Effects of Radiation sterilization Dose on the Molecular Weight and Gelling Properties of Commercial Alginate Samples

To estimate the molecular weight (Mw) and gelling properties, a total of 26 alginate samples consisting of control (n = 13) and 15 kGy γ-irradiated (n = 13) samples were characterized through viscometric and gel permeation chromatography (GPC-MALLS) methods. Based on the observations, a remarkable decrease in the intrinsic viscosity of all samples of alginates was evident due to the effects of radiation, with a linear relationship between viscosity and concentration in 0.01 M NaCl solution. The correlation among the Mw, percentage mass recovery, radii of gyration (Rz/Rg), and percentage reduction of Mw assessed by GPC was significant. The Mw decreased dramatically (from 3.1 × 105 to 0.49 × 105 mole/g in sample no. 12) by the effect of radiation with momentous relation to the % reduction of the molecular weight. The highest molecular weight reduction (84%), which is the most sensitive to γ-radiation, and the average reduction rate was ≥50%. The mass recovery was 100% obtained from samples no. 1,3,4,5,7,12, and 13, while the rest of the samples’ recovery rate was significantly higher. The reduction rate of mass molecular weight (Mw) is higher than the average molecular weight (Mv), but they showed a sensitivity towards radiation, consequently their performance are different from each other. The stability test was performed as a critical behaviour in the control, recurrently same as in the irradiated samples. Thus, the sterilization dose of 15 kGy for the Mw distribution, and subsequently for the characterization, was significantly effective.

Performance Analysis of Variable Mode Adsorption Chiller at Different Recooling Water Temperatures

Adsorption cooling can recover waste heat at low temperature levels, thereby saving energy and reducing greenhouse gas emissions. An air-cooled adsorption cooling system reduces water consumption and the technical problems associated with wet-cooling systems; however, it is difficult to maintain a constant recooling water temperature using such a system. To overcome this limitation, a variable mode adsorption chiller concept was introduced and investigated in this study. A prototype adsorption chiller was designed and tested experimentally and numerically using the lumped model. Experimental and numerical results showed good agreement and a similar trend. The adsorbent pairs investigated in this chiller consisted of silicoaluminophosphate (SAPO-34)/water. The experimental isotherm data were fitted to the Dubinin–Astakhov (D–A), Freundlich, Hill, and Sun and Chakraborty (S–C) models. The fitted data exhibited satisfactory agreement with the experimental data except with the Freundlich model. In addition, the adsorption kinetics parameters were calculated using a linear driving force model that was fitted to the experimental data with high correlation coefficients. The results show that the kinetics of the adsorption parameters were dependent on the partial pressure ratio. Four cooling cycle modes were investigated: single stage mode and mass recovery modes with duration times of 25%, 50%, and 75% of the cooling cycle time (denoted as short, medium, and long mass recovery, respectively). The cycle time was optimized based on the maximum cooling capacity. The single stage, short mass recovery, and medium mass recovery modes were found to be the optimum modes at lower (<35 °C), medium (35–44 °C), and high (>44 °C) recooling temperatures. Notably, the recooling water temperature profile is very important for assessing and optimizing the suitable working mode.

Mass Recovery following Caloric Restriction Reverses Lipolysis and Proteolysis, but not Gluconeogenesis, in Insulin Resistant OLETF Rats

