Photocatalytic and biological oxidation treatment of real textile wastewater

Abstract In this study, the discoloration of wastewater containing azo dyes by chemical oxidation process combined with a biological treatment was evaluated and applied to real textile wastewater generated from one Ethiopian industrial site. The use of TiO2 as photocatalyst and the effect of the addition of H2O2 on color removal was first investigated. Photocatalysis was followed by aerobic biological treatment, and their combination resulted in a high extent of color removal (93.3%) and chemical oxygen demand (COD) reduction (90.4%). This was reached without pH correction and with low energy consumption compared to the implementation of AOPs alone. This study performed with real textile wastewater allows the direct extrapolation of the data for the design of a cost-effective and applicable treatment procedure at a pilot scale. Graphic abstrac

A Seven-Step Block Multistep Method for the Solution of First Order Stiff Differential Equations

In this paper, a seven-step block method for the solution of first order initial value problem in ordinary differential equations based on collocation of the differential equation and interpolation of the approximate solution using power series have been formed. The method is found to be consistent and zero-stable which guarantees convergence. Finally, numerical examples are presented to illustrate the accuracy and effectiveness of the method.  Keywords: Power series, Collocation, Interpolation, Block method, Stiff

Frequency domain reflectometry for irrigation scheduling of cover crops.

Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.A well-managed irrigation scheduling system needs a rapid, preCIse, simple, costeffective and non-destructive soil water content sensor. The PRl profile probe and Diviner 2000 were used to determine the timing and amount of irrigation of three cover crops (Avena sativa L., Secale cereale L. and Lolium multiflonlm Lam.), which were planted at Cedara, KwaZulu-Natal. The PRl profile probe was first calibrated in the field and also compared with the Diviner 2000. For the calibration of the PRl profile probe the factory-supplied parameters (aJ = 8.4 and ao = 1.6) showed good correlation· compared to the soil-estimated parameters (aJ = 11.04 and ao = 1.02). The factorysupplied parameters gave a linear regression coefficient (r2 ) of 0.822 and root mean square error (RMSE) of 0.062. The soil-estimated parameter showed a linear regression coefficient of 0.820 with RMSE of 0.085. The comparison between the soil water content measured using the PR1 profile probe and Diviner 2000 showed a linear regression coefficient of 0.947 to 0.964 with a range of RMSE of 0.070 to 0.109 respectively for the first 100 to 300 mm soil depths. The deeper depths (400, 600 and 1000 mm) showed a linear regression coefficient ofO.716to 0.810 with a range of 0.058 to 0.150 RMSE. These differences between the shallow and deeper depths could be due to soil variability or lack of good contact between the access tube and the surrounding soil. To undertake irrigation scheduling using the PRl profile probe and Diviner 2000, the soil water content limits were determined using field, laboratory and regression equations. The field method was done by measuring simultaneously the soil water content using the PR1 profile probe and soil water potential using a Watermark sensor and tensiometers at three depths (100, 300 and 600 mm) from a 1 m2 bare plot, while the soil dries after being completely saturated. The retentivity function was developed from these measurements and the drained upper limit was estimated to be 0.355 m3 m-3 when the drainage from the pre-wetted surface was negligible. The lower limit was calculated at -1500 kPa and it was estimated to be 0.316 m3m,3. The available soil water content, which is the difference between the upper and lower limit, was equal to 0.039 m3 m,3. In the laboratory the soil water content and matric potential were measured from the undisturbed soil samples taken from the edge of the 1 m2 bare plot before the sensors were installed. Undisturbed soil samples were taken using a core sampler from 100 to 1000 mm soil depth in three replications in 100 mm increments. These undisturbed soil samples were saturated and subjected to different matric potentials between -1 to -1500 kPa. In the laboratory, the pressure was increased after the cores attained equilibrium and weighed before being subjecting to the next matric potential. The retentivity function was then developed from these measurements. The laboratory method moved the drained upper limit to be 0.390 m3 m,3 at -33 kPa and the lower limit be 0.312 m3m-3 at -1500 kPa. The regression equation, which uses the bulk density, clay and silt percentage to calculate the soil water content at a given soil water potential, estimated the drained upper limit to be 0.295 m3m-3at -33 kPa and the lower limit 0.210 m3 m,3 at -1500 kPa. Comparison was made between the three methods using the soil water content measured at the same soil water potential. The fieldmeasured soil water content was not statistically the same with the laboratory and estimated soil water content. This was shown from the paired-t test, where the probability level (P) for the laboratory and estimated methods were 0.011 and 0.0005 respectively at 95 % level of significance. However, it showed a linear regression coefficient of 0.975 with RMSE of 0.064 when the field method was compared with the laboratory method. The field method showed a linear regression coefficient of 0.995 with RMSE of 0.035 when compared with the estimated method. The timing and amount of irrigation was determined using the PR1 profile probe and Diviner 2000. The laboratory measured retentivity function was used to define the fill (0.39 m3 m-3 ) and high refill point (0.34 m3 m-3 ). The soil water content was measured using both sensors two to three times per week starting from May 29 (149 day of year, 2002) 50 days after planting until September 20 (263 day of year) 11 days before harvesting. There were five irrigations and twenty rainfall events. The next date of irrigation was predicted graphically using, the PRl profile probe measurements, to be on 3 September (246 day of year) after the last rainfall event on 29 August (241 day of year) with 8 mm. When the Diviner 2000 was used, it predicted two days after the PRl profile probe predicted date. This difference appeared since the Diviner 2000-measured soil water content at the rooting depth was slightly higher than the PRl profile probe measurements. The amount of irrigation was estimated using two comparable methods (graphic and mathematical method). The amount of irrigation that should have been applied on 20, September (263 day of year) to bring the soil water content to field capacity was estimated to be 4.5 hand 23 mm graphically and 5.23 hand 20 mm mathematically. The difference between these two methods was caused due to the error encountered while plotting the correct line to represent the average variation in soil water content and cumulative irrigation as a function of time. More research is needed to find the cause for the very low soil water content measurements of the PRI profile probe at some depths. The research should be focused on the factors, which could affect the measurement of the PRl profile probe and Diviner 2000 like salinity, temperature, bulk density and electrical conductivity. Further research is also needed to extend the non-linear relationship between the electrical resistance of the sensor and soil water potential up to -200 kPa. This non-linear equation of the Watermark is only applicable within the range of soil water potential between -10 and -100 kPa

