Determination of Soil Erosion and Sediment Yield in the Bonsa River Basin Using GIS and Revised Universal Soil Loss Equation (RUSLE)

The Bonsa river is an important tributary of the Ankobra river in the Western Region of Ghana. The catchment of the Bonsa river has been undergoing rapid land cover changes due to human activities such as farming, illegal mining, population growth, among others which are likely to promote soil erosion and sediment yield in the river basin. To estimate the amount of soil eroded over a period and subsequent sediment yielded along the Bonsa river basin, the Revised Universal Soil Loss Equation (RUSLE) was integrated with Geographic Information System (GIS) to model the spatial distribution patterns in soil erosion and sediment yield within the catchment. Data used included annual rainfall records, soil map, Digital Elevation Model (DEM) and land-use map of the study area. Parameters of the model were determined and converted into raster layers using the raster calculator tool in ArcMap to produce a soil erosion map. The concept of Sediment Delivery Ratio (SDR) was applied to determine the annual sediment yield by combining a raster SDR layer with soil erosion map. The predicted soil loss and sediment yield values were found to be low. This may be due to high soil protective cover provided by vegetation as well as low topographic relief in the river basin. Though, the elements and processes responsible for soil erosion and sediment yield prevailing in the basin was found to be low, adverse situations could be developed with time if the prevailing conditions are not checked, as soil erosion is a natural gradual slow process. The gains made could be sustained by putting measures in place to control human activities, particularly, illegal mining (galamsey) in the basin, indiscriminate cutting down of trees and farmining activities along the Bansa river basin. This study will support monitoring, planning of water resources and help to improve sustainable water quality

Communication: Direct tests of single-parameter aging

This paper presents accurate data for the physical aging of organic glasses just below the glass transition probed by monitoring the following quantities after temperature up and down jumps: the shear-mechanical resonance frequency (around 360 kHz), the dielectric loss at 1 Hz, the real part of the dielectric constant at 10 kHz, and the loss-peak frequency of the dielectric beta process (around 10 kHz). The setup used allows for keeping temperature constant within 100 micro Kelvin and for thermal equilibration within a few seconds after a temperature jump. The data conform to a new simplified version of the classical Tool-Narayanaswamy aging formalism, which makes it possible to calculate one relaxation curve directly from another without any fitting to analytical functions

Landfill Lifespan Estimation: A Case Study

Municipal Solid Waste (MSW) management is one of the most serious environmental challenges facing the world at large due to the decomposing effect from the toxic gases being released into the environment by the MSW. The siting of landfill in any environment is a vital consideration that must be looked at due to the many factors such as the lifespan of the landfill, site selection, design, construction, operation and management. For this reason, it is important to estimate the lifespan of landfill accurately so as to explore the risk involved in acquiring new lands for landfills. Moreover, it is also necessary to consider proper methodology for estimating the lifespan of landfills. Based on these factors enumerated, various researchers have performed several laboratory tests in order to conclude on appropriate model that could be used to predict the lifespan of modern landfills. Mathematical models or expressions have also been suggested in literature as an alternative approach to the estimation of landfills lifespan. This research used the future value of money equation to estimate the lifespan of the Aboso landfill in Tarkwa, Ghana. The result showed that the landfill could operate for the next twelve years before it could exhaust its usefulness. Keywords: Landfill, Municipal Solid Waste, Lifespan Estimatio

Rheological model for the alpha relaxation of glass-forming liquids and its comparison to data for DC704 and DC705

Dynamic shear-modulus data are presented for the two silicone oils DC704 and DC705 for frequencies between 1 mHz and 10 kHz at temperatures covering more than five decades of relaxation-time variation. The data are fitted to the alpha part of a phenomenological model previously shown to describe well the dynamic shear modulus of squalane, which has a large beta process [Hecksher \textit{et al.}, J. Chem. Phys. \textbf{146}, 154504 (2017)]; that model is characterized by additivity of the alpha and beta shear compliance and by a high-frequency decay of the alpha process in proportion to $\omega^{-1/2}$ in which $\omega$ is the angular frequency. The fits of the alpha part of this model to the DC704 and DC705 data are compared to fits by a Havriliak-Negami type model, the Barlow-Erginsav-Lamb model, and a Cole-Davidson type model. At all temperatures the best fit is obtained by the alpha part of the squalane model. This strengthens the conjecture that so-called $\sqrt{t}$-relaxation, leading to high-frequency decays proportional to $\omega^{-1/2}$, is a general characteristic of the alpha relaxation of supercooled liquids [Dyre, Phys. Rev. E {\bf 74}, 021502 (2006); Nielsen \textit{et al.}, J. Chem. Phys. \textbf{130}, 154508 (2009); Pabst \textit{et al.}, J. Phys. Chem. Lett. \textbf{12}, 3685 (2021)]

