Analyse of the Evolution of the Hygrothermal Properties of the Hemp-Based Mortar within the Framework of the Total Weathering Protocol

Author(s):  
Dmytro Kosiachevskyi ◽  
Kamilia Abahri ◽  
Anne Daubresse ◽  
Evelyne Prat ◽  
Mohend Chaouche

The use of bio-based composites for building insulation is interesting from the point of view of hygrothermal performances, economic and environmental benefits. Among different organic fibers for these materials, hemp is interesting because of its huge availability in France. Nevertheless, the broad application of the hemp-based insulation mortars is hampered due to the lack of a database on their durability. This paper consists of a better understanding of the evolution of the hemp-based composite and its hygrothermal properties. The main objectives are, first, to study the evolution of the hemp insulation mortar microstructure and properties under the accelerated aging cycles, and second, to characterize and analyze the interconnection between observed changes. Experimentally, the protocol of accelerated aging inspired by standardized one was proposed, the microstructural characteristics and the hygrothermal properties, as the total porosity, the thermal conductivity, and the moisture buffer value (MBV) before and after the aging cycles was identified. The MBV characterization was performed for both hemp mortar and hemp shives. The obtained results reveal the increase of the hemp mortar porosity and the decrease of the hemp mortar's thermal conductivity. Furthermore, the MBV value of hemp mortar changes slightly, unlike that of the bulk hemp, which is explained by the mineral matrix's influence. These results consist of data for a better forecast on the degradation of the hemp mortar.

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1978
Author(s):  
Dan Dobrotă ◽  
Valentin Petrescu ◽  
Cristinel Sabin Dimulescu ◽  
Mihaela Oleksik

An important problem that arises at present refers to the increase in performances in the exploitation of the conveyor belts. Additionally, it is pursued to use some materials, which can be obtained by recycling rubber and PVC waste, in their structure. Thus, the research aimed at creating conveyor belts using materials obtained from the recycling of rubber and PVC waste. Under these conditions, conveyor belts were made that had in their structure two types of rubber and PVC, which was obtained by adding in certain proportions of reclaimed rubber and powder obtained from grinding rubber waste. In order to study the effect of adding PVC on properties, four types of conveyor belts were made, with the structure of rubber, PVC and textile reinforcement. These have been subjected to certain mechanical tests, also being analyzed from the point of view of the behavior of the accelerated aging. The results obtained showed that the addition of PVC lead to a decrease in tensile stress for the strips made, but also an increase in the tensile strain. Additionally, the elasticity tests performed before and after the accelerated aging showed that the presence of PVC in the structure of the conveyor belts determined a substantial reduction of the aging process of the rubber in the conveyor belts. Under these conditions, it has been established that the use of PVC in the structure of rubber matrix conveyor belts is beneficial if conveyor belts are to be produced that are less subject to mechanical stress, but that work in conditions that can cause accelerated aging of materials. An analysis with the finite element method (FEM) of the test samples was also performed.


Author(s):  
Nourhan Mortada ◽  
Annabelle Phelipot-Mardele ◽  
Christophe Lanos

Reduce the impact of the building sector has become a key point of sustainable development. The production of lightweight materials for the building industry is therefore a must. To produce such materials, foaming is a process commonly used to trap air bubbles and achieve a range of low densities. A sufficient low thermal conductivity and an acceptable ability to regulate humidity variations in order to limit overall energy consumption are the sought properties. In this study, a direct foaming method is applied to formulate gypsum foams using a commercial Plaster and two biobased foaming agents based on proteins. An anionic surfactant (α-olefin sulphonate sodium salt) is used as a reference surfactant. Varying the mixing time, protein content and water content, gypsum foams were produced. The foam volume is measured continuously during the mixing step and the foam homogeneity is controlled. The densities of fresh foams and of the hardened foams are used to identify the links between formulation and foams properties. Gypsum foam specimens with different densities ranging from 300 to 750 kg/m3 are produced. The thermal conductivity and the Moisture Buffer Value measurements are performed. Such properties appear directly linked to the porosity and pore connection of the foams. The obtained results highlight the contribution of biobased surfactant to the performance of gypsum foams.


Methodology ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 97-105
Author(s):  
Rodrigo Ferrer ◽  
Antonio Pardo

Abstract. In a recent paper, Ferrer and Pardo (2014) tested several distribution-based methods designed to assess when test scores obtained before and after an intervention reflect a statistically reliable change. However, we still do not know how these methods perform from the point of view of false negatives. For this purpose, we have simulated change scenarios (different effect sizes in a pre-post-test design) with distributions of different shapes and with different sample sizes. For each simulated scenario, we generated 1,000 samples. In each sample, we recorded the false-negative rate of the five distribution-based methods with the best performance from the point of view of the false positives. Our results have revealed unacceptable rates of false negatives even with effects of very large size, starting from 31.8% in an optimistic scenario (effect size of 2.0 and a normal distribution) to 99.9% in the worst scenario (effect size of 0.2 and a highly skewed distribution). Therefore, our results suggest that the widely used distribution-based methods must be applied with caution in a clinical context, because they need huge effect sizes to detect a true change. However, we made some considerations regarding the effect size and the cut-off points commonly used which allow us to be more precise in our estimates.


