title: Total site heat integration of multi-effect evaporators with vapour recompression for older kraft mills

authors: Walmsley, Timothy Gordon

abstract: This paper aims to apply Total Site Heat Integration (TSHI) to appropriately integrate Mechanical and Thermal Vapour Recompression with multi-effect evaporators at older Kraft Mills, to cause a step reduction in fossil fuel use and its associated emissions. Heat and power demands for older Kraft Mills are chiefly satisfied from Recovery Boilers (RB), heavily supplemented by biomass/fossil fuel boilers, and integrated with steam turbines. Prior to firing, black liquor - the RB fuel - is concentrated from about 18 % to 67 % in a multi-effect evaporator, which demands 20 % of site-wide thermal energy. With access to renewable electricity, this study finds that vapour recompression can be economically integrated into a multi-effect evaporator at older Kraft Mills. The vapour recompression configuration with the greatest economic potential used 2-stages of mechanical vapour recompression and 1-stage of thermal vapour recompression. This system achieved a levelised profit of NZD 8.56 M/y, a payback period of 1.0 y and an internal rate of return of 103 %. An optimum integrated set-up needs to account for site-specific heat demand and utility supply profiles through TSHI.

text: Total site heat integration of multi-effect evaporators with vapour recompression for older kraft mills This paper aims to apply Total Site Heat Integration (TSHI) to appropriately integrate Mechanical and Thermal Vapour Recompression with multi-effect evaporators at older Kraft Mills, to cause a step reduction in fossil fuel use and its associated emissions. Heat and power demands for older Kraft Mills are chiefly satisfied from Recovery Boilers (RB), heavily supplemented by biomass/fossil fuel boilers, and integrated with steam turbines. Prior to firing, black liquor - the RB fuel - is concentrated from about 18 % to 67 % in a multi-effect evaporator, which demands 20 % of site-wide thermal energy. With access to renewable electricity, this study finds that vapour recompression can be economically integrated into a multi-effect evaporator at older Kraft Mills. The vapour recompression configuration with the greatest economic potential used 2-stages of mechanical vapour recompression and 1-stage of thermal vapour recompression. This system achieved a levelised profit of NZD 8.56 M/y, a payback period of 1.0 y and an internal rate of return of 103 %. An optimum integrated set-up needs to account for site-specific heat demand and utility supply profiles through TSHI.

year: 2017

title: Bayesian network classifiers in Weka

authors: Bouckaert, Remco R.

abstract: Various Bayesian network classifier learning algorithms are implemented in Weka [10].This note provides some user documentation and implementation details.
Summary of main capabilities:
_Structure learning of Bayesian networks using various hill climbing (K2, B, etc) and general purpose (simulated annealing, tabu search) algorithms.
_Local score metrics implemented; Bayes, BDe, MDL, entropy, AIC.
_Global score metrics implemented; leave one out cv, k-fold cv and cumulative cv.
_Conditional independence based causal recovery algorithm available.
_Parameter estimation using direct estimates and Bayesian model averaging.
_GUI for easy inspection of Bayesian networks.
_Part of Weka allowing systematic experiments to compare Bayes net performance with general purpose classi_ers like C4.5, nearest neighbor, support vector, etc.
_Source code available under GPL allows for integration in other systems and makes it easy to extend.

text: Bayesian network classifiers in Weka Various Bayesian network classifier learning algorithms are implemented in Weka [10].This note provides some user documentation and implementation details.
Summary of main capabilities:
_Structure learning of Bayesian networks using various hill climbing (K2, B, etc) and general purpose (simulated annealing, tabu search) algorithms.
_Local score metrics implemented; Bayes, BDe, MDL, entropy, AIC.
_Global score metrics implemented; leave one out cv, k-fold cv and cumulative cv.
_Conditional independence based causal recovery algorithm available.
_Parameter estimation using direct estimates and Bayesian model averaging.
_GUI for easy inspection of Bayesian networks.
_Part of Weka allowing systematic experiments to compare Bayes net performance with general purpose classi_ers like C4.5, nearest neighbor, support vector, etc.
_Source code available under GPL allows for integration in other systems and makes it easy to extend.

