Evaluation of the environmental sustainability of different waste‐to‐energy plant configurations

European strategy for waste management attributes primary importance to waste production prevention and imposes a priority order in waste management based on: “preparing for re-use; recycling; other recovery, e.g. energy recovery; and disposal” [1]. According to this strategy, those wastes for which the material recovery is not effectively applicable, should be used for energy recovery. Unsorted municipal residual waste (i.e. the waste left downstream of separate collection), has an average lower heating value higher than 10 GJ/Mg, in EU, and can be recovered in modern Waste-to-Energy (WtE) plants, producing combined heat and power (CHP) and reaching high levels of energy recovery. CHP is pinpointed as the best techniques for energy recovery from waste and also it is the technical solution that allows reaching high values according to the R1 criteria [1]. However, in some cases, heat recovery is not technically feasible – due to the absence of thermal user (industrial plant or district heating) in the proximity of the WtE plant - and only power production remains as the unique possibility. In these cases, some challenges are posed in order to increase as much as possible the energy performances: high values are obtainable only for large WtE plants [2-3]. High energy recovery efficiency values are very important, not only to comply with the R1 criteria, but also for the environmental sustainability of WtE plants. The highest the electricity and heat produced, the best saving of natural resources may be achieved. Pavlas et al. [3] evaluated the benefits of energy recovery in WtE by CHP applying a method based on Primary Energy Saving (PES). Damgaard et al. [4] showed that CHP is able provide higher saving, in Life Cycle Assessment (LCA) evaluations, than only electricity recovery. Within this frame, the aim of this work is to carry out an environmental assessment, through LCA, of different configurations of municipal residual waste WtE plant, i.e. only power production vs. increasing degree of cogeneration. The size ranging from small to large plants (12.5-300 MW thermal power input) was considered, including gradually the technical improvements that may increase the overall plant performances. Additionally, some specific configurations, related to energy recovery integration into the flue gas treatment (FGT) system, considering acid gas removal dry processes using calcium or sodium-based reactants, were investigated. The WtE process was simulated by a home developed thermodynamic model (using Engineering Equation Solver, F-Chart Software), providing the material and energy streams in input and output to/from the process, allowing the R1 calculation. LCA system boundary also included municipal residual waste transportation to WtE, production processes of input chemicals, bottom ash transport, treatment and recovery, fly ash and air pollution residues transport, treatment and disposal and, obviously, avoided effects of conventional heat and power production. Impact assessment results were calculated using cumulative energy demand (CED) and ReCiPe 2008 methods, even if here we discuss only climate change indicator results. Regarding only power production mode, the improved net electric efficiency along with the size allows for increasing the R1 value and decreasing the CO2 equivalent emissions. However, only medium-large plants (larger than 50 MW) reach R1 values higher than 0,65 and only 200-300 MW size plants reach negative CO2 equivalent emissions, even without cogeneration. Smaller plants need to operate in cogeneration mode – according to different extents - to reach imposed R1 value and to obtain negative CO2 equivalent emissions. As a matter of fact, a plant able to comply with the R1 limit, not always shows neutral carbon balance. Thus, in order to make WtE processes acting as carbon sink, cogeneration should be employed in larger extent than the minimum required for R1 compliance. Some specific configurations, related to energy recovery integration into the FGT system allow enhancing energy efficiency: a FGT line with injection of sodium bicarbonate at 180° C and a tail-end heat recovery used for pre-heating primary combustion air has a positive influence on R1 value and CO2 balance. References [1] Directive 2008/98/EC of the European Parliament and of the Council on waste and repealing certain Directives - Annex II, 19 November 2008. [2] Consonni, S. and Viganò, F., 2012. Waste gasification vs. conventional Waste-To-Energy: A comparative evaluation of two commercial technologies. Waste Manage, 32, 653–666. [3]Pavlas, M., Tous, M., Klimek, P., Bebar, L., 2011. Waste incineration with production of clean and reliable energy. Clean Technol. Environ. Policy 13, 595–605. [4]Damgaard, A., Riber, C., Fruergaard, T., Hulgaard, T., Christensen, T.H., 2010. Life-cycle-assessment of the historical development of air pollution control and energy recovery in waste incineration. Waste Manage, 30, 1244–1250

On the computation of preliminary orbits for Earth satellites with radar observations

We introduce a new method to perform preliminary orbit determination for satellites on low Earth orbits (LEO). This method works with tracks of radar observations: each track is composed by $nge 4$ topocentric position vectors per pass of the satellite, taken at very short time intervals. We assume very accurate values for the range $ho$, while the angular positions (i.e. the line of sight, given by the pointing of the antenna) are less accurate. We wish to correct the errors in the angular positions already in the computation of a preliminary orbit. With the information contained in a pair of radar tracks, using the laws of the two-body dynamics, we can write 8 equations in 8 unknowns. The unknowns are the components of the topocentric velocity orthogonal to the line of sight at the two mean epochs of the tracks, and the corrections $Delta$ to be applied to the angular positions. We take advantage of the fact that the components of $Delta$ are typically small. We show the results of some tests, performed with simulated observations, and compare this method with Gibbs' and the Keplerian integral

