Fume Hood Research Articles

Using Fume Hood to Reduce Nurses' Exposure to Particulate Matters Dispersed Into the Air During Pill Crushing.

Pill crushing is a common practice in patient care settings. Crushing pills can disperse particulate matter (PM) into indoor air. The PM is a widespread air pollutant composed of microscopic particles and droplets of various sizes and may carry active and/or inactive ingredients nurses can inhale. This study aimed to quantify PM sizes and concentration in indoor air when pills are crushed and examine the role of a fume hood in reducing particulate pollution. Two scenarios (with and without a fume hood) representing nurses' pill-crushing behaviors were set up in a positive-pressure cleanroom. Two acetaminophen tablets (325 mg/tablet) were crushed into powder and mixed with unsweetened applesauce. The PM sizes and concentrations were measured before and during crushing. Different sizes of PM, including inhalable, respirable, and thoracic particles, were emitted during medication crushing. The total count of all particle sizes and mass concentrations of particles were significantly lower during crushing when a fume hood was used (p = .00). Pill crushing increases PM and should be considered a workplace safety health hazard for nurses. Healthcare professionals should work under a fume hood when crushing pills and wear proper protective equipment. The findings of significant particulate pollution related to pill crushing suggest that further research is warranted.

Indoor air quality and energy-saving potential improvement of a range-hood-integrated air cleaner

Local exhaust systems based on range hoods are widely used to reduce cooking oil fumes (COF) of kitchen spaces. This work proposes a range-hood-integrated air cleaner to improve air distribution in residential kitchens and reduce individual inhalation exposure to COF. Effects of hood exhaust rates, cooking–heating intensities, and airflow parameters of the air cleaner on the volume-averaged concentration (VAC) of kitchen space and the intake fraction (IF) are discussed through orthogonal experimental design, and significant factors are the hood exhaust rate, the air supply velocity, and angle of the air cleaner by evaluating significance levels. Optimal airflow parameters of the air cleaner are obtained through single-factor analysis, and VAC is reduced by approximately 90% compared with the single range-hood exhaust system. The energy-saving potential of the air cleaner is identified and evaluated using the concept of the equivalent exhaust rate. The air cleaner is more conducive to creating a comfortable kitchen environment and reducing heat transfer load. This work provides a new solution for optimizing air distribution in highly polluted kitchen environments.

Aryl-diazonium salts offer a rapid and cost-efficient method to functionalize plastic microfluidic devices for increased immunoaffinity capture.

Microfluidic devices have been used for decades to isolate cells, viruses, and proteins using on-chip immunoaffinity capture using biotinylated antibodies, proteins, or aptamers. To accomplish this, the inner surface is modified to present binding moieties for the desired analyte. While this approach has been successful in research settings, it is challenging to scale many surface modification strategies. Traditional polydimethylsiloxane (PDMS) devices can be effectively functionalized using silane-based methods; however, it requires high labor hours, cleanroom equipment, and hazardous chemicals. Manufacture of microfluidic devices using plastics, including cyclic olefin copolymer (COC), allows chips to be mass produced, but most functionalization methods used with PDMS are not compatible with plastic. Here we demonstrate how to deposit biotin onto the surface of a plastic microfluidic chips using aryl-diazonium. This method chemically bonds biotin to the surface, allowing for the addition of streptavidin nanoparticles to the surface. Nanoparticles increase the surface area of the chip and allow for proper capture moiety orientation. Our process is faster, can be performed outside of a fume hood, is very cost-effective using readily available laboratory equipment, and demonstrates higher rates of capture. Additionally, our method allows for more rapid and scalable production of devices, including for diagnostic testing.

A gelation facility for the preparation of ceramic microspheres

A gelation facility has been commissioned inside a ‘walk-in’ fume hood for producing oxide microspheres through internal gelation process. This facility would serve both as a test bed for optimizing the process parameters and would serve ‘as a prototype’ for the system to be incorporated in a remotely operated facility for the production of (U,Pu) mixed oxide microspheres containing minor actinides. This facility consists of an indigenously designed 1.6 m tall modular glass column with stainless steel modular support structure, oil reservoir with a recirculation pump, resistive heater, double-jacketed feed tank, a controlled pressure transfer facility, a nozzle with an electromagnetic vibrator, cooling stations for broth preparation, mesh belt conveyor, soft gelled spheres collection tray and microsphere washing stations. The design of the glass column has been optimized to avert choking due to aggregation of the microspheres. The latter has been accomplished by arriving at the optimal flow with the help of a simple flow model. This flow model considers the temperature dependence of viscosity and the temperature distribution within the column, experimentally determined by using infrared thermography. The optimal composition of the feed (broth) has been arrived at by using an innovative measurement of the viscosity of the sol and gel during gelation. The innovation in both equipment and method are being reported for the first time. A novel method to quantify the gelation characteristics of sol has been devised and is being reported for the first time.

