scholarly journals Experimental Evaluation of Cement Mortars with End-of-Life Tyres Exposed to Different Surface Treatments

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 552
Author(s):  
Eduardo García ◽  
Bárbara Villa ◽  
Mauricio Pradena ◽  
Bruno Urbano ◽  
Víctor H. Campos-Requena ◽  
...  
Keyword(s):  
End Of Life ◽  
Construction Material ◽  
Cost Effective ◽  
Surface Treatments ◽  
Point Of View ◽  
Negative Effects ◽  
Design Strength ◽  
Cement Mortars ◽  
Concrete Mechanical Properties ◽  
Portland Pozzolana Cement

An end-of-Life Tyre (ELT) is a type of waste that can generate negative social and environmental impacts due to its disposal. Considering that rubber can improve concrete properties and the massive use of concrete as construction material, the addition of ELT rubber in concrete mixes is attractive. However, concrete mechanical properties are negatively affected due to the rubber-cementitious matrix interaction. Although rubber treatments have been developed to minimise the negative effects, the geo-dependency of the mix makes necessary to find cost-effective and practical solutions that will allow a real use of the ELT waste. Therefore, the objective of the present study is to characterise the properties of cement mortars with the addition of ELT rubber under three surface treatments: hydration, oxidation-sulphonation, and hydrogen peroxide. The results show that hydration is the most favourable treatment from a technical, practical, and economical point of view. In fact, with this treatment, it is possible to add up to 5% ELT rubber, with respect to the aggregate weight, and still exceed the design strength without adding more cement or additives as other investigations. The use of Portland Pozzolana Cement, with local fly ash waste, contributes as well to the promissory results obtained.

scholarly journals A New Microstructure Development Model for the Evaluation of Concrete Setting Time

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Ho-Jin Cho ◽  
Joo-Won Kang ◽  
Yong Han Ahn ◽  
Sunkook Kim ◽  
Xiao-Yong Wang
Keyword(s):  
Construction Material ◽  
Setting Time ◽  
Volume Ratio ◽  
Point Of View ◽  
Development Model ◽  
Mineral Admixtures ◽  
Strength Development ◽  
Hydration Reaction ◽  
Design Strength ◽  
High Durability

Concrete is an exceptionally attractive construction material, with stable material supply, adequate fire resistance, and high durability. Its plasticity can be both an advantage and a disadvantage from an engineering point of view, providing versatile shapes via casting and hardening but also requiring a relatively long period of time to reach its design strength. The setting time, or hardening period, needed before the freshly poured concrete can carry a load, which begins once the hydration reaction has commenced, is a key parameter for durability since it directly affects cracking resistance in early-aged concrete. The new analysis technique for calculating setting time that was developed for this study utilizes both percolation theory and the strength development model. To verify the analytical results obtained using the new model, a critical volume ratio of hydrates was determined and a series of final setting times in concrete were experimentally investigated for different temperatures, mineral admixtures (FA: fly ash; GGBFS: ground granulated blast furnace slag), and a chemical admixture (superplasticizer). The results were found to be in good agreement with the model predictions, confirming its potential utility.

The Role of Economic Evaluation in Dissemination and Implementation Research

2017 ◽  
Author(s):  
Ramesh Raghavan
Keyword(s):  
Service Providers ◽  
Implementation Strategies ◽  
Cost Effective ◽  
Point Of View ◽  
Dissemination And Implementation ◽  
Economic Point ◽  
Open Questions ◽  
Public Health Organizations ◽  
Quality Health ◽  
Dissemination And Implementation Research

This chapter presents an overview of how D&I research can be evaluated from an economic point of view. Dissemination and implementation imposes costs upon knowledge purveyors, provider organizations, public health organizations, and payers (including governments). However, whether these added costs will result in improved service delivery and, perhaps more importantly, client outcomes and improvements in population health remain as open questions. If emerging studies reveal that defined implementation strategies are more cost effective than “usual” implementation, then policymakers and service providers will need to resource these added costs of implementation in order to assure the success and sustainability of high-quality health services over the long term.

scholarly journals End-of-Life Alternatives of Glass Reinforced Polyester Boat Hulls Compared by LCA

