Integrated model predictive control of water resource recovery facilities and sewer systems in a smart grid: example of full-scale implementation in Kolding.

An integrated model predictive control (MPC) strategy to control the power consumption and the effluent quality of a water resource recovery facility (WRRF) by utilizing the storage capacity from the sewer system was implemented and put into operation for a 7-day trial period. This price-based MPC reacted to electricity prices and forecasted pollutant loads 24 hours ahead. The large storage capacity available in the sewer system directly upstream from the plant was used to control the incoming loads and, indirectly, the power consumption of the WRRF during dry weather operations. The MPC balances electricity costs and treatment quality based on linear dynamical models and predictions of storage capacity and effluent concentrations. This article first shows the modelling results involved in the design of this MPC. Secondly, results from full-scale MPC operation of the WRRF are shown. The monetary savings of the MPC strategy for the specific plant were quantified around approximately 200 DKK per day when fully exploiting the allowed storage capacity. The developed MPC strategy provides a new option for linking WRRFs to smart grid electricity systems.

Prioritize effluent quality, operational costs or global warming? - Using predictive control of wastewater aeration for flexible management of objectives in WRRFs.

This study presents a general model predictive control (MPC) algorithm for optimizing wastewater aeration in Water Resource Recovery Facilities (WRRF) under different management objectives. The flexibility of the MPC is demonstrated by controlling a WRRF under four management objectives, aiming at minimizing: (A) effluent concentrations, (B) electricity consumption, (C) total operations costs (sum electricity costs and discharge effluent tax) or (D) global warming potential (direct and indirect nitrous oxide emissions, and indirect from electricity production) . The MPC is tested with data from the alternating WRRF in Nørre Snede (Denmark) and from the Danish electricity grid. Results showed how the four control objectives resulted in important differences in aeration patterns and in the concentration dynamics over a day. Controls B and C showed similarities when looking at total costs, while similarities in global warming potential for controls A and D suggest that improving effluent quality also reduced greenhouse gasses emissions. The MPC flexibility in handling different objectives is shown by using a combined objective function, optimizing both cost and greenhouse emissions. This shows the trade-off between the two objectives, enabling the calculation of marginal costs and thus allowing WRRF operators to carefully evaluate prioritization of management objectives. The long-term MPC performance is evaluated over 51 days covering seasonal and inter-weekly variations. On a daily basis, control A was 9-30% cheaper on average compared to controls A, D and to the current rule-based control. Similarly, control D resulted on average in 35-43% lower greenhouse gasses daily emission compared to the other controls. Difference between control performance increased for days with greater inter-diurnal variations in electricity price or greenhouse emissions from electricity production, i.e. when MPC has greater possibilities for exploiting input variations. The flexibility of the proposed MPC can easily accommodate for additional control objectives, allowing WRRF operators to quickly adapt the plant operation to new management objectives and to face new performance requirements.

Value of the 30-minute adrenocorticotropin (ACTH) test in demonstrating hypothalamic-pituitary-adrenocortical insufficiency after acute ACTH deprivation.

Adrenocortical responsiveness to corticotropin was reestablished by daily administration of 1 mg ACTH depot for 4 days in seven patients with secondary adrenocortical insufficiency. Peak plasma cortisol concentrations during a 30-min ACTH test performed 2 days after stopping injection of ACTH depot increased in all seven subjects (they were normal in five subjects) compared to the initial subnormal responses. Repeated short ACTH tests 5, 8, and 12 days after the last administration of ACTH depot showed a gradual decrease in plasma cortisol responses. When tested 8 days after the last ACTH depot injection was given all seven patients again had a subnormal response to ACTH. Thus, acute ACTH deprivation leads to an impaired adrenocortical response at a short ACTH test within 8-12 days.

Omeprazole in the long-term treatment of severe gastro-oesophageal reflux disease in patients with systemic sclerosis.

Twenty-five patients with systemic sclerosis and severe gastro-oesophageal reflux disease were treated with 20-80 mg omeprazole daily for up to 5 years. Efficacy of treatment was assessed by symptom score, by endoscopic and histopathological surveillance of the oesophageal and gastric mucosa, and by laboratory screening including serum gastrin concentration. Statistically significant relief of symptoms and healing of oesophagitis confirmed the efficacy of this treatment. However, complete healing of oesophagitis was not achieved in half of the patients due to residual gastro-oesophageal acid reflux. Repeated adjustments of the maintenance dose of omeprazole may be needed for this group of patients. From the safety point-of-view, nothing was observed to discourage the long-term use of omeprazole in this group of patients.

