Nickel (II) phthalocyanine-multi-walled carbon nanotube hybrids as supercapacitors

The thesis examines for the first time the supercapacitive properties of three different nickel (II) phthalocyanine complexes, nickel (II) tetraamino phthalocyanine (NiTAPc), nickel (II) phthalocyanine and nickel (II) tetra tert-butylphthalocyanine as a) nanocomposites with multiwalled carbon nanotubes and as (b) an electropolymer supported on multiwalled carbon nanotube platform (MWCNT-polyNiTAPc). The supercapacitive properties of nickel (II) tetraaminophthalocyanine (NiTAPc)/multi-walled carbon nanotube (MWCNT) nanocomposite films have been found to possess a maximum specific capacitance of 981 F g-1 (200 mF cm-2), a maximum power density of 700 Wkg -1, a maximum specific energy of 134 Wh kg-1 and excellent stability of over 1500 chargedischarge continuous cycling. When compared to MWCNTs modified with unsubstituted nickel (II) phthalocyanine (MWCNT-NiPc) or nickel (II) tetra tert-butylphthalocyanine (MWCNT-tBuNiPc), MWCNT-NiTAPc exhibited superior supercapacitive behaviour, possibly due to the influence of nitrogen-containing groups on the phthalocyanine. The MWCNTpolyNiTAPc electrode had a maximum (112 mF cm-2) capacitance which was higher than that observed for MWCNT-polyNi(OH)TAPc (84.9 mFcm-2) but lower that of the MWCNT-NiTAPc (200 mF cm-2). CopyrightDissertation (MSc)--University of Pretoria, 2010.Chemistryunrestricte

Multipurpose stationary exercising pedaling system

Capstone Project submitted to the Department of Engineering, Ashesi University in partial fulfillment of the requirements for the award of Bachelor of Science degree in Electrical and Electronic Engineering, May 2020Middle to low-income people in developing countries usually spend most of their time making ends meet. Therefore they do not get time to enhance their physical fitness by exercising. Moreover, frequent power cuts make them stay in the dark at home at night. In this project, an affordable home multipurpose stationary pedaling system is made. The concept of speed detection using a Hall Effect sensor, a magnet, an Arduino and a comparator is used to obtain revolutions per minute (rpm) values and time using Millis. The average maximum speed detected after five experiments is 26.57 rpm. The low-speed detection capacity is attributed to the non-robust application nature of the components used in the project. Simulation results, however, show that the minimum speed that the MatLab Simulink DC machine operating as a generator has to be supplied with is 18850 rpm input to generate power that charges a 12V lead-acid battery. As speed increases, the power produced by the generator increases. Calories burnt are determined using measured power output of the generator and frictional losses of the system converted to Joules using the standard conversion. Moreover, a charge controller that allows discharging the battery above 80% and charging at 40% of its voltage is made using circuit breakers.Ashesi Universit

Induction of labour with titrated oral Misoprostol suspension: a comparative study with vaginal Misoprostol

A CAJM journal article comparing the effectiveness of titrated orally and vaginally administered misoprostol for induction of labour administered at the University of Zimbabwe Teaching Hospital..Objective: To compare the effectiveness of titrated orally and vaginally administered misoprostol for induction of labour. Study Design: Unmasked randomized controlled trial. Setting: Department of Obstetrics and Gynaecology University of Zimbabwe, Harare. Subjects: Pregnant women with singleton foetus in cephalic presentation booked for induction of labour, were randomized to receive titrated orally or vaginally administered misoprostol. Main Outcome Measures: The main outcomes were the duration of labour and induction to delivery interval. The secondary outcomes were neonatal and maternal complications. Methods: 134 women were recruited into the study; 69 and 65 were randomized into orally and vaginally administered misoprostol respectively. Results: The baseline characteristics in the two groups were similar. Women induced with titrated oral misoprostol suspension had a shorter interval from administration of the drug to initiation of uterine contractions (OR = 0.94 .95% Cl 0.42 to 2.12 ) and a longer duration of labour (OR = 0.36; 95% Cl 0.16 to 0.79). Labour was augmented with oxytocin in the oral group. The mean drug dose was 28mcg in the oral group. There was no difference in the mode of delivery between the two groups. Hypertonic uterine contractions were not detected. Ruptured uterus did not occur in the study population. There were more neonatal admissions in the vaginal than the oral group (OR = 1.03 .95% Cl 0.29 to 1.39). Conclusion: Titrated oral misoprostol suspension is as effective and safe as vaginal misoprostol for induction of labour even in poor resource countries where intrapartum monitoring is inadequate

Comparison of GO, GO/MWCNTs composite and MWCNTs as potential electrode materials for supercapacitors

