Liquid Buffer Research Articles

Improving ready-to-eat meat safety: Evaluating the bacterial-inactivation efficacy of microplasma-based far-UVC light treatment of food-contact surfaces and deli turkey breast

The safety of ready-to-eat (RTE) deli meats, especially those sliced in retail establishments, may be improved by light-based surface decontamination. Conventional 254 nm ultraviolet-C (UVC) systems have strong germicidal effects but pose human-health hazards that make them unsuitable for retail use. This study therefore explores the efficacy of microplasma-based 222 nm far-UVC lamps as a safer alternative for decontaminating liquid buffer, two common food-contact surfaces (polyethylene terephthalate and stainless steel), and RTE turkey breast. In all three non-meat cases, the system achieved approximately 5-log reductions of both Listeria monocytogenes and Salmonella Typhimurium. The system also caused a 1.3-log reduction of L. monocytogenes and a 1-log reduction of S. Typhimurium on turkey breast at the highest tested dose of 786.3 mJ/cm2. Color is a key quality indicator for RTE meat consumers, and treatment caused no significant change in L∗, a∗, or b∗ color values (p > 0.05) until doses reached 224.7 mJ/cm2. However, higher doses could lead to statistically significant color changes. Given that far-UVC light has been deemed human-safe by other studies, the proposed system has considerable potential to improve RTE food-related safety in retail establishments, even when consumers and workers are present.

Enzymatic CO2 Capture in intensified packed-bed column bioreactors: A techno-economic assessment

To reduce the impact of industrial carbon dioxide (CO2) emissions on climate change, energy-efficient and cost-effective carbon capture technologies are needed. With this in mind, our research group has proposed an intensified enzyme-mediated CO2 capture process in packed-bed column bioreactors with carbonic anhydrase (CA) immobilized on the packing surface and on magnetic nanoparticles (MNPs). This study, in continuation of our efforts to amend these processes, aims to showcase a techno-economic assessment (TEA) of this promising technology in an industrial-scale context and to emphasize the inherent benefits of intensification. The TEA results suggest that this enzyme-mediated technology has the potential to reduce capture costs, chiefly due to the possibility of utilizing an alternative solvent that requires less energy to regenerate, while also being non-corrosive and non-toxic. The capture process consumes 39.8% less energy than the benchmark process utilizing a MEA-based solution. Immobilizing the enzyme on MNPs has tangible benefits, such as enhancing mass transfer and reducing the equipment footprint, which improves flexibility and contributes to the viability of the industrial process. The intensified enzyme-mediated CO2 capture process achieves a 28.6% reduction in capture cost compared to the benchmark technology. Sensitivity analyses were conducted to highlight the impact of key parameters on the overall cost-effectiveness of the technology, providing beneficial insights for further improvement. The results indicate that it is crucial to maximize enzyme lifespan and minimize energy consumption. The liquid flow rate and buffer concentration are additional constraints that should be thoughtfully considered to ensure the feasibility of this process.

The low temperature liquid metal pressure sensors

Pressure measurement of geotechnical constructions subjected to low temperature plays significant roles in the safety and stability of geotechnical engineering activities. However, the research of pressure sensors in low temperature environment is lacked. In this work, a Galinstan liquid metal pressure sensor under low temperature condition is developed to detect pressure in geotechnical engineering. The elastomer PDMS (polydimethylsiloxane) is employed as the base material. Micro-channels are carved using microfluidic soft lithography technology. The liquid metal is filled as a conductor, and a spring steel case is used for encapsulation. The theoretical relationship between the resistance and pressure is derived, and the theoretical resistance values are compared with experimental resistance values to verify the accuracy of theoretical derivations. The key performance indexes of the designed sensor, such as the compliance, repeatability and hysteresis, are experimentally investigated. The numerical results show that the applied pressure can be uniformly transmitted to the internal PDMS chip with the help of the liquid buffer layer. The experimental results imply that this developed sensor with liquid buffer layer has high curve compliance, good repeatability and low hysteresis in low temperature environment, which provides effective tools for the pressure monitoring of geotechnical constructions subjected to low temperature.