Direct bronchial artery revascularization and en bloc double lung transplantation--surgical techniques and early outcome.

BACKGROUND: Lung transplantation including direct bronchial artery revascularization (BAR) has produced promising early results in small clinical series. METHODS: In Copenhagen primary en bloc double lung transplantation with BAR, with the left mammary artery used as conduit, has been performed in 47 patients from 1992 to the end of 1995. After introduction of the bloc into the recipient, the mammary-to-bronchial artery anastomosis is performed as the first anastomosis, allowing perfect exposure and early reperfusion. Internal mammary-bronchial artery arteriography has been performed routinely after operation. RESULTS: Bronchoscopic examination performed in all patients documented normal airway healing in 42, disturbed in two, and complicated in three. Arteriography performed in 42 patients demonstrated complete BAR in 25, incomplete in 15, and failed BAR in 2. Failed BAR was associated with complicated airway healing. The 1- and 2-year survival rate (Kaplan-Meyer) is 83%. Eleven patients have died, only one within 30 days. The total incidence of bronchiolitis obliterans syndrome at 3 years (with Kaplan-Meier technique) is 33%. Successful BAR has also been performed with an adjusted technique in a limited number of heart-lung and single lung transplantations. Our total experience of BAR in any type of lung transplantation includes 65 patients with an arteriographic BAR success rate of 94% (50 of 53 examined patients). CONCLUSIONS: Experience has improved the surgical technique and has made BAR reliable and safe, be it double lung, single lung, or heart-lung transplantation. Early results are good, but only follow-up will show if long-term results after lung transplantation will be improved by BAR. Already today, en bloc double lung transplantation with BAR is a viable alternative to sequential bilateral lung transplantation.

Re-mediastinoscopy in the assessment of resectability of lung cancer.

OBJECTIVE: Thirty-one patients underwent re-mediastinoscopy in the diagnostic assessment of lung cancer. The reason for a repeat mediastinoscopy was either a negative result at the first operation in spite of CT indication of enlarged nodes or an incomplete first mediastinoscopy. METHODS: All patients underwent a conventional mediastinoscopy. RESULTS: In 22 patients with enlarged mediastinal lymph nodes at computed tomography, 10 had a positive lymph node histology at re-mediastinoscopy, while 12 were negative. In 9 patients with no enlarged mediastinal nodes at CT scan, but incomplete biopsies at the first mediastinoscopy, 1 patient had lymph node metastases. The median duration from the first to the second mediastinoscopy was 43 days. No major complications occurred. The staging of the patients was greatly affected by the re-mediastinoscopy. Of 31 patients judged as operable according to the initial mediastinoscopy only 60% were found to be operable following the second mediastinoscopy. CONCLUSION: This study has demonstrated the value of re-mediastinoscopy in assessment of resectability of lung cancer.

[Lung volume reduction surgery. A new surgical therapeutic possibility for patients with emphysema]. / Lungevolumenreducerende kirurgi. Et nyt kirurgisk behandlingstilbud til patienter med emfysem.

Lung volume reduction surgery is a new surgical procedure for treatment of patients with pulmonary emphysema. At the operation the most peripheral parts of the lung are resected. Only 15-20% of the patients admitted for lung volume reduction surgery are suitable for operation. The preliminary results have demonstrated improvement in lung function in the majority of the patients. Most of the reports comprise small numbers of patients and have a short time of observation. The longest reported period of observation for a larger number of patients is 24 months and shows a continuing improvement in lung function, dyspnoea and six minute walk test. Because of the high incidence of emphysema, lung volume reduction is a procedure that could reach large extension in the future. However, better definition of criteria of inclusion and better evaluation of the operative procedures are needed.

[Coronary bypass surgery at the Rigshospitalet 1993-1995. Results after 1.000 consecutive operations]. / Koronar bypass-kirurgi på Rigshospitalet 1993-1995. Resultater efter 1.000 konsekutive operationer.

