation of the wounds during the treatment using the standardized Wound Healing Continuum indicated positive effects of the beta-acids on the overall wound healing. This is further supported by the microscopic data, which showed a clear improvement of the inflammatory parameters in the wounds treated by beta-acids. Thus, using the porcine model, we demonstrate significant therapeutic effects of hops compounds in the management of wounds infected by MRSA. Beta-acids from hops, therefore, represent a suitable candidate for the treatment of non-responsive nosocomial tissue infections by MRSA.
In this paper, we give a comparative study of several planar antenna concepts for reliable long range links in a tactical environment. The antenna elements are studied in terms of their electrical ...properties (bandwidth, reflection coefficient and radiation characteristics) and construction (robustness and material consumption). First, we model single antenna elements to investigate if they meet the requirements. Second, we arrange the elements with the best features into 2x2 arrays. Computer simulations of the arrays are verified by measurements. Finally, we formulate recommendations for large array (8x8 or 16x16 elements) synthesis to achieve the required properties.
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