Caloric restriction (CR) is one of the most important behavioral interventions to reduce excessive abdominal adiposity, which is a risk factor for the development of insulin resistance. Previous metabolomics studies have characterized substrate metabolism during healthy conditions; however, the effects of CR and subsequent mass recovery on shifts in substrate metabolism during insulin resistance (IR) have not been widely investigated. To assess the effects of acute CR and the subsequent mass recovery on shifts in substrate metabolism, a cohort of 15-week old Long Evans Tokushima Otsuka (LETO) and Otsuka Long Evans Tokushima Fatty (OLETF) rats were calorie restricted (CR: 50% × 10 days) with or without partial body mass recovery (PR; 73% x 7 days), along with their respective ad libitum controls. End-of-study plasma samples were analyzed for primary carbon metabolites by gas chromatography (GC) time-of-flight (TOF) mass spectrometry (MS) data acquisition. Data analysis included PCA, Pearson correlation vs previously reported variables (adipose and body masses, and insulin resistance index, IRI), and metabolomics maps (MetaMapp) generated for the most significant group comparisons. All treatments elicited a significant group differentiation in at least one principal component. CR improved TCA cycle in OLETF, and increased lipolysis and proteolysis. These changes were reversed after PR except for gluconeogenesis. Plasma lipid concentrations were inversely correlated to IRI in LETO, but not OLETF. These shifts in substrate metabolism suggest that the CR-induced decreases in adipose may not be sufficient to more permanently alter substrate metabolism to improve IR status during metabolic syndrome.

Feasibility of concentrating potassium minerals from Verdete ore by cell flotation

A silicate ore with K2O content above 10%, found in the central region of Minas Gerais (Brazil), called Verdete, was floated in flotation cell. The goal was to evaluate the flotation behaviour of the ore constituents (glauconite, muscovite, K-feldspar and quartz) relative to the use of different collectors (fatty acid soap obtained from rice oil, amine and oleic acid) and depressors (gelatinized cornstarch and sodium silicate). Flotation of the calcination products of Verdete with MgCl2 and CaCl2 were also evaluated. Mass recovery of flotation carried out with Verdete reached a maximum of 53% when amine and sodium silicate were used as collector and depressant, respectively. Mass recovery was directly proportional to collector dosage, and was also influenced by the type of depressor. Calcination of Verdete with MgCl2?xH2O partially consumed the micas and generated MgO. Flotation of this calcination product concentrated MgO in the floated fraction, reaching 93% when oleic acid was used as collector.

Energy and Exergy Analyses of Adsorption Chiller at Various Recooling-Water and Dead-State Temperatures

We conducted energy and exergy analyses of an adsorption chiller to investigate the effect of recooling-water temperatures on the cooling capacity and Coefficient of Performance (COP) with variable cycle modes. We investigated both the effect of the recooling-water temperature and the dead state temperature on the exergy destruction in the chiller components. Our results show that there is an optimum reheat cycle mode for each recooling-water temperature range. For the basic single stage cycle, the exergy destruction is mainly accrued in the desorber (49%), followed by the adsorber (27%), evaporator (13%), condenser (9%), and expansion valve (2%). The exergy destruction for the preheating process is approximately 35% of the total exergy destruction in the desorber. By contrast, the precooling process is almost 58% of the total exergy destruction in the adsorber. The exergy destruction decreases when increasing the recooling-water and the dead state temperatures, while the exergy efficiency increases. Nonetheless, the exergy efficiency decreases with an increase in the recooling-water temperature at fixed dead state temperatures. The effect of the mass recovery time in the reheat cycle on exergy destruction was also investigated, and the results show that the exergy destruction increases when the mass recovery time increases. The exergy destruction in the adsorbent beds was the most sensitive to the increase in mass recovery time.

First-order discontinuity in tracer mass recovery: indicative of (large) induced fracture(s)?