Efficiency enhancing of the local capture hood due to air barriers

AbstractThis article is related to investigations of the capture hoods of the local exhaust ventilation. The purpose of the research: to increase the zone of action of local exhaust hoods and reduce the amount of air removed. It is equipped with two barriers for air: ring and cylindrical. The empirical dependences for air velocity determination near the suction zone are obtained. Graphs, chart and three-dimensional image visualizations of removed air jet velocity near capture hood with barriers for air are designed. The reduction of production energy consumption, material, and ventilation system maintenance costs due to the correction of the design of the capture hood are the main benefits of the new solution.

The History of Flow Chemistry at Eli Lilly and Company.

Flow chemistry was initially used for speed to early phase material delivery in the development laboratories, scaling up chemical transformations that we would not or could not scale up batch for safety reasons. Some early examples included a Newman Kwart Rearrangement, Claisen rearrangement, hydroformylation, and thermal imidazole cyclization. Next, flow chemistry was used to enable safe scale up of hazardous chemistries to manufacturing plants. Examples included high pressure hydrogenation, aerobic oxidation, and Grignard formation reactions. More recently, flow chemistry was used in Small Volume Continuous (SVC) processes, where highly potent oncolytic molecules were produced by fully continuous processes at about 10 kg/day including reaction, extraction, distillation, and crystallization, using disposable equipment contained in fume hoods.

Computational Fluid Dynamics Simulations to Assess Spatial Variability and Optimal Ventilation Scenarios for Biological Laboratory Exposures

Introduction: A significant amount of uncertainty exists regarding potential human exposure to laboratory biomaterials and organisms in Biosafety Level 2 (BSL-2) research laboratories. Computational fluid dynamics (CFD) modeling is proposed as a way to better understand potential impacts of different combinations of biomaterials, laboratory manipulations, and exposure routes on risks to laboratory workers. Methods: In this study, we use CFD models to simulate airborne concentrations of contaminants in an actual BSL-2 laboratory under different configurations. Results: Results show that ventilation configuration, sampling location, and contaminant source location can significantly impact airborne concentrations and exposures. Depending on the source location and airflow patterns, the transient and time-integrated concentrations varied by several orders of magnitude. Contaminant plumes from sources located near a return vent (or exhaust like a fume hood or ventilated biosafety cabinet) are likely to be more contained than sources that are further from the exhaust. Having a direct flow between the source and the exhaust (through-flow condition) may reduce potential exposures to individuals outside the air flow path. Conclusion: Designing a BSL-2 room with ventilation and airflow patterns that maximize through-flow conditions to the return/exhaust vents and minimize dispersion and mixing throughout the room is, therefore, recommended. CFD simulations can also be used to assist in characterizing the impacts of supply and return vent locations, room layout, and source locations on spatial and temporal contaminant concentrations. In addition, proper placement of particle sensors can also be informed by CFD simulations to provide additional characterization and monitoring of potential exposures in BSL-2 facilities.

129 A Novel Controlled Test Atmosphere Generation System for the Exposure Assessment Method Setup and Validation

Abstract Active sampling and analytical methods for the exposure assessment to chemical compounds have to be validated prior to be used on field. Requirements for the evaluation of these measuring procedures are specified in the ISO 22065 standard and include experiments to be done with a dynamic system for generating known concentration of gas and vapour in air under controlled conditions. Unfortunately, laboratories are rarely equipped with this kind of system and they have to carry out manual spiking of samples with a liquid micro-syringe, which is time consuming and source of uncertainty. In order to meet the requirements for accurate methods, we have designed and developed a fully automated generation system -called COMET generation system- that allows producing simultaneously four distinct concentration levels of gaseous pollutants and to perform automated multiple samples in each concentration branch according to the ISO 22065 standard compliance. The system is based on innovative pollutant generation, temperature and humidity control and multiple sampling technologies to be contained under a fume hood. The design of the system allows performing all the required sampling within a week whereas manual spiking need several weeks and excluding some important experiments where the temperature and the moisture have to be controlled. An online gas chromatograph or an Infrared photoacoustic analyzer determine the actual concentration in each concentration level branch. Two different methods were validated with both manual spiking and with the COMET system and the results were similar. Repeatability and overall uncertainty are significantly lower with the COMET system.

