Development of Regression Models for Predicting Properties of High Strength Concrete Using Nondestructive Tests

High strength concrete (HSC) is a relatively recent development in concrete technology. It is being used increasingly in major civil engineering and building projects. This leads to the need for quality assurance of the in-situ concrete. Testing of concrete traditionally involved compression testing of cylinders or cubes to obtain the properties and these may not adequately represent the in-situ properties of concrete. This necessitates the use of non-destructive test (NDT). There are no standard relationships that had been established for high strength concrete physical and mechanical properties using Sclerometer test, Ultrasonic Pulse Velocity (UPV) methods and Pullout test. Prediction models need to be developed for concrete strength, density and static elastic modulus estimation. They are normally required in building or structural assessment, especially with the present trend of constructing modern structures using high strength concrete. Eight different mix proportions of HSC containing sandstone aggregate of nominal sizes of 10mm and 19mm and silica fume content were investigated in this study.The silica fume contents were varied at 0%, 5%, 10% and 15%. These mixes produced concrete at 28-day strength between 40 MPa to 100 MPa. A total of 360 standard cubes (150mm), 144 cylinders (150 x 300mm) and 16 reinforced beams were cast for this study. A total of forty-five standard cube specimens for each mix were tested at the age of 3, 7, 14, 28 and 56 days in both, nondestructive and destructive manner. On the other hand, eighteen cylinder specimens for each mix were tested at the age of 28 and 56 days in both, nondestructive and destructive manner. As for the pullout test some forty-five inserts were prepared for each mix at the age of 3, 7, 14, 28 and 56 days. For each destructive test, an average of 45 values of nondestructive tests was obtained, which depends on the type of NDT techniques used. The results were analyzed using statistical tools (SPSS ver.13). The prediction models for each NDT technique were developed based on the obtained experimental results. Statistical tests of significance on the predicted models were performed to ascertain their reliability in estimating the concrete properties. Predicted models were also further validated using data from other researchers. The models developed in this study are expected to be used to estimate strength, density and static elastic modulus parameters using Sclerometer test, UPV method and Pullout test. The generalized power models for strength, density and modulus of elasticity prediction using Sclerometer and Pullout test were found to be unaffected by the aggregate sizes. The maximum error of these models were found to be ±12.5% for strength-Sclerometer test, ±25% for strength-Pullout test, ±3% for density-Sclerometer test, ±2% for density-Pullout test and ±5% for static elastic modulus-Sclerometer test.Strength, density and static modulus of elasticity prediction for direct and indirect UPV methods indicated that aggregate sizes should be known in advance. Generalized quadratic models were proposed for concrete mix with nominal aggregate size 10mm (series A10) for strength, density and modulus of elasticity prediction using UPV direct method. The maximum error of these models was found to be ±20% for strength, ±3% and ±5% for density and static modulus of elasticity respectively. A linear model for strength, a power model for density and a logarithmic model for static elastic modulus was proposed for 19mm maximum aggregate size. The quadratic models are valid for pulse velocity range between 4.7 to 6.1 km/sec and the other models are 4.3 to 5.5 km/sec. All of these models are found to be capable of predicting strength between 30 to 110 MPa, density between 2320 to 2525 kg/m3 and static elastic modulus between 28 to 40 GPa. Combined NDT methods were found to improve some of strength prediction. Statistical significant tests on the prediction models have been carried out to ascertain their reliability in estimating strength, density and static elastic modulus properties of concrete. Moreover, validation of the predicted models with other researchers further enhances reliability of each model. Thus, the proposed models for different NDT techniques can be used as a practical guide in the assessment of in-situ concrete properties

Effectiveness Of Ultrasonic Pulse Velocity And Impact- Echo Ndt Techniques To Assess The Quality Of Concrete