Examining the Factors that Mediate the Relationship from Legal Advocacy Satisfaction to Resilience

Sexual assault is a public health issue that can impact one’s resilience. Using a multisystemic approach to resilience, there may be person-level and environment-level factors that can affect one’s resilience, such as one’s coping self-efficacy, satisfaction with the court process, and negative effects associated with court process. Legal advocacy programs, such as those offered by the King County Sexual Assault Resource Center (KCSARC), support clients during the court proceedings. In order to better serve KCSARC’s clientele, it is helpful to understand how the legal advocacy program impacts post-trauma resilience. This dissertation had three phases: (a) evaluating the structural validity of secondary victimization, resilience, and psychological stress measures; (b) conducting a serial mediation to see if court outcome satisfaction, secondary victimization, and sexual assault coping self-efficacy mediated the relationship between legal advocacy satisfaction on resilience; and (c) determining if race/ethnicity moderated the serial mediation. Participants were at least 13 years old, cis-women clients in the KCSARC legal advocacy program who spoke English (N = 87). Although the design of the program evaluation is longitudinal, data was taken from only one of the waves that the participant completed. The psychometric evaluation of the secondary victimization, resilience, and psychological stress measures in this dissertation supported their use in similar settings. Results suggested a significant indirect effect from legal advocacy satisfaction to resilience, through court outcome satisfaction, secondary victimization, and resilience. Even though the moderated serial mediation was statistically non-significant, results indicated that the mechanism was statistically significant for White/Caucasian participants, but not for Racial/Ethnic Minorities. Legal advocates may better serve their clients by having information specifically related to court outcomes and psychoeducation on secondary victimization; and by improving their relationship with their clients to notice the signs of secondary victimization and highlight their client’s coping self-efficacy and resilience. Limitations include self-selection bias, completion rates, artificially inflated fit indices associated with allowing errors to covary, and confounding variables associated COVID-19 pandemic. Future research should focus on validating the measures used across demographic factors and analyzing changes in variables over time

Global Variations of Ionospheric Total Electron Content (TEC) Derived from GPS Global Ionospheric Maps

This paper is aimed to investigate diurnal, monthly and seasonal variation of  ionospheric total electronic content (TEC) obtained from two GPS satellites IGS and COD and to inspect mean VTEC Correlation between the two satellites by the year  of 2008. TEC is defined by the integral of electron density in a 1 m2 column along  the signal transmission path. It is an important parameter to monitor possible space weather impacts. The processed and archived data taken from IGS and COD  satellites has been imported in to a MATLAB code which gave us the results of the  value of VTEC. Results of the two satellites revealed that, Out of the selected  equinox and solstice day’s maximum value of TEC is recorded on March 20/2008  over North and South west equator due to the maximum solar radiation reaching to  the ionosphere of the Earth. On the contrary, the Minimum peak ionospheric TEC  value is recorded on June 21/2008 over south Asia particularly Srilanka and  Bangladesh due to emission of low solar radiation. As regards to monthly variations  of ionospheric TEC, results of IGS and COD satellites show that highest mean TEC  value is recorded on March and July recorded the least peak TEC value. Results  regarding to seasonal variation also revealed that E-Season recorded maximum  TEC value and least TEC value is recorded on J-Season. The observations of the two satellites also show that the mean TEC value presents stronger solar activity sensitivity at lower-latitude bands than the middle and high latitudes. In general,  there was a very high correlation between Mean TEC value recorded by IGS and COD satellites by the year of 2008 in all low, middle and high latitudes.Keywords: IGS and COD satellites, GPS, Ionosphere, Low, middle and  high-latitudes, TEC

