In situ visualization of organic fouling and cleaning mechanisms in reverse osmosis and forward osmosis

Fouling models rely on knowledge of foulant accumulation and removal mechanisms. In this study, a fouling visualization apparatus is developed to elucidate centimeter-scale mechanisms of organic fouling and cleaning in reverse osmosis (RO) and forward osmosis (FO). Alginate is used as a model organic foulant and dyed with methylene blue, which is shown not to affect fouling or cleaning, and to sufficiently highlight the gel for visualization at low salinity (up to 1% NaCl). When cleaning by increasing the cross-flow velocity, with or without reverse permeation, foulant peels off the membrane in discrete pieces in both RO and FO. Videos of cleaning show that foulant cake swelling and wrinkling can facilitate gel detachment and removal. Despite their effectiveness in slowing fouling, spacers can hinder removal of detached foulant pieces by obstructing their path. Finally, photographs point to a new mechanism of internal fouling in FO: vapor formation due to sub-atmospheric pressure within the membrane. Awareness of these mechanisms allows for better modeling of fouling and motivates optimization of swelling-inducing cleaning procedures.Center for Clean Water and Clean Energy at MIT and KFUPM M (Project #R4-CW- 11)Martin Family Society of Fellows for Sustainability (Martin Fellowship for Sustainability

A quantitative study on the psychological capital, psychological climate, and organisational citizenship behaviours of academic lecturers across South Africa.

Masters Degree. University of KwaZulu-Natal, Durban.Psychological Capital (PsyCap), Organisational Citizenship Behaviour (OCB) and Psychological Climate (PC) are all positive constructs, which have shown a positive relationship to coping mechanism in the workplace, and wellbeing initiatives. In light of positive organisational literature, it has become increasingly important to investigate modalities to which individuals cope during change in the organisation and the dynamic between organisational change and wellness (Saks, 2008 ). However, change is not only a feature to corporate organisations, but are equally apparent in tertiary institutions. It is a goal of a tertiary institution to equip students with skills and knowledge that is relevant and valuable to the working world (Benedict, Gwija, Iwu, & Tengeh, 2013). If there is constant change in the corporate or world or work, which is considered constant, then the tertiary intuitions must equally dynamically shape their educational training to match those changes. This being constrained and often further shaped by socioeconomic and political dynamics of both the student and managerial body (Quinn, 2012). In light of such, it becomes important to contrast and understand the negotiation of change in a tertiary setting where there is a complex nature and structure (Benedict et al, 2013). Thus, it is important to facilitate research that adds to intervention and assessment based strategies that would be able to be utilized in a large scale change analysis strategies. However, a key anecdote in change studies has been an interplay of considering wellbeing as an antecedent to change strategies. Research exploring agility, stress, resilience, and so forth has often taken a diagnostic approach where the assessment is used to diagnose a situation, as a pose to explore its dilemma. Research by Cadwallader and Parish (2008) highlight this issue through exploring employee commitment to change. What becomes apparent is that identifying stressors and change methodologies is one element, the secondary element is contrasting such in a holistic approach whereby there is an extended significance placed on considering wellness (Cohn & Fredrickson, 2010). Wellness is taking into consideration all aspects of an individual’s wellbeing this includes environmental features, financial, social etc. (Field & Louw, 2012). Each of which have an equal weight into how change is understood and taken by an individual (Field & Louw, 2012). In order to consider such this research took on the psychological climate perspective in consideration with psychological capital and organisational citizenship behaviour. This is aimed to provide a triadic approach that places the individual and organisation in 3 spheres of the self, 4 the perspective of others, and perceptions of the organisation. Thus, this research aimed to determine the relationship that exists between psychological capital, psychological climate, and organisational citizenship behaviour. The study also sought to determine to what extent the sub factors from each of these scales had a moderating effect. A cross-sectional research design was used in the study. The researcher used a sample of 375 (N = 375) academics from across several different tertiary institutions across South Africa. The researcher used three questionnaires in the study. A biographical questionnaire created by the researcher, the Psychological Capital Questionnaire (PCQ), the Organisational Citizenship Behaviour Questionnaire (OCBQ), and the Organisational Climate Questionnaire (OCQ). The main findings of the study indicated that there were practically and statistically significant relationships between psychological capital, organisational citizenship behaviour and psychological climate. More specifically relationships were found to exist between the sub factors: resilience, expectations, and civic virtue. From the results, psychological capital was found to predict both organisational citizenship and psychological climate. However, it was noted that there was a higher predictive validity found in the psychological capital scale having a more significant impact on climate on citizenship behaviour. A secondary measure was preformed to confirm the findings– the Sobel test. The sobel test confirmed that psychological capital is the mediating variable between psychological climate and organisational citizenship behaviour as the Z score was confirmed as Z = 8.79 and p = 0.005. According to this mediation analysis, psychological capital is confirmed as a mediating the relationship between psychological climate and organisational citizenship behaviour. During the research, there were several limitations experienced. Firstly, due to the nature of the study being a nationwide study the researcher implemented a digital version of the survey in order to reach the target sample. However, this introduces a secondary level of ethical issues that needed to be carefully considered before interpreting any data. In addition, facilitating this research on an online platform whilst not unheard of is still gaining in research rigidity although its use in various methods. Considering such this research took steps to ensure data privacy and protection both with outsourcing the sample, and handling of the data. Ensuring that data stored is secure and without any breach. Furthermore, proof of legitimacy of the sample and the understanding of each question was carefully considered. However, it must be considered that interpretation of material may to 5 some extent be compromised. Just as with many assessments that are online based there must always include a measure that accounts for any variability in this instance. Furthermore, it was found that the climate measure itself has had an extensive variety of uses in many different settings and the original questionnaire was unavailable and not easily translatable. Due to this, the research adopted similar measures used in various studies. In future, recommending for research exploring the relationship between the three constructs of psychological capital, organisational citizenship behaviour and psychological climate. While there was little research on these three constructs initially, there most certainly is reason to believe that further research should be recommended. First of which is the imperative link between organisational citizenship behaviour and de-railers of psychological climate. Whilst this study relied heavily on positive constructs in order to construct a triadic approach, it would be beneficial to consider de-railer to these positive behaviours as such would only further strengthen any interventions proposed. Furthermore, still relatively few studies include climate. As it is a consistently valuable variable to consider to overall, organisational behaviours it becomes important to consistency contribute towards the body of knowledge from a South African perspective