2018 ◽  
Vol 27 (4) ◽  
pp. 096369351802700 ◽  
Author(s):  
Mehmet Önal ◽  
Gökdeniz Neşer
Keyword(s):  
End Of Life ◽  
Environmental Impacts ◽  
Raw Materials ◽  
Weight Ratio ◽  
Cost Effective ◽  
Raw Material ◽  
Photochemical Oxidation ◽  
Human Toxicity ◽  
Vacuum Infusion ◽  
Infusion Method

Glass reinforced polyester (GRP), as a thermoset polymer composites, dominates boat building industry with its several advantages such as high strength/weight ratio, cohesiveness, good resistance to environment. However, proper recovering and recycling of GRP boats is became a current environmental requirement that should be met by the related industry. In this study, to propose in a cost effective and environmentally friendly way, Life Cycle Assessment (LCA) has been carried out for six scenarios include two moulding methods (namely Hand Lay-up Method, HLM and Vacuum Infusion Method, VIM) and three End-of-Life (EoL) alternatives(namely Extruding, Incineration and Landfill) for a recreational boat's GRP hulls. A case study from raw materials purchasing phase to disposal/recycling stages has been established taking 11 m length GRP boat hull as the functional unit. Analysis show that in the production phase, the impacts are mainly due to the use of energy (electricity), transport and raw material manufacture. Largest differences between the methods considered (HLM and VIM) can be observed in the factors of marine aquatic ecotoxicity and eutrophication while the closest ones are abiotic depletion, ozon layer depletion and photochemical oxidation. The environmental impact of VIM is much higher than HLM due to its higher energy consumption while vacuum infusion method has lower risk than hand lay-up method in terms of occupational health by using less raw material (resin) in a closed mold. In the comparison of the three EoL techniques, the mechanical way of recycling (granule extruding) shows better environmental impacts except terrestrial ecotoxicity, photochemical oxidation and acidification. Among the EoL alternatives, landfill has the highest environmental impacts except ‘global warming potential’ and ‘human toxicity’ which are the highest in extrusion. The main cause of the impacts of landfill is the transportation needs between the EoL boats and the licenced landfill site. Although it has the higher impact on human toxicity, incineration is the second cleaner alternative of EoL techniques considered in this study. In fact that the similar trend has been observed both in production and EoL phases of the boat. It is obvious that using much more renewable energy mix and greener transportation alternative can reduce the overall impact of the all phases considerably.

scholarly journals The Impact of Post-Manufacture Treatments on the Surface Characteristics Important for Finishing of OSB and Particleboard

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 975
Author(s):  
Antonio Copak ◽  
Vlatka Jirouš-Rajković ◽  
Nikola Španić ◽  
Josip Miklečić
Keyword(s):  
Water Vapour ◽  
Oriented Strand Board ◽  
Construction Material ◽  
Surface Characteristics ◽  
Surface Treatments ◽  
Factors Affecting ◽  
Treatment Conditions ◽  
Water Vapour Absorption ◽  
The Impact

Oriented strand board (OSB) is a commonly used structural wood-based panel for walls and roof siding, but recently the industry has become interested in OSB as a substrate for indoor and outdoor furniture. Particleboard is mainly used in furniture productions and has become popular as a construction material due to its numerous usage possibilities and inexpensive cost. Moisture is one of the most important factors affecting wood-based panel performance and the post-treatment conditions affected their affinity to water. When OSB and particleboard are used as substrates for coatings, their surface characteristics play an important role in determining the quality of the final product. Furthermore, roughness can significantly affect the interfacial phenomena such as adsorption, wetting, and adhesion which may have an impact on the coating performance. In this research particleboard and OSB panels were sanded, re-pressed and IR heated and the influence of surface treatments on hardness, roughness, wetting, water, and water vapour absorption was studied. Results showed that sanding improved the wetting of particleboard and OSB with water. Moreover, studied surface treatments increased water absorption and water penetration depth of OSB panels, and re-pressing had a positive effect on reducing the water vapour absorption of particleboard and OSB panels.

scholarly journals Determinants of Corporate Anti-Corruption Disclosure: The Case of the Emerging Economics

2021 ◽  
Vol 13 (6) ◽  
pp. 3462
Author(s):  
Maider Aldaz Odriozola ◽  
Igor Álvarez Etxeberria
Keyword(s):  
Empirical Studies ◽  
Geographical Area ◽  
Control Variable ◽  
Emerging Countries ◽  
Point Of View ◽  
Press Freedom ◽  
Negative Effects ◽  
Key Factor ◽  
Using Data ◽  
Positive Effect