We report the synthesis of graphene oxide/multi-walled carbon nanotube (MWCNT) composites employing an alternative and novel approach for possible application as supercapacitor materials in energy storage devices. Integrating these nanostructures resulted in a strong synergistic effect between the two materials consequently leading to a robust and superior hybrid material with higher capacitance compared to either graphene oxide or MWCNTs. Specific capacitances of 251, 85 and 60 F g−1 were obtained for graphene oxide-multi-walled carbon nanotubes, MWCNTs and graphene oxide, respectively, in a potential range from −0.1 to 0.5 V. Most importantly, a 120% increase in capacitance was observed with increasing cycle number at 20 mV s−1. The ease of synthesis and the exceptional electrochemical properties make the use of this nanostructure an attractive, alternative way of designing future supercapacitors in both conventional fields and new emerging areas

Opportunities and challenges in the commercialisation of medicinal plants used in village chicken health management

Background: Medicinal plants (MPs) are widely accepted and used in most rural communities in sub-Saharan Africa and beyond to treat and control village chicken (VC) diseases and parasites. They are readily available, accessible and cheap. Moreover, they are nature friendly and have adapted to the local environment, making them easy to produce. Over and above, their use has health benefits for consumers. Little is known about the opportunities and challenges faced when commercialising these MPs. Aim: It is imperative to unpack the opportunities and challenges that are encountered while commercialising MPs used for treating VC diseases and controlling parasites. Despite these multiple benefits, the commercialisation of these plants seems to be under researched. In South Africa, different rural communities use various MPs in their locality. For instance, most rural families in South Africa are using Aloe ferox, Helichrysum petiolare, Tagetes minuta, Lippia javanica, Agave sisalana, Gunnera perpensa and Millettia grandis. Conspicuously, not much is known about the efforts made to commercialise these products. Method: Through a systematic review of the literature, this paper unpacks the trends, opportunities and challenges faced in commercialising MPs used to treat VC disease and control parasites. Results: Results have revealed that globally MPs for VC management are not widely recognised, despite their wide usage by local communities. If properly harnessed, they have the potential to strengthen local economic development through income generation. However, currently, little is derived from the sale of these products because of the presence of middlemen. Their commercialisation efforts are hampered by the lack of organised support systems and networks, lack of regularisation strategies and clear criteria for supporting quality, protection and presumed efficiency. Conclusion: By commercialising MPs, local farmers can exploit MPs beyond the village chickens to broiler and layer chickens, thus offering alternative chicken health and affordable medicinal options for the farmers. Contribution: The study contributes to understanding the available opportunities and challenges in commercialising MPs used for village chicken health management. It further demonstrates that MPs for village health can be used to transform the livelihoods of the custodians of these plants

Globular reduced graphene oxide-metal oxide structures for energy storage applications

In this work, we employed an in situ spray pyrolysis approach to fabricate metal oxide-graphene composites with highly porous morphologies.The materials exhibited unique globular structures comprising metal oxide nanoparticles embedded between graphene sheets with high capacitance

Advanced graphene-metal oxide nanostructured composites for supercapacitors

The development of alternative energy storage systems is undoubtedly one of the greatest challenges facing our modern society as a result of emerging ecological concerns. The ever-increasing environmental concerns and the need for efficient energy storage devices have catapulted research in this field, mainly focused on electric double layer capacitors (EDLC’s), also known as supercapacitors, which consist of carbon based materials. The ultimate performance of these devices strongly depends on the intrinsic properties of their constituent materials and their eventual architectural design. The main focus of this doctoral thesis is to develop high performance supercapacitor electrodes utilising simple and cost effective methods ideal for industrial and commercial use. The materials reported herein are therefore traditional pseudocapacitive metal oxides incorporated onto an electrical double layer material (graphene sheets and carbon nanotubes) to produce a synergistic network with high conductivity. The development of this work stems from previous work where we developed a graphene oxide-carbon nanotube composite for stable and high performance supercapacitor electrodes. It is against this background that the work reported herein was developed to incorporate metal oxides onto large graphene sheets and additionally a ternary system comprising metal oxide nanoparticles, carbon nanotubes and graphene. In this work, an in-situ spray pyrolysis approach to fabricate different metal oxide-graphene composites with highly porous morphologies for cost-effective high performance supercapacitor devices was used for the first time. An efficient encapsulation of metal oxide particles with graphene oxide (GO) while simultaneously reducing the GO is reported. In the first experiment, a high surface area (BET surface area of 139 m2g-1) self–organized, micron sized urchin-like composite made up of reduced graphene oxide (rGO) and needle-shaped manganese oxide (rGO-Mn2O3/Mn3O4) is reported. Maximum capacitances of 425 Fg-1 at 5 mVs-1 from a three electrode set up and 133 Fg-1 at a current density of 0.2 Ag-1 are reported from an asymmetric two electrode set up with graphene as the anode. The composite material also shows capacitance retention of 83% over 1000 cycles. These remarkable performances are attributed to the high specific surface area due to the “urchin-like” hollow structures and synergy between the manganese oxide and reduced graphene oxide materials within the composite. Apart from the outstanding performance, the synthesis technique can be exploited further in the bulk synthesis of cost effective graphene-metal oxide hybrid materials for energy storage applications. In a development of the first work, composites consisting of NiO and Co3O4 and rGO were synthesized and tested. As a result of spray pyrolysis, the composites exhibit unique globular lettuce-like structures comprising NiO or Co3O4 nanoparticles embedded between graphene sheets. An impressive overall performance arises from such structures by exploiting the pseudocapacitive nature of the metal oxide and conductive EDLC nature of the rGO. Specific capacitances as high as 687 and 656 Fg-1(three electrode set up) for rGO- Co3O4 and rGO-NiO composites were recorded respectively. Based on the same principle a more developed experiment, this time utilising reduced graphene oxide, functionalized multiwalled carbon nanotubes and nickel oxide nanoparticles is reported. Electrodes fabricated from this novel ternary system exhibit exceptionally high capacitance (2074 Fg-1 from a three electrode set up) due to the highly conductive network, synergistic link between graphene oxide and carbon nanotubes and achieving high surface area monodispersed NiO decorated rGO/CNTs composite employing the liquid crystallinity of GO dispersions. To further assess the practicality of this material for supercapacitor manufacture, we assembled an asymmetric supercapacitor device incorporating activated carbon as the anode. The asymmetric supercapacitor device showed remarkable capacity retention (\u3e96%), high energy density (23 Whkg-1) and a coulombic efficiency of 99.5%. In all three experiments, the benefits of fabricating composites of EDLC and pseudocapacitive metal oxide nanoparticles are reflected by the high specific capacitances, high energy densities and long cycle life