The deterioration of concrete in structure is a result of several internal or external degradation mechanism and which results in distress of the structure i.e. decrease in strength and integrity of the structure. The state of distress is often hidden from view and is only evident at a stage where there is significant reduction in strength of the structure. Defects are often introduced during construction and are viewed during in-service life. Some deterioration is viewed physically in the early age or during the service life of the structure in terms of spalling, surface crack, swelling and honeycombing. This deterioration collectively or individually results in reducing the load carrying capacity in terms of the distress of the structure. In this project, the common defects in the concrete structures and mapping techniques by nondestructive test are presented. Among the various techniques of the nondestructive tests, the Ultrasonic Pulse Velocity (UPV) and DOCtor's Impactecho were chosen for their effectiveness. The UPV is used to estimate the concrete strength, detecting flaws such as voids and cracks and also to investigate the effects of smaller diameter bar in the concrete. In detecting various sizes of voids by the Impact-echo test techniques a format was suggested to identify them from the frequency spectrum

A prospective study on prevalence and characteristics of hematologic effects associated with subclinical hypothyroidism

Background: Distinctive types of iron deficiency have been accounted for patients with obvious hypothyroidism with a predominance of up to 47%. Regardless of the fact that vitamin B12, folic corrosive and iron fixations are ordinary, weakness that standardizes in light of thyroxine substitution is found in up to 25% of hypothyroid patients.Methods: Briefly, 50 women with SCH were enrolled in the study. Patients between 18 and 65 years old, with TSH levels more than 5.0 mIU/L, the patients selected has a history of hypothyroidism for more than a year and were on oral levothyroxine. A total of 50 participants were enrolled in the study. Blood samples were collected from 50 selected hypothyroid patients on the basis of a history of a hypothyroidism, persistent Anemia, of these patients all were females.Results: In present study 25 cases of age group 41-65 years  there were almost 10 patients having high thyroid stimulating factor (Tsh) that is more than (0.3-5.0U/Ml), Constitute to be 40% cases in this age category. Hence patients with high age may slower the response towards a levothyroxine hormone and hence have the high risk of developing anemia.Conclusions: Thyroid dysfunctions have an immediate impact on hemoglobin levels and these progressions should be considered in therapeutic consideration by medical practitioner

False data injection attack (FDIA): An overview and new metrics for fair evaluation of its countermeasure

The concept of false data injection attack (FDIA) was introduced originally in the smart grid domain. While the term sounds common, it specifically means the case when an attacker compromises sensor readings in such tricky way that undetected errors are introduced into calculations of state variables and values. Due to the rapid growth of the Internet and associated complex adaptive systems, cyber attackers are interested in exploiting similar attacks in other application domains such as healthcare, finance, defense, governance, etc. In today’s increasingly perilous cyber world of complex adaptive systems, FDIA has become one of the top-priority issues to deal with. It is a necessity today for greater awareness and better mechanism to counter such attack in the cyberspace. Hence, this work presents an overview of the attack, identifies the impact of FDIA in critical domains, and talks about the countermeasures. A taxonomy of the existing countermeasures to defend against FDIA is provided. Unlike other works, we propose some evaluation metrics for FDIA detection and also highlight the scarcity of benchmark datasets to validate the performance of FDIA detection techniques. [Figure not available: see fulltext.] © 2020, The Author(s)

Dynamic Workload Management in Hybrid Cloud Computing

The main core part of this hybrid computing model, a very intelligent or skilled workload managing service has been designed for better throughput of proactive workload management. It allows a collaboration between on- and off-premise clouds structures for hosting Internet-based applications for clients in the organization, also its main striking feature lies in the explicit segregation of its modules like base workload and flash crowd workload, The main benefit of this application is that its service uses a very fast frequent data item detection algorithm, which allows the application to be robust and very fast processing of large volume of data. In this project we are going to demonstrate that off premise cloud is much better than a wide range of utilization administrations and particularly we can demonstrate it for both open and private mists. On reason implies on area, though off premise implies remote (in the cloud). Case in point if an application keeps running on an on-reason server it implies the server is physically in the organization. In the event that you have an off reason arrangement it\u27s facilitating in the cloud or unified area