Déploiement

Cet article décrit l'intervention des pompiers dans l'incendie de Eagle Bar dans Payette National Forest (Etats Unis) le 22 octobre 1988

Burn injuries in KwaZulu-Natal Province, South Africa: Quantifying the healthcare burden

Background. Most burn injuries occur in low- and middle-income countries (LMICs) and affect those of lower socioeconomic status disproportionally. A multifaceted approach is needed to improve burn outcomes. Healthcare strategies and reform should be data driven, but South Africa (SA) currently lacks sufficient baseline data related to burn injuries. The absence of local data is compounded by a global lack of published data from LMIC settings. The Pietermaritzburg Burn Service Registry (PBSR) is the only established registry for burn injuries in SA. Objectives. To use the high-quality, detailed data from the PBSR to estimate the KwaZulu-Natal (KZN) provincial burden of burns in terms of length of stay, need for surgery and mortality. Our broader aim is to quantify the magnitude of the problem to highlight the need for specific burn care strategies in SA. Methods. We conducted an observational, retrospective review of burns data from two databases, the District Health Information System (DHIS) between 2013 and 2018, and the more detailed PBSR between 2016 and 2019. We compared the distribution of mild, moderate and severe injuries as well as the distribution of adult and paediatric admissions between the DHIS and PBSR data sets. We then assumed that outcomes for the province would follow similar patterns to the Pietermaritzburg Burn Service and applied the proportions to the DHIS data set to estimate the annual provincial burden. Results. In the DHIS, there was an annual mean (standard deviation (SD)) of 4 807 (760) children (age ≤12 years) and 3 622 (588) adults (age >12 years) admitted to hospitals in KZN with burn injuries. Annual average injury severity was 76.0% mild (mean (SD) n=5 539 (1 112.4)), 19.8% moderate (n=1 441 (148.8)) and 4.2% severe (n=312 (24.5)). These proportions were similar in the PBSR. Projections estimate that 2 967 patients would need surgery, with 212 500 hospital days required annually in the province. Additionally, provincial mortality would be 586 patients, including 84% with burns of mild and moderate severity. These deaths are potentially preventable. Conclusion. There is a significant, unquantified burden of burn injury in KZN, highlighting the urgent need for development of specialised surgical services for burns. Collection of more robust national data to verify our projections is required to confirm the need and guide required healthcare reform.