year: 2004-09-01

title: Exploring patient experiences and power dynamics in an acute general surgical ward: A mixed methods study exploring patient and staff
perceptions of the inpatient experience at Waikato Hospital

authors: Drake, Emma Rose

subjects: Nursing

abstract: Background: Alongside health outcomes, patient experiences are considered crucial in identifying the quality of a health care setting. General surgery comprise the largest range of pathologies and accounts for the highest number of patient discharges of any surgical specialty. As a way to address the power imbalance between healthcare staff and patients, patient-centred models of care are increasingly being adopted and implemented within hospitals including surgery. This study aims to investigate the current experiences of acutely admitted patients in a general surgical ward at Waikato Hospital, including opportunities for and challenges to improvement initiatives. Furthermore, the study examines relevant staff members perspectives of the inpatient experience and seeks to determine the efficacy of a proposed intervention focusing on empowering patients and their families.
Methods: The study was a mixed method design involving two phases. Phase I obtained qualitative data from semi-structured interviews with six patients and twelve staff members. Themes which emerged from the qualitative data in phase I were used to inform the development of phase II, as well as to inform a proposed patient self- assessment intervention. Phase II obtained quantitative data through Likert scale response surveys provided to acute patients on, or near to, their day of discharge from the surgical ward over a two month period.
Results: A total of six patients and 12 healthcare staff (senior registered nurses, n=3; surgical registered nurse managers, n=2; surgical fellows, n=2; surgical registrar, n=1; dietitian, n=1; social worker, n=1; occupational therapist, n=1; and physiotherapist n=1) were involved in phase I. A total of 53 surveys were returned from patients in Phase II (63.1% response rate). Qualitative data from phase I was analysed using a general inductive approach. This revealed three themes including power and control concerns for patients, the hierarchy of the health care team and the surrounding stressors of the organisation and environment. Analysis of the quantitative data collected descriptive statistics and calculated chi-squares. Of note were the statistically significant differences particularly between patients of Māori ethnicity comparatively to non-Māori, and according to gender and reason in hospital. There were no statistically significant differences for patients according to age group.
Conclusion: This study identified both the experiences of patients and staff in an acute general surgical context. The study found that the proposed patient self- assessment intervention was not immediately recommended. This was due to the current recommendations from patients who identified their strong preference was for face-to-face communication with staff. It was also due to staff members identification of a perceived inability to consistently provide person-centred care which corresponded with the patient self-assessment data. Acute general surgical care needs of patients were perceived by staff as taking precedent and current workplace stressors, including staffing and skill mix deficits and perceived lack of staff wellbeing supports, were strong inhibitors for staff to provide their preferred capacity of patient-centred care.

text: Exploring patient experiences and power dynamics in an acute general surgical ward: A mixed methods study exploring patient and staff
perceptions of the inpatient experience at Waikato Hospital Background: Alongside health outcomes, patient experiences are considered crucial in identifying the quality of a health care setting. General surgery comprise the largest range of pathologies and accounts for the highest number of patient discharges of any surgical specialty. As a way to address the power imbalance between healthcare staff and patients, patient-centred models of care are increasingly being adopted and implemented within hospitals including surgery. This study aims to investigate the current experiences of acutely admitted patients in a general surgical ward at Waikato Hospital, including opportunities for and challenges to improvement initiatives. Furthermore, the study examines relevant staff members perspectives of the inpatient experience and seeks to determine the efficacy of a proposed intervention focusing on empowering patients and their families.
Methods: The study was a mixed method design involving two phases. Phase I obtained qualitative data from semi-structured interviews with six patients and twelve staff members. Themes which emerged from the qualitative data in phase I were used to inform the development of phase II, as well as to inform a proposed patient self- assessment intervention. Phase II obtained quantitative data through Likert scale response surveys provided to acute patients on, or near to, their day of discharge from the surgical ward over a two month period.
Results: A total of six patients and 12 healthcare staff (senior registered nurses, n=3; surgical registered nurse managers, n=2; surgical fellows, n=2; surgical registrar, n=1; dietitian, n=1; social worker, n=1; occupational therapist, n=1; and physiotherapist n=1) were involved in phase I. A total of 53 surveys were returned from patients in Phase II (63.1% response rate). Qualitative data from phase I was analysed using a general inductive approach. This revealed three themes including power and control concerns for patients, the hierarchy of the health care team and the surrounding stressors of the organisation and environment. Analysis of the quantitative data collected descriptive statistics and calculated chi-squares. Of note were the statistically significant differences particularly between patients of Māori ethnicity comparatively to non-Māori, and according to gender and reason in hospital. There were no statistically significant differences for patients according to age group.
Conclusion: This study identified both the experiences of patients and staff in an acute general surgical context. The study found that the proposed patient self- assessment intervention was not immediately recommended. This was due to the current recommendations from patients who identified their strong preference was for face-to-face communication with staff. It was also due to staff members identification of a perceived inability to consistently provide person-centred care which corresponded with the patient self-assessment data. Acute general surgical care needs of patients were perceived by staff as taking precedent and current workplace stressors, including staffing and skill mix deficits and perceived lack of staff wellbeing supports, were strong inhibitors for staff to provide their preferred capacity of patient-centred care.

year: 2022