Blade‐Coated Carbon Electrode Perovskite Solar Cells to Exceed 20% Efficiency Through Protective Buffer Layers

AbstractPerovskite solar cells with carbon electrode have a commercial impact because of their facile scalability, low‐cost, and stability. In these devices, it remains a challenge to design an efficient hole transport layer (HTL) for robust interfacing with perovskite on one side and carbon on another. Herein, an organic/inorganic double planar HTL is constructed based on polythiophene (P3HT) and nickel oxide (NiOx) nanoparticles to address the named challenge. Through adding an alkyl ammonium bromide (CTAB) modified NiOx nanoparticle layer on P3HT, the planar HTL achieves a cascade type‐II energy level alignment at the perovskite/HTL interfaces and a preferential ohmic contact at NiOx/carbon electrode, which greatly benefits in charge collection while suppressing charge transfer recombination. Besides, compared with the single P3HT layer, the planar composite enables a robust interfacial contact by protecting perovskite from being corroded by carbon paste during fabrication. As a result, the blade‐coated FA0.6MA0.4PbI3 perovskite solar cells (fabricated in ambient air in fume hood) with carbon electrode deliver an efficiency of 20.14%, the highest value for bladed coated carbon and perovskite solar cells, and withstand 275 h maximum power point tracking in air without encapsulation (95% efficiency retained).

Optimization Design of Bolt-on Exhaust Hood for Fire Fighting Robot

To solve the problem of frequent cracks in the air-cooled engine exhaust hood of a fire fighting robot, the structure parameters are optimized based on Beam element.Firstly,the finite element model of the exhaust hood is analyzed for pre-stress modal analysis, compared with the choice of Beam unit to simulate the bolted connection, and the RSM is used to optimize it.Secondly, the sample points are generated by Latin hypercube sampling, and the Kriging response surface model with good fitting is constructed. The sensitivity analysis is used to screen the targeted parameters, and the response surface optimization model with the total deformation, mass and first natural frequency as the target is established.Finally, MOGA is used to optimize the exhaust hood, and the optimal results are rounded and verified.The results show that the total deformation of the optimized exhaust hood is reduced by 7.18 %, the mass is reduced by 4.68 %, and the first natural frequency is increased by 74.98 %.The stiffness of the exhaust hood increases, which avoids the resonance interval. The application of Beam element effectively improves the simulation efficiency and provides a reference for the structural optimization of bolted connections.

Use of PLE-ATD-GC/MSMS for the Quantification of Airborne Pesticides in Active and Passive Samples and in Dust.

An analytical method coupling pressurized liquid extraction (PLE), pre-concentration by thermal desorption (ATD) and analysis by GC/MSMS was developed for the quantification of pesticides in air and dust near vineyards crops to evaluate potential exposure of residents living near these crops. PLE was done using acetonitrile and extracts were concentrated under fume hood to 1mL. 100μL of the extract was spiked in a Tenax TA tube and internal standards and N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide were added before thermal desorption at 300°C for 30min. GC/MSMS analysis was done in MRM mode and limits of quantification and limits of detection were determined for each matrix (passive air sample, active air sample and dust). The method was applied in the field and shows good sensitivity and accuracy.

Abstract Number ‐ 127: Poly(vinyl alcohol) grafts of brain aneurysms with patient‐specific morphologies

