Optical microscopic study of surface morphology and filtering efficiency of face masks

BackgroundLow-cost face masks made from different cloth materials are very common in developing countries. The cloth masks (CM) are usually double layered with stretchable ear loops. It is common practice to use such masks for months after multiple washing and drying cycles. If a CM is used for long time, the ear loops become stretched. The loop needs to be knotted to make the mask loop fit better on the face. It is not clear how washing and drying and stretching practices change the quality of a CM. The particulate matter (PM) filtering efficiency of a mask depends on multiple parameters, such as pore size, shape, clearance, and pore number density. It is important to understand the effect of these parameters on the filtering efficiency.MethodsWe characterized the surface of twenty different types of CMs using optical image analysis method. The filtering efficiency of selected cloth face masks was measured using the particle counting method. We also studied the effects of washing and drying and stretching on the quality of a mask.ResultsThe pore size of masks ranged from 80 to 500 μm, which was much bigger than particular matter having diameter of 2.5 μm or less (PM2.5) and 10 μm or less (PM10) size. The PM10filtering efficiency of four of the selected masks ranged from 63% to 84%. The poor filtering efficiency may have arisen from larger and open pores present in the masks. Interestingly, we found that efficiency dropped by 20% after the 4th washing and drying cycle. We observed a change in pore size and shape and a decrease in microfibers within the pores after washing. Stretching of CM surface also altered the pore size and potentially decreased the filtering efficiency. As compared to CMs, the less frequently used surgical/paper masks had complicated networks of fibers and much smaller pores in multiple layers in comparison to CMs, and therefore had better filtering efficiency. This study showed that the filtering efficiency of cloth face masks were relatively lower, and washing and drying practices deteriorated the efficiency. We believe that the findings of this study will be very helpful for increasing public awareness and help governmental agencies to make proper guidelines and policies for use of face mask.

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IoT and Deep Learning Based Approach for Rapid Screening and Face Mask Detection for Infection Spread Control of COVID-19

Applied Sciences ◽

10.3390/app11083495 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3495

Author(s):

Shabir Hussain ◽

Yang Yu ◽

Muhammad Ayoub ◽

Akmal Khan ◽

Rukhshanda Rehman ◽

...

Keyword(s):

Deep Learning ◽

Low Cost ◽

Face Mask ◽

World Health ◽

Rapid Screening ◽

Screening System ◽

Source Of Infection ◽

The Face ◽

Health Organization ◽

Vaccine Distribution

The spread of COVID-19 has been taken on pandemic magnitudes and has already spread over 200 countries in a few months. In this time of emergency of COVID-19, especially when there is still a need to follow the precautions and developed vaccines are not available to all the developing countries in the first phase of vaccine distribution, the virus is spreading rapidly through direct and indirect contacts. The World Health Organization (WHO) provides the standard recommendations on preventing the spread of COVID-19 and the importance of face masks for protection from the virus. The excessive use of manual disinfection systems has also become a source of infection. That is why this research aims to design and develop a low-cost, rapid, scalable, and effective virus spread control and screening system to minimize the chances and risk of spread of COVID-19. We proposed an IoT-based Smart Screening and Disinfection Walkthrough Gate (SSDWG) for all public places entrance. The SSDWG is designed to do rapid screening, including temperature measuring using a contact-free sensor and storing the record of the suspected individual for further control and monitoring. Our proposed IoT-based screening system also implemented real-time deep learning models for face mask detection and classification. This module classified individuals who wear the face mask properly, improperly, and without a face mask using VGG-16, MobileNetV2, Inception v3, ResNet-50, and CNN using a transfer learning approach. We achieved the highest accuracy of 99.81% while using VGG-16 and the second highest accuracy of 99.6% using MobileNetV2 in the mask detection and classification module. We also implemented classification to classify the types of face masks worn by the individuals, either N-95 or surgical masks. We also compared the results of our proposed system with state-of-the-art methods, and we highly suggested that our system could be used to prevent the spread of local transmission and reduce the chances of human carriers of COVID-19.

