TG pyrolysis of a mixture of dried sludge from urban wastewater and wood pellets and identification of the composition of the resulting gases by infrared spectroscopy

The recent tendency of sewage sludge disposal is targeted towards the gasification for heat generation in small towns far from waste incineration plants. The scope of this article is to present the investigation into the mixture of dried sewage sludge and wood pellets during pyrolysis by thermogravimetry (TG) with evolved gas analysis by TG-coupled Fourier transformation infrared spectroscopy (FTIR) method. The maximum intensity of mass loss of sewage sludge material occurs at 300–310°C temperature and it differs from wood cellulose case of 360°C. The 50:50% mixture of these materials was investigated in more details. Pyrolysis reaction kinetics is described by a variation of three constituent parts from TG data. Prefactor A and activation energy E of the Arrhenius law were found, and reaction order n was determined by the Ozawa method employing Avrami phase change. The maximum of gas evolution is always related to the most intense mass loss, and gas composition correlates with the initial material.

Spirit Confronts the Four-Headed Monster: Jean-Bertrand Aristide’s Mistik–Infused Flood-Rise in Duvalierist Haiti

To explore Jean-Bertrand Aristide’s rise from obscure rural Haiti to become the nation’s first democratically elected president—by a landslide—is to enter into a world and a swirl of events that reads like surreal fiction or magical realism. As a Catholic priest (Salesian order), Aristide was fueled by the religio-socialist principles of liberation theology, which emerged as a significant force in Latin America primarily in the 1970s and 1980s, forcefully and vocally advocating for the masses of Haitian poor mired in deeply-entrenched disenfranchisement and exploitation. As a charismatic spokesperson for the popular democratic movement in Haiti during an era of entrenched dictatorship and repressive violence, Aristide boldly confronted the “four-headed monster” of the Haitian power structure—the army, the church hierarchy, the tontons macoutes, and the wealthy elite. His seemingly impossible escape from multiple assassination attempts, together with the power of his colorful rhetoric and his close association with urban slum dwellers and rural peasants, led to a rising “flood” (or lavalas) that invested him with an aura of Spirit, or mistik, that in either/both the Haitian-embraced tradition of Christianity or vodoun (voodoo) served to energize and greatly reassure an intense mass movement arrayed against seemingly impossible odds. This article focuses on the rise of Aristide as the embodiment and voice of Spirit among the people and does not extend into his tumultuous secular years in and out of the presidency, having been twice the victim of coups (1991 and 2004); instead it focuses primarily on the years 1985–1990 and does not enter into an assessment of Aristide as president. Aristide’s own vivid narratives of this time, segments of his sermons, and later, passages of his poetry serve to bolster the literary quality or interpretation of this brief but vividly colorful historic epoch in the Haitian experience.

Virus resistance of potato genetic diversity under climate change

Aim. To determine the resistance of potato gene pool accessions to viruses in the southern forest-steppe of Ukraine and to select starting material for breeding. Results and Discussion. Our analysis of the climate changes for the period of 1955–2018 revealed that the unfavorable weather/climatic conditions during spring planting of tubers, as a result of which weakened plants were more easily depressed by viral infections, were the primary cause of potato cacogenesis in the southern forest-steppe of Ukraine. It was found that significant deviations from the multi-year average temperature and amount of precipitation contributed to the intense mass manifestation of symptoms of viral diseases or under favorable weather/climatic conditions, on the contrary, viral diseases were not visually detected. Studies have shown that the main factor in resistance to viral degeneration of potato varieties is the genotype, and its development and expression depend on growing conditions. It is also important to take into account emergence of new strains of viruses requiring continuous monitoring. Virus resistance of the varieties was visually determined. In order to identify viruses and study their morphology, electron microscopy, EIA and PCR were used. Conclusions. As a result of the study, sources of high field resistance to leaf-rolling, potato rugose and streak mosaics, which are valuable starting material for further practical use in breeding, as well as in scientific and educational programs, were identified.

