Open Tank Research Articles

Wastewater-based surveillance for Hepatitis A virus, Enterovirus, Poliovirus, and SARS-CoV-2 in São Tomé and Príncipe: A pilot study

BackgroundWastewater-based surveillance is a valuable tool for monitoring pathogen transmission in communities, especially in regions where formal surveillance systems are limited. AimThe aim of this study was to implement and evaluate a wastewater-based monitoring system for viral pathogens in São Tomé and Príncipe. MethodsA total of 122 water samples were collected bi-weekly from June 2022 to July 2023 at six locations in São Tomé city and analysed for molecular detection of Hepatitis A Virus (HAV), Enterovirus (EV), Poliovirus (PV), SARS-CoV-2, as well as JC-Polyomavirus (JCPyV) and pepper mild mottle virus (PMMoV) as indicators of human contamination. Prevalence was analysed per pathogen and across sampling locations. Results for SARS-CoV-2 were assessed together with notifications from national COVID-19 surveillance. Further, we estimated resources needed to establish a wastewater-based approach to assess community-level transmission of viral pathogens. ResultsAll 122 and 117 samples were found positive for PMMoV and JCPyV, respectively, demonstrating a high level of human contamination at all sampling locations. The prevalence of HAV and EV ranged from 0 % to 59 % and 56 % respectively. Consistent with national surveillance data the highest proportion of SARS-CoV-2 positive water samples coincides with the highest number of COVID-19 cases reported during the study, demonstrating the potential of wastewater-based surveillance to identify signals. In addition, for SARS-CoV-2 this approach provided evidence of continuous circulation of the virus in the community, most importantly during weeks when no COVID-19 cases were reported. ConclusionOur findings provide evidence of high transmission of HAV and EV in communities in São Tomé and continuous circulation of SARS-CoV-2, even in weeks without COVID-19 case notifications. This study demonstrates that monitoring of viral pathogens in humanly impacted open water streams and sewage tanks is a valuable tool to complement clinical surveillance in resource-limited settings.

Content analysis of conversations on Reddit: reactions to FDA’s ENDS prioritized enforcement policy

IntroductionOn January 2, 2020, the FDA announced a policy focused in part on prioritizing enforcement of flavored (other than tobacco- or menthol-flavored) cartridge-based electronic nicotine delivery systems (ENDS) without premarket authorization.MethodsWe used a query to identify Reddit conversations relevant to the policy from January 2 to May 6, 2020. Our sample included 576 posts (46 posts and 530 accompanying comments). Two analysts coded posts for mentions of use behaviors (e.g., switching, quitting), purchasing behaviors (e.g., purchasing from retailer new to the user), and flavored products. We summarized frequencies of coded data and provided illustrative quotes.ResultsOnly 21.0% (121/576) of posts mentioned use behavior. Switching behavior was the most common use behavior mentioned (50.4%, 61/121). Most switching behavior posts focused on ENDS-related switching (91.8%, 56/61). The most common ENDS-related switching behaviors mentioned were switching to an open tank (45.9%, 28/61) or device with refillable pods/cartridges (44.3%, 27/61); 8.2% (5/61) mentioned switching to disposables. Just 15.5% (89/576) of posts mentioned purchasing behavior, with the most common being purchasing from a retailer new to the user (32.6%, 29/89). Only 6.8% (39/576) of posts mentioned specific flavors.ConclusionReddit posts about the policy commonly discussed switching to non-cartridge-based ENDS products, such as open tank systems or disposable devices, and purchasing products from different online sources that were still selling these products. Findings suggest that publicly available Reddit data can complement data from traditional sources (e.g., surveys, sales) to understand potential unintended consequences associated with policies by exploring the public’s reactions.

Benincasa hispida Alleviates Stress and Anxiety in a Zebrafish (Danio rerio) Model.

