The importance of physical parameters for the penetration depth of impregnation products into cementitious materials: Modelling and experimental study

The performance of impregnation treatments used for protection and remediation of porous building materials relies on sufficient penetration depth. The penetration of sol-gel impregnation products into partially saturated porous material is driven by capillary suction and depends on material properties, such as pore size distribution on one hand, and on the other hand on sol physical properties, viscosity, density, surface tension and contact angle, along with the time in which the sol gels. In this work we analyse, by the way of modelling and experiments, the penetration depth of a sol-gel impregnation product as the function of pore size distribution and sol properties. The main goal is to determine the importance of sol's physical properties for the penetration depth for a specific pore size, which will serve as a basis of the optimization of impregnation products to maximize their penetration depth. The model is first calibrated in terms of penetration depth and sol uptake by the experimental data obtained from mortar samples each with a specific pore-size distribution. The correlation between penetration depth and physical parameters is then established by the use of Monte-Carlo method. The results show that the most important parameters for the optimization are surface tension, whose influence increases for larger pores, and gelation time, which with decreasing importance for larger pores. (C) 2020 The Author(s). Published by Elsevier Ltd

Nocebo Effects on Muscular Performance – An Experimental Study About Clinical Situations

Introduction: Nocebo effects are not only seen in studies of pharmacology and placebo/nocebo research but also in clinical everyday situations. For generation of objective and quantitative data on the impact of negative communication we have evaluated the immediate effects of common sentences, non-verbal signals and situations in the medical context on muscular performance.Methods: In an experimental study, 46 volunteers were tested by dynamometry of the deltoid muscle group to evaluate the maximal muscular strength during arm abduction. Baseline values were compared to performance after exposure to 18 verbal and non-verbal suggestions. Suggestions suspected to be negative were alternated with and compared to positively formulated alternatives.Results: Verbal and non-verbal communication produced significant effects on muscular performance, resulting mainly in weakening. The decrease in muscle strength after risk information for informed consent (91.4% of baseline) was absent, when benefits of the treatment were named coincidently. The weakening effect of asking about “pain” and “nausea” (89.4%), and of the announcement of medical interventions (91.7%) could be avoided with alternative wording. Impairment of muscular performance was also observed with the nocebo-inducers negative memory (89.5%) or uncertain future (93.3%), in contrast to a positive memory or the orientation into the presence. Non-verbal suggestions like overhead anesthesia induction (89.9%), a transport in strict flat supine position (89.1%), or a view from the window to a parking lot (94.1%) significantly reduced maximal muscle strength, whereas face-to face induction, half-sitting position and a view into the landscape did not. 8 out of 9 tested clinical situations reduced maximal arm muscle strength significantly, whereas alternative formulations did not.Conclusion: This study describes a quick, simple and uniform test using objective measurement of maximal muscle strength to allow for identification, quantification, and comparison of negative suggestions, regardless of their specific content and effect. Muscle strength is a clinically relevant parameter with regard to early mobilization, risk of falling and sufficient breathing. Furthermore, the observed impairment of muscular performance could reflect a general “weakening effect” of negative suggestions. In addition, the test facilitates development and verification of appropriate alternatives to prevent nocebo effects in patients, thereby improving patient communication

Pore structure and sorption capacity investigations of Ediacaran and Lower Silurian gas shales from the Upper Yangtze platform, China

The shale gas potential of Ediacaran and Lower Silurian shales from the Upper Yangtze platform is assessed in this study with a focus on the contributions of clay minerals and organic matter to sorption capacity. For this purpose, a multidisciplinary assessment was carried out using petrophysical, mineralogical, petrographic and geochemical methods. In terms of TOC contents (4.2%), brittle mineral contents (68.6%) and maximum gas storage capacities (0.054–0.251 mmol/g) Ediacaran shales from this study show comparable properties to other producing shale gas systems although the thermal maturity is extremely high (VRr = 3.6%). When compared to lower Silurian shales from the same region, it is evident that (1) deeper maximum burial and (2) a lack of silica-associated preservation of the pores resulted in a relatively lower mesopore volume, higher micropore volume fraction and lower overall porosity (Ediacaran shales: 1.4–4.6%; Silurian shales: 6.2–7.4%). Gas production is therefore retarded by poor interconnectivity of the pore system, which was qualitatively demonstrated by comparing experimental gas uptake kinetics. TOC content exhibits a prominent control on sorption capacity and micropore volume for both shales. However, different contributions of clay minerals to sorption capacity were identified. This can partly be attributed to different clay types but is likely also related to burial-induced recrystallisation and different origins of illite. Additionally, it was shown that variations in sorption capacity due to incorrect estimates of clay mineral contribution are in the same range as variations due to differences in thermal maturity. Article highlights Pore structure and gas storage characteristics are evaluated for the first time for Ediacaran Shales from the Upper Yangtze platform Due to a lower free gas storage capacity and diffusivity, the Ediacaran shale can be regarded as a less favorable shale gas prospect when compared to the Silurian shale Clay mineral contribution to sorption capacity is evaluated taking clay mineralogy into consideration Maturity-related changes of organic matter sorption capacity have been discussed on the basis of a compiled data setRWTH Aachen University (3131

Time-Dependent Negative Effects of Verbal and Non-verbal Suggestions in Surgical Patients—A Study on Arm Muscle Strength

