Policies and Strategies to Overcome Barriers to Rainwater Harvesting for Urban Use in Ethiopia

The Ethiopian government has been working on rainwater harvesting (RWH) for more than three decades. Despite its efforts, the results are not as expected. Different barriers have posed challenges to promoting RWH in Ethiopia. This study was done to identify the main problems and obstacles, and reflect on potential solutions. As a result, absence of clear policy definitions, lack of sustainably implemented projects, poor societal perceptions of RWH, local professionals lacking proper knowledge, and initial investment costs are found to be major causes of poor outcomes. Considering the site-specific nature of water issues, the authors propose various management strategies such as policy-oriented promotion, formulation of design guidelines, proactive planning, collaborative research, and integration of RWH with cost covering practices.     

NiO–ZnO based junction interface as high-temperature contact materials

Contact materials play a crucial role in an electronic device operating at moderate and elevated temperatures where chemical and thermal stability is of great importance. Oxide materials and their interfaces are potential candidates as high-temperature contact materials due to their high chemical and thermal stabilities. In this work, polycrystalline oxides of Ni_0.98Li_0.02O and Zn_0.98Al_0.02O were used to make junction interfaces, where the solid-state synthesis method was used to obtain the individual oxide materials. After assembly of the junction interfaces, properties such as electrical, chemical, and thermal stabilities of the interfaces were investigated. The electrical properties were assessed through current-voltage (I–V) and electrochemical impedance spectroscopy (EIS) measurements, where the interface revealed a transition from electrically rectifying to slightly ohmic contact within a temperature range from 500–1000 °C. After annealing the junction interfaces at these elevated temperatures, no secondary phase was observed at the junction interface, i.e., the interfaces remain chemically stable. Moreover, the effect of isothermal annealing on the I–V characteristics curve of the junction showed an increased reverse current output over long annealing time, attributed mainly to the increased effective contact area at the junction interface and cation inter-diffusion processes. Furthermore, an investigation of the cation inter-diffusion mechanism revealed mainly lattice diffusion of Zn²⁺ into Ni_0.98Li_0.02O, while Ni²⁺ diffusion into Zn_0.98Al_0.02O exhibited both lattice and grain-boundary diffusion mechanisms.     

Hall and ion-slip effects on mixed convection flow of Williamson nanofluid over a nonlinear porous stretching sheet with variable thermal conductivity

The intent of this investigation is to analyze the Williamson nanofluid stream past a nonlinearly broadening surface through a leaky medium in the existence of mixed convection, Hall, ion-slip, thermal radiation, and viscous dissipation impacts. Suitable similitude changes give joined nonlinear differential schemes, which were numerically explained via spectral relaxation method. Effectiveness of various physical parameters on velocity ingredients, temperature, and nanoparticle concentration distributions alongside the physical quantities of interests was uncovered graphically. It is found that both velocity profiles increment with an expansion in the Hall parameter. Also, the opposite behavior is noticed for the primary and auxiliary velocity profiles as the ion-slip parameter rises. Moreover, it is observed that the primary velocity and concentration profiles expand with an expansion in the velocity power index parameter, however, the secondary velocity profile reduces. Further, it was showed that the fluid velocities decay while temperature distribution advances by the superior values of the Williamson fluid parameter. Finally, the authenticity of the outcomes was confirmed by contrasting them with prior outcomes under some limited presumptions and discovered to be in terrific understanding.     

Enhanced thermoelectric performance of poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) with long‐term humidity stability via sequential treatment with trifluoroacetic acid

This paper reports a range of effective sequential chemical processes to enhance the thermoelectric performance of conducting poly(3,4‐ethylenedioxythiophene) films doped with poly(styrene sulfonate) anions (PEDOT:PSS). The electrical conductivity of the PEDOT:PSS films was significantly increased from 0.33 to 3748 S cm^?1 after a series of sequential treatments with trifluoroacetic acid (TFA) while the Seebeck coefficient and thermal conductivity were slightly reduced from 17.5 ± 1.2 to 16.0 ± 1.1 μV K^?1 and 0.537 to 0.415 W m^–1 K^?1 for the pristine film and treated film, respectively, leading to a significant improvement in power factor up to 97.1 ± 5.4 μW m^–1 K^?2. More importantly, around 80% of the electrical conductivity and Seebeck coefficient was retained after 20 days for these TFA‐treated PEDOT:PSS films, revealing the potential for real thermoelectric applications. © 2019 Society of Chemical Industry     

Effects of orange juice pH on survival, urease activity and DNA profiles of Yersinia enterocolitica and Yersinia pseudotuberculosis stored at 4 degree C

