383 research outputs found
Sort by
Recovery of Lead from Lead Laden Cupels by a Simultaneous Leaching and Electrowinning Process in a Methanesulphonic acid bath
No full textResearch ArticleCupels are generated by mines during the fire assaying of precious group metals. The cupels contain
lead which is a known environmental hazard hence the need to recover it. This work illustrates how leaching
and electrowinning processes can be combined to produce a hybrid lead recovery process. Bench scale tests
were conducted for the hybrid leaching and electro winning process using Methane Sulfonic Acid (MSA) as a
leaching solvent at a concentration of 200g MSA per litre of water. A glass electrowinning cell fitted with a
9cm ? 4cm pure lead cathode and 9cm ? 4cm graphite anode with inter electrode gap of 15cm and a magnetic
stirrer bar was used. Lead laden cupels (containing 30g lead) were subjected to simultaneous leaching and
electrowinning and lead recovery after a period of 80 minutes was found to be 98%. The hybrid process was
found to require about 20% less solvent than that required for the convectional leaching process which requires
multiple stages to reduce the concentration of the solute in the raffinate to the same extent
Risk and Concentration of Portfolios on the Zimbabwe Stock Exchange after Currency Reform
No full textAn article published in British Journal of Economics, Management & Trade
4(8): 1191-1202, by SCIENCEDOMAIN international in 2014. It deals with Risk and Concentration of Portfolios on the
Zimbabwe Stock Exchange after Currency
Reform.Aims: The objectives of this study are to assess the level and impact of concentration of
portfolios on the ZSE and to determine the number of stocks to be held in a concentrated portfolio to achieve effective risk reduction. Study Design: Portfolio Model.
Place and Duration of Study: Zimbabwe, Department of Insurance and Actuarial
Science and Department of Finance, between February 2013 and March 2013.
Methodology: We analysed the level of concentration of portfolios held on the Zimbabwe
Stock Exchange (ZSE). The market capitalization weights and the daily closing prices of 62 stocks in the industrial index for the four-year period form 19 February 2009 to 31
December 2012.
Results: The Herfindahl-Hirschman Index and the Roll measure of concentration were
employed to analyse the level of concentration of portfolios mimicking the industrial index and it was observed that portfolios held on the ZSE are highly un concentrated with an approximate measure of 14% under the HHI measure as at 31 December 2012. The daily returns over the period were calculated and used to estimate the risk of the portfolio. The
findings indicates that stocks in the industrial index of the ZSE have relatively low correlation due to the small difference in risk between equally weighted portfolios with no correlation and equally weighted portfolios with historical correlation.
Conclusion: The empirical evidence highlights that an optimal portfolio size averaging 20 to 25 stocks of the Industrial Index stocks will have to be included in order to achieve effective risk reduction
Imaging Ellipsometry Study on the effect of Electrolyte on the drainage of an Aqueous Film trapped between a Plane Hydrophilic Silica Surface and an approaching Organic droplet
No full textAn imaging ellipsometer is used to study the drainage of an aqueous film trapped between a
hydrophilic silica equilateral prism surface and a heptane or butylacetate droplet. The interfacial droplet profile on approach to the hydrophilic silica surface is such that the droplet is dimpled at its center with the
periphery of the droplet (the barrier ring) being the region of closest approach to the hydrophilic silica surface. The time it takes for these drops to either achieve an equilibrium film thickness at the barrier ring or to coalesce with the macroscopic hydrophilic silica surface was experimentally determined; drainage time increases whilst equilibrium film thickness decreases with increasing salt concentration in the continuous phase. The increase in drainage time is attributed to hindered drainage of the aqueous film due probably to an increase in the aqueous film viscosity, which should translate into a decrease in the film elasticity. Compression of the double layer may also qualitatively explain the observed decrease in equilibrium film thickness at the barrier ring as the salt concentration increases. When aluminum chloride is used as the electrolyte the equilibrium film thickness is relatively constant (around 90 ? 10 nm) for the range of concentrations studied. This may be due to the fact that the aluminum ion has a valence of three and may screen electrostatic interactions between the oil droplet and the hydrophilic silica surface at
relatively lower aluminum chloride concentrations
From Patriarchy to Gender Mainstreaming: Creating gender-neutral participatory practices in higher education institutions
No full textThis is an article on Conference ProceedingsIn human societies across the globe, disparities in equitable distribution of resources to achieve education goals by
members of societies have been perpetuated by human social constructions that have favoured one social grouping
at the expense of another. These human constructions often couched in gender terms have become entrenched as
stereotype phenomena, which eventually become viewed as ?givens,? when in reality they are constructions that