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Тhree–level face lifting

Klinicheskaia khirurgiia ◽

10.26779/2522-1396.2018.04.38 ◽

2018 ◽

Vol 85 (4) ◽

pp. 38-40

Author(s):

I. Yu. Slyusaryev ◽

N. I. Slyusaryev ◽

P. А. Denischuk

Keyword(s):

Middle Zone ◽

Women Patients ◽

Classic Method ◽

Long Time ◽

The Face ◽

Anchor Points

Objective. To follow–up and to compare a quality of stabilization of covering tissues in middle zone of the face, using ultrasonographic investigations, in long time after performance of a three–level face lifting and classical SMAS lifting. Маterials and methods. In the investigation 40 women–patients, ageing 42–70 yrs old, took part, in whom a face lifting was performed 5 – 8 yrs before. Investigation group consisted of 20 women, to whom three–level face lifting was performed, and a control one – 20 women, in whom face lifting was done in accordance to classic method. Results. Median indices of the covering elements thickness in projection of the anchor points in women–patients in 5 – 8 yrs after classic face liftinghave constituted: B – 3.9 mm, D – 5.9 mm, H – 6.6 mm; after three–level face lifting operation: В – 4.8 mm, D – 8.5 mm, H – 6.6 mm. Conclusion.Меthod of a three–level face lifting is indicated to the patients, suffering pronounced salient deformities of the face middle zone and depletion of the suborbital and cheekbone zones.

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Changes on Speech Transmission Characteristics by Types of Mask

Audiology and Speech Research ◽

10.21848/asr.200053 ◽

2020 ◽

Vol 16 (4) ◽

pp. 295-304

Author(s):

Jeongho Jeong ◽

Mina Kim ◽

Youngsun Kim

Keyword(s):

High Frequency ◽

Face Mask ◽

Octave Band ◽

Transmission Characteristics ◽

High Frequencies ◽

Working Environments ◽

Transmission Index ◽

Speech Transmission ◽

Long Time ◽

The Face

Purpose: Given the increased levels of fine and ultrafine dust, as well as the spread of COVID-19, current opinion is that most people will wear a face mask such a KF94 mask for a long time. To test speech transmission through the face masks, various types of masks including dust masks available in the market at the time of the study were tested under laboratory conditions.Methods: Fourteen types of masks worn on a head and torso simulator (HATS) and test signals were played on a speaker installed in the mouse position of the HATS. Speech Transmission Index (STI) and the speech level in the octave band were measured at distances of 1 m and 2 m.Results: STI at a distance of 2 m was decreased to 3.4-5.7% and speech levels in the octave band at 4 kHz or higher were also decreased when wearing disposable masks and a cotton mask. KF80 and KF94 masks showed decreased STI similar to those of disposable masks; however, a decrease in the speech level was observed at the octave bands of above 2 kHz. Dust masks and single-cartridge half-face respirators showed approximately 11.2% and 33.7% to 39.3% decreases in STI levels, respectively.Conclusion: When wearing masks, STI and the speech level was decreased in the high-frequency bands. However, speech level differences at high frequencies may be related to the increased voice level of the speaker and the understanding of consonants with the masks for several hours in living and working environments.

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Detection of Hidden Facial Surface Masking in Stored and Real Time Captured Images: A Deep Learning Perspective in Covid Time

Traitement du signal ◽

10.18280/ts.380632 ◽

2021 ◽

Vol 38 (6) ◽

pp. 1875-1885

Author(s):

Ruchi Jayaswal ◽

Manish Dixit

Keyword(s):

Deep Learning ◽

Real Time ◽

Preventive Measure ◽

Face Mask ◽

Histogram Equalization ◽

Test Accuracy ◽

The Face ◽

Novel Coronavirus ◽

Face Detector

A novel coronavirus has spread over the world and has become an outbreak. This, according to a WHO report, is an infectious disease that aims to spread. As a consequence, taking precautions is the only method to avoid catching this virus. The most important preventive measure against COVID-19 is to wear a mask. In this paper, a framework is designed for face mask detection using a deep learning approach. This paper aims to predict a person having a mask or unmask and also presents a proposed dataset named RTFMD (Real-Time Face Mask Dataset) to accomplish this objective. We have also taken the RFMD dataset from the internet to analyze the performance of system. Contrast Limited Adaptive Histogram Equalization (CLAHE) technique is applied at the time of pre-processing to enhance the visual quality of images. Subsequently, Inceptionv3 model used to train the face mask images and SSD face detector model has been used for face detection. Therefore, this paper proposed a model CLAHE-SSD_IV3 to classify the mask or without mask images. The system is also tested at VGG16, VGG19, Xception, MobilenetV2 models at different hyperparameters values and analyze them. Furthermore, compared the result of the proposed dataset RTFMD with the RFMD dataset. Additionally, proposed approach is compared with the existing approach on Face Mask dataset and RTFMD dataset. The outcomes have obtained 98% test accuracy on this proposed dataset RTFMD while 97% accuracy on the RFMD dataset in real-time.

