iosr-JMCE   Volume-18 ~ Issue-6 ~ Nov. – Dec. 2021

Abstract: Drops are widely used in many artificial water streams such as open channel drains and flash flood channels to allow for the sudden increase in the discharge and consequently the flow depth. Turbulency associated with flow over drops results in deterioration in the channel bed due to the scour hole that takes place downstream the drop. This paper presents the results of a laboratory study of short duration (5 to 90 min) clear water scour tests downstream drops in erodible bed (medium sand). Experiments examined the effects of time, flow parameters and drop geometry on the dimensions of the scour hole. The dimensions under.....

Key words: Open Channel, Local Scour, Laboratory Study, Drops, Scour Hole Dimensions

[1]. Adduce C., and La Rocca M., "Local scouring due to turbulent water jets downstream of a trapezoidal drop: Laboratory experiments and stability analysis", Water Resources Research, Vol. 42, W02405, doi:10.1029/2005WR004139, 2006
[2]. Castillo L., and Carrillo J., "Comparison of methods to estimate the scour downstream of a ski jump", International Journal of Multiphase Flow, Vol. 92, 2017, pp 171–180
[3]. Cheng L., Conghao X., and Zhenhua H., "A three-phase flow simulation of local scour caused by a submerged wall jet with a water-air interface", Journal of Advances in Water Resources, Vol. 129, 2019, pp 373–384[4]. Dey S., and Raikar R., "Scour Below a High Vertical Drop", Journal of Hydraulic Engineering, ASCE Vol. 133, No. 5, May 2007, pp 564-568.
[5]. Doehring F., and Abt S., "Drop Height Influence on Outlet Scour", Journal of Hydraulic Engineering, ASCE Vol. 120, No. 12, December 1997, pp1470-1476.

Abstract: Background: Passenger Car Unit (PCU) is used for converting a mixed vehicle flow into an equivalent passenger car flow. PCU value for a vehicle is not constant but varies with traffic and roadway conditions. In this research, it was attempted to find the PCU value of different types of vehicles at selected intersections of Kathmandu Ring Road. These intersections are chosen based upon the significant queuing during peak hour and the manual traffic control by Traffic Police. Methods: Traffic flow as the primary source of data was collected using videography during peak hour. Secondary data are vehicle dimensions, PCU value adopted by Nepal Road Standard (NRS) 2013 and study reports of Kathmandu Sustainable....

Key words: Passenger Car Unit, PCU, Highway Capacity, Chandra method

[1]. Ambarwati, L., Pel, A.J., Verhaeghe, R. and van Arem, B., 2014. Empirical analysis of heterogeneous traffic flow and calibration of porous flow model. Transportation research part C: emerging technologies, 48, pp.418-436.
[2]. Chandra, S. & Kumar, P., 2003. Effect of Lane Width on Capacity under Mixed Traffic Conditions in India. Journal of Transportation Engineering, ASCE, Volume 129, No 2, pp. 155-160.
[3]. Chandra, S. and Sikdar, P.K., 2000. Factor affecting PCU in mixed traffic on urban roads. Road Transport Res, 9(3)
[4]. Craus, J., Polus, A. & Grinberg, I., 1980. A revised method for determination of passenger car equivalents.. Transp. Res., 14(A), pp. 241-246.
[5]. DoLIDAR, 2016. Statistics of Local Road, Kathmandu: Department of Local Infrastructure Development (DoLIDAR).

Abstract: The objective of present research was to evaluate the "heat transfer characteristics, efficiency ratio and friction factor" of a twin tube heat exchanger for the rounded bare tube and with the complete length perverted tape with trapezoidal twist cut for fractions of 6.0 and 4.4, individually. For the "Reynolds Number" assortment of 2000-12000, experimental evaluations were directed to assess the "friction factor and heat transfer characteristics" for a rounded tube. The experimental recorded data from a rounded bare tube were likened to the regular correlation to ensure the authentication of investigational outcomes. The outcomes of the trapezoidal-cut twisted tape-fitted tube was tested to those of the rounded bare tube. The consequences validate that the twisted tape with trapezoidal-cut has a large increase in "Heat Transfer and Friction Factor Coefficient" and furthermore the Heat Transfer growth was also discovered to be rational, since the resulting output ratio is greater than unity..

Key words: Twist Ratio, Trapezoidal-Cut, Performance Ratio, Friction Factor, Heat Transfer Estimation

[1]. S.W. Chang, W.L. Cai, R.S. Syu, (2016) "Heat transfer and pressure drop measurements for tubes fitted with twin and four twisted fins on rod", Exp. Therm. Fluid Sci. 74 220–234.
[2]. P.V. Durga Prasad, A.V.S.S.K.S. Gupta, (2016) "Experimental investigation on enhancement of heat transfer using Al2O3/water nanofluid in a u-tube with twisted tape inserts", Int. Communication. Heat Mass Transfer 75 154–161.
[3]. Z.H. Ayub, S.F. Al-Fahed, (2013) "The effect of gap width between horizontal tube and twisted tape on the pressure drop in turbulent water flow", Int. J. Heat Fluid Flow 14 (1) 64–67.
[4]. A. Boonloi, W. Jedsadaratanachai, (2016) "Turbulent forced convection and heat transfer characteristic in a circular tube with modified-twisted tapes", J. Thermodynamics 1–16.
[5]. M.M.K. Bhuiya, A.K. Azad, M.S.U. Chowdhury, M. Saha, (2016) "Heat transfer augmentation in a circular tube with perforated double counter twisted tape inserts", Int. Communication Heat Mass Transfer 74 18–26.