only exist in the constructors? minds and are essentially not real. For equity and equality in accessing resources for
education, for all regardless of a person?s sex or gender, a deconstruction of stereotype gender traits and roles has to
take place first, through changing mind-sets so that members of communities and societies see gender and roles as
nothing but labels that have come about through socialization and then come to appreciate that any human being
regardless of sex or gender is capable of achieving any endeavor if given the requisite support. This paper searched
literature to explore what mind-sets needed to change, so as to achieve equity and equality in opportunities in
institutions of higher education in Zimbabwe. The paper deriving views from extant literature, concluded that
patriarchy, subservience of girls and women, girls and women as belonging in the kitchen, creation of double-binds
for women, shattering the glass ceilings and removing sticky floors, making glass escalators accessible to both
genders, making gender inequality a humanity challenge rather than a feminist challenge, all have to be re-visited
with changed mind-sets, if communities are to succeed in eradicating the ugly faces of misogyny and misandry
Effect of Mo content on the structural and physical properties of Cr100-xMox alloys
No full textProceedings of South African Institute of Physics (SAIP), 2014. The 59th annual conference of the South African Institute of Physics.Alloying Cr with Mo, which is isoelectric with it, shows an unexpected decrease in
the N?el temperature (TN) with an increase in Mo concentration. This is attributed to a
delocalization of the 3-d bands in Cr through the introduction of 4-d electrons of Mo. In the
present investigation the effect of Mo concentration on the structural, magnetic and electrical
properties of Cr is systematically studied. A series of Cr100-xMox
alloys, with x = 0, 3, 7, 15 and
25, was prepared and the actual concentrations established using electron microprobe analyses.
XRD studies confirm the bcc structure of these alloys as in pure Cr and indicate an increase in
lattice constant with an increase in Mo concentration. The crystallite sizes calculated from
these results for the Cr100-xMox
alloys ranges between 15 and 30 nm. The physical properties of
these alloys were investigated through magnetic susceptibility (?), Seebeck coefficient (S),
electrical resistivity (?) and Hall coefficient (RH) as function of temperature (T) measurements.
TN values obtained from these measurements are comparable.South African National Research Foundatio
Knowledge, attitudes and practices of University students on Web 2.0 tools: Implications for academic libraries in Zimbabwe
No full textKnowledge, attitudes and practices of university students on web 2.0 tools: Implications foracademic libraries in Zimbabwe is a journal articleWeb 2.0 technologies have provided both opportunities and challenges for academic libraries. These socio technological
innovations have enabled interactivity and gathering of knowledge through experience and
practice on a global scale. The concept of collaborative work, social networking and the ease in the usage of these applications has brought a significant change in the internet usage by university students. Many academic
libraries are beginning to leverage the power of these services to provide better and more relevant services to their patrons. The use of web 2.0 tools in academic libraries and has begun to take shape recently in Zimbabwe.
However, studies reveal that utilisation these tools is still low in Zimbabwean academic libraries. Understanding knowledge, attitudes and practices of university students on web 2.0 tools paves the way for the efficient and effective use of these tools in Zimbabwean libraries. This study aimed at determining the knowledge, attitudes
and practices of university students on web 2.0 tools. The survey method was used to gather data. A self administered questionnaire was used to gather data from 280 undergraduate students who were conveniently selected to participate in the study. The findings reveal that most students have excellent knowledge of specific web 2.0 tools such as Instant Messaging and Social networking. Most tools were used mainly for
communication purposes. A small percentage of respondents indicated that they use the tools for educational purposes. Students displayed lack of knowledge and use on mashups, social bookmarks, and relatively simple syndication (RSS) feeds. The fact that most of these tools are already being widely used by students entail that academic libraries can utilise these technologies in developing user services. However, the issues of awareness, access, confidentiality, and accuracy of these tools need to be addressed to ensure their successful implementation and use
Recovery of Lead from Lead Laden Cupels by a Simultaneous Leaching and Electrowinning Process in a Methanesulphonic acid bath
No full textThis article is published under the International Journal of ChemTech Research Vol.6, No.4, pp 2404-2413 by Sphinx Knowledge House. It is a reserch dealing with "Recovery of Lead from Lead Laden Cupels by a Simultaneous Leaching and Electrowinning Process in a Methanesulphonic acid bath"Cupels are generated by mines during the fire assaying of precious group metals. The cupels contain lead which is a known environmental hazard hence the need to recover it. This work illustrates how leaching
