An Investigation of Dynamic Influence to Doctors’ Stress in Government Hospitals in Nigeria Using Logistic Regression Approach

This study examined some dynamic factors related to doctors’ stress in government hospitals in Nigeria using Lagos State as case study. The working hours and the number of patients the professionals attended to showed that they are likely to be stressed. A model was developed to predict the dynamic influence to doctors’ stress using logistic regression model. It was discovered that illness, environmental factors, profession and workloads and hours are the variables that highly influenced Doctors’ stress

Dynamic control of sensor and actuator failures in multivariable distillation column

This paper examines the impact of sensor and actuator failures in the operation of a multivariable distillation column. Several failure scenarios are evaluated including failures of sensors and actuators in various scales of magnitudes and durations. The results obtained illustrate the ability of process controllers in suppressing the impact of these unwanted events. Closed-loop dynamic responses of the process revealed capabilities of these controllers in dealing with upsets that are small in magnitude and duration. In the case of larger and longer process upsets, process controllers are not adequate in providing the necessary corrective measures. This leaves the necessary interventions to be taken by the plant operators, following alarms that would have been triggered in typical plant operation scenario

Methyl orange, an organic dye: its health impact and sorptive removal from waste water

AbstractMethyl Orange (MO) a member of Azo dyes are commonly used as synthetic dyes in textile, food, paper and cosmetics. Their use is easy and cost-effective, compared with natural dyes. However, azo bonds are hardly removed because of their high water solubility as well as low exhaustion with the potential for persistence and accumulation in the environment, therefore aqueous solution of MO is toxic and irritating. Thus, the removal of them from industrial wastewaters is capital with regard to protect public health, environment, and aquatic life

Perceptions of rewards among volunteer caregivers of people living with AIDS working in faith-based organizations in South Africa: a qualitative study

<p>Abstract</p> <p>Background</p> <p>Volunteer caregivers are a critical source of support for the majority of people living with HIV and AIDS in southern Africa, which has extremely high HIV/AIDS prevalence rates. While studies have shown that volunteer caregiving is associated with negative health and socio-economic outcomes, little is known about the positive experiences of volunteers in the home-based care context in South Africa. The purpose of this study is to explore the perception of rewards among volunteers working in home-based care settings.</p> <p>Methods</p> <p>This study uses a qualitative design. Qualitative interviews were conducted with a purposively selected sample of 55 volunteer caregivers using an interview schedule containing open-ended questions.</p> <p>Results</p> <p>Volunteer caregivers derived intrinsic rewards related to self-growth and personal (emotional and psychological) development on the job; they also derived satisfaction from community members taking a liking for them and expressing a need for their services. Volunteers felt gratified by the improvements in their health behaviours, which were a direct consequence of the experiences of caring for terminally ill patients with AIDS. Extrinsic rewards came from appreciation and recognition shown by patients and community members. Extrinsic rewards also accrued to volunteers when the services they rendered made their patients happy. Perhaps the greatest sources of extrinsic rewards are skills and competencies acquired from training and experience while caring for their patients, and volunteers' ability to make a difference in the community.</p> <p>Conclusions</p> <p>Insights into volunteer caregiver rewards provide opportunities for policy makers and programme managers to develop a model of home-based care that facilitates the accrual of rewards to volunteers alongside volunteers' traditional duties of patient care. Programme managers could employ these insights in recruiting and assisting volunteers to identify and reflect on rewards in the caregiving situation as a means of reducing the burden of care and sustaining volunteer interest in caregiving.</p

Unknown input observer design for fault detection and diagnosis in a continuous stirred-tank reactor

Early and accurate fault detection and diagnosis (FDD) minimises downtime, increases the safety and reliability of plant operation, and reduces manufacturing costs. This paper presents a robust FDD strategy for a nonlinear system using a bank of unknown input observers (UIO). The approach is based on structure residual generation that provides not only decoupling of faults from model uncertainties and unknown input disturbance but also decoupling the effect of a fault from the effects of other faults. The generated residual was evaluated through the statistical threshold to avoid fault missing or false alarm. The performance of the robust FDD scheme was assessed by some sensor fault scenarios created in a continuous stirred-tank reactor (CSTR). The simulation result showed the effectiveness of the proposed approach