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Overtourism – occurrences and effects

Present Environment and Sustainable Development ◽

10.15551/pesd2021152023 ◽

2021 ◽

Vol 15 (2) ◽

pp. 281-295

Author(s):

Maria Catrinel Dragan ◽

Gabriel Camara

Keyword(s):

Quality Of Life ◽

Natural Environment ◽

Low Cost ◽

Local Communities ◽

Short Term ◽

Cost Of Transport ◽

Tourist Destinations ◽

Long Time ◽

The Media

A phenomenon that has been felt for a long time, but which has recently become widely known, captured the attention of the science and of the media with the new term “overtourism”, leading current studies to a timely conceptualization. The present study tends to conceptualizes the overtourism phenomenon particularly through the analysis of existing literature, both academic and from media, with particular attention to its multidisciplinarity. The findings suggest that the manifestation of overtourism is determined by excessive promotion of same branded destinations, the low cost of transport, the cruises with pre-arranged and fixed stops, and the short-term rental accommodation system. The overtourism affects the quality of life of local communities, it contributes significantly to the alteration of the cultural heritage and to the loss of the destination’s identity, it affects also the natural environment by waste and by the resources taken, and finally it can contributes to the decline of famous tourist destinations.

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Use of Multiple Low Cost Carbon Dioxide Sensors to Measure Exhaled Breath Distribution with Face Mask Type and Wearing Behaviour

Sensors ◽

10.3390/s21186204 ◽

2021 ◽

Vol 21 (18) ◽

pp. 6204

Author(s):

Naveed Salman ◽

Muhammad Waqas Khan ◽

Michael Lim ◽

Amir Khan ◽

Andrew H. Kemp ◽

...

Keyword(s):

Carbon Dioxide ◽

Low Cost ◽

Co2 Concentration ◽

Face Mask ◽

Base Station ◽

Exhaled Breath ◽

Co2 Sensor ◽

Improper Use ◽

The Face ◽

Carbon Dioxide Co2

The use of cloth face coverings and face masks has become widespread in light of the COVID-19 pandemic. This paper presents a method of using low cost wirelessly connected carbon dioxide (CO2) sensors to measure the effects of properly and improperly worn face masks on the concentration distribution of exhaled breath around the face. Four types of face masks are used in two indoor environment scenarios. CO2 as a proxy for exhaled breath is being measured with the Sensirion SCD30 CO2 sensor, and data are being transferred wirelessly to a base station. The exhaled CO2 is measured in four directions at various distances from the head of the subject, and interpolated to create spatial heat maps of CO2 concentration. Statistical analysis using the Friedman’s analysis of variance (ANOVA) test is carried out to determine the validity of the null hypotheses (i.e., distribution of the CO2 is same) between different experiment conditions. Results suggest CO2 concentrations vary little with the type of mask used; however, improper use of the face mask results in statistically different CO2 spatial distribution of concentration. The use of low cost sensors with a visual interpolation tool could provide an effective method of demonstrating the importance of proper mask wearing to the public.