The Ayurvedic medical system uses fruits of the Benincasa hispida plant to treat mental diseases, including schizophrenia. The goal of the current study was to assess the aqueous extract of B. hispida fruit's ability to relieve stress and anxiety induced in zebrafish models using neuropharmacological evaluation, which included determining behavioral parameters in tests such as the T-maze, open tank test (OTT), and light-dark preference test (LDPT). After measuring the zebrafish survival rate for 96 h, the LC50 was found to be 5 µg. AChE (acetylcholinesterase) inhibitory activity and the status of antioxidant enzymes (SOD, CAT, and LDH) were also used to evaluate the toxicity. Furthermore, the administration of the aqueous extract of B. hispida fruit increased the frequency of entry and duration of time spent in the bright section, suggesting a noteworthy reduction in levels of stress and anxiety. Additionally, the antistress and antianxiety activity was confirmed by the docking studies' mechanism of action, which involves the AChE receptor binding stability of the homogalactaconan molecule found in the aqueous extract of B. hispida fruit. Overall, the findings of this study demonstrated that the aqueous extract of B. hispida fruit is a viable therapeutic molecule for the creation of novel drugs and the treatment of stress since it has the therapeutic advantage of reversing the negative effects of stress and anxiety.

A mathematical model describing an unsteady leak of compressed air from an open underwater storage tank

A new mathematical model is developed here to predict the discharge dynamics of compressed air from a massive leak occurring at the top of a submerged storage tank with an original bottom opening. The model represents a transient leak due to variations in the air volume and air pressure remaining inside the tank using a mass balance equation and the compressible Bernoulli equation. A first-order-non-linear ordinary differential equation is solved in terms of the air height inside the reservoir for different tank geometries: a right circular cylinder and a remaining combined with a hemisphere of the same radius to form a bell. The total discharge time is obtained by analytical integration. The model is then applied to a case study in which the amount of air is fixed, and the investigated parameters are the immersion depth (ranging from 75 to 200 m) and the radius of the storage tanks (5 or 7.5 m) on the discharge time. Finally, a representative steady rate is given based on the average discharge rate in order to rapidly estimate the discharge time without further knowledge of the storage tank configuration. The immersion depth has no influence in the discharge time of a cylindrical tank, and a wide tank causes a longer discharge than a narrow one. It has also been shown that, in the range of initial air height considered (close to ten meters), the variation of density can be neglected in the model for the cylindrical geometry, and for the bell geometry provided that the ratio radius-to-initial height remains low.

The implementation of ZnS–SnS BM NPs for phenanthrene degradation: An adsorptive photocatalyst approach and its toxicity studies in adult zebrafish

Phenanthrene is a persistent organic pollutant released by numerous industries. The purpose of the study is to construct a batch reactor for phenanthrene degradation using a bimetallic (BM) ZnS–SnS nanoparticle as a photocatalyst. ZnS–SnS BM NPs were used as a photocatalyst, employed from precursors Zinc acetate dihydrate and tin (II) chloride dihydrate, with crystalline cubic-shaped particle sizes. ZnS–SnS BM NPs were utilized in batch adsorption assays to assess the impact of phenanthrene degradation parameters on various PAHs (Polycyclic aromatic hydrocarbons) concentrations, pH levels, and irradiation sources. Adsorption kinetic and isotherm tests revealed that the pseudo-first order kinetic model, pseudo-second order kinetic model, and Langmuir isotherm model all fit effectively with the effective phenanthrene degradation using ZnS–SnS BM NPs. The degraded product were analyzed for GC-MS, revealing that organic pollutant phenanthrene was converted into harmless by-products like n-hexadecenoic acid, oleic acid, and octadecanoic acid. The toxicity of phenanthrene was observed to decrease with an increase in ZnS–SnS BM NPs concentration. ZnS–SnS BM NP concentration of 150 μg/mL, the zone of inhibition values was recorded highest zone of inhibition (19 ± 1.2 mm) against the strains S. epidermis followed by B. cereus and Clostridium spp. Further adult zebrafish were found to be less toxic to ZnS–SnS BM NPs after 96 h of exposure, with an LD50 of 100 μg/L. The toxicity escalated as concentrations increased. Behavior test showed normal swimming, learning, and memory in open tank and T-maze tests, while 100 μg/L showed pausing/frozen time in zebra fish therefore low doses are considered safe. Hence by employing ZnS–SnS BM NPs can be engaged in waste water treatment for PAH degradation.