Corruption is a key factor that affects countries’ development, with emerging countries being a geographical area in which it tends to generate greater negative effects. However, few empirical studies analyze corruption from the point of view of disclosure by companies in this relevant geographical area. Based on a regression analysis using data from the 96 large companies from 15 emerging countries included in the 2016 International Transparency Report, this paper seeks to understand what determinants affect such disclosure. In that context, this paper provides empirical evidence to understand the factors that influence reporting on anti-corruption mechanisms in an area of high economic importance that has been little studied to date, pointing to the positive effect of press freedom in a country where the company is located and with the industry being the unique control variable that strengthens this relationship.

scholarly journals Lower Limb Kinematics in Individuals with Hip Osteoarthritis during Gait: A Focus on Adaptative Strategies and Interlimb Symmetry

2021 ◽  
Vol 8 (4) ◽  
pp. 47
Author(s):  
Micaela Porta ◽  
Massimiliano Pau ◽  
Bruno Leban ◽  
Michela Deidda ◽  
Marco Sorrentino ◽  
...  
Keyword(s):  
Lower Limb ◽  
Functional Limitations ◽  
Hip Osteoarthritis ◽  
Movement Analysis ◽  
Human Movement ◽  
Point Of View ◽  
Negative Effects ◽  
Gait Patterns ◽  
Limb Kinematics

Among the functional limitations associated with hip osteoarthritis (OA), the alteration of gait capabilities represents one of the most invalidating as it may seriously compromise the quality of life of the affected individual. The use of quantitative techniques for human movement analysis has been found valuable in providing accurate and objective measures of kinematics and kinetics of gait in individuals with hip OA, but few studies have reported in-depth analyses of lower limb joint kinematics during gait and, in particular, there is a scarcity of data on interlimb symmetry. Such aspects were investigated in the present study which tested 11 individuals with hip OA (mean age 68.3 years) and 11 healthy controls age- and sex-matched, using 3D computerized gait analysis to perform point-by-point comparisons of the joint angle trends of hip, knee, and ankle. Angle-angle diagrams (cyclograms) were also built to compute several parameters (i.e., cyclogram area and orientation and Trend Symmetry) from which to assess the degree of interlimb symmetry. The results show that individuals with hip OA exhibit peculiar gait patterns characterized by severe modifications of the physiologic trend at hip level even in the unaffected limb (especially during the stance phase), as well as minor (although significant) alterations at knee and ankle level. The symmetry analysis also revealed that the effect of the disease in terms of interlimb coordination is present at knee joint as well as hip, while the ankle joint appears relatively preserved from specific negative effects from this point of view. The availability of data on such kinematic adaptations may be useful in supporting the design of specific rehabilitative strategies during both preoperative and postoperative periods.

scholarly journals Comparison between Concentrated Solar Power and Gas-Based Generation in Terms of Economic and Flexibility-Related Aspects in Chile

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1063
Author(s):  
Catalina Hernández Moris ◽  
Maria Teresa Cerda Guevara ◽  
Alois Salmon ◽  
Alvaro Lorca
Keyword(s):  
Natural Gas ◽  
Solar Power ◽  
Renewable Energy Sources ◽  
Cost Effective ◽  
Hybrid Plant ◽  
Point Of View ◽  
Concentrated Solar Power ◽  
Economic Point ◽  
Hybrid Plants ◽  
Cost Of Energy

The energy sector in Chile demands a significant increase in renewable energy sources in the near future, and concentrated solar power (CSP) technologies are becoming increasingly competitive as compared to natural gas plants. Motivated by this, this paper presents a comparison between solar technologies such as hybrid plants and natural gas-based thermal technologies, as both technologies share several characteristics that are comparable and beneficial for the power grid. This comparison is made from an economic point of view using the Levelized Cost of Energy (LCOE) metric and in terms of the systemic benefits related to flexibility, which is very much required due to the current decarbonization scenario of Chile’s energy matrix. The results show that the LCOE of the four hybrid plant models studied is lower than the LCOE of the gas plant. A solar hybrid plant configuration composed of a photovoltaic and solar tower plant (STP) with 13 h of storage and without generation restrictions has an LCOE 53 USD/MWh, while the natural gas technology evaluated with an 85% plant factor and a variable fuel cost of 2.0 USD/MMBtu has an LCOE of 86 USD/MWh. Thus, solar hybrid plants under a particular set of conditions are shown to be more cost-effective than their closest competitor for the Chilean grid while still providing significant dispatchability and flexibility.

