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Abstract

The present study deals with the estimation of the evolution tendency of the environmental stage of a protected habitat with predominant forest vegetation, during a short period of time, using techniques specific to remote sensing. Therefore, two important spectral indexes were tested while assessing the health of the forest ecosystems: i.e. the Normalized Difference Vegetation Index (NDVI) and the Structure Insensitive Pigment Index (SIPI). The period of time taken into consideration for the study was, 2013 - 2019, having used medium resolution satellite photos, Landsat 8 OLI, having initially undergone standard pre-processing operations (resize data, radiometric calibration, atmospheric correction). The satellite images modified according to the Top of Atmosphere Reflectance and corrected topographically resulted into getting values for the two before mentioned indexes. The quantity-spatial results obtained, correlated to the monthly values of the precipitations processed in order to obtain the SPI (Standardized Precipitation Index), mostly reveal, in what SIPI and also NDVI are concerned, a slight decrease in the quality of the forest on the analysed area in the sense that the vegetation stress is increased under meteorological factors, expressed differently depending on the morphometric and pedological parameters of the habitat.

Abstract

Productivity is a significant aspect of construction industry that plays vital role for success and failure of any construction project. This industry generates 11% to 13% of GDP all around the globe and the cost of labour in any building project is 20% to 35% of the cost of Building. On daily basis labour utilizes 30% of time on productive activities rest 70% of the time is ruined in non-productive activities, there are multi factors which are affecting the labour production in construction industry hence this study provides an overview of productivity, Total Factor productivity, method used to measure accurate productivity in construction projects. The objective of this study is find out percentage up to what extent labour production is affected due to weather conditions, however this study is carried out in arid climate region in Month of June 2018, where minimum temperature was recorded 26.0 Celsius degree at 7:30 AM and Maximum was 47.80 Celsius degree at 3:00 PM. A descriptive survey research design approach was adopted using continuous observation method of study. Project work study manual served as the research instrument to collect the data on selected building sites for 30 working days. Data collected were analyzed using descriptive statics. The results show that average monthly production of mason gang was recorded with less production of 28.759%, Carpentry gang with average monthly loss of production 16.74% & steel fixer gang had average monthly loss of production was 12.188. This concludes that prior to signing the contract for construction project. The location, environment, topography of region, capacity of construction operatives must be kept in mind to decide the proper timeline for the successful of project.

Abstract

The purpose of this article is to present selected threats that may affect the security of IT systems caused by cyberattacks coming from cyberspace, as well as to prescribe the results that could be caused by the failure to implement security measures to protect information system (IS).

Abstract

This paper proposed a novel structure of a 10-bit, 400MS/s pipelined analog to digital convertor using 0.18 µm TSMC technology. In this paper, two stages are used to converter design and a new method is proposed to increase the speed of the pipeline analog to digital convertor. For this purpose, the amplifier is not used at the first stage and the buffer is used for data transfer to the second stage, in the second stage an amplifier circuit with accurate gain of 8 that is open loop with a new structure was used to speed up, also the design is such that the first 4 bits are extracted simultaneously with sampling. On the other hand, in this structure, since in the first stage the information is not amplified and transferred to the second stage, the accuracy of the comparator circuit should be high, therefore a new structure is proposed to design a comparator circuit that can detect unwanted offsets and eliminate them without delay, and thus can detect the smallest differences in input voltage. The proposed analog to digital convertor was designed with a resolution of 10 bits and a speed of 400MS/s, with the total power consumption 74.3mW using power supply of 1.8v.

Abstract

Fragility curves are useful tools for evaluating the probability of structural damage due to earthquakes as a function of ground motion indices. The force reduction factor (R) is one of the seismic design parameters that determine the nonlinear performance of building structures during strong earthquakes. R factor itself is mostly a function of displacement ductility (µ), natural period of a structure, and soil conditions. A statistical method (Path Analysis) is proposed for the first time to determine the effect of R, µ and T on the column fragility curve parameters of typical box girder, two spans reinforced concrete highway bridge class. An analytical approach was adopted to develop the fragility curves based on numerical simulation. The R, µ and fundamental period T have been used to characterize different bridge configurations. The total, direct, and indirect effects of the variables as having significant effect on fragility curve parameters were identified.