Enantioselective Separation of Synthetic Cathinones by Capillary Electrophoresis with Ionic Liquid and Cyclodextrin Buffer Co-Additives

The enantioselective separation of synthetic cathinones via capillary electrophoresis with ultraviolet detection (CE-UV) was successfully achieved using an acidic formate buffer with the ionic liquid tetrabutylammonium chloride (TBAC) and beta-cyclodextrin (β-CD) as co-additives. Synthetic cathinones (also known as “bath salts”) belong to a class of unregulated drugs labeled new psychoactive substances (NPS). These drugs are readily available and can cause paranoia, confusion, violence, and suicidal thoughts. The stereochemistry of synthetic cathinones, as with other drugs, can influence their potency, toxicity, metabolism, and interaction with other molecules. Thus, it is important to be able to effectively separate different types of synthetic cathinone as well as to resolve enantiomers of each. A study of buffer additives, pH, and counter ions was conducted to identify a system yielding complete enantioselective separation of synthetic cathinones by capillary electrophoresis. Buffer additives TBAC and β-CD, when used separately, did not afford the desired separation; however, when employed as co-additives, enantiomers of each of six different bath salt standards (pentylone, 4-MEC, methylone, MDPBP, MDPV, and naphyrone) were resolved. Achieving this separation of a complex mixture of closely related illicit drugs by CE using an ionic liquid and cyclodextrin together, as buffer co-additives, may provide a new starting point from which to approach the enantiomeric analysis of other drug samples as syntheses of NPS continue to rapidly evolve to evade regulation and law enforcement.

Tribo-sanitizer: A portable and self-powered UV device for enhancing food safety

Food safety is of constant major concern worldwide. Each year, hundreds of millions of people fall ill due to consuming contaminated food, and the resulting economic loss runs into hundreds of billions of dollars. To mitigate these issues, we developed Tribo-sanitizer, which utilizes a freestanding rotational triboelectric nanogenerator (FSR-TENG) to convert mechanical energy into sustainable, low-cost or free electricity that powers an ultraviolet-C (UVC) lamp for food-safety applications. Thanks to the air gap in its circuit – a design inspired by a natural phenomenon, lightning, which can lead to electrical breakdown of air – the optimal FSR-TENG can generate a high voltage output of more than 4,000 V. This high electrical output, in turn, enables brighter illumination of the UVC lamp. Tribo-sanitizer’s decontamination efficacy was evaluated against a gram-positive bacterial strain (Listeria monocytogenes) and a gram-negative one (Escherichia coli O157:H7) inoculated in a liquid buffer, on a polymer widely used in the food-packaging industry, and on two types of fresh produce. Tribo-sanitizer achieved a 5.03-log reduction and a 5.95-log reduction for E. coli O157:H7 in buffer solution and on polyethylene terephthalate (PET), respectively, in line with the 5-log reduction recommended in government guidelines for microbial control. The log reductions for L. monocytogenes in buffer solution and on PET were 4.36 and 3.81, respectively. Lesser effectiveness was observed with the apples and romaine lettuce, likely due to these fresh produce samples’ greater surface roughness as compared to PET, one of the most widely used polymers for the construction of food packaging and drinks bottles. Our results also demonstrate that biomechanical motions can provide Tribo-sanitizer with sufficient power to achieve bacterial inactivation, demonstrating its excellent potential for use in low-resource settings. With further improvements, it could help mitigate severe food-safety problems around the world, leading to a more secure and sustainable food system.

Theoretical evaluation of the tritium extraction from liquid metal flows through a free surface and through a permeable membrane

Effective tritium extraction from PbLi flows is a requirement for the functioning of any PbLi based breeding blanket concept. For a continuous plant operation, the removal of the tritium dissolved in the PbLi has to be performed in line and sufficiently fast. Otherwise, tritium inventories in the liquid metal, start-up inventories and buffer inventories would be excessive from the safety point of view. Moreover, a slow response of the tritium extraction systems could also compromise the tritium self-sufficiency of the plant. A promising solution to this problem is to use highly permeable membranes in contact with the PbLi flow to promote the extraction via permeation. This technique is usually known as Permeation Against Vacuum (PAV). As an alternative, tritium could be extracted directly by permeation through a fluid free surface (FS) in contact with vacuum. In both configurations, the dynamics of tritium transport is ruled by a combination of convection, diffusion and surface recombination. In this paper, the tritium extraction processes in the FS and PAV configurations are studied in detail. For the first time, general analytical expressions for the extraction efficiency are derived for both techniques in a Cartesian geometry. These expressions are general in the sense that they do not impose any kind of assumption concerning the permeation regime of the membrane or the fluid boundary layer. The derived expressions have been used to analyze numerically the response of both configurations in a close loop system, such as the one of DEMO. The presented methodology allows comparing the FS and PAV configurations, assessing in which conditions one will be behave better than other.