Multiple Linear Regression Model for Estimating the Price of a Housing Unit

This paper uses the respective unit costs, over fifteen (15) years, of selected Housing Unit Major Components (HUMC): cement, iron rods, aluzinc roofing sheets, coral paint, wood and sand, to develop Multiple Linear Regression Model (MLRM) for determining Housing Unit Price (HUP) for one-bedroom and two-bedroom housing units. In the modeling, the Ordinary Least Squares (OLS) normality assumption which could introduce errors in the statistical analyses was dealt with by log transformation of the data, ensuring the data is normally distributed and there is no correlation between them. Minimisation of Sum of Squares Error method was used to derive the model coefficients. The resultant MLRM is:  Ŷi MLRM = (X'X)-1 X'Y(xi') where X is the sample data matrix. The specific model for one-bedroom housing unit is loge (HUPMLRM)1-Bed = 1.017 – 2.225 x 10-5 x CC + 2.512 x 10-6 x CS + 6.016 x 10-4 x CIR  +  1.985 x  10-4 x CR + 5.694 x 10-4 x CP -7.437 x 10-4 x CW and that for two-bedroom housing unit is loge (HUPMLRM)2-Bed = 5.760 – 7.501 x 10-7 x CC + 2.935 x 10-6 x CS + 1.898 x 10-3 x CIR  +  6.695 x 10-4 x CR - 9.157 x 10-3 x CP +6.136 x 10-3 x CW, where CC, CS, CIR, CR, CP and CW are costs of the total quantity of cement, sand, iron rods, roofing, paint and wood respectively. The MLRM was validated by using it to estimate the known HUP in the 15.5th year. From the results, the percentage absolute deviations of the estimated HUP from the known HUP are 1.27% and 2.02% for one-bedroom and two-bedroom housing units respectively, which are satisfactory. The novel approach presented in this paper is a valuable contribution to the body of knowledge in modeling. Keywords: Multiple Regression Analysis, Housing Unit Major Components, Housing Unit Pric

Physical ageing studied by a device allowing for rapid thermal equilibration

Ageing of organic glasses to the equilibrium liquid state is studied by measuring the dielectric loss utilizing a microregulator where temperature is controlled by means of a Peltier element. Compared to conventional equipment the new device adds almost two orders of magnitude to the span of observable ageing times. Data for five organic glass-forming liquids are presented. The existence of an "inner clock" is confirmed by a model-free test showing that the ageing of structure is controlled by the same material time that controls the dielectric properties. At long times relaxation is not stretched, but simple exponential, and there is no "expansion gap" between the limits of the relaxation rates following up and down jumps to the same temperature

Identical temperature dependence of the time scales of several linear-response functions of two glass-forming liquids

The frequency-dependent dielectric constant, shear and adiabatic bulk moduli, longitudinal thermal expansion coefficient, and longitudinal specific heat have been measured for two van der Waals glass-forming liquids, tetramethyl-tetraphenyl-trisiloxane (DC704) and 5-polyphenyl-4-ether. Within the experimental uncertainties the loss-peak frequencies of the measured response functions have identical temperature dependence over a range of temperatures, for which the Maxwell relaxation time varies more than nine orders of magnitude. The time scales are ordered from fastest to slowest as follows: Shear modulus, adiabatic bulk modulus, dielectric constant, longitudinal thermal expansion coefficient, longitudinal specific heat. The ordering is discussed in light of the recent conjecture that van der Waals liquids are strongly correlating, i.e., approximate single-parameter liquids.Comment: 8 pages, 6 figures, Substantially revised versio