Computational fluid dynamics coupled to biokinetic models: Numerical methodology for microalgae cultivation optimization

Mixing of the algal culture medium in a photobioreactor (PBR) is a crucial factor to enhance microalgae cultivation and production, since it ensures microalgae cells can homogeneously access nutrients and light radiation. Hydrodynamic conditions in an industrially applicable PBR cannot be tested in laboratory cultivation systems since the scale-up methodology is not specified; hence requiring complex tests at a demonstrative scale or the application of mathematical models. In this study, a three-dimensional numerical model of the hydrodynamic conditions in a hybrid horizontal tubular PBR was developed to investigate the mixing of the culture medium under various operating conditions, in order to optimize biomass production in this type of system. The PBR consists of two open tanks connected through sixteen polyethylene transparent tubes, at a demonstrative scale (total volume 11.7 m3). Microalgae cells movement inside the tubes was simulated. Cell trajectory prediction allows to simulate the intensity of mixing of the culture medium. Subsequent coupling with the biokinetic BIO_ALGAE model allows to monitor the influence of hydrodynamic conditions on the distribution of light in the culture medium and the yield of microalgae. The simulations were experimentally validated. The more intense mixing of the culture medium caused by increasing flow rate (Re = 23,700–46,200) allows more frequent exposure of the microalgae cells to the light source, which according to the results obtained can increase the microalgal yield by 14% in the summer cultivation period and by 151% in the winter period.

A perspective on methodologies and system boundaries to develop abatement cost for on-farm anaerobic digestion

ABSTRACTMarginal Abatement Cost Curves compare and assess greenhouse gas mitigation options available to various sectors of the economy. In the Irish agricultural sector, large anaerobic digestion facilities are currently considered a high-cost abatement solution. In prior studies of anaerobic digestion abatement costs, two options were assessed: the generation of heat and electricity from biogas (115 €/tCO2eq) and the production of renewable heat from biomethane (280 €/tCO2eq). Both scenarios encompass single cost values that may not capture the potentially variable nature of such systems. In contrast, prior techno-economic analyses and lifecycle analyses can provide a comparison of the abatement costs of anaerobic digestion systems at a range of scales. This work compares two case studies (based on prior literature) for small and medium-scale on farm anaerobic digestion systems. The small-scale system is set in Ireland with cattle slurry collected in open tanks during the winter, while the medium-scale system is set in the USA with cattle slurry collected periodically indoors all year-round. It was found that the abatement cost can vary between −117 to +79 € per t CO2eq. The key variables that affected the abatement cost were additional revenue streams such as biofertilizer sales, displaced energy savings, and additional incentives and emissions savings within the system boundary. Including only some of these options in the analysis resulted in higher abatement costs being reported. Based on the variation between system topologies and therefore system boundaries, assigning a single mitigation cost to anaerobic digestion systems may not be representative.

Simplified and cost-effective modulatory photobioreactor setup for upscaling microalgal culture for research and semi-industrial purposes

