bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of sterilization treatment on mechanical properties, biodegradation, bioactivity and printability of GelMA hydrogels
Authors: Rizwan Muhammad , Chan Sarah W , Comeau Patricia A , Willett Thomas L , Yim Evelyn K F 
Published: July 2020

Abstract
Gelatin methacryloyl (GelMA) hydrogel scaffolds and GelMA-based bioinks are widely used in tissue engineering and bioprinting due to their ability to support cellular functions and new tissue development. Unfortunately, while terminal sterilization of the GelMA is a critical step for translational tissue engineering applications, it can potentially cause thermal or chemical modifications of GelMA. Thus, understanding the effect of terminal sterilization on GelMA properties is an important, though often overlooked, aspect of material design for translational tissue engineering applications. To this end, we characterized the effects of FDA-approved terminal sterilization methods (autoclaving, ethylene oxide treatment, and gamma (γ)-irradiation) on GelMA prepolymer (bioink) and GelMA hydrogels in terms of the relevant properties for biomedical applications, including mechanical strength, biodegradation rate, cell culture in 2D and 3D, and printability. Autoclaving and ethylene oxide treatment of the GelMA decreased the stiffness of the hydrogel, but the treatments did not modify the biodegradation rate of the hydrogel; meanwhile, γ-irradiation increased the stiffness, reduced the pore size and significantly slowed the biodegradation rate. None of the terminal sterilization methods changed the 2D fibroblast or endothelial cell adhesion and spreading. However, ethylene oxide treatment significantly lowered the fibroblast viability in 3D cell culture. Strikingly, γ-irradiation led to significantly reduced ability of the GelMA prepolymer to undergo sol–gel transition. Furthermore, printability studies showed that the bioinks prepared from γ-irradiated GelMA had significantly reduced printability as compared to the GelMA bioinks prepared from autoclaved or ethylene oxide treated GelMA. These results reveal that the choice of the terminal sterilization method can strongly influence important properties of GelMA bioink and hydrogel. Overall, this study provides further insight into GelMA-based material design with consideration of the effect of terminal sterilization.
Late Neolithic and Chalcolithic maritime resilience? The 4.2 ka BP event and its implications for environments and societies in Northwest Europe
Authors: Kleijne Jos , Weinelt Mara , Müller Johannes 
Published: July 2020

AbstractThis paper deals with prehistoric communities at the end of the 3rd millennium BC in Northwest Europe in relation to the 4.2 ka BP climatic event. In particular, the question of the resilience of these communities to climatic change will be studied here by comparing various climatic records and analysing specific archaeological parameters for social and cultural change. These parameters include the duration and intensity of settlement occupation, the variability of subsistence activities (e.g.cereal cultivation, animal husbandry, hunting, fishing, and gathering) and the connectedness of communities within exchange networks. Rather than answering the often-asked yes/no question with regard to human–environment relations, our research asks what effect resulted from the 4.2 ka BP climatic event, and, from the perspective of resilience, how did communities adopt to these changes in their practices and cultural choices during the later 3rd millennium BC.In short, we maintain that climate change took place at the end of the 3rd millennium BC, but the changes in humidity and temperature with their effects on vegetation were probably regionally varied across Northwest Europe. We also observe that the studied communities developed differently during the second half of the 3rd millennium BC. On the one hand, we identify new food storage and house building techniques in the Low Countries and Schleswig-Holstein and, on the other hand, substantiate population decrease on the Orkney Islands around 2300 BC. Finally, we note a development of the Bell Beaker phenomenon into an Early Bronze Agemaritoryof connected communities across the North Sea, in which these communities expressed their resilience to climate change.
Fuzzy node flow analysis of water distribution networks using Jaya algorithm
Authors: Sreethu S , Gupta Rajesh 
Published: July 2020