Abstract

Mortar is widely used in the construction industry for different purposes. Its compressive strength is the main parameter which is brought under focus. Compressive strength of mortars depends upon many factors such as water-cement ratio, fine aggregates size, and different curing conditions. This experimental study was undertaken to investigate the effect of GGBFS on compressive strength of mortars under different curing regimes using GGBFS as a partial replacement of cement. A total of 60 cubes of standard size of 2 x 2 x 2 inches were casted in laboratory, out of which 12 cubes each were prepared with 0%, 5%, 10%, 15% and 20% GGBFS replacement for cement. Cubes were cured for 3, 7, 14 and 28 days. Bases on obtained results it is observed that the maximum compressive strength was achieved by sample with 5% GGBFS, although 10% GGBFS samples achieved higher compressive strength than the control sample with 0% GGBFS. Further replacement beyond this value causes reduction in strength.

Abstract

Shear stress is one of the most critical parameters in hydraulic and coastal engineering, which is often measured indirectly. Since there is no instrument to measure this parameter directly and given that it is usually calculated by measuring other parameters such as velocity and pressure and using some equations, shear stress measurement is often accompanied with large measurement errors. In this study, a new technique and direct measurement using physical modeling in a hydraulic knife-edge flume and load cell were employed to measure the shear stress in a rectangular channel with rigid unsubmerged vegetation with Dv= 20, 25, and 32mm in

Q=25 and 30 Lit/S and y=10, 12, 17, and 20 cm. The results indicate that the shear stress and the dimensionless τ0τ ratio decrease in a constant flow discharge with increasing the flow depth. It was also shown that the shear stress would be enhanced with an increase

in vegetation diameter due to increasing vegetation density against flow. According to dimensionless ratios of τ0τ and Dvy in the graphs and considering the trend lines with appropriate correlation coefficients, some equations were presented to calculate the shear stress in the concerned range.

Abstract

Rutting and Fatigue are taken as main premature failures among all distresses, as these distresses have wide effect on performance of pavement. Sudden variation of heavy axle loaded vehicles, improper mix design and traditional design methodologies used in pavement design industries are major factors behind these failures. For proper performance and good serviceability, these premature distresses should be resisted. Thus, there is a need of using a Mechanistic based design methodology like KENPAVE software, so that traditional design errors should be overcome. KENLAYER is a part of KENPAVE software. KENLYER software tool is utilized to calculated accurately stresses and strains in asphaltic pavement that are ultimately used in calculating allowance for rutting and fatigue failure utilizing Asphalt Institute design models or formulas. Resistance to Rutting failure is checked by calculating vertical compressive stress at the top of soil sub-grade layer, while resistance to fatigue failure is checked by calculating horizontal tensile strain at the bottom of asphaltic layer using KENLAYER software tool. Thus, the object of this research study is to analyze a flexible pavement with respect to rutting and fatigue distresses using KENLAYER software tool. For achieving that objective NHA (N-55) section of road in Sehwan Pakistan was taken as a reference pavement. Pavement was analyzed by altering the thicknesses of bituminous courses by ± 25 percent. From that we obtained total 20 cross-sections to be analyzed using KENLAYER software in terms of Rutting and Fatigue premature failures.

Abstract

In the paper, there has been constructed a discrete model of the non-classical Bittner operational calculus with a derivative understood as the operation S b{x(k)} := {x(k+n)b(k)x(k)}, which is a generalization of the n th-order forward difference. It has also been pointed out that there is a possibility to generalize operational calculus models with backward and central differences of higher orders.

Abstract

In recent years, nano technology has been significantly implemented in geotechnical engineering, especially for soil remediation. Using this technology has improved soil resistance parameters and led to the stabilization of many problematic soils. Clay soils, due to their nature, have a large dispersion on the surface of the earth. The widespread dispersion of these types of soils in the site of structures, describes the necessity of studying and investigating new methods of improving and amending the resistive properties of these soils. This research is a review of the use of nanotechnology for the improvement of soil resistive properties by geotechnical researchers.