Eighth order Predictor-Corrector Method to Solve Quadratic Riccati Differential Equations

In this paper, the eighth-order predictor-corrector method is presented for solving quadratic Riccati differential equations. First, the interval is discretized and then the method is formulated by using Newton’s backward difference interpolation formula. The stability and convergence of the method have been investigated. To validate the applicability of the proposed method, two model examples with exact solutions have been considered and numerically solved. Maximum absolute errors are presented in tables and figures for different values of mesh size h and the present method gives better results than some existing numerical methods reported in the literature. &nbsp

Cultural differences in coping self-efficacy, perceived social support, and satisfaction with their legal advocate in individuals who have experienced sexual assault

The King County Sexual Assault Resource Center’s (KCSARC) legal advocacy program assists individuals who have been sexually assaulted to navigate the justice system and serves a diverse clientele. Research suggests that there exists differences between ethnic groups in the qualitative psychological reactions to trauma, prevalence of post-trauma victimization, and use of therapeutic and tangible services. Thus, the purpose of our study is to examine the association between ethnicity, the three critical outcome variables (coping self-efficacy, perceived social support, and legal advocate satisfaction) and posttraumatic recovery

Die spätquartäre Entwicklung des Südasiatischen Monsuns

The Indian summer or South Asian monsoon (SAM) is a major component of the global climate system that dominates weather patterns and impacts the livelihood of billions of people across the subcontinent. Despite significant improvements over the past decade, the SAM remains difficult to predict and to model. This is directly related to the fact that instrumental records of monsoon precipitation at most date back few centuries. Consequently, the need to generate proxy records of monsoon precipitation and analysis of paleoclimate data is crucial to understand the various forcing mechanism of the monsoon on different timescales. In this thesis, the link between interhemispheric insolation changes and monsoon precipitation is explored and a working hypothesis is provided. High-resolution paleoclimate datasets have been generated from three sediment cores in the Andaman Sea. I develop potential proxies of SAM precipitation and perform paleoclimate time series analysis to better understand orbital and sub-orbital forcing mechanisms of the monsoon. The first continuous long-term high resolution records of monsoon precipitation based on paired Mg/Ca and δ18O analyses of near surface dwelling planktonic foraminifera are presented, from which I estimate sea surface temperature (SST) and seawater δ18O (δ18Osw). In addition, monsoon intensity changes are evaluated using proxies such as Ba/Ca, x-ray fluorescence (XRF) Ti/Ca, and Si/Al, which have been associated with the monsoon via different causal linkagesDer indische oder Südasiatische Monsun (SAM) ist eine wichtige Komponente des globalen Klimasystems, das das Wettergeschehen und somit die Existenzgrundlage von Milliarden Menschen innerhalb des Subkontinents kontrolliert. Trotz signifikanter Verbesserungen während der letzten Dekade bleibt es schwierig, den SAM vorherzusagen und zu modellieren. Dies liegt hauptsächlich an der Tatsache, dass instrumentelle Aufzeichnungen des Monsunniederschlags bestenfalls einige Jahrhunderte zurückreichen. Folglich gibt es den klaren Bedarf, den Monsunniederschlag anhand von Proxydaten zu rekonstruieren und die Analyse von Paläoklima-Daten ist entscheidend, um die verschiedenen Mechanismen die den Monsun über lange Zeitskalen antreiben, zu verstehen. Im Rahmen dieser Dissertation wird die Verbindung zwischen der Veränderung von interhemisphärischer Insolationsintensität und Monsunniederschlag untersucht. Hochauflösende paläoklimatische Datenreihen wurden für drei Sedimentkerne aus der Andamansee generiert. Die Analyse der Proxy-Indikatoren für SAM Niederschlag resultierten in paläoklimatischen Zeitserienanalysen, die es möglich machen, orbitale und suborbitale Steuerungsmechanismen des Monsuns besser zu verstehen. Ich präsentiere die ersten langfristigen Aufzeichnungen des Monsunniederschlags basierend auf δ18O Werten des Meerwassers (δ18Osw), die aus kombinierten Mg/Ca (Oberflächenwassertemperaturen) und δ18O Analysen von Foraminiferen, die in den oberen Wasserschichten leben, rekonstruiert wurden. Zusätzlich wurden die Veränderungen der Monsunintensität dadurch untersucht, dass weiteren Proxy-Indijkatoren wie Ba/Ca, XRF Ti/Ca und Si/Al einbezogen wurden, die über unterschiedliche kausale Zusammenhänge mit dem Monsun assoziiert waren

The economic impacts of maize-based bioethanol production in South Africa

In South Africa, the production and use of biofuels is increasingly being contemplated as a policy instrument to stimulate rural development and reduce poverty by creating sustainable income earning opportunities. By using social accounting matrix, this thesis examines economic gains, if any, in South Africa following maize-based bioethanol production using the country’s surplus maize as feedstock. The findings suggest this particular biofuel policy leads to a moderate increase in domestic industries’ production, value-added and foreign exchange earnings. However, the vast income inequality among the country’s various population groups remains unchanged