The objective of this study was to determine the survival, growth rate and possible cellular adaptation mechanisms of Y. pseudotuberculosis and Y. enterocolitica in orange juice under different pH conditions. Yersinia was inoculated in orange juice with adjusted pH levels of 3.9, 4.0, and 7.0 and stored at 4 C for 3, 24, 72 and 168 hours (h). The inter-and intra-species variation is significant to the pH and time of incubation variables (p<0.05). At 3.9 pH the CFU (colony forming units) count decreased significantly.At pH 3.9 and 4.0, Y. enterocolitica and Y. pseudotuberculosis survived for at least 30 days and 15 days, respectively. Yersinia that survived under low pH in orange juice revealed enhanced urease activity within 12 h of incubation. The attachment gene (ail) could not be detected by PCR in Y. enterocolitica from undiluted sample incubated for 24 h or longer. Moreover, the FesI-restriction profile was altered when Y. pseudotuberculosis was stored at pH 4.0 orange juice for 7 days. These results indicate that Yersinia could survive and grow at low pH and the survival mechanisms could also enable the bacteria to survive the stomach pH barrier to cause enteric infection.     

Removal of Bisphenol A and its Reaction-Intermediates from Aqueous Solution by Ozonation

In this study, the oxidation of Bisphenol A (BPA) and its reaction-intermediates in aqueous solution by ozonation was investigated. The results of the study indicated that ozonation is effective in oxidizing BPA. Catechol, resorcinol, acetone, formaldehyde and organic acids, acetic, formic, maleic, and oxalic acid, are identified as reaction-intermediates. Ozonation of 51 μM (770 μM C) of BPA resulted in peak concentrations of 16.3, 8.7, 6.8, and 2.0 μM C of catechol, resorcinol, acetone, and formaldehyde, respectively. These concentrations correspond to 2.1, 1.1, 0.9, and 0.3% of the initial concentration of BPA in terms of total organic carbon for catechol, resorcinol, acetone, and formaldehyde, respectively. It was observed that BPA's reaction-intermediates were resistant to ozonation compared to the parent compound and complete mineralization of BPA may need extended ozonation.     

Toward robust and accurate contact solvers for large deformation applications: a remapping/adaptivity framework for mortar-based methods

In recent years, the mortar method has proven to be an effective spatial discretization strategy for large deformation contact problems, particularly when such problems feature deformable-to-deformable contact. The mortar approach has been shown to greatly enhance both the spatial accuracy and the robustness with which such problems can be solved in many circumstances. In this work, we concern ourselves with problems that arise in the context of many practical applications, both in manufacturing and in other areas. Specifically, it is frequently necessary to remesh a problem in the midst of an ongoing incremental loading strategy, either because of adaptive mesh refinement being used to improve resolution, or excessive mesh distortion which necessitates an overall remeshing. This work focuses on a particularly important issue associated with contact remeshing; i.e., the remapping of contact variables after the remesh so that a simulation can successfully continue. We develop and demonstrate our algorithm in the context of a mortar-discretized approach to contact. The approach is applicable to either two or three dimensional analysis, and is demonstrated by a number of three dimensional numerical examples.     

A unified approach on residuals,leverages and outliers in the linear mixed model

Although the linear mixed model can be viewed as a direct extension of multiple regression, it is not obvious how to generalize the standard diagnostic tools such as residual analysis and detection of leverage points and outliers, which are available in the linear regression situation. A unified approach to residuals, leverages and outliers in the linear mixed model is developed. Formal and informal procedures are proposed to display the general features of residuals and leverages in order to detect outliers and high-leverage points in the linear mixed models. The relationship between the best linear unbiased predictor (BLUP) and residuals is established. Some properties of BLUPs are formulated and their use in detecting outlying observations are investigated.      

Comparative resource analyses for ethanol produced from corn and sugarcane in different climatic zones

Comparative analysis of resource input for ethanol produced from corn and sugarcane in temperate, dry, and tropical climate zones was conducted. Parameters such as the Net Energy Value (NEV), water requirement, land requirement, carbon dioxide emission with and without impact of changes in land use, and fertilizer released to the environment—as surface runoff for nitrogen and phosphate, were compared for corn and sugarcane ethanol production. The estimates of NEV for corn ethanol varied from ?462 to 1757 kJ l^?1, while those of sugarcane ethanol were between 16 057 and 17 092 kJ l^?1 for the three climatic zones considered in this study. The results of the study also indicate that ethanol produced from sugarcane uses less or comparable amount of resources in contrast to ethanol produced from corn. Copyright © 2011 John Wiley & Sons, Ltd.