Introduction The medical environment is full of suggestions that affect patients and their healing. Most of them inadvertently are negative, thus evoking nocebo effects. Recently, we have reported on the effect of such verbal and non-verbal suggestions as well as alternative formulations on maximal muscular arm strength in healthy volunteers. In the present study, we tested the same suggestions in patients at two time points to evaluate nocebo effects in a clinical situation and the impact of the approaching surgery date. Methods In 45 patients, maximal muscular strength during arm abduction was measured by dynamometry of the deltoid muscle group. One test was several days before and the second on the evening before surgery. Baseline values were compared to the performance after exposure to 18 verbal and non-verbal suggestions. The sequence of presumably negative and positive suggestions was randomized for each patient in order to avoid cumulation effects of immediate succession of two negatives. State anxiety was evaluated at both time points, and suggestibility was measured after surgery. Results Strong and statistically significant weakening effects were observed with all presumed negative suggestions from daily clinical practice including words of encouragement (91.4% of baseline), evaluation of symptoms (89.0%), announcement of a medical intervention (82.8%), a negative memory (86.5%), expectation of an uncertain future (82.8%), and non-verbal signals (87.7-92.2%). In contrast, alternative formulations did not interfere with muscular performance in most cases. A more pronounced effect was observed in the test repeated closer to the date of surgery, accompanied by a 15% higher anxiety level. The increase in anxiety correlated slightly with stronger weakening effects of suggestions, as did suggestibility. Conclusions Negative suggestions cause a decrease in arm muscle strength, i.e., a "weakening" of the patient. This effect is enhanced by an increase in anxiety as the time of treatment, like surgery, approaches. The reaction can be avoided by alternative formulations. These nocebo effects that are objectively measured and quantified by a decrease in arm muscle strength are more pronounced in patients, i.e., in a clinical situation, than in healthy volunteers

Deep Brain Stimulation Surgery without Sedation

Background: Sedatives and opioids used during deep brain stimulation (DBS) surgery interfere with optimal target localization and add to side effects and risks, and thus should be minimized. Objective: To retrospectively test the actual need for sedatives and opioids when cranial nerve blocks and specific therapeutic communication are applied. Methods: In a case series, 64 consecutive patients treated with a strong rapport, constant contact, non-verbal communication and hypnotic suggestions, such as dissociation to a "safe place," reframing of disturbing noises and self-confirmation, were compared to 22 preceding patients under standard general anaesthesia or conscious sedation. Results: With introduction of the protocol the need for sedation dropped from 100% in the control group to 5%, and from a mean dose of 444 mg to 40 mg in 3 patients. Remifentanil originally used in 100% of the patients in an average dose of 813 mu g was reduced in the study group to 104 mu g in 31% of patients. There were no haemodynamic reactions indicative of stress during incision, trepanation, electrode insertion and closure. Conclusion: With adequate therapeutic communication, patients do not require sedation and no or only low-dose opioid treatment during DBS surgery, leaving patients fully awake and competent during surgery and testing. (C) 2018 S. Karger AG, Base

Understanding pore structure of mudrocks and pore-size dependent sorption mechanism using small angle neutron scattering

To quantitatively analyse the pore structure at a broad pore scale range (~ 2 nm to ~ 2 μm), low pressure sorption (LPS) and small angle neutron scattering (SANS) were conducted on several mudrocks originating from radioactive waste storage sites, hydrocarbon seals and shale gas reservoirs across the globe. These include Opalinus Clay, Switzerland, Posidonia Shale, Germany, and Carmel Claystone, Bossier Shale, and Eagle Ford Shale, USA. Furthermore, upon injection of supercritical fluids (deuterated methane, CD 4) into the pore space of mudrocks, the phase behaviour depending on pore size was investigated with subsequent neutron scattering. The results have revealed a vast heterogeneity, which can be related to the high clay contents. Due to the high clay contents, pores smaller than 10 nm constitute a large fraction of total porosity (25-30 %) and up to 80 % of specific surface area (SSA). Moreover, total porosity and SSA are not significantly affected by thermal maturation. However, thermal maturity contributes to different pore size distribution (PSD) related to meso-and macro-pores. Thermal maturation is likely to develop porosity at macroscale range, which can enhance the permeability for continuum flow in organic rich mudrocks. Results obtained from supercritical fluid sorption within SANS experiments demonstrated the formation of an adsorbed phase characterised by a higher density than predicted for the bulk fluid by the equation of state. The effect of sorbed phase is pore size dependent. It implies that the density as well as the volume fraction of the adsorbed phase are influenced by the pore structure; sorbed phase tends to fill small pores, followed by progressively filling larger pores. Mineralogy and maturity interplays contribute to a pore network of few-to-several nano-Darcy permeability in which pore size dependent transport mechanisms can vary from diffusional transport in small pores to slip flow in progressively larger pores. In order to improve pore 2 URTEC-198285-MS network models, the incorporation of SANS PSD as well as pore size dependent sorption are important to more realistically understand storage capacity and/or transport phenomena in mudrocks

Long-term performance of cementitious materials used in nuclear waste disposal-a case study at SCK center dot CEN

This paper presents an overview of a research program at the Belgian Nuclear Research Centre (SCK center dot CEN) concerning long-term durability of cementitious materials. The need for this research originates from the Belgian nuclear waste disposal concept, which proposes ordinary portland cement as the candidate binder for engineered barriers. Three main degradation mechanisms are considered: calcium leaching, carbonation and combined leaching/carbonation. Specifically, the effect of these mechanisms on microstructural changes and hence on physical and transport properties are discussed. The discussion concerns recent advances in experimental techniques and numerical tools in support of experimental programme. Novel experimental techniques cover accelerated degradation experiments for sound/fractured material, and transport experiments to determine water permeability and diffusion coefficient. Numerical tool covers recent implementation of lattice-Boltzmann based reactive transport code to handle micro-meso-continuum scale modelling