Introduction Current animal models of brain aneurysms used for testing neuro‐interventional devices have highly simplistic vascular anatomy in comparison with human aneurysm‐parent vessel complexes. Poly(vinyl alcohol) (PVA) is a leading biomaterial for manufacture of artificial vascular grafts because of its biocompatibility, hemocompatibility, availability, low cost, moldability/castability, and tunable mechanical properties to match arterial compliance [1,2]. However, PVA is non‐cell adhesive and requires modification with additives to promote endothelialization of the luminal surface to maintain long‐term graft patency [1,3]. We have previously studied the biocompatibility of resorcinol bis(diphenyl phosphate) (RDP) coated clays blended with polymers and have found excellent cell adhesion and proliferation with human dermal fibroblasts as well as dental pulp stem cells [4]. Our overall goal is to develop a new in vivo model of brain aneurysms by manufacturing patient‐specific aneurysm anatomies with a blend of PVA and RDP clay and grafting them into animals. Here, we evaluate the casting of PVA in the shape of patient‐specific aneurysms. Methods 10% PVA (w/w) (99% hydrolyzed, 85–124K molecular weight, Sigma Aldrich) was dissolved in deionized water, to which 1% RDP clay (ICL Industrial Products, Be’er Sheva, Israel) was added. The PVA was crosslinked using 15% (w/w) of sodium trimetaphosphate and 30% (w/w) of sodium hydroxide, after which rheological studies (stress sweeps using a Bohlin Gemini rheometer) were conducted. In the casting procedure, negative molds of both simple tubes and complex aneurysm geometries were designed using Rhinoceros 3D software (Robert McNeel & Associates, Seattle, WA) and 3D printed in ABS plastic. The negative mold was then filled with beeswax, resulting in a positive wax mold that was dip‐coated 8 times in PVA solution, and spun on a two‐axis spinner in between each dip to ensure even coverage. After overnight drying in a fume hood, the model was placed in heated water, allowing the wax to melt out and leaving behind the luminal PVA cast. Results Rheology on the crosslinked polymers showed that the PVA/RDP blend exhibited over twice the elastic modulus of unblended PVA (Figure A). Such enhanced mechanical properties are consistent with previous studies [5]. Both simple tubular geometries and patient‐specific anatomies were able to be successfully cast using the methodology developed here (Figure B). Conclusions This proposed casting methodology demonstrates a realistic, efficient way to replicate complex aneurysm geometries with comparatively inexpensive materials and short time frame. Future endeavors will include further exploration of the PVA/RDP biocompatibility as well as completing the casting procedure with a PVA/RDP blend.

Compact capillary high performance liquid chromatography system for pharmaceutical on-line reaction monitoring.

Due to their size, conventional high performance liquid chromatographs (HPLCs) are difficult to place close to a reaction vessel within a pharmaceutical manufacturing or development site. Typically, long transfer lines are required to move sample from the reactor to the HPLC for analysis and high solvent usage is required. However, herein a compact and modular separation system has been developed to enable co-location of an HPLC with a small-scale reactor for reaction monitoring in the synthesis of active pharmaceutical ingredients. Using a framework based on capillary HPLC, a compact gradient separation system with a fully modular architecture is described. A custom miniature diode-array detector with a linear dynamic range (up to 1500 mAU at 210nm) was integrated and evaluated for on-line reaction monitoring. In evaluating system suitability, average peak area %RSD of <3%, and an average retention time %RSD of <0.7%, were achieved. To demonstrate practical utility, the compact system was coupled directly to an on-line lab-scale flow through reactor for continuous reaction monitoring in the laboratory fume hood, where a study of the 3rd Bourne reaction was used to compare the performance of the compact system with a commercially available process HPLC instrument (Waters PATROL UPLC). Further, 33 off-line samples from a continuous crystallization reactor were analysed and it was found that the developed compact HPLC system showed equivalent quantitative performance to an Agilent 1290 Infinity II HPLC system.

Numerical Calculation of the Boundaries of Vortex Zones at the Inlet to Round Exhaust Hoods with Three Shelves

Numerical Calculation of the Boundaries of Vortex Zones at the Inlet to Round Exhaust Hoods with Three Shelves

The Need for Mandatory Academic Laboratory Sustainability Training – A Fume Cupboard Case Study

While scientific research is paramount to understanding the solar system, ecosystem, human disease and cures (etc) it continues to contribute to human-caused climate change. Scientists are becoming increasingly aware of the carbon footprint associated with their research and recognise the need to work more efficiently with their resource use and laboratory operations. &#x0D; &#x0D; University laboratories are spaces that allow for research to be carried out safely, however, they consume five times more energy per square meter than office buildings. Fume cupboards are amongst the most energy intensive equipment and thus are a dominant factor when working towards creating safer and greener laboratories. In this paper, we report on the gas, electricity, carbon and financial savings derived by upgrading 105 constant air volume fume cupboards to variable air volume systems. We also report on the frequency of fume cupboard use by research staff, postgraduate students, and their overall understanding of fume cupboard best practice operations. The results reflect that while savings were achieved, they were lower than predicted. A factor to this may be poor student and staff understanding of how fume cupboards work resulting in their incorrect usage, therefore hampering sustainable progression. This study highlights that a major gap exists between laboratory technical upgrades and researcher awareness of proper and safe equipment use and operation. To overcome this, we propose that in addition to health and safety training, mandatory laboratory sustainability operations training should be provided to all laboratory users.