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Study of Electrostatic Field Responses of Locally Marketed Face Masks in the Philippines

Journal of Physics Conference Series ◽

10.1088/1742-6596/2071/1/012055 ◽

2021 ◽

Vol 2071 (1) ◽

pp. 012055

Author(s):

J Esmeria ◽

P N Fernandez ◽

G G Oyong

Keyword(s):

Transmission Rate ◽

Public Awareness ◽

Face Mask ◽

The Philippines ◽

Pore Sizes ◽

Small Pore ◽

Different Types ◽

The Face ◽

Market Opportunities ◽

The Government

Abstract The face mask is the first line of defense against infectious particulates and droplets that may cause illness. Currently in the Philippines, the wearing of face mask is compulsory whenever citizens leave their residences as mandated by the government to mitigate the spread of COVID-19. The wearing of face masks has become a new normal among Filipinos. This created market opportunities for different types which became commonly and immediately available for purchase. This study aimed to differentiate the effectiveness of locally available face masks in terms of electrostatic filtration capability. Twelve different types of face masks grouped into five categories – surgical, fabric, N95 variants, foam type, and novelty type – were evaluated. Electrostatic fields were measured from each face mask including pore sizes via scanning electron microscopy. Moreover, by utilizing the estimated charge and mass of the SARS-CoV-2 virion, the transmission rate was simulated using COMSOL Multiphysics®. It was observed that face masks with negatively charged materials combined with small pore sizes afforded less particle transmission. The results of this study are of timely significance in potentially laying out public awareness in the selection and utilization of face masks that can provide foremost shielding against viral transmission.

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Aerosol filtering efficiency of respiratory face masks used during the COVID-19 pandemic

10.1101/2020.07.16.20155119 ◽

2020 ◽

Author(s):

Glykeria Loupa ◽

Dimitra Karali ◽

SPYRIDON RAPSOMANIKIS

Keyword(s):

Respiratory System ◽

Indoor Air ◽

Size Range ◽

Protective Measure ◽

Particle Sizes ◽

Personal Protection ◽

Protection Measures ◽

The Face ◽

Filtering Efficiency

The spread of the COVID-19 pandemic, effected the imposition of personal protection measures in a large number of countries. The use of commercially available personal face masks was widely accepted as such a protective measure. Since the quality of the face masks scanned the spectrum from surgical to the home made fabric ones, it was considered appropriate to experimentally establish their effectiveness for stopping aerosol in entering the respiratory system of the bearer. Presently, the masks were tested with polydisperse indoor air. Their effectiveness was examined for aerosol of aerodynamic diameters of 0.006 μm to 10 μm. Of these masks, only two were effective for the whole range of aerosol. Cloth masks were found to be ineffective for the whole spectrum of aerosol particle sizes and especially in SARS-CoV-2 virus most abundant size range.

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Fertility Preservation in Sub-Sahara Africa: Myth or Reality

Journal of Gynecology Research Reviews & Reports ◽

10.47363/jgrrr/2019(2)109 ◽

2020 ◽

pp. 1-5

Author(s):

Bamgboye M Afolabi ◽

◽

Abayomi B Ajayi ◽

Victor D Ajayi ◽

◽

...

Keyword(s):

Fertility Preservation ◽

Public Awareness ◽

Group Discussion ◽

Child Bearing ◽

Long Time ◽

Sociocultural Characteristics ◽

Supporting Material ◽

Knowledge And Attitude ◽

The Government

Due to current developments in cancer therapy, there has been an increase in the number of cancer survivors. Nevertheless, cancer patients or those with other intractable diseases may be confronted with fertility challenges. Though the option of fertility preservation (FP) techniques are on the increase, yet it is not certain if this is a myth or a reality in sub-Sahara Africa. Methods: The objective of this study was to assess the opinions, knowledge and attitude of gynecologists from different parts of Nigeria on fertility preservation among women in child-bearing age with cancer. A Focus Group Discussion (FGD) was conducted among gynecologists who were asked about their opinions on the possibility of FP in the country and about factors that could support or degrade it. Findings: Gynecologists agreed that awareness and cost are important as people have to know the availability of such facility before accessing it. Sociocultural aspects of FP were deliberated upon positively. There is always suspicion about how “the doctors can take out my eggs, freeze them for a long time and these eggs still survive.” Certain participant held the view “a lot of people have issued with mixing up gametes” while another wanted the subsidy of FP by the government. Interpretation: The positive opinions of the gynecologists towards fertility preservation far out-weight negative opinions. Public awareness, cost and sociocultural characteristics were deliberated upon by participants in the FGD. Greater emphasis should be placed on counselling opportunities, the provision of adequate information and supporting material. A better understanding of these issues will hopefully enhance patients’ decision-making about FP options and assist the development of strategies to improve quality of care.

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