Algal biomass and algal substances attract much interest from researchers, entrepreneurs, and farmers. Macroalgal biomass can be collected from the wild or cultivated in open tanks with a relatively low risk of contamination; however, achieving a sufficient amount of microalgal biomass is much more challenging, as the study of algal substances requires rather large amounts of biomass for extraction procedures and analyses. Due to budgetary constraints, most research institutes cannot afford to purchase large-scale ready-for-use photobioreactors, and knowledge regarding the self-construction and operation of such systems is not commonly shared. For this purpose, we present a straightforward, cost-effective methodology for modulatory mid-scale microalgal cultivation, using low-cost materials and instruments existing in most laboratories. We purchased a long polyethylene sleeve roll to assemble the photobioreactors and trimmed it to individual sleeves containing up to 20 L of culture medium each. A large medium volume was sterilized using commercial bleach (sodium hypochlorite), followed by dechlorination with thiosulfate. After a cultivation period of 7–14 days, flocculation induction was achieved by adding calcium hydroxide to facilitate an efficient harvest process. Cultures were enriched with CO2 in response to increasing pH throughout the cultivation process using a simple controller. Using an isolate of one of our species of interest, Mucidosphaerium pulchellum, we demonstrated how using one pH regulatory system can regulate a set of cultures (each in a different sleeve) to remain in the pH range 7.4–8.1 while saving CO2. This economical CO2-enrichment method increased algal growth rates by 23 %, reaching ca. 20 % higher total suspended solids compared to air-supplemented cultures. Such a cultivation system can be implemented with a surprisingly low budget of only USD800, efficiently producing hundreds of grams of biomass per cultivation period to support research on highly nutritious substances production and bioactive compounds discovery.

Relationship between boldness and exploratory behavior in adult zebrafish

Behavioral responses vary between individuals and may be repeated in different contexts over time. When a behavioral response set is linked and present regardless of the context, it characterizes a behavioral syndrome. By evaluating how bold and shy (profiles related to risk-taking) individuals perform about exploration and anxiety, we can predict relationships of behavioral syndromes and better understand how different axis of personality is formed. Here we classified the profiles by risk-taking and evaluated their exploration behavior in the open field test. In this context, the two groups showed significant differences in thigmotaxis behavior: bold individuals habituate faster and show decreased thigmotaxis (less anxiety), while shy ones are less prone to leave the security of the side areas of the open tank and present higher anxiety. We emphasized the importance of further investigating the behavior of these profiles in other contexts and the importance of each one for the evolution and fitness of the species, in addition to a better understanding of which behaviors are involved in the behavioral syndromes in zebrafish.

Simultaneous Measurement of Fluid Level and Flow in Gravity Tanks using Ultrasonic Sensors

Modern instruments for level measurement are becoming more sophisticated making them too expensive to some simpler applications. In order for the procurement of these instruments become more cost effective, we need to utilize their added features to other possible applications. This study presents the results of an experimental investigation involving the use of an existing ultrasonic level sensor for simultaneous level and flow measurements in gravity tanks. The experiment utilizes the data logging feature of the ultrasonic level sensor to log the instantaneous tank level and a sample discharge fitting as the variable head flow meter. The results showed that the values of coefficient of discharge (Cd) corresponding to the sample discharge fitting used can be determined accurately using an open tank draining model as proven by Torricelli’s Law. Instantaneous values of coefficient of discharge (Cd) are then used to determine the discharge of the tank.

Design of a Bean Sprouts Device by Soilless Automatic Cultivation

In order to solve problems: the existing household bean sprouts cultivation device is relatively simple; bean sprouts are easy to be contaminated in the open cultivation tank which affects the quality of bean sprouts, and the automation is poor. The bean sprouts device by soilless automatic cultivation adopts cylindrical closed culture bin structure, and the temperature and humidity sensor is set in the culture bin, which can monitor the environment in real time. At the same time, the heating plate, fan and humidifier are set in the culture bin to heat up, cool down and humidify the environment, so as to realize automatic bean sprouts cultivation. The prototype test showed that: at the temperature 26°C-30°C, humidity 85%-95%, the diameter of mung bean sprouts can reach 2.5mm, and the height can reach 150mm. the diameter of yellow bean sprouts can reach 3mm, and the height can reach 160mm. The average yield of the two sprouts was 98%. The device has the advantages of soilless, intelligence, miniaturization and simple operation, which can meet the requirements of automatic bean sprouts cultivation. It is a necessary product for household in the future.

