Kinetic Model of CCA Fixation on Wood. Part I. The Initial Reaction Zone

The fixation process for chromated copper arsenate (CCA-C) preservative treated wood has at least two distinctly different zones. One of these is a fast "Initial Reaction," characterized by a rapid increase in pH and a decrease in available hexavalent chromium (Crvi). In the present study we develop a mathematical model that describes the initial reaction kinetics for red pine (Pinus resinosa Ait.) treated with 1% CCA-C. The results show that the initial fixation reactions follow pseudo 10th order kinetics. The activation energy and pre-exponential factors were found to be 37.8 kj.mol-1 and 8.7 X 10-19 h-1 mol-9 I9, respectively. At all treatment temperatures tested, the initial reaction resulted in approximately 47% chromium reduction. At 4° the time required to complete the initial reaction is approximately 4.5 h; at room temperature the initial reaction is complete in about 1.7 h. At 50° the initial reaction is complete in about 25 min. The complete model incorporates the rate equation, Arrhenius temperature dependence, and the fixation definition into a single equation that expresses % chromium fixation as a function of initial chromium concentration in the treating solution and time and temperature history of the wood following treatment.This model can also be used as an integral part of an overall fixation model that can be used to predict the percent fixation at a given treatment condition based on knowledge of the temperature history of the wood during fixation

Kinetic Model of CCA Fixation in Wood. Part II. The Main Reaction Zone

Fixation of chromated copper arsenate type C (CCA-C) solution on wood, measured by hexavalent chromium reduction, follows different rates in different reaction zones. We identify two main zones: an initial reaction and a second main reaction. The main reaction zone in red pine (Pinus resinosa Ait.) starts once approximately 47% of the total CrvI in the impregnated CCA-C solution is fixed on wood matrix. The second main fixation reaction follows first-order reaction kinetics, and an Arrhenius type of correlation can be used in modeling the fixation kinetics. We obtained similar values of Arrhenius parameters for CCA-C concentrations of 1% and 3%. The activation energies for fixation reactions in the second zone were 87.6 and 88.1 kJ/mol for 1% and 3% CCA-C concentrations, respectively. The pre-exponential factors of the reaction rate constant were 2.7 X 1013 and 2.2 X 1013 h-1 for 1 and 3% solutions, respectively. By combining the reaction rate equations and the temperature-dependence (Arrhenius) relationship, a mathematical model for the main reaction of 1% CCA-C fixation in red pine was produced.This model estimates the percentage of CCA-C solution fixation on red pine for a given time (in hours)/temperature (K) history of the wood following treatment

Geo-spatial reporting for monitoring of household immunization coverage through mobile phones: Findings from a feasibility study

Background: The addition of Global Positioning System (GPS) to a mobile phone makes it a very powerful tool for surveillance and monitoring coverage of health programs. This technology enables transfer of data directly into computer applications and cross-references to Geographic Information Systems (GIS) maps, which enhances assessment of coverage and trends.Objective: Utilization of these systems in low and middle income countries is currently limited, particularly for immunization coverageassessments and polio vaccination campaigns. We piloted the use of this system and discussed its potential to improve the efficiency of field-based health providers and health managers for monitoring of the immunization program.Methods: Using 30×7 WHO sampling technique, a survey of children less than five years of age was conducted in random clusters of Karachi, Pakistan in three high risk towns where a polio case was detected in 2011. Center point of the cluster was calculated by the application on the mobile. Data and location coordinates were collected through a mobile phone. This data was linked with an automated mHealth based monitoring system for monitoring of Supplementary Immunization Activities (SIAs) in Karachi. After each SIA, a visual report was generated according to the coordinates collected from the survey.Result: A total of 3535 participants consented to answer to a baseline survey. We found that the mobile phones incorporated with GIS maps can improve efficiency of health providers through real-time reporting and replacing paper based questionnaire for collection of data at household level. Visual maps generated from the data and geospatial analysis can also give a better assessment of the immunizationcoverage and polio vaccination campaigns.Conclusion: The study supports a model system in resource constrained settings that allows routine capture of individual level data through GPS enabled mobile phone providing actionable information and geospatial maps to local public health managers, policy makers and study staff monitoring immunization coverage