Abstract: To improve the thermal conductivity and compressive strength of concrete, the use of pozzolana aggregate as a partial substitution for natural aggregate in the concrete mix was examined. Natural pozzolana (volcanic tuff) deposits abound in Al Hale Mountain, Tafila, Jordan. In this study, concrete with natural aggregate was employed as a control sample to compare with pozzolana concrete. Twenty-five concrete specimens were produced by replacing 0%, 10%, 20%, 30%, and 40% of natural aggregate with five different aggregate sizes of 2.36, 4.75, 9.50, 12.50, and 19.00 mm. Thermal conductivity and compressive strength were measured for concrete cubes with dimensions of 100 x 100 x 100 mm. Results indicated that aggregate size had no substantial influence on the thermal.....

Key Word: Pozzolana concrete; natural aggregate; pozzolana aggregate; thermal conductivity; compressive strength.

[1]. De Belie, N., Lenehan, J.J., Braam, C.R., Svennerstedt, B., Richardson, M. and Sonck, B., 2000. Durability of building materials and components in the agricultural environment, Part III: Concrete structures. Journal of Agricultural Engineering Research, 76(1), pp.3-16.
[2]. Raheem, A.A. and Adesanya, D.A., 2011. A study of thermal conductivity of corn cob ash blended cement mortar. The Pacific Journal of Science and Technology, 12(2), pp.106-111.
[3]. Kim, K.H., Jeon, S.E., Kim, J.K. and Yang, S., 2003. An experimental study on thermal conductivity of concrete. Cement and Concrete Research, 33(3), pp.363-371.
[4]. Yun, T.S., Jeong, Y.J., Han, T.S. and Youm, K.S., 2013. Evaluation of thermal conductivity for thermally insulated concretes. Energy and Buildings, 61, pp.125-132.
[5]. Gomes, M.G., Flores-Colen, I., Manga, L.M., Soares, A. and De Brito, J., 2017. The influence of moisture content on the thermal conductivity of external thermal mortars. Construction and Building Materials, 135, pp.279-286..

Abstract: The continuous improvement in the expansion soil properties makes helpful in the construction of flexible pavement. The stability of the soil is mainly determined by the force chains and pore channels, whereas the hydraulic conditions act as external disturbances. The erosion process is accompanied by contact failure, force chain bending, kinetic energy burst of particles, and other processes due to multi-factor coupling. This paper recaps the various researches done using the discrete element method and explores the new advanced techniques for the simulation of particles such as clay, sand, and many....

Key Word: discrete element modeling; site characterization; erosion; calibration camber

[1]. J. Ai, J.-F. Chen, J. M. Rotter, and J. Y. Ooi. Assessment of rolling resistance models in discrete element simulations. Powder Technology, 206(3):269–282, 2011.
[2]. J. P. Bardet. Experimental Soil Mechanics. Prentice-Hall, Upper Saddle River, New Jersey, 1997.
[3]. P. J. Owen and P. W. Cleary. Prediction of screw conveyor performance using the Discrete Element Method (DEM). Powder Technology, 193(3):274–288, 2009.
[4]. A. Thornton, T. Weinhart, S. Luding, and O. Bokhove. Modeling of particle size segregation: Calibration using the discrete particle method. Int. J. Mod. Phys. C, 23:1240014(08), 2012.
[5]. P. A. Cundall and O. D. L. Strack. A discrete numerical model for granular assemblies. Géotechnique, 29(1):47–65, 1979

Abstract: Being the administrative and economic hub of Nepal, Kathmandu valley experienced rapid urbanization in the last decades. The rapid population growth resulted in the huge travel demand and numerous transportation problems as well. The lack of a reliable public transport system augmented private vehicle ownership is increasing rapidly. In order to improve the urban transport scenario, several initiatives have been attempted in the past. However, desired results could not be achieved. In this context, alternative as well as innovative methods shall be worked out on the basis of integrated approach among various modes and services. Over the last decades, numerous........

Key Words: Multi-Modal transport, Sustainability, Integrated Transport, Transport Modes, Modal Share

[1] Asian Development Bank (2006). Energy Efficiency and Climate Change: Considerations for On Road Transportation in Asia.
[2]. Central Bureau of Statistics, UNFPA (2014). Population Monograph of Nepal
[3]. Dimitriou, Harry T, 1990. Transport Planning for Third World Cities, Routledge Revivals
[4]. Givoni, M. and Banister, D. (2010). Integrated Transport from Policy and Practice, 2010
[5]. GON, 2001. National Transport Policy, Ministry of Physical Planning and Works.