During 1993-95 1000 consecutive patients were admitted for coronary bypass surgery. The total 30-day mortality of 1.9% was 0.9% for elective cases, 0.8% for reoperations and 0.2% for urgent cases. Perioperative myocardial infarction occurred in 44 patients of whom 25% had infarction at the start of the operation. Respiratory insufficiency occurred in 1.4% of the patients, 3.6% developed renal insufficiency and 1.8% had neurological defects postoperatively. Reoperation for bleeding occurred in 6%, and 0.2% developed sternal or mediastinal infection. This study demonstrates that the results of coronary bypass surgery at Rigshospitalet, Copenhagen are fully comparable to similar results in our neighbouring countries. The results can probably be further improved by more intensive treatment of perioperative ischaemia, especially in reoperations and urgent cases.

Long-term ranitidine in progressive systemic sclerosis (scleroderma) with gastroesophageal reflux.

Eighteen patients with progressive systemic sclerosis and symptomatic gastroesophageal reflux were studied for 20 weeks. All patients were initially treated with ranitidine for a 6-week period. From the 7th week the patients were randomized to further treatment with either ranitidine or placebo. Heartburn and dysphagia, the endoscopic appearance of the esophageal mucosa, the esophageal motility, and gastroesophageal reflux were assessed during the study. The efficacy of ranitidine was maintained during the 20-week period. A shift to placebo was recognized by the patients almost immediately and caused heartburn and esophageal mucosal inflammation to increase significantly.

Esophageal manometry and pH-probe monitoring in the evaluation of gastroesophageal reflux in patients with progressive systemic sclerosis.

Fifty-five patients with progressive systemic sclerosis (PSS) were evaluated with esophageal manometry, 12-h pH-probe monitoring in esophagus, and registration of symptoms of gastroesophageal reflux (GER). Thirty-nine patients had symptoms suggestive of GER. The 12-h pH-monitoring showed pathologic GER in 30 patients. We found that 33% of the patients with symptoms did not have pathologic GER, and 25% of the patients without symptoms had pathologic GER. Characteristic changes of impaired motility in the esophagus were found in 46 patients. When combining esophageal manometry, reflux measurement, and symptoms of GER, we found a positive correlation in 60% of patients with reduced peristalsis in the lower two-thirds of the esophagus and GER. We therefore recommend sensitive esophageal pH-monitoring in all PSS patients to ensure treatment of patients with pathologic GER.

The progress of oesophageal involvement in progressive systemic sclerosis during D-penicillamine treatment.

In 21 patients with initial signs of progressive systemic sclerosis, oesophageal motility was monitored manometrically from the start of D-penicillamine treatment and over a period of up to 5 years. Urinary excretion of the collagen-specific amino acids hydroxyproline and hydroxylysine, and of proline was used as a guideline for monitoring the bioavailability of D-penicillamine. D-penicillamine therapy was found to be unable to arrest the progress of oesophageal involvement. A downward trend over time--statistically significant at p = 0.03, p = 0.02, and p less than 0.005--was found for lower oesophageal sphincter pressure, peristaltic wave pressure in the distal third, and peristaltic wave pressure in the middle third of the oesophagus, respectively.

Flushing and plasma substance P concentration during infusion of synthetic substance P in normal man.

Six normal subjects received synthetic substance P intravenously in successively increasing doses of 0.5, 1.0, 2.0, 4.0, and 8.0 pmol X kg-1 X min-1. Each dose was given for 20 min. Concentrations of substance P in plasma and infusions were measured radioimmunochemically. The incremental plasma concentration of substance P correlated linearly to the dose infused. Metabolic clearance rate was 0.361 X kg-1 X min-1, and the half-life of exogenous substance P 1.6 min. Lacrimation and sustained flushing were elicited at plasma concentrations above normal range. Transient flushing in spite of continued infusion was seen at 'physiological' levels. Pulse rate and blood pressure did not change significantly.

Inability to elicit vagal responses from the acid-infused esophagus of pigs.

Acid application in the esophagus and esophageal distension were undertaken in pigs. One group (n = 9) had operatively induced esophagitis. The other group (n = 7) was normal. We found no discrepancy between the groups neither in inspiratory pressure nor in expiratory PCO2 nor in plasma concentrations of pancreatic polypeptide. The results indicate inability to elicit vagal responses from the acid-infused esophagus of pigs.