The Efficacy of Plant-Based Ionizers in Removing Aerosol for COVID-19 Mitigation

Small-sized droplets/aerosol transmission is one of the factors responsible for the spread of COVID-19, in addition to large droplets and surface contamination (fomites). While large droplets and surface contamination can be relatively easier to deal with (i.e., using mask and proper hygiene measures), aerosol presents a different challenge due to their ability to remain airborne for a long time. This calls for mitigation solutions that can rapidly eliminate the airborne aerosol. Pre-COVID-19, air ionizers have been touted as effective tools to eliminate small particulates. In this work, we sought to evaluate the efficacy of a novel plant-based ionizer in eliminating aerosol. It was found that factors such as the ion concentration, humidity, and ventilation can drastically affect the efficacy of aerosol removal. The aerosol removal rate was quantified in terms of ACH (air changes per hour) and CADR- (clean air delivery rate-) equivalent unit, with ACH as high as 12 and CADR as high as 141 ft3/minute being achieved by a plant-based ionizer in a small isolated room. This work provides an important and timely guidance on the effective deployment of ionizers in minimizing the risk of COVID-19 spread via airborne aerosol, especially in a poorly-ventilated environment.

The Efficacy of Plant-ionizers in Removing Aerosols for COVID-19 Mitigation

Small size droplets/aerosols are believed to be potentially responsible for COVID-19 transmission in addition to large droplets and surface contamination (fomites). While large droplets and surface contamination can be relatively easier to deal with (i.e. using mask and proper hygiene measures), aerosols present a different challenge due to their ability to remain airborne for a long time. This calls for mitigation measures that can rapidly eliminate the airborne aerosols. Pre-COVID-19, an air ionizer has been touted as an effective tool to eliminate small particulates such as these. In this work, we sought to evaluate the efficacy of a novel plant-based air ionizers in eliminating aerosols. It was found that factors such as the ion concentration, humidity, and ventilation can drastically affect the aerosols removal efficacy. Furthermore, the aerosols removal rate was quantified in terms of ACH (air changes per hour)-equivalent unit, with ACH as high as 12 being achieved by using deploying a plant-based air ionizer in a small isolated office room. Lastly, this work provides an important and timely guidance on the effective deployment of plant ionizers in minimizing the risk of COVID-19 spread via airborne aerosols, especially in poorly-ventilated environment.

Predicting the Future Capacity and Dimensions of Container Ships

Since the introduction of the container ship, there has been an impressive increase in its use to take advantage of economies of scale. In the last two decades, the capacity of vessels has trebled. Currently, vessels of 23,000 TEU (20-ft equivalent unit) sail the seas. With the exponential growth experienced in this sector, the question arises if it is possible to reach a peak capacity, as has occurred with bulk cargo vessels and, recently, aircraft. This paper aims to predict the possible size and dimensions of a new generation of mega container ships. Based on economies of scale, port infrastructure, demand, environmental trends, and naval design criteria, the limit to ship size has been estimated. The results suggest that additional increases in ship size are still possible. The aim of this study is to help port authorities to understand the needs of the shipping container industry and to calculate the expansion and investment necessary.

Design and simulation of a mechanical system for the machining of parts and printing in 3D (x, y, z)

The design and simulation of a multifunctional system for the machining of mechanical parts and printing in 3D (x, y, z) using CAD software Solid works, was used to determine the static behavior of the system with the analysis of tension, deformation, displacement, safety factor, buckling, fatigue and frequency. For the above, it was determined that the lateral base supports a tension of 3.5x108Pa, causing a displacement of 25 mm and an equivalent unit strain (ESTRN) of 0.0012. And the base guiding a cumulative damage of 300% of deterioration that reduces its useful life to a range between 1x106and 1x1065utility cycles and a safety factor (F S) between 104.632 to 7869.86. On the other hand, the transverse base has a maximum cumulative damage percentage of4.10535 and a life cycle range ranging from 24358.5 to 1x106with a minimum SF of 5974

Evaluation and Screening of Co-Culture Farming Models in Rice Field Based on Food Productivity