Overview and status of the Long-Baseline Neutrino Facility Far Site cryogenics system

The Sanford Underground Research Facility (SURF) will host the Far Detector of the Deep Underground Neutrino Experiment (DUNE), an international multi-kiloton Long-Baseline neutrino experiment that will be installed about one and a half kilometers underground in Lead, SD. Detectors will be located inside four cryostats filled with almost 70,000 metric tons of ultrapure liquid argon, with a level of impurities lower than 100 parts per trillion of oxygen equivalent contamination. The cryogenics infrastructure supporting this experiment is provided by the Long-Baseline Neutrino Facility (LBNF). This contribution presents modes of operation, layout, and main features of the LBNF Far Site cryogenic system, which is composed of three subsystems: Infrastructure, Proximity, and Internal cryogenics. The Infrastructure cryogenics supports the needs of the cryostat and Proximity cryogenics. It includes the equipment to receive the argon in liquid phase, vaporize it and transfer it underground as a gas, the nitrogen system (composed of the refrigeration system, liquid nitrogen buffer tanks and liquid and gaseous nitrogen distribution), liquid and gaseous argon distribution and process controls. The Proximity cryogenics receives fluids from the Infrastructure cryogenics and delivers them to the Internal cryogenics at the required temperature, pressure, purity and mass flow rate. It includes the argon condensers, liquid and gaseous argon purification and regeneration systems, nitrogen and argon phase separators, piping, valves, and instrumentation. The Internal cryogenics comprises the liquid and gaseous argon distribution inside the cryostats for the commissioning, cool down, fill, and steady state operations of the cryostats and detectors. An international engineering team is designing these systems and will manufacture, install, commission, and qualify them. This contribution describes the main features, performance, functional requirements, and modes of operation of the LBNF Far Site cryogenics system. It also presents the status of the design, along with present and future needs to support the DUNE experiment.

Insights into the Partitioning of DNA in Aqueous Biphasic System Containing Ammonium-based Ionic Liquid and Phosphate Buffer

Aqueous biphasic system (ABS), as an efficient separation process, can be applied in the extraction and purification of DNA which is an integral part of life science studies. Ammonium-based ionic liquids (ILs) were synthesized, and ABS formation was evaluated with phosphate buffer [K2HPO4-KH2PO4 (1.82:1.00)] as the second phase forming component. The structural influences of the cation of ILs, including alkyl chain length and the effect of functional groups on phase formation, were methodically assessed. The experimental binodal data were correlated with Merchuks’ equation and showed adequate fitting. The constituents of ABS were carefully selected to obtain a biocompatible system with controlled pH to use for the partitioning of biomolecules. The proposed system was applied in model DNA partitioning and resulted in a single step, highly efficient extraction at 298.15 K. The structural variations of the selected ILs influenced the partitioning, and thus, ABS containing benzyltributylammoniumchloride ([BTBA]Cl) IL was found to be efficient among the studied systems. Furthermore, the partition conditions were optimized in terms of the concentrations of IL and buffer using [BTBA]Cl/K2HPO4-KH2PO4 (1.82:1.00)/water system. Finally, the extraction mechanism involved in the partitioning and stability of DNA was investigated through FT-IR and circular dichroism spectra.