Analysis of drinking water quality based on biological, physical and chemical parameters in Lekobalo Village, Gorontalo City, Indonesia

Abstract. Katili L, Baderan DWK, Kumaji SS. 2023. Analysis of drinking water quality based on biological, physical and chemical parameters in Lekobalo Village, Gorontalo City, Indonesia. Intl J Bonorowo Wetlands 13: 22-29. Lekobalo Village is a part of the Gorontalo City, Indonesia area, which has not yet received full clean water coverage. Therefore, the community in Lekobalo used the wellsprings as the source of drinking water. An open water tank around the wellspring has been the source of drinking water for people in the surrounding. It becomes a place for household chores such as bathing, doing laundry, and serving as a lavatory. That makes the place look messy due to the household waste around the wellspring, which decreases the drinking water quality there. Hence, a test of the drinking water in Lekobalo is crucially needed. This study is descriptive-qualitative research that was conducted by a direct survey. Sample collection was conducted using sterilized bottles from the laboratory, and the data obtained were analyzed descriptively. This study aims to determine drinking water quality based on biological, physical, and chemical parameters. The research revealed that the quality of drinking water in Lekobali based on the biological parameter was considered polluted by Escherichia coli and coliform bacteria. The findings revealed that the average score of E. coli was 10.3 MPN/100 ml and coliform 200.5 MPN/100 mL. In physical parameters, the drinking water quality is relatively good with an average temperature of 20°C, turbidity NTU, scentless, tasteless, and colorless. The drinking water criterion that did not meet the physical parameters is the TDS (Total Dissolved Solid), which is 1,525 mg/L. According to the chemical parameter, the quality of the drinking water is considered relatively good with some average score of arsenic (As) 0 mg/L, fluoride (F) 1 mg/L, nitrite (NO2) 0.02 mg/L, nitrate (NO3) 3.6 mg/L, iron (Fe) 0.12 mg/L, Power of Hydrogen (pH) 6.6 mg/L and manganese (Mn) 0 mg/L. The chemical parameters that did not meet the standard qualification of drinking water based on the chemical parameters are chromium (Cr), and cadmium (Cd), as the average scores are 0.34 mg/L and 0.047 mg/L. This study can be used as one of the government's databases as an input in developing programs and activities to improve drinking water quality and control water pollution.

Effect of simplified wind girder modelling on MNA-LBA analysis of open steel tanks

The MNA/LBA design methodology for metal shells, including open-top tank steel shells, plays an important role in the European Standard on Strength and Stability of Shell Structures. However, when using this design format, particular doubts as to the correctness of the obtained results may arise when simplifications are used in modelling of key elements of tank structures in order to improve modelling and numerical calculation processes. This paper presents the results of numerical studies that address the question of how the simplifications in the modelling of the primary wind girder affect the values of the elastic buckling resistance and the plastic reference resistance determined from linear bifurcation analysis (LBA) and materially nonlinear analysis (MNA), respectively. Forty-two computational models of wind-loaded open storage tanks with three height-to-diameter ratios and with variable or constant wall thickness of a cylindrical shell, equipped with six different representations of the wind girder, were investigated in order to provide guidelines in the above-mentioned scope. It has been proven that the applied simplifications in the modelling of the primary wind girder allows for relatively faithful representation of the reference models, i.e. models in which the stiffening ring was modelled using shell finite elements, in the LBA analysis. In turn, a varied influence of the applied simplifications in modelling on the results of the MNA analysis was observed. The obtained results indicated a limited range of applicability of the results of the materially nonlinear analysis for the formal assessment of the relative overall slenderness of the considered shells. Finally the obtained results allowed for the formulation of practical conclusions for the purposes of design of open-top steel tanks using the MNA/LBA methodology.

Water mixing in rectangular storage tanks: small-scale versus field tests

ABSTRACT Mixing and renewal processes are crucial for maintaining adequate drinking water quality in storage tanks. This paper studies the influence of baffle structures and of fill-and-draw cycles on water mixing and renewal in rectangular cross-section tanks through laboratory tracer tests carried out in two small-scale tanks (with and without baffles) and compares with results from a full-scale test. This study shows that the use of baffles inhibits water mixing and keeps older water pockets in small recirculation zones, though baffles allow faster water renewal than in open tanks for lower flow rates. High water volume variation in fill-and-draw cycles (between 50% to 80%) promotes water renewal, independently of the tank configuration (i.e. cross-section and the existence of baffles). Despite the existing baffle structure in the full-scale rectangular tank with 20% water volume variation, the high flow rates allowed a rapid renewal of the stored water.

