Experimental and Numerical study of a hydrogen fuelled I.C. engine fitted with the hydrogen assisted jet ignition system

The use of hydrogen as an engine fuel poses several challenges as well as opportunities in engine design and control. These challenges are mainly due to hydrogen's high flame temperatures at near stoichiometric mixtures, as well as the reactant volume fraction which can reduce the engine power output significantly. However, the wide flammability limits of hydrogen combustion in air means that a large part of the engine operation regime can be achieved without the use of the engine throttle or exhaust after treatment. This paper presents results of experiments and computations for a research single cylinder pressure boosted hydrogen fuelled internal combustion engine (H2ICE) fitted with the Hydrogen Assisted Jet Ignition system (HAJI) and running extremely lean mixtures

Event-based Classification with Recurrent Spiking Neural Networks on Low-end Micro-Controller Units

Due to its intrinsic sparsity both in time and space, event-based data is optimally suited for edge-computing applications that require low power and low latency. Time varying signals encoded with this data representation are best processed with Spiking Neural Networks (SNN). In particular, recurrent SNNs (RSNNs) can solve temporal tasks using a relatively low number of parameters, and therefore support their hardware implementation in resource-constrained computing architectures. These premises propel the need of exploring the properties of these kinds of structures on low-power processing systems to test their limits both in terms of computational accuracy and resource consumption, without having to resort to full-custom implementations. In this work, we implemented an RSNN model on a low-end, resource-constrained ARM-Cortex-M4-based Micro Controller Unit (MCU). We trained it on a down-sampled version of the N-MNIST event-based dataset for digit recognition as an example to assess its performance in the inference phase. With an accuracy of 97.2%, the implementation has an average energy consumption as low as 4.1μJ and a worst-case computational time of 150.4μs per time-step with an operating frequency of 180 MHz, so the deployment of RSNNs on MCU devices is a feasible option for small image vision real-time tasks

Evaluation of cortisol precursors for the diagnosis of pituitary-dependent hypercortisolism in dogs

The serum concentrations of cortisol, 17alpha-hydroxypregnenolone, 17alpha-hydroxyprogesterone, 21-deoxycortisol and 11-deoxycortisol were measured in 19 healthy dogs, 15 dogs with pituitary-dependent hypercortisolism (pdh) and eight dogs with other diseases before and one hour after an injection of synthetic adrenocorticotrophic hormone (acth). At both times the dogs with pdh had significantly higher concentrations of cortisol, 17alpha-hydroxypregnenolone, 17alpha-hydroxyprogesterone and 21-deoxycortisol than the healthy dogs. Basal 11-deoxycortisol concentrations were also significantly higher in dogs with pdh compared with healthy dogs. When compared with the dogs with other diseases, the dogs with pdh had significantly higher basal and post-acth cortisol and basal 21-deoxycortisol, and significantly lower post-acth 11-deoxycortisol concentrations. The dogs with other diseases had significantly higher post-acth cortisol, 17alpha-hydroxyprogesterone and 11-deoxycortisol concentrations than the healthy dogs. In general, the post-acth concentrations of 17alpha-hydroxypregnenolone, 17alpha-hydroxyprogesterone, 11-deoxycortisol and 21-deoxycortisol were more variable than the post-acth concentrations of cortisol, resulting in large overlaps of the concentrations of these hormones between the three groups. A two-graph receiver operating characteristic (ROC) analysis was used to maximise the sensitivity and specificity of each hormone for diagnosing hypercortisolism; it showed that the post-acth concentration of cortisol had the highest sensitivity and specificity. The overlaps between the healthy dogs, the dogs with pdh and the dogs with other diseases suggested that the individual precursor hormones would not be useful as a screening test for hypercortisolism

Haptoglobin preserves the CD163 hemoglobin scavenger pathway by shielding hemoglobin from peroxidative modification

Detoxification and clearance of extracellular hemoglobin (Hb) have been attributed to its removal by the CD163 scavenger receptor pathway. However, even low-level hydrogen peroxide (H(2)O(2)) exposure irreversibly modifies Hb and severely impairs Hb endocytosis by CD163. We show here that when Hb is bound to the high-affinity Hb scavenger protein haptoglobin (Hp), the complex protects Hb from structural modification by preventing alpha-globin cross-links and oxidations of amino acids in critical regions of the beta-globin chain (eg, Trp15, Cys93, and Cys112). As a result of this structural stabilization, H(2)O(2)-exposed Hb-Hp binds to CD163 with the same affinity as nonoxidized complex. Endocytosis and lysosomal translocation of oxidized Hb-Hp by CD163-expressing cells were found to be as efficient as with nonoxidized complex. Hp complex formation did not alter Hb's ability to consume added H(2)O(2) by redox cycling, suggesting that within the complex the oxidative radical burden is shifted to Hp. We provide structural and functional evidence that Hp protects Hb when oxidatively challenged with H(2)O(2) preserving CD163-mediated Hb clearance under oxidative stress conditions. In addition, our data provide in vivo evidence that unbound Hb is oxidatively modified within extravascular compartments consistent with our in vitro findings

Altered serum thyrotropin concentrations in dogs with primary hypoadrenocorticism before and during treatment