Raising a child with down’s syndrome: perspectives from South African urban care-givers

Objectives: This study addresses a gap from a South African urban perspective on the knowledge and emotional responses of caregivers with children diagnosed with Down’s syndrome (DS). The study is an initial step towards informing health professionals who adopt a biopsychosocial approach, in an effort to improve interventions for both caregivers and children.Methods: A simple descriptive survey was utilized with 57 participants who were caregivers of children with DS. Data was analyzed descriptively using the Statistical Package for Social Scientists (SPSS) (version 21).Results: The caregivers’ initial reactions when discovering that the child had DS included shock, sadness and anxiety. When considering the etiology of Down’s syndrome, findings reflected that caregivers understood DS as a medical condition relating to chromosomal abnormalities rather than attribution of the syndrome to a fault of their own. Despite the immediate reactions, the caregivers’ initial emotions toward the child rather than the situation were positive and unchanged by the subsequent challenges in caring for the child. The caregivers indicated feelings of love toward the child notwithstanding the diagnosis.Conclusion: This study allowed for the subjective experience, perceptions and attitudes of caregivers to be investigated, and raised further questions into the deeper meanings and experiences of caregivers towards assisting practitioners in understanding the dynamics surrounding care-giving that may influence holistic interventions.Keywords: Down’s syndrome, caregivers, perceptions, emotional response

Performance studies of the tubular filter press.

Thesis (Ph.D.)-University of Natal, Durban, 1992.The tubular filter press is a novel tubular configured filter press for the filtration or dewatering of sludges. The unique features of the filter press are: (i) during the cake deposition cycle, cake is deposited on the internal walls of a self-supporting array of horizontal collapsible porous fabric tubes; (ii) during the cake removal cycle, cake is dislodged from the tube walls by means of a roller cleaning device and the dislodged flakes of cake are hydraulically transported out of the tubes by the feed sludge which is simultaneously re-circulated at a high flow rate through the tubes. The two main problems experienced on a prototype tubular filter press, which was erected at a water treatment plant to dewater the sludge from the clarifier underflow, were: (i) tube blockage problems during the filtration cycle; (ii) low cake recoveries (high cake losses) during the cake removal cycle. The following objectives which were defined for this study, were regarded as fundamental prerequisites for any solution of the two main problems: (i) to develop a predictive dead-end internal cylindrical model for compressible cake filtration inside a porous tube; (ii) to investigate the cake losses during the cake removal cycle of the tubular filter press; (iii) to develop a predictive unsteady-state internal cylindrical cross-flow microfiltration model for a non-Newtonian sludge which, when filtered, produces a very compressible cake. (An alternative to dead-end filtration during the filtration cycle of a tubular filter press is low axial velocity cross-flow filtration). On the basis of the objectives the study was divided into three separate investigations. To date no one has developed a model which incorporates the cylindrical configuration of the filter medium for dead-end compressible cake filtration inside a porous tube. The most comprehensive model for dead-end external cylindrical compressible cake filtration is that of Tiller and Yeh (1985). This model was adapted for internal cylindrical compressible cake filtration. In essence the model by Tiller and Yeh (1985) requires the solution of a system of two ordinary differential equations in order to calculate the radial variation of solids compressive and liquid pressures in a compressible filter cake deposited externally on a cylindrical surface. The relevant equations were derived for internal cylindrical compressible cake filtration and it was found that one of the differential equations changes from: dPl/dr = H1/2nrK (external cylindrical) to dPl/dr = H12nrK (internal cylindrical). The other differential equation remains unaltered for internal cylindrical compressible cake filtration. A batch of waterworks clarifier sludge from the prototype tubular filter press was used for experiments to evaluate the performance of the internal cylindrical filtration model. The cake produced by the filtration of this sludge had to be characterized for the model. Compression-permeability data were obtained over a wide solids compressive pressure range. A Compression-Permeability (C-P) cell was used for high solids compressive pressures (10 kPa<_ ps<_400 kPa) and settling tests were used