Influence of the heifer international pass on programme on livehoods of households: the case of Wanezi Ward in Mberengwa District of Zimbabwe

MRDVInstitute for Rural DevelopmentFood and nutritional insecurity, poverty and hunger are some of the 21st -century challenges baffling most developing economies. Worldwide, 1.2 billion people are estimated to be living in poverty. Since 1990, the number of people living in extreme poverty has increased by over 50 million in 2014. Among the many public and private institutions that have made several gritty efforts to address the poverty challenge is the Heifer international through its Heifer International Pass on Programme (HIPP). Under the HIPP, the Pass on the Gift programme has been implemented in Ward 1 of Mberengwa District for over two decades targeting the food and nutritional insecure, hungry and poverty-stricken people who are given a gift in form of cattle, goats, chicken etc. This was done with the belief that the gift will add value to their asset base and serve as stepping stone out of poverty, food and nutrition insecurity. Various reports have been written on how the programme helped in improving household livelihood. However, the voice of the beneficiaries was not being heard. This study explored how the Pass-on-the-Gift programme influenced the household‘s livelihoods in Ward 1, Mberengwa District of Zimbabwe. A multi-stage integrated approach was employed. Both the case study and a cross-sectional survey designs were employed. Two sequentially integrated phases were followed. On the first phase, a case study was used to gather data from the Heifer International Pass on Programme beneficiaries and other key stakeholders. During this stage, data were collected using a semistructured interview guide. Results obtained from the first phase informed formulation of the questionnaire used in the second phase. Respondents were purposefully sampled in both stages. Data obtained through semi-structured interviews were analyzed using Atlas ti 8 software while that from a survey was analyzed using IBM SPPS version 25 software to generate descriptive statistics and inferential statistics components. Results from the first phase of data collection were triangulated with those from the second phase. This synchronized the two data sets and allowed subsequent discussion of the results. The research findings revealed that the HIPP influenced all the households of the participating farmers financially, socially and economically where p= 0.000. Thus, the study confirmed that the notion that cattle ownership can be used as an avenue of confronting the multi-dimensional rural development challenges. Furthermore, it was revealed that cattle ownership empowers the rural smallholder farmers and has potential to assist households dismantle the perpetual dependency on external support, improve their livelihoods and contribute to sustainable development goals.NR

Rietveld analysis of the effect of annealing atmosphere on phase evolution of nanocrystalline TiO 2 powders

The struclUral evolution of nanocrystaUine Ti02 was studied by X-ray diffraction (XRD) and the Rietveld refinement method (RRM). Ti02 powders were prepared by the sol-gel technique. Post annealing of as·synthesized powders in the temperature range from 500°C to 600 °C under air and argon atmospheres led to the formation of Ti02 nanoparticles with mean crystallite size in the range of 37-165 nm. based on the Rietveld refinement results. It was found that the phase structure, composition, and crystallite size of the resulting particles were dependent on not only the annealing temperature, but also the annealing atmosphere. Rietveld refinement of the XRD data showed that annealing the powders under argon atmosphere promoted the polymorphic phase transformation from anatase to rutile. Field emission scanning electron microscopy (FESEM) was employed to investigate the morphology and size of the annealed powders