Occurrence Of Volatiles Research Articles

ESG Volatility Prediction Using GARCH and LSTM Models

Abstract This study aims to predict the ESG (environmental, social, and governance) return volatility based on ESG index data from 26 October 2017 and 31 March 2023 in the case of India. In this study, we utilized GARCH (Generalized Autoregressive Conditional Heteroskedasticity) and LSTM (Long Short-Term Memory) models for forecasting the return of ESG volatility and to evaluate the model’s suitability for prediction. The study’s findings demonstrate the GARCH effect inside the ESG return volatility data, indicating the occurrence of volatility in response to market fluctuations. This study provides insight concerning the suitability of models for volatility predictions. Moreover, based on the analysis of the return volatility of the ESG index, the GARCH model is more appropriate than the LSTM model.

Previsão de preços futuros de Commodities agrícolas com diferenciações inteira e fracionária, e erros heteroscedásticos

O presente trabalho tem como objetivo modelar séries temporais para efeito de previsão com diferenciações inteira e fracionária, utilizando dados de preços futuros de commodities agrícolas. Modelos de séries temporais do tipo ARMA/ARIMA (diferenciação inteira) serão estimados como termo de comparação com os modelos do tipo ARFIMA (diferenciação fracionária). Em ambos os casos, os erros dos modelos serão estimados assumindo-se a possibilidade de estimação da volatilidade. O poder de previsão de cada modelo será comparado pelo critério do erro quadrado médio da previsão (EQM). A estimação do termo de diferenciação fracionário (d) também será utilizada para examinar as características de longa dependência das séries. Os resultados indicaram que todas as séries de retornos de preços futuros utilizados são estacionárias. O valor do d fracionário da série de açúcar indicou um comportamento de antipersistência a choques, enquanto que esses valores para as demais commodities apresentaram comportamento persistente. Na maioria dos casos os modelos ARFIMA mostraram um melhor poder de previsão.

Analysis of benzene transport in a two-dimensional aquifer model

In this study, the fate and transport of aqueous benzene was investigated in a laboratory-scale homogeneous aquifer by conducting a two-dimensional plume test. Benzene solution was introduced as a pulse type along the width of the aquifer model through a recharge zone situated at the upper-left part of the model and followed by a steady state flow. Solution samples were collected at various locations on the front side of the model to capture two-dimensional plumes at discrete time intervals. The benzene plumes showed a moderate retardation relative to chloride plumes observed from the previous study conducted for the same aquifer model. The retardation factor was obtained from the ratio of travel distances of benzene peaks to chloride peaks from the injection point, computed using a line integral method. Mass recovery of aqueous benzene revealed that there was a significant reduction of benzene mass, indicating the occurrence of volatilization and/or irreversible sorption during transport. Thus, retardation along with volatilization and/or irreversible sorption may be important processes affecting the fate and transport of aqueous benzene in the aquifer model. Copyright © 2005 John Wiley & Sons, Ltd.

Adsorption of mercury and copper ions by oral microorganisms.

The metal ion accumulation by oral bacterial cells was investigated in this study using two heavy metals, copper and mercury at pH 4.0 and 7.0. However, the adsorption rate of mercury was especially examined at pH 4.0 because of the loss of metal ions caused by the adsorption on the walls of the container and the occurrence of volatilization at pH value on the neutral and alkaline side.Higher mercury adsorption by bacterial cells were demonstrated in Propionibacterium acnes, Treponema denticola and Eikenella corrodens in order of strength at pH 4.0. Regarding copper ion adsorption by oral bacteria, the higher metal adsorptions were also shown at pH 4.0 and 7.0 in P. acnes, Peptostreptococcus anaerobius and Corynebacterium matruchotii, respectively.The metal adsorptive abilities of these oral microorganisms appeared to be higher than that of Actinomyces levoris which had extremely high uranium accumulation abilities etc.There were no marked differences between the intact cells and the lyophilized cells of P. acnes, even when treated with heat at 100°C for 10 min.These metal ion adsorptions by microorganisms always proceeded immediately after adding metal to bacterial suspension and reached a plateau around 5 min later.These findings obtained strongly suggest that some oral bacteria have the potential the adsorption of heavy metal ions, and that the mode of adsorption is based on a physico-chemical action governed by the Freundlich adsorption isotherm equation.