Abstract
Fuzzy analysis helps in understanding how the uncertainty in various independent parameters of water distribution network such as, nodal demands, pipe roughness values, reservoir heads, pipe diameters and so forth will affect the dependent parameters such as pipe velocities, discharges and nodal pressures. The membership functions of dependent parameters are obtained by considering membership functions of uncertain independent parameters. The Impact Table method from literature suggests a repetitive analysis by considering the monotonous relationship between dependent and independent parameters. The Impact Table method was also employed for carrying out fuzzy analysis under pressure deficient condition to obtain fuzzy membership function of nodal outflows. Optimization based methods of fuzzy analysis are more useful when relationship between dependent and independent parameters are non-monotonous. A novel algorithm, Jaya is used in this study for performing fuzzy analysis on a benchmark network by pressure dependent approach. The analysis is performed by setting up hydraulic model in the software EPANET and linking it with the MATLAB for performing optimization through an EPANET-MATLAB toolkit. The propagation of the uncertainties of the input parameters for some non-linear hydraulic responses were identified and the algorithm was found to be a powerful tool for optimization.
Incorporation of non-stationarity in precipitation intensity-duration-frequency curves for Kerala, India
Authors: Soumya R , Anjitha U G , Mohan Smitha , Adarsh S , Gopakumar R 
Published: July 2020

AbstractIntensity-Duration-Frequency (IDF) curve is an essential hydrologic tool used for the design of hydraulic infrastructure. In a changing climate scenario, the assumption of a static return period of precipitation extremes is not valid; the under-estimation of rainfall intensity values may lead to the failure of critical infrastructure. This paper is focused on identifying the extent of non-stationary behaviour at different locations in Kerala. The annual maxima rainfall data prepared from daily time series was idealized into non-stationary Generalized Extreme Value (GEV) distributions, with time-varying parameters after rainfall disaggregation operation. Non-stationary rainfall intensities were estimated using different non-stationary models, and the best model was identified using Akaike Information Criteria (AIC). From the analysis using station-wise data, it was found that districts including Palakkad, Malappuram, Idukki and Pathanamthitta were experiencing significant non-stationarity in extreme precipitation events. Non-stationary rainfall extremes were concentrated at Eastern regions of Kerala compared to coastal and midlands of Kerala.
Partitioning behaviour of heavy metals in Ashtamudi estuary, india
Authors: Manaf Febina A , Priya K L 
Published: July 2020

Abstract
The pH, salinity, SSC and variations of heavy metals were studied for Ashtamudi estuary during the pre-monsoon period of 2019. Both pH and salinity decreased from the mouth of the estuary, while SSC exhibited a higher value within 4 to 10 Kms from the estuarine mouth. Concentrations of Fe, Cr, Cu, Zn and Ni decreased from the mouth towards the head of the estuary. Among which both Fe and Cr showed higher concentrations within 4 to 10 Kms. Variation of the distribution coefficients (Kd) of trace metals with pH, salinity and suspended sediments indicated lower values for Fe, Cr and Zn at the locations 2 and 3, . As the dissolved concentrations of Fe and Cr showed higher values at locations with higher SSC, adsorption and desorption studies were performed using sediments at those locations. Adsorption studies on Fe indicated higher adsorption at higher salinity values, while for Cr, the adsorption decreased with salinity. Kinetic adsorption and desorption studies for Fe and Cr indicated that the adsorption rates of Fe and Cr approached equilibrium after 2 hours and 1.5 hours respectively, while the desorption rates did not exhibit an equilibrium within the experiment duration. The results of kinetic sorption and desorption studies conducted for Fe and Cr exhibiting higher rate of adsorption for Fe and lower rate of adsorption for Cr at higher salinities, were in agreement with the higher Kd values of Fe and lower Kd values of Cr obtained from the field analysis.
Seismic analysis of plan irregular RC building frames
Authors: Krishnan P A , Thasleen N 
Published: July 2020

Abstract
The presence of irregularity in buildings is a matter of concern when it is subjected to devastating earthquakes. A sudden change in vertical or plan configuration in buildings tends to weaken the structure. To prevent failure and minimize the hazard potential of irregular buildings, the responses of such buildings to lateral loads have to be studied in detail. In this paper, the responses of irregular buildings are analyzed using Pushover analysis. 10 re-entrant corner models are analyzed to study their effect as per IS 1893 (Part 1): 2016 codal provisions. The analytical tools used include ETABS v 16.2.0 software and SeismoMatch 2018 software. The parameters considered in this study are storey displacement, stress concentration and performance levels. Strengthening techniques to strengthen vulnerable models are also discussed. The results obtained are compared with that of a regular structure.
A simplified procedure for the seismic analysis of RC moment resisting setback frames
Authors: Akhil S , Sajeeb R 
Published: July 2020