for low solids compressive pressures (0,0065 Pa <_ ps < 525,6 Pa). The cake was found to be very compressible (compressibility coefficient = 0,989). Empirical equations of the form, K' = Fps - b and (1 - E) = B pbs , were derived from the C-P cell and settling tests to relate permeability and porosity to solids compressive pressure. The equations were slightly different to those proposed by Tiller and Cooper (1962). The predictions by the internal cylindrical compressible cake filtration model were compared to the results of constant pressure internal cylindrical filtration experiments, at filtration pressures of 100 kPa, 200 kPa and 300 kPa, using the waterworks clarifier sludge. The internal diameter of the filter tube which was used for the experiments was 26,25 mm. The model accurately described the results of the filtration experiments in terms of volume of filtrate, average cake dry solids concentration, filtrate flux and internal cake diameter. The differences between external cylindrical, internal cylindrical and planar compressible cake filtration were highlighted. Since the tubular filter press is a novel process, the cake losses during the cake removal cycle have not been investigated before. An investigation was therefore conducted into the cake losses which occur during the cake removal cycle. The same batch of clarifier sludge was also used for the investigation of cake losses during the cake removal cycle at filtration pressures of 100 kPa and 300 kPa. It was found that significant cake losses occurred due to: (i) the shear of the cleaning fluid prior to the action of the rollers (losses varied between 10 % to 20 % of the deposited cake dry solids); (ii) the combined action of the rollers when dislodging the cake and the hydraulic conveyance of the dislodged flakes of cake (losses varied between 30 % to 40 % of deposited cake dry solids). A new shear model, which was developed, accurately predicted the cake losses and increase in internal cake diameter and average cake dry solids concentration, which occurred due to the shear of the cleaning fluid. For the shear model the sludge (cake) rheology was determined using a capillary-tube viscometer. It was found that the sludges exhibited Bingham plastic behaviour in the solids concentration range: 3,58 % m/m <_Cs <_16,71 % m/m. The cake losses due to the action of the rollers and hydraulic conveyance of the dislodged flakesof cake decreased markedly as filtration pressure and filtration time were increased, while a decrease in path length for hydraulic conveyance of dislodged cake flakes resulted in a mild decrease in these cake losses. A literature review revealed that to date only one mathematical model (Pearson and Sherwood, 1988) is available for the unsteady-state cross-flow microfiltration of a non-Newtonian sludge which, when filtered, produces a compressible cake. A new unsteady-state internal cylindrical axial convection shear model (for laminar flow of the feed sludge) was developed for cross-flow microfiltration of a Bingham plastic sludge which, when filtered, produces a very compressible cake. Similar to the approach by Pearson and Sherwood (1988) this model is a combination of the dead-end internal cylindrical compressible cake filtration model and the "cleaning fluid" shear model. The major difference between the new model and the model by Pearson and Sherwood (1988) is that unlike the convection-diffusion model of Pearson and Sherwood (1988), diffusive and shear induced diffusive back-mixing of particles were assumed to be negligible. The existence of a shear plane within the cake forms the basis of the model. Those cake layers with a yield stress less than the shear stress exerted by the flowing feed sludge at the inner cake wall are convected along the shear plane. It was assumed that the axial convection of the solids in the moving cake layer along the shear plane is the sole mechanism for removal of solids deposited at the cake surface. The model was compared to the results of cross-flow microfiltration experiments at one filtration pressure (300 kPa) and cross-flow flow rates of 0,84 l / min; 1,58 l / min; 2,43 l / min and 4,44 l /min. The model accurately described the variation of filtrate flux, internal cake diameter and average cake dry solids concentration during the unsteady-state time period. The model, however, had to be "extended" by incorporating empirical equations for changes in permeability and porosity (due to further cake compaction) to obtain a good fit between the model and experimental results during the pseudo steady-state time period. The results of all three investigations provide a greater understanding of the cake deposition process (during both dead-end and cross-flow filtration modes) and the cake removal process for the tubular filter press. This should assist in finding solutions to the two main problems which were experienced on the prototype tubular filter press