A cultivation trial of Chaetoceros calcitransin an air-lift photobioreactor

Chaetoceros calcitrans is a marine planktonic diatom with small-sized and high-nutrient commonly used as a feed for larvae of aquatic species. In Vietnam, C. calcitrans is often cultivated from small vessels and subsequently gradually increased the culture volume to large open tanks. Although C. calcitrans is widely cultured in aquaculture hatcheries, the cultivation process is still facing many difficulties such as unstable growth, low density or collapse due to the high risk of contamination, low quality of seeding, insufficient mixing or aeration and the control of ambient conditions. This study investigated the airlift photobioreactor systems (ALPBR) for seedling cultivation of C. calcitrans. The ALPBR was constructed by using transparent glass tubes with a diameter of 32 mm, a total length of 18 m, and volume 14.5 l. The system was optimally operated at an inoculation of 0.5-0.75×106 cell.ml-1, the flow rate at 40 cm.s-1and the solar light intensity at 12.5 klux at a temperature of 26-28°C. The highest cell density was at 7.65×106 cells. ml-1. The obtained results may develop a model scale-up for algae seeding and biomass production as feed for aquaculture.

Using Algae for Biofuel Production: A Review

One of the greatest challenges of the 21st century is to obtain an ecological source of transport fuels. The production of biofuels based on feedstock obtained through the exploitation of arable land translates into an increase in food prices and progressive degradation of the environment. Unlike traditional agricultural raw materials, algae are a neutral alternative in many respects. They can even be obtained as waste from polluted water reservoirs. One of the manifestations of the deterioration of surface waters is the eutrophication of water reservoirs, which leads to an increase in the number of algae. Algae reaching the shores of water reservoirs can be used as a raw material for the production of biofuels, including biogas, bioethanol and biodiesel. However, it should be remembered that water blooms are a periodic phenomenon, appearing in the summer months. Therefore, in order to ensure the continuity of obtaining energy from biomass, it is necessary to conduct algae cultivation in artificial open tanks or photobioreactors. Accordingly, this review first briefly discusses the properties and possible applications of different species of algae in various industrial areas, and then describes the process of eutrophication and the presence of algae in eutrophicated reservoirs. Technologies of algal cultivation in various systems and technologies of algal biomass pretreatment were critically discussed. Various methods of obtaining biomass from algae were also reviewed, and the process conditions were summarized. Biofuels of various generations and raw materials from which they are obtained are presented in order to determine the possible future directions of development in this field. Parameters affecting the selection of algae species for the production of biofuels were also examined and presented. Overall, algal biofuels still face many challenges in replacing traditional fossil fuels. Future work should focus on maximizing the yield and quality of algae-derived biofuels while increasing their economic viability.

Dispersal Movements and Hot Spot Areas of Juvenile Bonelli’s Eagles on the Island of Crete, Greece

The Bonelli’s Eagle (Aquila fasciata) is the main avian predator in almost all the islands of the Greek archipelagos. The phase of its natal dispersal has never been studied in Greece, though it constitutes a crucial part of the species ecology and conservation. In an effort to investigate the movement patterns and settlement areas of young eagles, we tagged 30 fledglings on the island of Crete during 2019–2023 with GPS/GSM transmitters. Fledging date was set the first day with full satellite coverage and consecutive GPS fixes for individual birds while the initiation of the dispersal period was established when they performed consecutive long flights, overstaying away from their natal territory (>10 km). Mean fledgling date was calculated at May 27 (range = 20/5–8/6), whereas the dispersal period started on average on September 03 (range = 30/8–21/9), namely ca. 90–100 days after the abandonment of the nest. All juvenile birds wandered around over the entire island residing primarily in two distinct habitat types i.e. coastal cliffs and satellite islets around Crete and agricultural areas in the lowlands covered with olive groves and vineyards. Preliminary surveys show that the juvenile birds avoid active Bonelli’s Eagle territories and select rural areas near landfills, water reservoirs, fowl pens, and uninhabited islets, specializing on prey species that are readily available (i.e. gulls, corvids, rock pigeons, wild rabbits and poultry). This fact makes them particularly susceptible to human-induced mortality such as electrocution, drowning in open water tanks and poaching, which accounted for ca. 60% of the casualties of this age group. Overall, the study confirms that land use changes and human pressure are the major threats for the species on Crete, likewise in the rest of its distribution range in the Mediterranean.