Abstract
Irregularity in elevation of buildings is increasingly popular in modern urban construction. One of the prominent forms of vertically irregular frames is the setback building frames. The seismic performance of buildings with irregular distribution of mass, stiffness, and strength along the height may be significantly different from that of regular buildings. The present paper focuses on quantification of irregularity and studying the effect of irregularity on the seismic performance of setback building frames. An index namely Geometric Regularity Index (GRI), calculated based on the geometric parameter of the building frame, is proposed in the study to quantify the vertical irregularity of setback building frames. 55 numbers of 3 bay frames with stories 5, 7, 9, 11 and 13, with varying levels of irregularity, are considered in the study. Linear dynamic analysis of the frames is performed in ETABS using response spectrum method. The proposed index is correlated with the actual seismic response of the structure such as base shear and overturning moment. Based on the results of analysis, a simple method which employs the GRI of the frame is proposed to estimate the seismic responses such as base shear and overturning moment at the base. The proposed method is found to estimate the seismic response of setback frames with reasonable accuracy.
A new ground motion prediction model for Northeast India (NEI) shallow crustal
Authors: Rahman T , Nunia Bindesh 
Published: July 2020

Abstract
In this paper, a new ground-motion prediction model (GMPE) for North-eastern India (NEI) is developed based on the available recorded events. NEI has already faced several high magnitude earthquakes (moment magnitude [Mw
]>7.0) during the period 1200 to 2018. It is difficult to develop GMPE and estimating the seismic hazard of NEI, due to sparse recorded strong motion database. To date, seismic hazard maps for NEI have not been prepared. All developed countries have developed seismic hazard maps for their cities using region-specific GMPE. So, to prepare the seismic hazard maps of NEI, a ground motion prediction model will be required. The success of earthquake hazard mitigation depends to a large extent on how accurately the ground motion hazard can be estimated at a vulnerable site. The GMPE developed in this study has been compared with other ground-motion models as well as with the available limited recorded strong motion database. Based on the comparison, it is observed that the new model is reasonably correct as the model is unbiased with respect to both magnitude and hypocentral distance. This model needs to be upgraded as and when more recorded strong ground motion database is available for this region.
A numerical study of fiber reinforced polymer laminate plates
Authors: Cisily Thomas Priscila , Bindu S 
Published: July 2020

Abstract
Layered composites are used in various engineering fields like the aircraft, marine, automotive, sports and health sectors. The widespread use of these materials can be attributed to its high stiffness, high strength-to-weight ratio, and ease of installation. Among the various layered composites, fiber-reinforced polymers (FRP) laminates have high strength and stiffness of its constituent fibers and low-density due to its matrix properties. FRP laminate consists of unidirectional plies that can be tailor-made to achieve desirable performance. The demand for layered composite materials has driven the need for development of efficient analytical tools for accurate prediction of its performance. The present paper provides an insight into the analysis of a laminate plate. The effect of the number of layers, aspect ratio and the stacking sequence on the transverse deformation of a laminate plate under bending is analyzed. It is observed that the transverse deflection of the plate decreases with an increase in the number of layers. Also, the increase in aspect ratio leads to an increase in the deformation of the plates.
Study of the mechanical and corrosion resistance properties of ferrocement
Authors: Sneha S S , Soman Karthika , Prajith C , Davis Aiswaria K , Dhanya B S 
Published: July 2020