Study on HemoTypeSC™ test for the rapid screening of sickle cell disease patients in Government Medical College and Hospital, Ambikapur

Background: Sickle cell disease (SCD), also known as sickle cell anemia, is a dangerous disease in which the body produces an abnormal form of hemoglobin, the protein in red blood cells that transport oxygen throughout the body. The body produces sickle- or crescent-shaped red blood cells as a result of this genetic change. Aims and Objectives: This study aims to study on HemoTypeSC™ test for the rapid screening of SCD patients in Government Medical College and Hospital, Ambikapur. Materials and Methods: Fifty patients have been diagnosed as sickle cell anemia by sickle cell solubility test at Govt. Medical College, Ambikapur, Chhattisgarh,India. All the patients were admitted in the Department of Medicine at Govt. Medical College, Ambikapur, Chhattisgarh,India, from April 1, 2021, to June 1, 2021. Results: The study group (HbSS patients) comprised 22 (42%) males and 28(58%) females.The ages ranged from 1 to 45 years; these 50 patients have been diagnosed as sickle cell anemia by sickle cell solubility test positive at Govt.Medical College, Ambikapur, Chhattisgarh,India. Conclusion: Sickle cell illness can be counted and observed in a variety of ways. Experience includes things such as electrophoresis and hand counting. HemoTypeSC™ is a blood test kit that determines hemoglobin type in whole blood in a short amount of time. At the point of care, this test detects the hemoglobin phenotype HbAA (normal), HbSS and HbSC (SCD), HbCC (hemoglobin C illness), and HbAS and HbAC (carrier or trait). Monoclonal antibodies are highly specific and sensitive to hemoglobin’s A, S, and C. The fetal hemoglobin has no effect. There are no liquid buffer components or requirements for refrigeration. In high temperatures, it remains stable and the test takes only 10 min to complete.

Consumption Response to Credit Expansions: Evidence from Experimental Assignment of 45,307 Credit Lines

In a field experiment that constructs a randomized credit limit shock, participants borrow to spend 11 cents on the dollar in the first quarter and 28 cents by the third year. Effects extend to those far from the limit, those who had the new limits as available credit, and those with a liquid asset buffer. In the short-run, flexible and installment contracts are used in tandem, with unconstrained using installments more. Long-run borrowing is predominantly using installments. Near limits, participants borrow when credit expands but save out of constraints when limits are tight. Findings support a buffer-stock interpretation emphasizing precautionary saving. (JEL C93, E21, G21, G51, O12, O16)

Electrolyte-gated carbon nanotube field-effect transistor-based biosensors: Principles and applications

Nowadays, there is a high demand for sensitive and selective real-time analytical methods suitable for a wide range of applications, from personalized telemedicine, drug discovery, food safety, and quality control, to defense, security, as well as environmental monitoring. Biosensors are analytical devices able to detect bio-chemical analytes (e.g., neurotransmitters, cancer biomarkers, bio-molecules, and ions), through the combination of a bio-recognition element and a bio-transduction device. The use of customized bio-recognition elements such as enzymes, antibodies, aptamers, and ion-selective membranes facilitates achieving high selectivity. Among the different bio-transduction devices currently available, electrolyte-gated field-effect transistors, in which the dielectric is represented by an ionic liquid buffer solution containing the targeted analyte, are gaining increasing attention. Indeed, these bio-transduction devices are characterized by superior electronic properties and intrinsic signal amplification that allow the detection of a wide range of bio-molecules with high sensitivity (down to pM concentration). A promising semiconducting material for bio-transduction devices is represented by carbon nanotubes, due to their unique electrical properties, nanosize, bio-compatibility, and their simple low-cost processability. This work provides a comprehensive and critical review of electrolyte-gated carbon nanotube field-effect transistor-based biosensors. First, an introduction to these bio-sensing devices is given. Next, the device configurations and operating principles are presented, and the most used materials and processes are reviewed with a particular focus on carbon nanotubes as the active material. Subsequently, different functionalization strategies reported in the literature, based on enzymes, antibodies, aptamers, and ion-selective membranes, are analyzed critically. Finally, present issues and challenges faced in the area are investigated, the conclusions are drawn, and a perspective outlook over the field of bio-sensing technologies, in general, is provided.

Flexible Microswimmer Manipulation in Multiple Microfluidic Systems Utilizing Thermal Buoyancy-Capillary Convection.