2014 ◽  
Vol 1 (1) ◽  
pp. 24-34
Author(s):  
Alireza K. ◽  
Hossein Ahmadi ◽  
Mohsen Mohammadi

Lubricants and leather dressings are the most common treatments of dry and water logged historical leathers. Color change has a great importance during the time and treatment process, due to visual and aesthetic values of historic leather relics. Polyethylene glycol (PEG) and silicone oil (SiO) are frequently used leather dressings in the conservation procedures. Therefore, color stability of treated leathers with PEG and SiO were investigated before and after heat accelerated aging. Moreover, application of ascorbic acid was evaluated as an antioxidant additive for PEG (PEG+AA).Color change after treatment and aging were studied by colorimetry technique in the CIE *L*a*b system. Results indicated to severe color alteration in PEG treated and aged leathers with or without ascorbic acid. Whereas, SiO treated samples showed better stability and minimum color shift after aging. Silicone oil was characterized as the best dressing for historical leathers with compared to PEG and PEG+AA, due to its high stability and aesthetical properties.


2018 ◽  
Vol 69 (8) ◽  
pp. 2232-2235
Author(s):  
Marius Moga ◽  
Mark Edward Pogarasteanu ◽  
Antoine Edu

The role of arthroscopy in incipient and mild arthrosis, even combined with proximal tibial ostetomy, is well known and well documented. On the other hand, its role in the treatment of advanced arthrosis of the large joints, especially the knee, is a subject of controversy. The proponents of the use of arthroscopy in advanced arthrosis claim that meniscectomy, synovectomy, ostophytectomy, chondral lesion stabilization, arthroscopic release, plica and loose body removal greatly improve the quality of life for most patients, especially if followed by the use of viscoelastic injection, by diminishing pain and improving joint range of motion. The opponents claim that, even though the advantages are clear in the cases that refuse arthroplasty, in all the other cases the surgical indication should be total knee arthroplasty, as the clinical relief is temporary, but with all the risks of a surgical intervention. We have conducted an overview of the recent literature, in order to find objective evidence to sustain either point of view. We focused on articles published that included an objective measurement of before and after clinical status through clinical scores and objective measurements. We also focused on the follow-up period and on the evolution of the pathology after arthroscopy.


Healthcare ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 726
Author(s):  
Fulvia Ceccarelli ◽  
Venusia Covelli ◽  
Giulio Olivieri ◽  
Francesco Natalucci ◽  
Fabrizio Conti

Background: The COVID-19 pandemic contributes to the burden of living with different diseases, including Systemic Lupus Erythematosus (SLE). We described, from a narrative point of view, the experiences and perspectives of Italian SLE adults during the COVID-19 emergency, by distinguishing the illness experience before and after the lockdown. Methods: Fifteen patients were invited to participate. Illness narratives were collected between 22 and 29 March 2020 using a written modality to capture patients’ perspectives before and after the COVID-19 lockdown. We performed a two-fold analysis of collected data by distinguishing three narrative types and a qualitative analysis of content to identify the relevant themes and sub-themes reported. Results: Eight narratives included in the final analysis (mean length 436.9 words) have been written by eight females (mean age 43.3 ± 9.9 years, mean disease duration 13.1 ± 7.4 years). Six patients provided a quest narrative, one a chaos and the remaining one a restitution narrative. By text content analysis, we identified specific themes, temporally distinct before and after the lockdown. Before COVID-19, all the patients referred to a good control of disease, however the unexpected arrival of the COVID-19 emergency broke a balance, and patients perceived the loss of health status control, with anxiety and stress. Conclusions: We provided unique insight into the experiences of people with SLE at the time of COVID-19, underlining the perspective of patients in relation to the pandemic.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yushen Wang ◽  
Wei Xiong ◽  
Danna Tang ◽  
Liang Hao ◽  
Zheng Li ◽  
...  