Abstract
Ferrocement is a lightweight, homogeneous and versatile structural material which is made as a composite of wire mesh and tightly wound skeletal steel impregnated with cement mortar. Ferrocement excels reinforced concrete system because of the minimal formwork and scaffolding requirement, possibility of casting elements on ground at site, fast erection and decrease in time of construction, and savings in the overall cost. Even though ferrocement has been used for various applications since 1800s, the technology is not properly standardized and unconventional local construction practices continue to prevail. Due to this and the poor workmanship, the durability of ferrocement structures has become an issue. Factors such as the corrosion of mesh and or the skeletal reinforcement, improper mix design etc. lead to deterioration of ferrocement structures. The major corrosion prevention methods used in reinforced concrete systems are application of coating to the steel such as epoxy or cement polymer composite (CPC) coatings and use of corrosion inhibitor in the cementitious matrix. The present study evaluates the possibility of adoption of these corrosion prevention strategies in ferrocement. The objective of the study is to analyse the flexural and corrosion resistance behaviour of four different types of ferrocement systems. The systems studied include ferrocement with normal welded mesh in normal cement mortar(WM); CPC coated weld mesh in normal cement mortar (CPC); normal weld mesh in cement mortar with corrosion inhibitor (WM CI); and CPC coated weld mesh in cement mortar with corrosion inhibitor (CPC CI). The corrosion analysis is done by using half cell potential measurements following ASTM C876-15 and flexural analysis by flexural strength test following IS 516: 1959. The results indicate that usage of both corrosion inhibitor and CPC coating can prominently increase the durability of ferrocement structures.
Evaluation of the mechanical performance of M25 grade recycled aggregate concrete
Authors: Dhanya B S , Koshy Bino I , Jisha K V , Jayamohanan Aisu , Mathew Neethu 
Published: July 2020

Abstract
Recycling, sustainability and environmental stewardship are some of the concepts that are in the front line now-a-days. Some strategies that can be adopted in order to bring these concepts in to the construction processes are the efficient use of materials, use of recycled materials, reduction in the waste materials produced etc. Use of recycled concrete aggregates as a substitute for natural (virgin) aggregates is a way to bring in these concepts into the manufacture of concrete. An experimental investigation was conducted to assess the effect of replacement of normal coarse aggregate with recycled coarse aggregate (prepared from old concrete specimens) on M25 grade concrete. Different levels of replacements studied include 0%, 20%, 50%, 80% and 100% were considered. The properties studied are fresh properties as well as mechanical properties which include compressive strength, split tensile strength and flexural strength. It is concluded from the study that as the RCA content increases, it is necessary to increase the cement content and or to decrease the water cement ratio in order to attain target compressive strength.
Effect of hybrid fibres on the mechanical properties of high performance concrete
Authors: SulphiaBeevi U , Joseph Anitha , Nazeer M 
Published: July 2020

Abstract
Fibre reinforcement is a technique used to provide toughness and ductility to brittle cementitious matrices. Reinforcement of concrete using a single type of fibre could improve the properties to a limited level. A hybrid composite refers to two or more types of fibres that are rationally combined to produce a composite that stems benefits from each of the individual fibres and exhibits a synergetic response. This study intends to illustrate and quantify the mechanical properties of Hybrid Fibre Reinforced Concrete. For this purpose, a reference High Performance Concrete (HPC) of grade M65 with water-binder ratio of 0.34 was used. Specimens of plain concrete mix, HPC with silica fume, Steel Fibre Reinforced High Performance Concrete (SFRHPC) containing only steel fibres, and Hybrid Fibre Reinforced High Performance Concrete (HFRHPC) containing steel fibres and carbon fibres were prepared. Optimum amount of silica fume was taken as 12.5%. The crimped steel fibre was added initially at 0.25%, 0.5%, 0.75%, 1% and 1.25% by weight of concrete and its optimum percentage was found out. Once the optimum dosage of crimped steel fibre was obtained, carbon fibre was used to replace the optimum steel fibre dosage at 25%, 50%, 75% and 100% by volume fraction. Thus an optimum hybrid fibre dosage was obtained. The mechanical properties of the HFRHPC like compressive strength, flexural strength, splitting tensile strength, modulus of elasticity and impact resistance were studied and compared with HPC mix. The results revealed that the addition of steel fibre improved all the mechanical properties of concrete.
Strength of concrete with wood ash and waste glass as partial replacement materials
Authors: Thomas Anu V , Ramaswamy K P , Nair Adarsh , Padmanabhan R , Isac Tom K , Anilkumar Vishnu 
Published: July 2020