Flexible and accurate control of microswimmers is significant for lots of applications. Herein, we present a method for effective microswimmer manipulation in multiple microfluidic systems by thermal buoyancy-capillary convection. In the microdevice, four strips of microheaters arranged at the bottom of the microchannel are used to unevenly heat microfluids, and the convection flow forms under the influence of gravity and interfacial tension gradient. By adjusting the DC signals applied on these four heating elements, the intensity and direction of convection flow can be flexibly adjusted. Accordingly, granular samples dispersed in liquid buffer can be controllably driven to the target position by the Stokes drag. The swimming behavior of polystyrene (PS) microspheres at the solid-liquid interface of the device is first investigated. It shows that the PS microswimmers can migrate along various geometrical patterns by powering the microheaters with designed voltage combinations, and the migration velocity is positively affected by the increased voltage. Then, the butyl acrylate (BA) microswimmers are manipulated at the gas-liquid interface of the microchip. It turns out that the BA microswimmers migrate oppositely compared with PS swimmers under the same energization strategy. Additionally, the translation direction of BA swimmers can be changed over a 360° range by different voltage combinations. The multifunctionality of our approach is further demonstrated by conveniently driving the trimethylolpropane triacrylate microswimmers at the liquid-liquid interface of the microplatform along different directions and pathlines. Therefore, this technique can be promising for many cases needing granular sample control, such as cargo delivery and sensing.

Effect of Ph On Survival of Escherichia coli O157, Escherichia coli O121, and Salmonella enterica During Desiccation and Short-term Storage

One intrinsic characteristic of low-moisture foods that is frequently overlooked is pH. Although pH affects the survival of microorganisms in high-moisture foods, its influence in low-moisture foods with less available moisture has not been examined. Escherichia coli O157:H7, E. coli O121, Salmonella enterica Anatum, and S. enterica Agona were grown on solid media with and without added glucose, harvested, and then suspended in buffer at pH 4, 5, and 7 for 10 min. All cultures were spotted individually onto cellulose filters and dried in a biohazard cabinet (23 ± 2°C) overnight (24 ± 2 h) and then stored in a 25°C incubator at 33% relative humidity. Populations were examined at regular intervals up to 26 (E. coli) or 29 (Salmonella) days. Additional controls for pH consisted of cultures held in buffer at pH 4, 5, and 7 at 25°C for the same time periods as the desiccated cells. For all strains tested, pH had an effect on survival whether stored dried or in liquid buffer (P < 0.05). However, when grown on solid media, acid adaptation (grown with glucose) before acid treatment did not appear beneficial to Salmonella during desiccation. Instead, both acid-adapted Salmonella serovars appeared less resistant during drying than did non-acid-adapted cells. Once dried, the rates of decline for Salmonella were not significantly different for acid-adapted and nonadapted cells (P > 0.05), indicating similar persistence following desiccation. A reverse trend was observed for E. coli O121; acid adaptation on solid media improved survival during desiccation and subsequent storage at low pH (P < 0.05). E. coli O157:H7 survival was significantly lower than that of either Salmonella or E. coli O121 under all conditions tested. Results indicate that the response to desiccation and pH stress differs between the microorganisms and under different growth conditions.

Adaptive illumination for optimal image quality in phase contrast microscopy

Zernike phase contrast microscopy is a powerful and well established microscopy technique. Due to its ability to enhance contrast of transparent, unlabelled specimens, it is widely used for live cell imaging. But for samples contained in small culture dishes or multiwell plates filled with buffer solution, the curved surface of the liquid buffer distorts the illumination light path. This leads to a misalignment of the ring shaped illumination with respect to the phase ring inside the objective lens. As a consequence, the image contrast and quality can be severely degraded, especially when imaging at the margin of the containers.Here we present a solution to this problem that is based on using a programmable illumination unit. This allows us to compensate the illumination for the distortions induced by the interface meniscus. We find that a simple strategy, which is based on correcting illumination angles where possible and removing light in angles where such a correction is not possible, can maintain the image contrast over a large percentage of a culture dish bottom area.Furthermore, we show that our approach can be extended beyond the ring-shaped mask design of Zernike imaging to phase masks consisting of multiple spots, a method which has been shown to be superior regarding the minimization of artefacts and for quantitative phase measurements.