Discharge Through a Vertical, Rectangular Orifice

In this paper, the derivation of a formula is presented to determine the time taken for the discharge of an open tank through a vertical, rectangular orifice. This formula allows a simpler and more accurate determination of the discharge time.The formula obtained by the integration of velocity distribution was checked using a numerical model. It is shown the great correspondence between the derived formula and a formula for small orifices, regardles of whether the orifice is small or not, except in the cases where the height of orifice is much greater than the height of water level from the upper edge of the orifice. The presented formula takes into account the velocity distribution down the orifice and can be treated as a formula for all rectangular orifices.

Understanding the Effects of Self-Induced Anaerobic Fermentation on Coffee Beans Quality: Microbiological, Metabolic, and Sensory Studies.

In this study, an investigation of the microbial community structure and chemical changes in different layers of a static coffee beans fermentation tank (named self-induced anaerobic fermentation-SIAF) was conducted at different times (24, 48, and 72 h). The microbial taxonomic composition comprised a high prevalence of Enterobacteriaceae and Nectriaceae and low prevalence of lactic acid bacteria and yeast, which greatly differs from the traditional process performed in open tanks. No major variation in bacterial and fungal diversity was observed between the bottom, middle, and top layers of the fermentation tank. On the other hand, the metabolism of these microorganisms varied significantly, showing a higher consumption of pulp sugar and production of metabolites in the bottom and middle layers compared to the top part of the fermentation tank. Extended processes (48 and 72 h) allowed a higher production of key-metabolites during fermentation (e.g., 3-octanol, ethyl acetate, and amyl acetate), accumulation in roasted coffee beans (acetic acid, pyrazine, methyl, 2-propanone, 1-hydroxy), and diversification of sensory profiles of coffee beverages compared to 24 h of fermentation process. In summary, this study demonstrated that SIAF harbored radically different dominant microbial groups compared to traditional coffee processing, and diversification of fermentation time could be an important tool to provide coffee beverages with novel and desirable flavor profiles.

Analytical predictions of cryogen storage in open and closed tanks

• Storage dynamics of cryogen in a closed tank subjected to external heat leak. • An analytical model predicts the rise in pressure and vapour space temperature. • Comparison of characteristics of storing cryogen in a closed and open tank. • Parametric study relating the effects of heat leak rate and initial ullage volume. • Storage of cryogens in cylindrical and spherical tanks in open and closed states. The manuscript elaborates a new analytical approach illustrating the dynamic pressure and temperature variations of stored cryogen in a closed tank subjected to external heat input (also known as ‘ self-pressurization ’). The proposed method follows a proven formalism adopted for predicting the evaporation of cryogenic liquid in an open tank (often termed isobaric storing). While the new mathematical model for ‘self-pressurization’ has been validated with other researchers’ available experimental data, the ‘ open ’ storage performance analyses are verified with the in-house test results. The parametric studies involving external heat ingress, ullage space, and the geometrical tank shapes (spherical and cylindrical) reveal the essential features of storing (considering liquid hydrogen as the cryogen), highlighting the similarities and dissimilarities of the two storage options. Although the expressions for the ullage space temperatures of a ‘ closed ’ and ‘ open ’ tank are similar, the actual variations differ in two fundamentally dissimilar storage systems. The average temperature rise of the ullage space vapour in a closed tank reaches a maximum before falling in contrast to a monotonic increase of the same in an open tank. Under identical circumstances, storage performance in the spherical tank, both open and closed, is better than a cylindrical one.