Preliminary orbits with line-of-sight correction for LEO satellites observed with radar

In Fusco et al (2011 Inventiones Math. 185 283–332) several periodic orbits of the Newtonian N-body problem have been found as minimizers of the Lagrangian action in suitable sets of T-periodic loops, for a given T  >  0. Each of them share the symmetry of one Platonic polyhedron. In this paper we first present an algorithm to enumerate all the orbits that can be found following the proof in Fusco et al (2011 Inventiones Math. 185 283–332). Then we describe a procedure aimed to compute them and study their stability. Our computations suggest that all these periodic orbits are unstable. For some cases we produce a computer-assisted proof of their instability using multiple precision interval arithmetic

design of an after market lower limb protector for scooters preliminary estimation of effectiveness

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[The complexity of risk stratification in older patient candidate to non-cardiac surgery]

During the last decades the older patients who are candidates for surgery have grown esponentially due to the increase in life expectancy and the surgery technique improvement. Despite this, the mortality remains high and our ability to predict the surgery outcomes continues to be low in the elderly. The main reason is related to different difficulties; we are unable to differentiate properly the chronological from the biological age, and the current surgery and cardiology risk scores are poorly geriatric-oriented. We must underline how the measure of comorbidity during the preoperative evaluation is often limited to a simple count of comorbid conditions, without a more detailed assessment of their severity. On the other hand different comorbidity scores have been validated in geriatric populations showing a good correlation with prognosis, such as the Index of Coexisting Disease-ICED or the Geriatric Index of Comorbidity-GIC. Our predictive deficiency about the outcomes is linked to poor attention for identifying the frail patients that are already at high risk of disability. Recently, the evaluation of frailty is a key target for geriatric medicine, and geriatricians have developed various methods for measuring this parameter and suggesting the physical performance indexes as a reliable surrogate of frailty. Surrogate frailty measures, such as the "gait speed" or the "Short Physical Performance Battery-SPPB" seem to be the valid tools for evaluating older surgery patients due to their simplicity and short administration time. We think that the future challenge will be their widespread use in this specific clinical setting

Colonic Metastasis from Carcinoma of the Breast that Mimicks a Primary Intestinal Cancer

Although the lung, liver, or bones are the most common location for distant metastases in breast cancer patients, metastases to the intestinal tract are very rarely recognized in the clinic. We will present an unusual case of colonic metastasis from a carcinoma of the breast that mimics a primary intestinal cancer, along with a through review of English language medical literature. Despite the fact that isolated gastrointestinal (GI) metastases are very rare and much less common than benign disease processes or second primaries of the intestinal tract in patients with a history of breast cancer, metastatic disease should be given consideration whenever a patient experiences GI symptoms

Prevention of suicide behind bars: first Italian results

Background: The reduction of suicides in jails and prisons is an international priority and, after the publication of a report about the necessity to prevent the suicide risk, in Tuscany (Italy) was created a new biphasic protocol. The aim of our study was to show the preliminary results after the introduction of this protocol in the Penitentiary of Pistoia. Methods: We conducted an ecological pilot study from April to December 2016. In the Penitentiary of Pistoia, a multidisciplinary staff collected socio-demographic and clinical information of the new inmates, and estimated the suicide risk administering the Arboleda-Florez Checklist. Results: Ninety-three new prisoners (all males) were conducted in the Penitentiary of Pistoia: 12 (12.90%) came from another prison; 81 (87.09%) were free before the arrival. 16 (17.2%) were homeless, 52 (55.91%) were unemployed, 1 (1.07%) was retired. 32 declared to use drugs; 7 of them declared also the alcohol abuse. Three detainees claimed only the alcohol abuse. 9 prisoners were already assisted by the Service for Drug Addiction when they have been arrested. 77 (82.79%) were positive for at least 1 item of the Arboleda-Florez Checklist. The measures of great surveillance were disposed for 67 prisoners. Three were the measures of Greatest Surveillance for high suicide risk. 13 inmates needed a specific pharmacological treatment prescribed by a psychiatrist. A therapy for mild anxiety and insomnia was prescribed in 29 cases: 21 after the first visit; 8 later. A psychological support was furnished to 23 prisoners who didn’t need the prescription of psychotropic medication, but only an emotional support. Conclusions: Our pilot study showed that the biphasic protocol could be able to manage in a good way the suicide risk, in fact no suicide occurred in the examined period of time. However, studies covering longer periods of time and involving other realities are needed to give more reliable results about its real efficacy