Location of Firearm Suicides in the United States, 2003-2021

Suicide is a leading cause of death in the US, with firearms accounting for more than half of those deaths. Current research about firearm suicide prevention largely focuses on promoting secure storage to reduce or delay access to lethal means at home. While such prevention measures are essential, their exclusive focus on the home environment may fail to address firearm suicides outside the home, which may vary by subpopulation and circumstance. However, there is little information on these factors. We sought to quantify and describe firearm suicides that occur outside the home to inform more comprehensive and effective prevention strategies for these deaths

Neurobehavioural challenges experienced by HIV exposed infants : a study in South Africa

BACKGROUND : The newborn infant is a complexly organized, competent being, who plays an active role in shaping their environment through their increasing skills in autonomic regulation, motor control, regulation of state and social interaction. Infants born to HIV positive mothers, are exposed to HIV and antiretroviral therapy inutero, and may experience adverse effects from this. METHODS : A cross-sectional study of 132 mother-infant dyads from a large public health hospital in South Africa. Infants were assessed using the Neonatal Behavioural Assessment Scale on day two of life, and mothers mental health assessed using the Edinburugh Postnatal Depression Scale. Medical and demographic data on mothers and infants was collected, including maternal age, HIV status, length of time on antiretrovirals, relationship status, employment status, gravid status, mode of delivery, infant anthropometrics and infant gender. Data was input into IBM SPSS statistics 21, where frequencies and percentages for descriptive analysis, and Chi-square and student’s two sample t-tests were run to compare data from HIV infected-exposed and HIV uninfected-unexposed mothers and infants. RESULTS : HIV exposed infants were smaller than HIV unexposed infants, even though low birth weight was an exclusion criteria. Statistically significant differences were found between HIV exposed and unexposed infants in neurobehavioiral items of social interaction (p = 0.00), motor system (p = 0.00) and state organization (p = 0.01), with HIV exposed infants performing less optimally in these domains. HIV exposed infants also presented with more abnormal reflexes. Infants born to depressed mothers showed superior motor skills, state organization and state regulation than infants born to mothers who did not score in the possibly depressed range. CONCLUSIONS : HIV exposed infants have inferior neurobehavioural functioning, which may affect their quality of life and ability to develop a reciprocal relationship with a primary caregiver. This may have an effect on development, behaviour and mental health in later childhood. HIV exposed infants shoud be monitored closely and their functioning in autonomic stability, motor control, resualtion of state and social interaction assessed regularly. Guidance for caregivers in incorporating strategies into the care of these infants is essential to buffer the possible long term negative effects on development.MRC for funding allowing for teaching relief under the National Health Scholars Programme.http://www.biomedcentral.com/bmcpediatram2023Occupational Therap

Maternal mental health and caregiver competence of HIV-positive and negative women caring for their singleton newborns in KwaZulu-Natal Province, South Africa

BACKGROUND. Maternal mental health during the perinatal period has been of interest to many researchers, with antenatal depression and postnatal depression (PND) being a leading cause of morbidity. The adverse effects of maternal depression on the offspring throughout infancy, childhood and adolescence are well documented. Studies on the mental health of persons living with HIV have also reported a high prevalence of depression. OBJECTIVES. To describe the prevalence of PND in a sample of HIV-positive and HIV-negative mothers delivering healthy singleton infants at one obstetric unit in KwaZulu-Natal (KZN) Province, South Africa, and the subsequent factors influencing neonatal behaviour and perceptions of caregiver competence. Correlations between the presence of PND and perceptions of caregiver competence (with the mother as caregiver), and between infant behaviour, the mother’s confidence in her competence as caregiver, and demographic and medical variables, were also examined. METHODS. Demographic and clinical data were collected from 132 mothers at initial contact and from 32 mothers at the 6-week follow-up appointment. Mothers independently completed the Edinburgh Postnatal Depression Scale at each time point, and the Mother and Baby Scales (MABS) at the 6-week follow-up appointment. RESULTS. The prevalence of depression among all mothers at initial contact was 72.0%, remaining high (68.8%) among the mothers who returned for follow-up. There was a statistically significant correlation between depression and employment at follow-up (p=0.013), and between depression and delivery method (p=0.030). The majority of mothers reported being ‘able to laugh and see the funny side of things’ and ‘looking forward with enjoyment to things’ at initial contact and follow-up. Thoughts of self-harm were reported by 44.7% of mothers at baseline, and by 53.1% at follow-up. Although most infants scored in the average clinical band for neonatal behavioural factors in the MABS, mothers reported lack of confidence, globally and in caring for their infant. CONCLUSION. This study of maternal mental health of a sample of HIV-positive and HIV-negative mothers of infants in KZN revealed a higher prevalence of PND than reported in other studies. This population of mothers and infants is at risk of adverse outcomes of maternal depression, in addition to other possible risk factors.The South African Medical Research Council via the National Health Scholars Programme (now called the Bongani Mayosi National Health Scholars Programme) and the University of KwaZulu-Natal (via the University Development and Capacity Programme).http://www.samj.org.zadm2022Occupational Therap

Beneficiation of recycled process water at DRDGOLD's ERGO plant, and its effect on gold recovery

To conserve fresh water resources and comply with environmental regulations, DRDGOLD, a South African gold producer re-treating surface tailings, has transitioned to a fully closed water circulation system. Consequently, the accumulation of contaminants, as well as addition of reagents, has led to changes in water composition that have compromised leach performance and overall gold recovery. A two-sample t-test confirmed a significant difference in gold recoveries between the use of Rand Water, which was used as a benchmark, and untreated process water. Atomic absorption analysis of ERGO’s process water, confirmed the presence of iron, nickel, zinc, and manganese. A study of the effect of the identified contaminants on gold recovery showed that iron, nickel, and zinc have the largest negative effect on gold recovery, with iron and nickel being more detrimental than zinc. Sulphates were shown to have a possible passivation effect, which also influenced gold recoveries, although to a lesser extent than the heavy metals. Calcium, when present in excess, had a positive influence on gold recovery indicating the possible formation of a calcium aurocyanide complex. Lime softening successfully reduced the heavy metal and sulphate concentrations, and the gold recoveries obtained with the treated process water were similar to those as achieved with Rand Water