and electrowinning processes can be combined to produce a hybrid lead recovery process. Bench scale tests
were conducted for the hybrid leaching and electro winning process using Methane Sulfonic Acid (MSA) as a
leaching solvent at a concentration of 200g MSA per litre of water. A glass electrowinning cell fitted with a
9cm ? 4cm pure lead cathode and 9cm ? 4cm graphite anode with inter electrode gap of 15cm and a magnetic
stirrer bar was used. Lead laden cupels (containing 30g lead) were subjected to simultaneous leaching and
electrowinning and lead recovery after a period of 80 minutes was found to be 98%. The hybrid process was
found to require about 20% less solvent than that required for the convectional leaching process which requires
multiple stages to reduce the concentration of the solute in the raffinate to the same extent
Optimisation of the Linear Probability Model for Credit Risk Management
No full textA journal article from International Journal of Computer and Information Technology Volume 03 ? Issue 06, November 2014One of the aims of the banking business is to provide loans to applicants. Credit risk management plays an important role in banks, as loans generally account for half to three quarters of the total value of bank assets. Credit scoring is a systematic method for evaluating credit risk and assists decision makers determine whether or not to provide loans to applicants. Scoring models are systematic means of evaluating the
creditworthiness of a loan applicant. However, existing scoring models cause some loan applications to be rejected unnecessarily as their credit rates are lowered to rejection levels due to lack of information such as previous loan payment data. This might be
refusal of good credit, which potentially can cause the loss of future profit margins. This study aims at optimising one such credit scoring model to ensure that it uses only the critical scoring criteria to determine a credit score. The optimised model will not only reduce the proportion of unsafe borrowers, but also identify profitable borrowers
Gauge Invariant Massive Long Range and Long Lived Photons
No full textGauge Invariant Massive Long
Range and Long Lived Photons is a published article of the Applied physics department.Prevailing and conventional wisdom holds that intermediate gauge Bosons for long range interactions such as
the gravitational and electromagnetic interactions must be massless as is assumed to be the case for the photon
whichmediates the electromagnetic interaction. We have argued in a different reading that it should in-principle
be possible to have massive photons. The problem of whether or not these photons will lead to short or long
range interactions has not been answered. Naturally, because these photons are massive, one would without
much pondering and excogitation on the matter assume that these photons can only take part in short range
interactions. Contrary to this and to conventional wisdom; via a subtlety ? namely, the foregoing of the Lorenz
gauge and in line with ideas set out in out proposed Unified Field Theory, the introduction of a vector potential
whose components are 4 ? 4 hermitian matrices; we show within the confines of Proca Electrodynamics under
the said modifications, that massive photons should be long lived (i.e., stable) and be able to take part in long
range interactions without any problem.
Effect of Including Some Insects as Feed Supplement on Broilers Reared in Zimbabwe
No full textThis article is published by International Journal of Poultry Science in 2014 vol. 13 (1): pp.42-46. The ISSN for the article is 1682-8356.A trial to test the effect of including some insects as feed supplement on broilers reared in
Zimbabwe was conducted. The initial weight of the day old chicks was 48 g they all looked healthy. The feed
was provided as mash which the young birds ate normally. On day 12 and 18 when Bursa gomboro vaccine
was administered there was no change in feeding frequency. Growth was steady the birds approximately
doubling their own weight every 5 days. Throughout the study period day temperatures were between 25 and
35?C Celsius and night temperature were between 15 and 20?C Celsius. Humidity ranged between 65 and
95% the mean being 75%. Rainfall with thunder occurred at least 5 times but did not affect the birds with
regards to feeding frequency. The birds that fed on Encosternum delegorguei had a lower mass than the
others until slaughter. Those fed on Macrotermes falciger had a higher mass until day 25 after which the
control group took the lead. There was a significant difference in growth rate between hens and cocks in all
the groups (H, I, C) p>0.05. Comparison of cocks fed on Macrotermes falciger, Encosternum delegorguei and
the control showed no significant difference p>0.05. Comparison of hens fed on Macrotermes falciger,
Encosternum delegorguei and the control showed no significant difference p>0.05. There was significant
difference between feed consumed during the day and that consumed at night among all the three groups
p>0.05. The sizes of the various body parts were within range for all the groups indicating food utilization by
the birds was even and not channeled to one organ. No unusual ill health effects were recorded, the
appearance of the birds was normal, internal organs did not show any signs indicating ill health for hens and
cocks fed on Macrotermes falciger, Encosternum delegorguei and the control