scholarly journals Assembly of UV-Ozone Reactor to Combat of Coronavirus and Other Pathogenic Microorganisms

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Emerson Roberto Santos ◽  
Juliana Aparecida Vendrami ◽  
Antonio Celso Duarte ◽  
Elvo Calixto Burini Júnior ◽  
Roberto Koji Onmori ◽  
...  
Keyword(s):  
High Pressure ◽  
Ozone Concentration ◽  
Low Cost ◽  
Aluminum Foil ◽  
Mercury Vapor ◽  
Metal Halide ◽  
Ultraviolet Rays ◽  
Pathogenic Microorganisms ◽  
Uv Ozone ◽  
Uv C

The contamination on the surface of objects caused by: fungi, microbes, bacteria and viruses (and also coronavirus) can be solved using UV rays and/or ozone gas. For this reason, a UV-Ozone reactor apparatus with low cost was mounted to test two different types of HID (high intensity discharge) lamps: high pressure mercury vapor lamp (HPMVL) and metal halide lamp (MHL), both with nominal power of 400 watts and E-40 (base, screw) were studied as possible method of disinfection. Each lamp used the respective electromagnetic ballasts and both were manufactured by Osram Company. These lamps have two bulb types: the outer bulb which was removed and it is responsible for filtering the ultraviolet wavelengths and the internal bulb (where there is mercury, argon or metal halide confined at high pressure) that is the main source of ultraviolet rays. The complete apparatus was assembled using: aluminum reflector (used as a chamber), two microcomputer fans and a wooden base covered by an aluminum foil. A rubber strip was placed at the edge of the reflector for better adhesion on the aluminum foil (for better confinement ozone gas). The ozone concentration inside the reactor was measured with a monitor, the temperatures were measured near lamps with a thermocouple and a spectroradiometer with optical fiber was used to obtain the wavelengths. The results revealed to the elapsed time of 2 minutes a maximum peak of ozone concentration of 23 ppm for LVMAP, while the MHL presented 4.5 ppm only. The temperature obtained by HPMVL was lower with 31.5 ºC, while the MHL presented 48.0 ºC. The HPMVL presented higher amount of wavelengths at the ranges: UV-A, UV-B and UV-C, while the MHL presented only UV-A. For these reasons, it is suggested to be most promissory the use of HPMVL to combat the coronavirus and other pathogenic microorganisms.

Understanding the Role of Chlorine and Ozone to Control Postharvest Diseases in Fruit and Vegetables: A Review

2020 ◽  
Vol 16 (4) ◽  
pp. 455-461
Author(s):  
Gabriela M. Baia ◽  
Otniel Freitas-Silva ◽  
Murillo F. Junior
Keyword(s):  
Chlorine Dioxide ◽  
Broad Spectrum ◽  
Fruits And Vegetables ◽  
Low Cost ◽  
Residual Effects ◽  
Pathogenic Microorganisms ◽  
Postharvest Diseases ◽  
Post Harvest ◽  
By Products

Fruits and vegetables are foods that come into contact with various types of microorganisms from planting to their consumption. A lack or poor sanitation of these products after harvest can cause high losses due to deterioration and/ or pathogenic microorganisms. There are practically no post-harvest fungicides or bactericides with a broad spectrum of action that have no toxic residual effects and are safe. However, to minimize such problems, the use of sanitizers is an efficient device against these microorganisms. Chlorine is the most prevalent sanitizing agent because of its broad spectrum, low cost and well-established practices. However, the inevitable formation of disinfection by-products, such as trihalomethanes (THMs) and haloacetic acids (HAAs), is considered one of the main threats to food safety. Alternative sanitizers, such as chlorine dioxide (ClO2) and ozone, are becoming popular as a substitute for traditional post-harvest treatments. Thus, this review addresses the use of chlorine, chlorine dioxide and ozone emphasizing aspects, such as usage, safe application, spectrum of action and legislation. In order to ensure the quality and safety of final products, the adoption of well-prepared sanitation and sanitation programs for post-harvest fruits and vegetables is essential.

A Very Low-Cost, Labor-Efficient, and Simple Method to Block Scattered Ultraviolet Light in PDMS Microfluidic Devices by Inserting Aluminum Foil Strips

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuo Wang ◽  
Peter Shankles ◽  
Scott Retterer ◽  
Yong Tae Kang ◽  
Chang Kyoung Choi
Keyword(s):  
Soft Lithography ◽  
Uv Light ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Aluminum Foil ◽  
Material Synthesis ◽  
Simple Method ◽  
Micro Particles ◽  
Complex Shapes ◽  
The Cost

Abstract Opto-microfluidic methods have advantages for manufacturing complex shapes or structures of micro particles/hydrogels. Most of these microfluidic devices are made of polydimethylsiloxane (PDMS) by soft lithography because of its flexibility of designing and manufacturing. However, PDMS scatters ultraviolet (UV) light, which polymerizes the photocrosslinkable materials at undesirable locations and clogs the microfluidic devices. A fluorescent dye has previously been employed to absorb the scattered UV light and shift its wavelength to effectively solve this issue. However, this method is limited due to the cost of the materials (tens of dollars per microchip), the time consumed on synthesizing the fluorescent material and verifying its quality (two to three days). More importantly, significant expertise on material synthesis and characterization is required for users of the opto-microfluidic technique. The cost of preliminary testing on multiple iterations of different microfluidic chip designs would also be excessive. Alternatively, with a delicate microchannel design, we simply inserted aluminum foil strips (AFS) inside the PDMS device to block the scattered UV light. By using this method, the UV light was limited to the exposure region so that the opto-microfluidic device could consistently generate microgels longer than 6 h. This is a nearly cost- and labor-free method to solve this issue.