Experimental evaluation on engineering properties and microstructure of the high-performance fiber-reinforced mortar with low polypropylene fiber content

2021 ◽  
Vol 72 (7) ◽  
pp. 824-840
Author(s):  
Hung Vu Viet ◽  
Cuong Nguyen Tuan ◽  
Duy Nguyen Huu ◽  
Tho Ngo Nguyen Ngoc ◽  
Phuoc Huynh Trong
Keyword(s):  
High Performance ◽  
Polypropylene Fiber ◽  
Cost Effective ◽  
Fiber Content ◽  
Engineering Properties ◽  
Fiber Reinforced ◽  
Cement Mortars ◽  
High Performance Fiber ◽  
New Construction ◽  
Local Materials

Recently, high-performance fiber-reinforced mortar/concrete (HPFRM) has been researched and developed in many fields such as repair, maintenance, and new construction of infrastructure works due to its high strain capacity and tight crack width characteristics. Optimizing the design of mixture proportions and structures using HPFRM is still a complex mechanical and physical process, depending on the design principles, specific site conditions, and their local materials. This study aims to develop an HPFRM with low polypropylene fiber content by using locally available ingredients in Southern Vietnam to address the deficiencies commonly observed in traditional cement grout mortars. Three mixture proportions were prepared with different water-to-binder (w/b) ratios of 0.2, 0.25, and 0.3. Then, the performance of HPFRM was evaluated in both fresh and hardened stages. Additionally, the microstructural characteristics of each mix design were also assessed through scanning electron microscope observation. The experimental results showed that the optimum w/b of 0.25 and a fixed dosage of 0.6% polypropylene fiber produced positive impacts on the rheological, mechanical properties, and also ductility of the high-performance mortar. It was concluded that HPFRMs are promising for cost-effective and sustainable cement mortars.

Clinical Profile and Prediction of Response to Treatment in Childhood Epilepsy - A Single-Centre Experience from Eastern India

2021 ◽  
Vol 8 (15) ◽  
pp. 977-981
Author(s):  
Prakash Chandra Ghosh ◽  
Mitali Bera ◽  
Punyabrata Barma ◽  
Arijit Roy ◽  
Sananda Majumder ◽  
...  
Keyword(s):  
Management Strategies ◽  
Poor Response ◽  
Cost Effective ◽  
Point Of View ◽  
Clinical Profile ◽  
Response To Treatment ◽  
Childhood Epilepsy ◽  
Primary Health Centres ◽  
Single Centre Experience ◽  
Active Epilepsy

BACKGROUND Though epilepsy remains a significant problem for children and adolescents in our country, studies delineating the clinical profile and response to treatment in childhood epilepsy are lacking. The current study was carried out for obtaining a baseline profile and to predict the response to treatment in childhood epilepsy in India that may be helpful in planning management strategies from a public health point of view. METHODS Patients with clinical suggestion of active epilepsy (N = 141) from one month to 12 years, were enrolled into the study over a period of 1 year (February 2010 to January 2011) from the out-patient department and epilepsy clinic of Bangur Institute of Neurology. Detailed history was taken along with neurological examination. Electroencephalography (EEG) and neuroimaging (MRI / CT scan) were done on all patients. Each patient included in the study was kept in followup for a period of 6 months and their response to the treatment was recorded. RESULTS About 48.9 % (N = 69) patients had localisation related epilepsy while the rest had generalised epilepsy. Of those with generalised epilepsy, generalised tonicclonic seizures (GTCS) was by far the most common type. Of those with focal EEG activity, the highest proportion (50 %), were localised to the temporal lobe. Symptomatic aetiology accounted for 59.6 % (N = 84) of the patients. 20.6 % (N = 29) had poor response to treatment at 6 months follow-up. Abnormal neuroimaging (OR = 6.708) and abnormal EEG (OR = 6.357) were effective factors in predicting poor response to treatment. CONCLUSIONS Our study highlights the need to link specialised epilepsy services with primary health centres for early detection and treatment. EEG is an essential cost-effective modality in determining seizure localisation and response to treatment. KEYWORDS Paediatric, Epilepsy, Clinical Profile, Response to Treatment

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