Traditional farming practice of rice field co-culture is a time-tested example of sustainable agriculture, which increases food productivity of arable land with few adverse environmental impacts. However, the small-scale farming practice needs to be adjusted for modern agricultural production. Screening of rice field co-culture farming models is important in deciding the suitable model for industry-wide promotion. In this study, we aim to find the optimal rice field co-culture farming models for large-scale application, based on the notion of food productivity. We used experimental data from the Jiangsu Province of China and applied food-equivalent unit and arable-land-equivalent unit methods to examine applicable protocols for large-scale promotion of rice field co-culture farming models. Results indicate that the rice-loach and rice-catfish models achieve the highest food productivity; the rice-duck model increases the rice yield, while the rice-turtle and rice-crayfish models generate extra economic profits. Simultaneously considering economic benefits, staple food security, and regional food output, we recommend the rice-duck, rice-crayfish, and rice-catfish models. Simulating provincial promotion of the above three models, we conclude that food output increases from all three recommended models, as well as the land production capacity. The rice-catfish co-culture model has the most substantial food productivity. None of the three models threatens staple food security, as they do not compete for land resources with rice cultivation.

Research on the Reliability Allocation Method for a Production System Based on Availability

This paper involves a production system, which is composed of units (workstations) and buffers. The buffer is used to store semifinished and finished products in the production process, to reduce the impacts of bad equipment in the production system on the entire system performance. Considering the characteristics of the large number of components and the state of the buffers in the production system, this paper considers the influences of buffer states on upstream and downstream units. When using the availability as the allocation index and combining it with Markov theory, the production unit (workstation) and upstream and downstream buffers are regarded as an equivalent unit (workstation) with multiple output states. We establish the relationship between the availability of each equivalent unit (workstation) and the production system availability and determine a scaling factor for the availability of the equivalent unit to account for the system availability. The expected availability goal of the production system is allocated to each equivalent unit (workstation) by the scaling factor; then, the availability of each equivalent unit (workstation) is assigned to each unit. Finally, the Plant Simulation software is used to simulate and analyze the production system to verify the correctness of the allocation method and realize the reliability allocation from a complex production system to a unit.

Regional household poverty and mobility analysis – a transition probability approach

The main objective of this paper was to estimate and analyse transition-probability matrices for all 16 of Poland’s NUTS-2 level regions (voivodeship level). The analysis is conducted in terms of the transitions among six expenditure classes (per capita and per equivalent unit), focusing on poverty classes. The period of analysis was two years: 2015 and 2016. The basic aim was to identify both those regions in which the probability of staying in poverty was the highest and the general level of mobility among expenditure classes. The study uses a two-year panel sub-sample of unidentified unit data from the Central Statistical Office (CSO), specifically the data concerning household budget surveys. To account for differences in household size and demographic structure, the study used expenditures per capita and expenditures per equivalent unit simultaneously. To estimate the elements of the transition matrices, a classic maximum-likelihood estimator was used. The analysis used Shorrocks’ and Bartholomew’s mobility indices to assess the general mobility level and the Gini index to assess the inequality level. The results show that the one-year probability of staying in the same poverty class varies among regions and is lower for expenditures per equivalent units. The highest probabilities were identified in Podkarpackie (expenditures per capita) and Opolskie (expenditures per equivalent unit), and the lowest probabilities in Kujawsko-Pomorskie (expenditures per capita) and Małopolskie (expenditures per equivalent unit). The highest level of general mobility was noted in Małopolskie, for both categories of expenditures.

Tendency toward Mega Containerships and the Constraints of Container Terminals

This paper focuses on the coping ability of the existing container terminals when mega containerships call at a port. The length of 30,000 TEU (Twenty Equivalent Unit) ships are predicted to be 453 m and occupy 498 m of a quay wall. As a result, the length of berth should be more than a minimum of 500 m. If a 25,000 TEU ship or 30,000 TEU ship call at a terminal, the outreach of QC (Quay Crane) should be a minimum 74.3 m or 81.0 m respectively. As mega ships are calling at the port, the ship waiting time, the available stacking area, and the number of handling equipment can be limited. The analysis reveals that larger ships wait for longer than the smaller ones because they have difficulty allocating the proper seat on berth. As a result of the survey in a terminal, the average occupancy is shown to be 60.4%, the minimum is 52.4%, and the maximum is 73.3%. Surveying the monthly equipment operation rate for 3 years, the average is 85.8%, the minimum is 80.1%, and the maximum is 90.1%. If a mega ship of more than 25,000 TEU appears, the rate will be excessively increased during peak time.