BACKGROUND: Thyrotropin (TSH) can be increased in humans with primary hypoadrenocorticism (HA) before glucocorticoid treatment. Increase in TSH is a typical finding of primary hypothyroidism and both diseases can occur concurrently (Schmidt's syndrome); therefore, care must be taken in assessing thyroid function in untreated human patients with HA. OBJECTIVE: Evaluate whether alterations in cTSH can be observed in dogs with HA in absence of primary hypothyroidism. ANIMALS: Thirty dogs with newly diagnosed HA, and 30 dogs in which HA was suspected but excluded based on a normal ACTH stimulation test (controls) were prospectively enrolled. METHODS: cTSH and T4 concentrations were determined in all dogs and at selected time points during treatment (prednisolone, fludrocortisone, or DOCP) in dogs with HA. RESULTS: cTSH concentrations ranged from 0.01 to 2.6 ng/mL (median 0.29) and were increased in 11/30 dogs with HA; values in controls were all within the reference interval (range: 0.01-0.2 ng/dL; median 0.06). There was no difference in T4 between dogs with increased cTSH (T4 range 1.0-2.1; median 1.3 μg/dL) compared to those with normal cTSH (T4 range 0.5-3.4, median 1.4 μg/dL; P=0.69) and controls (T4 range 0.3-3.8, median 1.8 μg/dL; P=0.35). After starting treatment, cTSH normalized after 2-4 weeks in 9 dogs and after 3 and 4 months in 2 without thyroxine supplementation. CONCLUSIONS AND CLINICAL RELEVANCE: Evaluation of thyroid function in untreated dogs with HA can lead to misdiagnosis of hypothyroidism; treatment with glucocorticoids for up to 4 months can be necessary to normalize cTSH

Forest ecosystem monitoring in Tuscany (Italy): past activities, present status and future perspectives

Since 1987 the Region of Tuscany has been actively monitoring crown status in its forests, in order to protect them from atmospheric pollution, biotic factors and environmental change. Over this period the Region has performed periodical inventories on crown condition in publicly-owned forests (Level I network) and established a network of permanent plots (MON.I.TO., Level II – III) to study long-term changes occurring in forest ecosystems. Some of these permanent plots were later included in the national programme CONECOFOR, managed by the Ministry for Policy in Agriculture and Forest. Currently a further development of MON.I.TO. is being implemented, called MONITO III – TOpModel, the aim of which is to broaden the information potential of the monitoring system to include carbon stocks and biodiversity evaluation. This paper provides an up-to-date report on the status of the various surveys and recommends a closer connection between MON.I.TO. and the other regional information systems, especially the Regional Forest Inventory, in order to produce information that may be useful in forest planning and in Sustainable Forest Management

The importance of interacting climate modes on Australia’s contribution to global carbon cycle extremes

The global carbon cycle is highly sensitive to climate-driven fluctuations of precipitation, especially in the Southern Hemisphere. This was clearly manifested by a 20% increase of the global terrestrial C sink in 2011 during the strongest sustained La Niña since 1917. However, inconsistencies exist between El Niño/La Niña (ENSO) cycles and precipitation in the historical record; for example, significant ENSO-precipitation correlations were present in only 31% of the last 100 years, and often absent in wet years. To resolve these inconsistencies, we used an advanced temporal scaling method for identifying interactions amongst three key climate modes (El Niño, the Indian Ocean dipole, and the southern annular mode). When these climate modes synchronised (1999-2012), drought and extreme precipitation were observed across Australia. The interaction amongst these climate modes, more than the effect of any single mode, was associated with large fluctuations in precipitation and productivity. The long-term exposure of vegetation to this arid environment has favoured a resilient flora capable of large fluctuations in photosynthetic productivity and explains why Australia was a major contributor not only to the 2011 global C sink anomaly but also to global reductions in photosynthetic C uptake during the previous decade of drought

Patient blood management: A solution for South Africa

For more than 70 years the default therapy for anaemia and blood loss was mostly transfusion. Accumulating evidence demonstrates a significant dose-dependent relationship between transfusion and adverse outcomes. This and other transfusion-related challenges led the way to a new paradigm. Patient blood management (PBM) is the application of evidence-based practices to optimise patient outcomes by managing and preserving the patient’s own blood. ‘Real-world’ studies have shown that PBM improves patient outcomes and saves money. The prevalence of anaemia in adult South Africans is 31% in females and 17% in males. Improving the management of anaemia will firstly improve public health, secondly relieve the pressure on the blood supply, and thirdly improve the productivity of the nation’s workforce. While high-income countries are increasingly implementing PBM, many middle- and low-income countries are still trying to upscale their transfusion services. The implementation of PBM will improve South Africa’s health status while saving costs

Dynamic model of supercritical Organic Rankine Cycle waste heat recovery system for internal combustion engine

The supercritical Organic Rankine Cycle (ORC) for the Waste Heat Recovery (WHR) from Internal Combustion (IC) engines has been a growing research area in recent years, driven by the aim to enhance the thermal efficiency of the ORC and engine. Simulation of a supercritical ORC-WHR system before a real-time application is important as high pressure in the system may lead to concerns about safety and availability of components. In the ORC-WHR system, the evaporator is the main contributor to thermal inertia of the system and is considered to be the critical component since the heat transfer of this device influences the efficiency of the system. Since the thermo-physical properties of the fluid at supercritical pressures are dependent on temperature, it is necessary to consider the variations in properties of the working fluid. The wellknown Finite Volume (FV) discretization method is generally used to take those property changes into account. However, a FV model of the evaporator in steady state condition cannot be used to predict the thermal inertia of the cycle when it is subjected to transient heat sources. In this paper, a dynamic FV model of the evaporator has been developed and integrated with other components in the ORC-WHR system. The stability and transient responses along with the performance of the ORC-WHR system for the transient heat source are investigated and are also included in this paper