Purpose Traditional simulation research of geological and similar engineering models, such as landslides or other natural disaster scenarios, usually focuses on the change of stress and the state of the model before and after destruction. However, the transition of the inner change is usually invisible. To optimize and make models more intelligent, this paper aims to propose a perceptible design to detect the internal temperature change transformed by other energy versions like stress or torsion. Design/methodology/approach In this paper, micron diamond particles were embedded in 3D printed geopolymers as a potential thermal sensor material to detect the inner heat change. The authors use synthetic micron diamond powder to reinforced the anti-corrosion properties and thermal conductivity of geopolymer and apply this novel geopolymer slurry in the direct ink writing (DIW) technique. Findings As a result, the addition of micron diamond powder can greatly influence the rheology of geopolymer slurry and make the geopolymer slurry extrudable and suitable for DIW by reducing the slope of the viscosity of this inorganic colloid. The heat transfer coefficient of the micron diamond (15 Wt.%)/geopolymer was 50% higher than the pure geopolymer, which could be detected by the infrared thermal imager. Besides, the addition of diamond particles also increased the porous rates of geopolymer. Originality/value In conclusion, DIW slurry deposition of micron diamond-embedded geopolymer (MDG) composites could be used to manufacture the multi-functional geological model for thermal imaging and defect detection, which need the characteristic of lightweight, isolation, heat transfer and wave absorption.


PEDIATRICS ◽  
1948 ◽  
Vol 2 (2) ◽  
pp. 200-206
Author(s):  
AUGUSTA STUART CLAY

THIS study was made in the belief that family living and growth can be healthier if parents understand how mother and baby develop and what they need. Eleven mothers were visited weekly for two months before and after the birth of their firstborn to discover what guidance they wanted, what was offered, and what additional guidance was needed. The writer secured their cooperation by agreeing to work with them as a consultant, to interpret their point of view to the doctor, to explain medical instructions when permitted, and to teach the normal growth processes of mother and baby. Ten mothers were registered in the prenatal clinics of the New Haven Hospital; the eleventh had a private physician. They had no recorded problems beyond the needs of healthy pregnancy and they wanted to participate. Eight husbands agreed to take part in the study. The other three were overseas, but their wives reported for them. Backgrounds varied; 20 of the 22 had had college or high school education; all were between 18 and 32. None dropped out, and after the four months all asked for continued guidance. Cases were too few and the study too brief for statistical evidence. But problems were uncovered which needed to be considered and which have largely been neglected in routine obstetric and pediatric care. These parents wanted to learn—not in classes, but in the privacy of home—how to care for mother and baby without disrupting their accustomed way of living. All wanted the care and interest of one doctor for mother and one for baby. However, six women and five men preferred to talk with a consultant who was not a doctor, but who was affiliated with their doctors. The doctors seemed too busy for "little things" and "family affairs," and they saw so many doctors that they all seemed strangers. Once they felt sure that the consultant's interest was in themselves rather than in teaching them, they set the pace and pattern in the conference. There was no questionnaire, no probing, no set procedure. If they had any immediate interests or problems: job, move, presents, trips, in-laws, illness—these were discussed before they talked of pregnancy and baby.


2021 ◽  
Author(s):  
Francesco Busca ◽  
Roberto Revelli

<p>In recent years, safeguarding approaches and environmental management initiatives have been adopted both by international institutions and local governments , aimed at sustainable use of natural resources and their restoration, in order to manage hazard level of climate change consequences (urban flooding, droughts and water shortages, sea level rise, issues with food security).</p><p>Cities represent the main collectors of these effects, consequently they need to implement specific adaptation plans mitigating consequences of such future events: Green Infrastructures (G.I.) fall within the most effective tools for achieving the goal. In the urban context, they also identify themselves as valid strategies for biodiversity recovery and ecological functions.</p><p>This work analyzes the role of a G.I. in an urban environment, with the aim of quantifying Ecosystem Services (E.S.) provided by vegetation: through usage of <em>i-Tree</em>, specific software suite for E.S. quantification, the sustainability offered by “Le Vallere” park, a 34-hectares greenspace spread between municipalities of Turin and Moncalieri (Italy), was analyzed, in collaboration with the related management institution (<em>Ente di gestione delle Aree Protette del Po torinese</em>). The study, carried out using two specific tools (<em>i-Tree Eco and i-Tree Hydro</em>), focuses on different aspects: carbon sequestration and storage, atmospheric pollutants reduction, avoided water runoff and water quality improvement are just some of the environmental benefits generated by tree population. Tools enable to carry out the analysis also from an economic point of view, evaluating monetary benefits brought by the green infrastructure both at present day and in the future,  taking into account climate change effects through projections based on the regional climatic model COSMO-CLM (RCP 4.5 and RCP 8.5 scenarios).</p><p>The work led to deepen potential held by the greenspace, helping the cooperating management institution  to plan future territorial agenda and to find innovative approaches for an integrated and sustainable hazard control.</p>


1927 ◽  
Vol 23 (2) ◽  
pp. 258-258
Author(s):  
G. Baksht

From a social point of view, the problem of abortion was and is, perhaps, more topical today than ever before. The comprehensive coverage of this problem, which involves the most intimate aspect of human life, social and domestic conditions, and ethical issues, can only be the product of the collective efforts of physicians, sociologists, and lawyers.


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