Vibrant Producers Group is the Key Instrument to Bring Prosperity of the Marginal Producers in Agricultural Sector: Experience Capitalization of Samriddhi Project

Producers of the agricultural sectors are the key instrument for the economic development of Bangladesh. A subsequent number of total agro productions of this country come from individual rural producers. However this contribution can be accelerated if those individual producers can effectively participate in the value chain of agro market. So the milestone of being successful participant in this process is the formation of group producing. This study has been conducted on Bangladesh perspective for analyzing the problems of individual producers and their success rate after forming producer group. To find a justified result the study has conducted based on both primary and secondary data. As a representative area Sunamganj district has been selected to collect primary data. Because, as an agro producing region this district is contributing a vital part in Bangladesh and most of the producers in this area are individual producer. So it can represent the real scenario of individual production and the afterward result of group production. The discussion of this research is centered on the problems of individual producers like insufficient and poor quality of production; high transportation cost; less access to technology, business and financial services; less access to market information about price and demand etc. Addition to that the report has evaluated a project experience of “Samriddhi” in identifying and overcoming the constraints that hinders the progress of poor and extreme poor producers through facilitating producers groups under specific value chain development. Furthermore the contribution and support of Local Service Providers (LSPs), Local traders, input suppliers and collection centers also have got priority in the study. The analysis also focused on the rural women participation and prosperity in this field. The result generated from the study can help the producers, facilitators, government and non-government institutions to understand the success parameter of these vibrant producers groups and to establish future policies regarding this issue. However justified the situation some recommendations have come up with practical solutions. Key Words: Producer Group, Samriddhi Project, Micro and Small Enterprise (MSE

Enumeration, Isolation and Identification of Nitrogen-Fixing Bacterial Strains at Seedling Stage in Rhizosphere of Rice Grown in Non-Calcareous Grey Flood Plain Soil of Bangladesh

Non-symbiotic diazotrophic systems for biological nitrogen fixation (BNF) in agriculture are most promising but the possibility for the extension of nitrogen fixation by rice is still speculative. Accordingly, the present study was conducted for the Enumeration, isolation and identification of nitrogen fixing bacterial strains at seedling stage (30 days after seed sowing) in rhizosphere of rice (BR 10, Oryza sativa L.) grown in Non-Calcareous Grey Flood Plain soil of Bangladesh. The soil is classified as ‘Inceptisol’ order and ‘Aquept’ suborder. It was identified as ‘Dhamrai series’, had ‘silt’ texture, pH 7.1 and 5.5 C/N ratio. The present results of the microbial tests on the rice rhizosphere soil evinced that out of 263 isolates, only 91 were branded as nitrogen fixing organisms per gram of soil, which was about 34.6 % of the total isolates. As per selection criteria, four individual strains were considered for identification. Biochemical tests were conducted for proper identification and the selected strains were identified as Enterobacter spp., Klebsiella spp., Bacillus spp. and Azospirllum spp

Autonomous reconnaissance mission: development of an algorithm for collaborative multi robot communication

A collaborative team of two resource constrained semi-autonomous hexapod robots have been developed that perform navigation tasks while satisfying communication constraints. Our approach is based on the use of a control structure where each hexapod performs elementary tasks, a behavior-based controller generates motion directives to achieve the collaborative tasks, and controller generates the actuator commands to follow the motion directives. The control technique has been developed for a mission where a target location spread across a static environment has to be visited once by the two hexapods while maintaining a relative given distance with wireless communication. Wireless communication under mobile ad-hoc networks are communication networks that do not rely on fixed, preinstalled communication devices like base stations or predefined communication cells. This wireless networks consist of mobile nodes which are characterized by their decentralized organization and the potentially high dynamics of the network structure, therefore ad-hoc network communication system has been the focus in this multi-robot communication. The ad-hoc network has to provide position data to support localization of the mobile robots, which might be of great importance to guide the robots to specific targets and locations. Communications standards considered for the ad-hoc network are Wireless LAN, Bluetooth and ZigBee. In this project Bluetooth and ZigBee are integrated on robots for real experiments