ASSESSMENT OF A MICROPLATE SYSTEM FOR MEASURING INDIVIDUAL REAL-TIME RESPIRATION IN SMALL MODEL ORGANISMS OF AGING

The ability to measure oxygen consumption rates of a living organism in real-time provides an indirect method of monitoring dynamic changes in metabolism reflecting organismal level mitochondrial function. In this study, we assessed the Loligo Systems microplate system for measuring individual respiration in small organisms. This included adult nematodes (Caenorhabditis elegans, N2), zebrafish embryos (Danio rerio, AB), and adult fruit flies (Drosophila melanogaster, w1118). Organisms were placed inside 80 µL glass chambers on a 24-well microplate atop a 24-channel optical fluorescence oxygen reading device. Adult nematodes and zebrafish embryos were in liquid culture, M9 buffer and egg water respectively, and the adult flies were in room air. The microplate and reader were placed inside an incubator for temperature control. A silicone gasket with a thin liner was used to seal the chambers. Reference standard oxygen consumption (respiration) of single and multiple adult nematodes (n=1–4 animals/well), zebrafish embryos (n=1–4 animals/well), and adult flies (n=1–2 animals/well) in the microplate system were achieved. Significant differences across numbers of animals/well and by sex were observed. Validation experiments of the oxygen consumption rates measured in C. elegans in parallel with Seahorse extracellular flux (XF) experiments are underway. The Loligo Systems microplate system offers a non-invasive, non-destructive method to measure real-time respiration in smaller organisms. These data provide preliminary evidence for utility of the system for a variety of biomedical applications that relate to organismal and mitochondrial function/dysfunction, including research in the basic biology of aging in these highly-utilized, pre-clinical, genetic model organisms.

Weathering Volatility 2.0: A Monthly Stress Test to Guide Savings

Inconsistent or unpredictable swings in income and expenses make it difficult for families to plan spending, pay down debt, or determine how much to save. In this report, the JPMorgan Chase Institute uses administrative banking data to study the nature and trends of month-to-month fluctuations in income and spending and the levels of cash buffer families need to weather adverse income and spending shocks. We analyze monthly take-home income, spending, and account balances of over six million families’ Chase checking accounts between 2013 and 2018. We measure volatility with the Coefficient of Variation (CV) of monthly total take-home income. In addition to absolute volatility, we also measure income and spending spikes and dips separately. We examine the extent to which levels of volatility differ for sub-populations across the income spectrum, age, gender, and cash buffer. Finally, we empirically estimate the minimum levels of cash buffer families need to weather adverse shocks to their savings including income dips and spending spikes. We find that month-to-month income volatility has remained relatively constant over the past six years from 2013 to 2018. The level of income volatility remains high with those at the median level experiencing a 36 percent change in income month-to-month. Similarly, month-to-month spending volatility has also been flat during this period, with its level 15 percent lower than that of income but still high. In addition, families experience large income swings, including spikes and dips, in five months out of a year, where income spikes are twice as likely as dips and most common in March and December. Families with the most volatile incomes experience larger but not more frequent swings than those with less volatile incomes. There is wide variation in the levels of income volatility families experience and is greatest amongst the young and those in the highest income quintile. However, low-income families experience larger and more frequent income dips, an indication of downside risks. Finally, we find that families need roughly six weeks of take-home income in liquid assets to weather a typical and simultaneous income dip and expenditure spike. More than 60 percent of families lack a sufficient buffer to do so. In follow up work underway, we examine the impact of the 2019 January government shutdown on employees’ consumption and savings pattern as a case study of negative income shock. Altogether, our results offer important empirical guidance for the minimum levels of liquid buffer families need and implications for strategies to improve families’ financial health.

A primer in the European Commission’s proposed new prudential rules for investment firms

This paper considers the European Banking Authority (EBA) and European Commission proposals for a new prudential rulebook for investment firms. It is relevant to staff in finance, risk and compliance functions at asset management, securities trading and broker-dealer firms and their advisers. The paper opens by considering the EBA’s objectives in proposing a new prudential regime for investment firms. It then goes on to consider the European Commission’s proposal for new legislation that would give effect to these new requirements. It examines the scope of the new rules and the new categorisation of investment firms. The following requirements of the new rules are considered in detail: capital requirements, internal risk management processes, reporting to regulators, disclosure to the market and the minimum liquid assets buffer. The reader will glean an elementary understanding of the new rule requirements on each of these areas. For readers in the UK, there is an assessment of how changes in the UK’s future relationship with the European Union may have an impact on the introduction of this proposed legislation. Finally, the paper considers the most likely practical impact of the new rules on different types of investment firms.