The Use of Organoclays to Reduce Organic Waste Volatilization During Solidification

One of the major difficulties experienced when solidifying organic waste is the volatilization of organic compounds during mixing and curing. The occurrence of volatilization has made solidification's ability to reduce organic waste leachability suspect. This paper recounts the ability of organoclays to reduce the volatilization of nitrobenzene (NB) and 1,2-dichlorobenzene (DCB) from cement-based solidification samples. The results indicated the incorporation of organoclays reduced the volatilization caused by cement-based solidification of NB and DCB to 1/6 and 1/10 of their original values, respectively. The samples utilizing the organoclays retained the majority of NB and DCB added to them, 65-100% and 63-94%, respectively. The ability of organoclays to reduce volatilization appeared to be inversely correlated to their increasing percent organic matter content.

Influence of vacuum treatment on the physicochemical properties of solid solutions based on zirconium dioxide

Such data suggest that the conductivity of solid solutions based on zirconia at temperatures below 900-I000~ can be increased by the partial removal of the anions and the cations of the stabilizer from the crystal lattice of the solid solution being formed. It is known that during vacuum firing oxygen vacancies are formed in the zirconia [i, 2], and there is rapid volatilization of the Ca and Mg cations [3, 4]. The volatilization of the cations of stabilizer containing yttrium oxide. The present authors attempted to establish whether it is possible in principle to improve the electrophysical properties of zirconia stabilized with oxides of alkaline-earth elements at temperatures below 900-I000~ Investigations were carried out using as an example, solid solutions ZrO=-CaO and zirconium dioxide, stabilized with a mixture of oxides of alkaline earth and rare-earth elements (Table i). The powders for the solid solutions were prepared with the method developed in the East Institute of Refractories, involving combined precipitation of the components from solutions of their chlorides and employing a solution of ammonia and ammonium carbonate as the precipitants [5]. Using the solid solution powders and a pressure of i00 N/mm 2 we pressed specimens of diameter i0 and height 10-15 mm. Firing was done at 1700~ in air and in vacuum. To eliminate breakdown of the stoichiometric composition with respect to oxygen occurring in specimens subjected to vacuum heat processing, subsequently they were fired at 1400~ in air. The results of x-ray analysis indicate that the specimens fired both in air and in vacuum consist only of the cubic solid solution of the fluorite type. X-ray structural analysis did not reveal any significant change in the lattice parameters of the solid solutions heated with either method (see Table i). However, for specimens fired in vacuum we noted a marked reduction in the apparent density compared with the specimens fired in air. In our view, this indicates the occurrence of volatilization of cations of alkaline-earth elements from the crystal lattice of the solid solution; its geometry under these conditions is not altered.

Sites of production and occurrence of volatiles in Douglas-fir beetle,Dendroctonus pseudotsugae hopkins

Volatiles were found to be distributed throughout adult Douglasfir beetles,Dendroctonus pseudotsugae Hopkins, suggesting that the hindgut may not be the sole site of production. The volatile content of individual beetles increased dramatically with feeding; qualitative changes reflected the different bark habitats of newly emerged and established beetles. All detected volatiles were also found in beetle frass. Myrcene was the predominant monoterpene of emergent beetles and α-pinene of fed beetles. Linalool and bornyl acetate occurred in significant amounts after feeding, and diacetone alcohol and sulcatol were also detected for the first time. The presence of sulcatol explains the reported cross-attraction withGnathotrichus spp.cis-Verbenol was also found to occur in addition totrans-verbenol. The volatile content of male beetles was similar to that of females but amounts of individual compounds were less. Acetic acid was found in both emerged and fed beetles and in lesser amounts in frass, suggesting that microbial metabolism could be a potential source of volatile production.