Integration of fault tree and importance measure for toxic prevention barrier

This paper discusses the procedure of integrating importance measures into fault tree analysis. Importance measures (IM) are analytical tools developed to quantitatively appraise the contribution of a plant component towards the overall risk. As part of safety assessment, this method can be used to rank and identify the root cause of undesired events. The critical component is usually prioritised in order to improve the reliability of the system. Fussell-Vesely (FV) importance measure is one of the most commonly used IM. This method is applied to a case study involving typical toxic prevention barriers based on an LNG liquefaction plant. This paper also includes event ranking using other IM

Physicochemical, mineralogy, and thermo-kinetic characterisation of newly discovered nigerian coals under pyrolysis and combustion conditions

In this study, the physicochemical, microstructural, mineralogical, thermal, and kinetic properties of three newly discovered coals from Akunza (AKZ), Ome (OME), and Shiga (SHG) in Nigeria were examined for potential energy recovery. Physicochemical analysis revealed high combustible but low levels of polluting elements. The higher heating values ranged from 18.65 MJ/kg (AKZ) to 26.59 MJ/kg (SHG). Microstructure and mineralogical analyses revealed particles with a rough texture, surface, and glassy lustre, which could be ascribed to metals, quartz, and kaolinite minerals. The major elements (C, O, Si, and Al), along with minor elements (Ca, Cu, Fe, K, Mg, S, and Ti) detected are associated with clays, salts, or the porphyrin constituents of coal. Thermal analysis showed mass loss (ML) ranges from 30.51% to 87.57% and residual mass (RM) from 12.44% to 69.49% under combustion (oxidative) and pyrolysis (non-oxidative) TGA conditions due to thermal degradation of organic matter and macerals (vitrinite, inertinite and liptinite). Kinetic analysis revealed the coals are highly reactive under the oxidative and non-oxidative conditions based on the Coats–Redfern Model. The activation energy (Ea) ranged from 23.81 to 89.56 kJ/mol, whereas the pre-exponential factor (ko) was from 6.77 × 10–4/min to 1.72 × 103/min under pyrolysis and combustion conditions. In conclusion, the coals are practical feedstocks for either energy recovery or industrial applications

Modelling ultrasound waves bubble formation in ethanol/ethyl acetate azeotrope mixture

The separation of an azeotropic mixture such as ethanol/ethyl acetate in distillation process can be enhanced by ultrasound wave. The application of ultrasound wave creates bubble cavitation in the mixture and shifts the vapour-liquid equilibrium favouring the separation of the azeotropic mixture. This study investigates the formation of bubbles in the mixture through modelling and simulation. The results obtained show that bubble formation at low ultrasound frequency is favoured by the increase in intensity, which has a direct relation to sonic pressure. The optimal sonic pressure for bubble formation at equilibrium is 5 atm and conforms to the model for small bubble formation with radius of 0.14 /<m. Furthermore, the maximum possible number of bubbles at equilibrium in the ethanol/ethyl acetate azeotropic mixture of 1 L is 91 × 1015. The developed model can be used to determine the optimal sonic pressure, sound intensity, size of bubble, and possible number of bubbles formed at equilibrium

Significance of Wood Anatomical Features to the Taxonomy of Five Cola Species

Wood anatomy of five Cola species was investigated to identify and describe anatomical features in search of distinctive characters that could possibly be used in the resolution of their taxonomy. Transverse, tangential and radial longitudinal sections and macerated samples were prepared into microscopic slides. Characteristic similarity and disparity in the tissues arrangement as well as cell inclusions were noted for description and delimitation. All the five Cola species studied had essentially the same anatomical features, but the difficulty posed by the identification of Cola acuminata and Cola nitida when not in fruit could be resolved using anatomical features. Cola acuminata have extensive fibre and numerous crystals relative to Cola nitida, while Cola hispida and Cola millenii are the only species having monohydric crystals. Cola gigantica is the only species that have few xylem fibres while other species have extensive xylem fibre. These features have proved very functional and strongly of diagnostic value in the classification and delimitation of the studied Cola species