&lt;p&gt;Forced-gradient flow sustained by a geothermal well doublet in a porous-fissured reservoir (more or less karstified, Jurassic formation, cf. Behrens et al. 2020 for a conceptual-hydrogeologic model outline and competing hypotheses as to what role &lt;em&gt;large fractures&lt;/em&gt; might play) is subject to a tracer test anew, following a significant augmentation of fluid turnover rates. The distinct aromatic sulfonates (N2S and P4S) used as tracers in the first (lower-rate) and the second (higher-rate) test are supposed to be transported conservatively and similarly under this reservoir&amp;#8217;s in-situ conditions; in terms of solute diffusivity, the larger molecule size of P4S ought to be roughly matched by N2S&amp;#8217;s stronger hydratization in-situ, and for assuming else physicochemically conservative behavior one may invoke vast evidence from past applications in mineralogically variate, saline, hot reservoirs (Behrens 1992ff; Rose 1997ff). Cumulative mass recovery for each tracer can be calculated based on its theoretical &amp;#8216;single-passage&amp;#8217; signal, deconvolved from its measured signal (eliminating &amp;#8216;redundant&amp;#8217; contributions from fluid recirculation; to account for flow-rate variability, we set up an ad-hoc deconvolution algorithm). From tracer sampling to date, CMR amounts to ~28% for P4S, and ~70%* for N2S &amp;#8211; whose first 20-30%* mass amounts were swept through the reservoir under the lower-rate flow regime, and its subsequent amounts under the higher-rate regime, reaching 60-65%* by the time P4S was added (for the latter, a certain time lag after flow rate augmenting was allowed, not having in pectore whether the higher flow rate would prove sustainable, and how long it would take for the flow field to reach a new &amp;#8216;quasi-steady&amp;#8217; state at reservoir scale; pressure buildup/drawdown changes at injection/production wells stayed uninterpretably low). Those N2S %* cannot be told accurately due to short-term flow-meter (instrumental) failures during precisely this transition. CMR for P4S exhibits a significantly lower growth rate than for N2S (even when plotted against cumulative fluid turnover, which should compensate for flow-rate disparities), and, more strikingly, a marked first-order discontinuity (tangent drop) after reaching ~20% (which would correspond to ~30% N2S after the same cumulative fluid turnover, counted since tracer injection). Three hypotheses which might explain these findings are evaluated: P4S decay? reservoir &amp;#8216;stimulation&amp;#8217; &amp;#8594; stronger P4S dilution? reservoir &amp;#8216;compartmenting&amp;#8217; &amp;#8594; P4S &amp;#8216;loss&amp;#8217; into some &amp;#8216;non-pay&amp;#8217; zone? Accordingly, special monitoring options that would allow to disambiguate (or refute) some &amp;#8216;induced fracture&amp;#8217; / &amp;#8216;activated fault&amp;#8217; / &amp;#8216;karst window&amp;#8217; scenarios are discussed. [*Note: not only these particular values for N2S, but its entire subsequent CMR calculation is impeded by the flow-meter data gap; as a substitute, one may attempt to reconstruct the missing flow-rate data from &amp;#8216;geothermal&amp;#8217; power generation data, but here operator-provided information is insufficient. For P4S however, being injected way later after this metering gap, its tangent discontinuity in CMR stays independent upon the missing data] &amp;#8211; &amp;#8211; &lt;strong&gt;Reference:&lt;/strong&gt; SGP-TR-216, pp.195-201, pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2020/Behrens.pdf (for a reservoir model outline, and early tracer signal illustrations)&lt;/p&gt;

IMPACT OF COVID-19 ON TOURISM IN GEORGIA-AN OVERVIEW

Coronavirus has posed a great challenge to the whole world, including Georgia. The restrictions have taken a heavy toll on the tourism industry worldwide. It has been clear since the spring of the current year that the mass recovery of international tourism will not be possible by 2020. Consequently, the necessity has led to changes, especially in the direction of domestic tourism. Countries apply different strategies. This review article is based on the results of a mini-survey and data from the National Statistics Office. It is analyzed what impact COVID-19 had on local tourism in Georgia, what is the public mood, which places were visited, where did the epidemic break out after the restrictions were lifted, what are the statistics of international tourists in Georgia, etc. Besides, tourism support measures developed around the world are discussed.

IMPACT OF COVID-19 ON TOURISM IN GEORGIA-AN OVERVIEW

Coronavirus has posed a great challenge to the whole world, including Georgia. The restrictions have taken a heavy toll on the tourism industry worldwide. It has been clear since the spring of the current year that the mass recovery of international tourism will not be possible by 2020. Consequently, the necessity has led to changes, especially in the direction of domestic tourism. Countries apply different strategies. This review article is based on the results of a mini-survey and data from the National Statistics Office. It is analyzed what impact COVID-19 had on local tourism in Georgia, what is the public mood, which places were visited, where did the epidemic break out after the restrictions were lifted, what are the statistics of international tourists in Georgia, etc. Besides, tourism support measures developed around the world are discussed.