National Institute of Technology, Meghalaya

About: National Institute of Technology, Meghalaya is a education organization based out in Shillong, India. It is known for research contribution in the topics: Control theory & Computer science. The organization has 503 authors who have published 1062 publications receiving 6818 citations. The organization is also known as: NIT Meghalaya & NITM.

Damage detection in RC beam utilizing feed-forward backpropagation neural network technique

Abstract: Accumulation of damages during the service life of a structure can reduce its safety. Every structure that is constructed has a particular age, but these structures can deteriorate before their service life due to various factors such as harsh environmental conditions, fatigue due to service loading, etc. To access the information regarding the health index of structure, the need for various unconventional damage assessment practices and dependable structural health monitoring systems is presently high. Structures to perform damage assessment efficiently and appropriate retrofitting are required. Structural health monitoring (SHM) has been verified to be an economical technique for damage assessment in structures over the past several decades. In reinforced concrete beams, flexural cracks distribute non-linearly and propagate along in all directions. The crack continues to propagate until the structure or structural component fractures. Due to this complex behavior of cracks, simplified damage simulation techniques such as reductions in the modulus of elasticity or section depth or stiffness of rotational spring elements cannot be applied to simulate flexural cracks in reinforced concrete components. Besides these simplified techniques, dynamic properties have been used extensively in the past. Dynamic properties such as frequency, mode shapes vary a lot with environmental changes, so they are not very reliable. This research will address the above gap in knowledge by developing a model that can represent the complex behavior of cracks and then utilize artificial neural networks to assess damage in RC flexural members.

Evaluation of Structural Performance of Concrete with Ambient-Cured Alkali-Activated Binders

Abstract: Enormous global CO2 emissions associated with cement production necessitates the use of sustainable cementitious alternatives. Alkali-activated binder (AAB) which utilizes industrial wastes as precursors is a promising substitute for cement. To promote the practical use of AAB concrete, this paper presents an investigation on the mechanical and microstructural properties of ambient-cured AAB concrete. Fly ash/slag ratio is varied and the optimum mix is proposed based on compressive strength test results. Pull-out test is performed to evaluate the bond strength of ambient-cured reinforced AAB concrete. The specimen-level tests are supplemented with results from X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) along with energy-dispersive spectroscopic (EDS) analysis of the AAB paste samples. This is done to corroborate the microstructural characteristics with the mechanical properties at specimen-level. Fly ash: slag ratio of 70:30 is recommended as the optimum proportion considering both strength and economical aspects. Incorporation of slag results in the formation of the additional reaction products, refining the pore structure and enhancing strength. The AAB mix with fly ash: slag ratio of 50:50 exhibits the highest compressive strength and bond strength.

PCM assisted reverse electro discharge machining process for pattern generation

Abstract: This research work reports about pattern generation using the photochemical machining (PCM) assisted reverse electro discharge machining (EDM) process on an aluminum 6061 workpiece. A mixture of fi...

Hillslope instability induced by toe excavation: A comparative study of LEM-based deterministic and probabilistic approaches

Abstract: Toe cutting of hillslopes that are intended for the expansion of the transportation networks across the hilly regions need to follow an engineered basis to avert catastrophic failures. The commonly utilized deterministic Limit Equilibrium Method (LEM) does not incorporate the uncertainties in geotechnical properties and might exhibit inappropriate or erroneous consequences of toe excavation. In order to highlight the chances of toe-excavation induced slope failures, this paper reports the outcomes of the probabilistic stability analysis while considering one-dimensional spatial variability of soil shear strength parameters. The importance of such probabilistic analyses is established by finding that 79% of the toe-excavated slopes, which are judged safe from deterministic analysis, actually exhibit high probabilities of failure. Further, the influences of coefficient of variation (CoV) and the correlation between the shear strength parameters are also highlighted. The probability of failure of the cut slopes is found to be decreased by around 70% when the correlation coefficient of the shear strength parameters decreased from +0.5 to −0.5. The permissible width of toe excavation is found to be governed by the indicators of spatial variability. It is revealed that for a CoV value of 0.2 and 0.3, a maximum horizontal extent of 7 m and 5 m can be excavated without leading to slope failure for a dimensionless correlation length up to 0.2 and 0.1, respectively.

Experimental studies on multi-operand adders

Abstract: In this paper, different multi-operand adders have been analyzed in terms of propagation delay, power consumption and resource utilization. The functionality of the adders have been verified using Verilog hardware description language and synthesized in Xilinx ISE. The device chosen for implementation is Virtex 6 (XC6VLX240T) with FF1156 package. Simulation results show that Wallace tree adder is the fastest adder and consumes least amount of power. The Wallace tree adder also consumes the least amount of hardware resources as per the synthesis results.