Evaluating formulation and storage of Arthrobacter aurescens strain TC1 as a bioremediation tool for terbuthylazine contaminated soils: Efficacy on abatement of aquatic ecotoxicity

Recently, a bioremediation tool consisting of freshly grown cells of the Arthrobacter aurescens strain TC1 proved successful in the cleanup of terbuthylazine (TBA) contaminated soil, with potential to prevent TBA dispersal via the soil-water pathway. The present work aimed at examining the feasibility of preparing and formulating bioaugmentation bacterial cells in advance which retain adequate viability and herbicide-degrading activity during storage and transport to contaminated sites. Three different types of formulation of A. aurescens TC1 cells were performed, namely cell paste, lyophilized, and adsorbed onto the mineral carrier vermiculite. Vermiculite-based cell material and cell paste offered survival rates significantly higher (≥78% of cells recovered viable, when compared to the initial numbers) than lyophilized cells (≥65%) after storage at 4 °C for up to a maximum period of 30 days. Inocula prepared from the three types of formulated and stored cells supported adequate levels of herbicide-biodegradation activity, ultimately allowing an almost complete removal of TBA from either liquid buffer or soil. In soil microcosms, the efficacy of bioremediation of TBA-contaminated soil in terms of decontamination (%) based on the ecotoxicity assessment of soil eluates towards a freshwater microalga was found to differ within formulations in the order: lyophilized cells (~100% efficacy at the end of one or two weeks of bioremediation treatment with an initial inoculum of ~2.5 × 107 viable cells/g of soil; similar to fresh cells) > vermiculite-adsorbed cells (81% with ~2.4 × 108 cells/g) > cell paste (68% with ~2.4 × 108 cells/g). The limitations and advantages of each type of bacterial formulation, together with the prediction of their applicability in the field are discussed.

Study on cooling down law and temperature control method of liquid blast furnace slag storage device from energy saving of steel industry

The metallurgical industry is a typical energy-intensive industry, whose energy-saving potential is enormous. Liquid blast furnace slag temperature is about 1400 °C, and its volume is large and discharged discontinuously. Existing technologies, using boilers and steam turbine to recover the waste heat, need to be carried out continuously. To solve the bottleneck of mismatch between intermittent slagging and waste heat continuous recovery, this paper discussed the liquid slag storage and temperature control device referring to the liquid metal buffer device such as ladle and tundish. Then, the heat transfer process and temperature distribution of the liquid blast furnace slag at different baking temperatures were numerically simulated by using the solidification-melting model. The effects of different baking temperature and slag residence time on the temperature distribution of slag were analyzed. The optimum baking temperature was obtained. The slag solidification crust phenomenon was overcome, so that slag can maintain a high-temperature level to facilitate its subsequent waste heat recovery and resource utilization.

Simulation research on the slag control tube during energy recovery from steel industry

In the process of steel smelting, a large amount of liquid slag with temperature from 1400°C to 1550°C is produced. The sensible heat contained per ton of blast furnace slag is equivalent to the calorific value of 60 kg standard coal. In 2017, China’s crude iron production reached 710 million tons, producing 213 million tons of blast furnace slag, whose sensible heat is equivalent to 12.84 million tons of standard coal. Thus, recovery of waste heat from high temperature liquid slag has great energy conservation potential. To resolve the contradiction between the discontinuity of slag discharge and the continuity of waste heat recovery system, this paper carried out numerical simulation research on high-temperature liquid slag buffer and flow control process. The variations of flow rate with time and liquid level were obtained by numerical simulation of slag discharge in the slag control tube. The main conclusions are as follows: A critical liquid level of 1.65 m was found and confirmed. As the liquid level fell to the critical level, the flow rate decreased rapidly and approached zero in a short time. When the internal diameter was 27 mm and the slag temperature was 1450°C, the rate change of the slag met the system requirements of 6 t·h-1~7 t·h-1, and the relational expression of the flow level could be fitted. This study has essential guiding significance for liquid level control in actual operation.