Episodic accretion in focus: revealing the environment of FU Orionis-type stars

The earliest phases of star formation are characterised by intense mass accretion from the circumstellar disk to the central star. One group of young stellar objects, the FU Orionis-type stars exhibit accretion rate peaks accompanied by bright eruptions. The occurance of these outbursts might solve the luminosity problem of protostars, play a key role in accumulating the final star mass, and have a significant effect on the parameters of the envelope and the disk. In the framework of the Structured Accretion Disks ERC project, we are conducting a systematic investigation of these sources with millimeter interferometry to examine whether they represent normal young stars in exceptional times or they are unusual objects. Our results show that FU Orionis-type stars can be similar to both Class I and Class II systems and may be in a special evolutionary phase between the two classes with their infall-driven episodic eruptions being the main driving force of the transition.

Population III microquasars

We present the first results obtained in the elaboration of a complete model of a microquasar where the donor star is from Population III. These stars do not produce stellar winds so we consider that the mass loss is due exclusively to matter overflowing the Roche lobe towards the compact object, a maximally rotating black hole. The rate of accretion is extremely super-Eddington, with an intense mass loss from the system in the form of winds and jets. We calculate the relativistic particle content of the jet and the corresponding spectral energy distribution (SED) considering a lepto-hadronic model. Prospects for the cosmological implications of these objects are briefly discussed.

A detailed study toward the Water fountain IRAS 15445-5449

Post-Asymptotic giant branch (post-ABG) sources with high-velocity spectral features of H2O maser emission detected toward their circumstellar envelopes (CSEs) are known as Water Fountain (WF) nebulae. These are low- or intermediate-mass Galactic stellar sources that are undergoing the late stages of an intense mass-loss process. The velocity and the spatial distribution of the H2O maser spectral features can provide information about the kinematics of the molecular gas component of their CSEs. Hence, observational studies toward WF nebulae could help to better understand the formation of the asymmetric structures (hundred to thousand AUs) commonly seen toward Planetary nebulae (PNe). Here we present preliminary results of observations done toward the WF IRAS 15445-5449 using the Australia Telescope Compact Array (ATCA) and the Very Large Telescope (SINFONI/VLT). Assuming that the pumping of the H2O maser transitions is a consequence of shocks between different velocity winds, the spatial distribution of the emission shed light on the scales of the regions affected by the propagation of the shock-fronts.

Thermal analysis of physical and chemical changes occuring during regeneration of activated carbon

High-temperature thermal process is a commercial way of regeneration of spent granular activated carbon. The paper presents results of thermal analysis conducted in order to examine high-temperature regeneration of spent activated carbon, produced from coconut shells, previously used in drinking water treatment. Results of performed thermogravimetric analysis, derivative thermogravimetric analysis, and differential thermal analysis, enabled a number of hypotheses to be made about different phases of activated carbon regeneration, values of characteristic parameters during particular process phases, as well as catalytic impact of inorganic materials on development of regeneration process. Samples of activated carbon were heated up to 1000?C in thermogravimetric analyser while maintaining adequate oxidizing or reducing conditions. Based on diagrams of thermal analysis for samples of spent activated carbon, temperature intervals of the first intense mass change phase (180-215?C), maximum of exothermic processes (400-450?C), beginning of the second intense mass change phase (635-700?C), and maximum endothermic processes (800-815?C) were deter-mined. Analysing and comparing the diagrams of thermal analysis for new, previously regenerated and spent activated carbon, hypothesis about physical and chemical transformations of organic and inorganic adsorbate in spent activated carbon are given. Transformation of an organic adsorbate in the pores of activated carbon, results in loss of mass and an exothermic reaction with oxygen in the vapour phase. The reactions of inorganic adsorbate also result the loss of mass of activated carbon during its heating and endothermic reactions of their degradation at high temperatures.