Abstract
This paper discusses a study on the use of wood ash as partial replacement of cement and waste glass as partial replacement of fine aggregate in concrete. Wood ash was used to replace cement at 5% and 10% and waste glass was used to replace fine aggregate at 10% and 15%. When wood ash was added to concrete, the compressive strength of concrete was found to reduce marginally with respect to the reference mix and the optimal value of compressive strength was obtained at 5% replacement. Addition of waste glass to replace fine aggregate resulted in marginal reduction of compressive strength of concrete at 10% replacement. However, a drastic reduction in compressive strength was observed at 15% replacement level of waste glass. Replacing 5% of cement with wood ash and 10% of fine aggregate with waste glass yielded satisfactory results and thereby at these replacement levels, wood ash and waste glass can be used as replacement materials in concrete. Incorporating the waste materials in concrete will be an efficient and effective way to dispose these materials and will result in lower consumption of natural materials in the manufacturing process of concrete thereby resulting in an environment friendly and cheaper concrete.
Effects of slag and superplasticizers on alkali activated geopolymer paste
Authors: Raju Thushara , Ramaswamy K P , Saraswathy B 
Published: July 2020

Abstract
Geopolymers are a type of amorphous alumino-silicate product, and can be synthesised by the polycondensation reaction of geopolymeric precursor and alkali polysilicates. The binder is prepared by the alkaline activation of industrial by-product materials like fly ash, slag, metakaolin, rice husk ash, etc. as a source for aluminosilicate. The most commonly used alkaline activator is the combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Chemical admixtures are indispensable in alkali activated systems owing to its poor fresh properties such as workability, too quick setting etc. In this study, the chemical admixture – alkali activated binder interactions were carried out by using latest generation superplasticizers, such as Polycarboxylic ether admixture (PCE) and Sulphonated naphthalene formaldehyde (SNF). Mini slump test, initial and final setting time tests were conducted in alkali activated slag blended fly ash based geopolymer paste and the test results were analyzed with respect to parameters such as alkali to binder ratio (a/b), proportion of slag in blended geopolymer paste, type and dosage of superplasticizers. The test results indicated that the workability and setting time of alkali activated geopolymer paste enhanced due to the increase in alkali content and the reduction in slag content. Based on the effect of chemical admixtures in geopolymer mix, SNF performed better than PCE admixture with regards to mini slump test for all the mixes; whereas in the case of setting time test, SNF showed better results only for the mix with 100% slag. In the case of slag blended fly ash based geopolymer paste, both PCE and SNF showed similar effects, and also it was observed that, the flow of the paste got enhanced when the dosage of superplasticizers is increased from 0 to 3% by weight of binders.
Effect of superplastizicer type on the fresh and strength properties of alkali activated slag composites
Authors: Muhammed Nabil K , Namitha S , Sundhar Reshma , Mohammed Rafeeque N V , Raju Thushara , Ramaswamy K P 
Published: July 2020

Abstract
Nowadays, the demand for green concrete has increased due to the greenhouse gas emissions and uncontrolled pollution from the cement industry. At the same time, the green concrete should exhibit better mechanical properties and durability characteristics when replacing conventional concrete without compromising on the fresh properties. A better solution for the production of green concrete is to use air cured Alkali Activated Slag (AAS) composites, an innovative and sustainable binding material with very low carbon footprint. However, AAS exhibits demerits such as quick setting and poor workability and this demands the use of superplasticizers in such binder systems which are less explored thus far. Hence, this paper presents a study on the influence of superplasticizer type on the fresh and strength properties of AAS mortar. Paste/mortars were prepared with alkali activators composed of sodium silicate and sodium hydroxide and tested to study the setting times, workability, and evolution of compressive strength. It is found that the fresh properties are improved by increasing the alkali to binder ratio and the dosage of superplasticizer. Both sulphonated naphthalene formaldehyde (SNF) and polycarboxylate ether (PCE) based admixtures were found to be effective in alleviating the negatives of air cured alkali activated paste/mortar systems.