Expert system for control of anaerobic digesters

Continuous anaerobic digesters are systems that present challenging control problems including the possibility that an unmeasured disturbance can change the sign of the steady-state process gain. An expert system is developed that recognizes changes in the sign of process gain and implements appropriate control laws. The sole on-line measured variable is the methane production rate, and the manipulated input is the dilution rate. The expert system changes the dilution rate according to one of four possible strategies: a constrained conventional set-point control law, a constant yield control law (CYCL) that is nearly optimal for the most common cause of change in the sign of the process gain, batch operation, or constant dilution rate. The algorithm uses a t test for determining when to switch to the CYCL and returns to the conventional set-point control law with bumpless transfer. The expert system has proved successful in several experimental tests: severe overload; mild, moderate, and severe underload; and addition of phenol in low and high levels. Phenol is an inhibitor that in high concentrations changes the sign of the process gain.Continuous anaerobic digesters are systems that present challenging control problems including the possibility that an unmeasured disturbance can change the sign of the steady-state process gain. An expert system is developed that recognizes changes in the sign of process gain and implements appropriate control laws. The sole on-line measured variable is the methane production rate, and the manipulated input is the dilution rate. The expert system changes the dilution rate according to one of four possible strategies: a constrained conventional set-point control law, a constant yield control law (CYCL) that is nearly optimal for the most common cause of change in the sign of the process gain, batch operation, or constant dilution rate. The algorithm uses a t test for determining when to switch to the CYCL and returns to the conventional set-point control law with bumpless transfer. The expert system has proved successful in several experimental tests: severe overload; mild, moderate, and severe underload; and addition of phenol in low and high levels. Phenol is an inhibitor that in high concentrations changes the sign of the process gain

Optimal and suboptimal control of anaerobic digesters

Anaerobic digester failure due to entry of inhibitors or sudden changes in the feed substrate concentration may be encompassed beneficially by applying optimal control theory. An almost proportional relationship between the dilution rate and the methane production rate leads to a simple suboptimal control law with only minor loss in performance, after the occurrence of the above mentioned events

PRIME: a programme to reduce the treatment gap for mental disorders in five low- and middle-income countries

The majority of people living with mental disorders in low- and middle-income countries do not receive the treatment that they need. There is an emerging evidence base for cost-effective interventions, but little is known about how these interventions can be delivered in routine primary and maternal health care settings. The aim of the Programme for Improving Mental Health Care (PRIME) is to generate evidence on the implementation and scaling up of integrated packages of care for priority mental disorders in primary and maternal health care contexts in Ethiopia, India, Nepal, South Africa, and Uganda. PRIME is working initially in one district or sub-district in each country, and integrating mental health into primary care at three levels of the health system: the health care organisation, the health facility, and the community. The programme is utilising the UK Medical Research Council complex interventions framework and the “theory of change” approach, incorporating a variety of qualitative and quantitative methods to evaluate the acceptability, feasibility, and impact of these packages. PRIME includes a strong emphasis on capacity building and the translation of research findings into policy and practice, with a view to reducing inequities and meeting the needs of vulnerable populations, particularly women and people living in poverty