scholarly journals Applying heat and humidity using stove boiled water for decontamination of N95 respirators in low resource settings

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0255338
Author(s):  
Siddharth Doshi ◽  
Samhita P. Banavar ◽  
Eliott Flaum ◽  
Surendra Kulkarni ◽  
Ulhas Vaidya ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Low Resource Settings ◽  
Low Resource ◽  
Surgical Masks ◽  
Temperature And Humidity ◽  
Similar Temperature ◽  
N95 Respirators ◽  
Electricity Access ◽  
Uv C

Global shortages of N95 respirators have led to an urgent need of N95 decontamination and reuse methods that are scientifically validated and available world-wide. Although several large scale decontamination methods have been proposed (hydrogen peroxide vapor, UV-C); many of them are not applicable in remote and low-resource settings. Heat with humidity has been demonstrated as a promising decontamination approach, but care must be taken when implementing this method at a grassroots level. Here we present a simple, scalable method to provide controlled humidity and temperature for individual N95 respirators which is easily applicable in low-resource settings. N95 respirators were subjected to moist heat (>50% relative humidity, 65–80°C temperature) for over 30 minutes by placing them in a sealed container immersed in water that had been brought to a rolling boil and removed from heat, and then allowing the containers to sit for over 45 minutes. Filtration efficiency of 0.3–4.99 μm incense particles remained above 97% after 5 treatment cycles across all particle size sub-ranges. This method was then repeated at a higher ambient temperature and humidity in Mumbai, using standard utensils commonly found in South Asia. Similar temperature and humidity profiles were achieved with no degradation in filtration efficiencies after 6 cycles. Higher temperatures (>70°C) and longer treatment times (>40 minutes) were obtained by insulating the outer vessel. We also showed that the same method can be applied for the decontamination of surgical masks. This simple yet reliable method can be performed even without electricity access using any heat source to boil water, from open-flame stoves to solar heating, and provides a low-cost route for N95 decontamination globally applicable in resource-constrained settings.

scholarly journals Commercial Gold Nanoparticles on Untreated Aluminum Foil: Versatile, Sensitive, and Cost-Effective SERS Substrate

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Kristina Gudun ◽  
Zarina Elemessova ◽  
Laura Khamkhash ◽  
Ekaterina Ralchenko ◽  
Rostislav Bukasov
Keyword(s):  
Gold Nanoparticles ◽  
Low Cost ◽  
Aluminum Foil ◽  
Cost Effective ◽  
Sers Substrate ◽  
Au Film ◽  
Response Range ◽  
Sers Detection ◽  
Film Substrate ◽  
Linear Response Range

We introduce low-cost, tunable, hybrid SERS substrate of commercial gold nanoparticles on untreated aluminum foil (AuNPs@AlF). Two or three AuNP centrifugation/resuspension cycles are proven to be critical in the assay preparation. The limits of detection (LODs) for 4-nitrobenzenethiol (NBT) and crystal violet (CV) on this substrate are about 0.12 nM and 0.19 nM, respectively, while maximum analytical SERS enhancement factors (AEFs) are about 107. In comparative assays LODs for CV measured on AuNPs@Au film and AuNPs@glass are about 0.35 nM and 2 nM, respectively. The LOD for melamine detected on AuNPs@ Al foil is 27 ppb with 3 orders of magnitude for linear response range. Overall, AuNPs@AlF demonstrated competitive performance in comparison with AuNPs@ Au film substrate in SERS detection of CV, NBT, and melamine. To check the versatility of the AuNPs@AlF substrate we also detected KNO3 with LODs of 0.7 mM and SERS EF around 2 × 103, which is on the same order with SERS EF reported for this compound in the literature.

A simple capacitive proximity sensor experiment for exploring the effects of body capacitance and earth ground

2018 ◽  
Vol 55 (4) ◽  
pp. 367-377 ◽  
Author(s):  
Aaron D Scher
Keyword(s):  
Low Cost ◽  
Aluminum Foil ◽  
Parasitic Capacitance ◽  
Simple Design ◽  
Simple Circuit ◽  
Proximity Sensor ◽  
First Case ◽  
Lcr Meter

Capacitive proximity sensors are well-suited for educational projects due to their low cost and simple design. Traditional undergraduate textbooks and lab exercises rarely highlight the fact that the performance of capacitive proximity sensors can be quite sensitive to ground loading. This paper presents a simple classroom demonstration for exploring this topic in detail. The capacitive proximity sensor for this demonstration is a hand-held LCR meter connected to a homemade capacitor composed of two strips of aluminum foil. Students explore the operation of this sensor for two different system ground configurations. In the first case the LCR meter is battery powered (floating ground referenced) and in the second case the LCR meter is powered by AC mains supply (earth ground referenced). When a student positions their hand near the foil strips, the battery-powered sensor measures an increase in capacitance. Conversely, the AC-mains-powered sensor measures a decrease in capacitance. The instructor guides students to discover for themselves the reason for this seemingly puzzling difference by modeling parasitic capacitance and ground loading using simple circuit models.

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