Reduced-scale experimental investigation on flow field characteristics of exhaust hood of double helix lifting transportation equipment in an industrial plant

In this study, the double screw lifting device of a rubber factory is taken as the case study object, and a scale model experiment was designed to determine the temperature field, velocity field and concentration field of pollutant escape of double spiral lifting transportation device are compared, and the capture efficiency is compared under the conditions of different dimensionless installation height and local exhaust hood air flow velocity Vexh. Reduced-scale experiments were conducted with a geometric scale of 1:4. Compared with no local exhaust hood, the concentration at the same measuring point decreases significantly under the action of local exhaust hood (dimensionless distances z/d = 3/4 and z/d = 2/4). Under the condition of maintaining the same local exhaust hood air flow velocity Vexh, the capture efficiency of local exhaust hood increased by 4% and 1% respectively on the dimensionless installation distance Z/D was 3/4 and 2/4 respectively. The experimental method of this case study and the air flow field experimental data obtained can provide a reference for the subsequent design and installation of exhaust hood.

Acetylcholinesterase Activity Staining in Freshwater Planarians.

The serine hydrolase acetylcholinesterase (AChE) is an important neuronal enzyme which catalyzes the hydrolysis of the neurotransmitter acetylcholine and other choline esters. The breakdown of acetylcholine by AChE terminates synaptic transmission and regulates neuromuscular communication. AChE inhibition is a common mode of action of various insecticides, such as carbamates and organophosphorus pesticides. Freshwater planarians, especially the species Dugesia japonica, have been shown to possess AChE activity and to be a suitable alternative model for studying the effects of pesticides in vivo. AChE activity can be quantified in homogenates using the Ellman assay. However, this biochemical assay requires specialized equipment and large numbers of planarians. Here, we present a protocol for visualizing AChE activity in individual planarians. Activity staining can be completed in several hours and can be executed using standard laboratory equipment (a fume hood, nutator, and light microscope with imaging capability). We describe the steps for preparing the reagents, and the staining and imaging of the planarians. Planarians are treated with 10% acetic acid and fixed with 4% paraformaldehyde and then incubated in a staining solution containing the substrate acetylthiocholine. After incubation in the staining solution for 3.5 hr on a nutator at 4°C, or stationary on ice, planarians are washed and mounted for imaging. Using exposure to an organophosphorus pesticide as an example, we show how AChE inhibition leads to a loss of staining. Thus, this simple method can be used to qualitatively evaluate AChE inhibition due to chemical exposure or RNA interference, providing a new tool for mechanistic studies of effects on the cholinergic system. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Preparing the staining solution Basic Protocol 2: Fixing, staining, and imaging whole-mount planarian specimens for visualization of acetylcholinesterase activity.

Cooling of Steam Turbine Exhaust Hood and Last Stage Blade

This paper describes a novel semi-numerical method of water droplets path lines calculation in steam turbine axial exhaust hood 2D space. The axial velocity profile of steam as well as droplets evaporation are taken into account. Water droplets occur in several cooling nozzles placed on the outer wall of axial exhaust hood. Mathematical model of all water nozzles used in Doosan Škoda steam turbines was developed. Position and angle of cooling nozzles towards the outer exhaust hood wall influence the possibility of last stage blade trailing edges erosion given by droplets flow from the nozzles. The turbine lifetime is prolonged as the final consequence.

The study on influencing factors of airflow in laboratory fume hood

This study investigates the influence of the side wind flowing directly from different indoor environments on the airflow of the laboratory fume hood (LFH). When an LFH is used to discharge the harmful from the laboratory, the side wind can affect the airflow of the LFH, which is likely to cause the leakage of harmful fumes. In this study, incense was used to simulate harmful fumes, sampling and analysis of the total suspended particulate concentrations were performed in an LFH under different side wind conditions with or without air conditioning, operator, laboratory door open, and electric fan when the fume hood sash (FHS) is at the top, middle, and bottom positions, respectively. A laser pen and hot-wire anemometer are employed to demonstrate the airflow of the smoke and wind speed in different indoor environmental conditions. The experimental results reveal that the airflow field and distribution of harmful fumes in the LFH can be changed according to the different heights of the FHS and changes in the external airflow. Therefore, when using the LFH, the influence of the external airflow should be reduced, and the LFH should be operated for a few minutes before switching it off.

Development of Jet Stream Attraction Type Ventilation System to Suppress Down Capture Efficiency of Exhaust Hood by Disturbance Airflow

Development of Jet Stream Attraction Type Ventilation System to Suppress Down Capture Efficiency of Exhaust Hood by Disturbance Airflow