Effect of Tree Litter Application on Lowland Rice Yield in Bangladesh

The effect of tree litters on rice yield (cv. BR11) was evaluated in the study. Four kinds of tree litter, i.e., ipil-ipil or lamtoro (Leucaena leucocephala (Lamk) De Witt), sissoo (Dalbergia sissoo), akashmoni (Acacia auriculiformis) and mander (Erythrina orientalis) were incorporated into the soil 15 days before transplanting at rate of 5 ton/ha supplemented with inorganic fertilizers (83 kg N, 48 kg P205­, 42 kg K20, 10 kg S and 3.6 kg Zn/ha). In the control plots only recommended inorganic fertilizer were applied. Results showed that tree litter application had a significantly positive effect on the yield parameters such as plant height, panicle length, tillers per hill, filled grain and index of 1000-grain weight. Grain yield of plots treated with ipil-ipil, sissoo, akashmoni and mander was 5.61, 4.49, 4.95 and 5.36 ton/ha, and the yield increased over control plots 39.6, 11.7, 23.1 and 33.3%, respectively. It is worthy to note that addition of tree litter to inorganic fertilizer produced significantly higher yield than inorganic fertilizers solely. Among the tree litter, ipil-ipil and mander had the greatest increase in rice yield, while akashmoni was intermediate and sissoo was the least

Prospects and Challenges of Green Hydrogen Economy via Multi-Sector Global Symbiosis in Qatar

Low carbon hydrogen can be an excellent source of clean energy, which can combat global climate change and poor air quality. Hydrogen based economy can be a great opportunity for a country like Qatar to decarbonize its multiple sectors including transportation, shipping, global energy markets, and industrial sectors. However, there are still some barriers to the realization of a hydrogen-based economy, which includes large scale hydrogen production cost, infrastructure investments, bulk storage, transport & distribution, safety consideration, and matching supply-demand uncertainties. This paper highlights how the aforementioned challenges can be handled strategically through a multi-sector industrial-urban symbiosis for the hydrogen supply chain implementation. Such symbiosis can enhance the mutual relationship between diverse industries and urban planning by exploring varied scopes of multi-purpose hydrogen usage (i.e., clean energy source as a safer carrier, industrial feedstock and intermittent products, vehicle and shipping fuel, and international energy trading, etc.) both in local and international markets. It enables individual entities and businesses to participate in the physical exchange of materials, by-products, energy, and water, with strategic advantages for all participants. Besides, waste/by-product exchanges, several different kinds of synergies are also possible, such as the sharing of resources and shared facilities. The diversified economic base, regional proximity and the facilitation of rules, strategies and policies may be the key drivers that support the creation of a multi-sector hydrogen supply chain in Qatar. Copyright 2021 Eljack and Kazi.This paper was made possible by NPRP grant no. 10-0205-170347 from the Qatar National Research Fund (a member of Qatar Foundation).Scopu

A review on the mobile applications developed for COVID-19: An exploratory analysis

The objective of this research is to explore the existing mobile applications developed for the COVID-19 pandemic. To obtain this research objective, firstly the related applications were selected through the systematic search technique in the popular application stores. Secondly, data related to the app objectives, functionalities provided by the app, user ratings, and user reviews were extracted. Thirdly, the extracted data were analyzed through the affinity diagram, noticing-collecting-thinking, and descriptive analysis. As outcomes, the review provides a state-of-the-art view of mobile apps developed for COVID-19 by revealing nine functionalities or features. It revealed ten factors related to information systems design characteristics that can guide future app design. The review outcome highlights the need for new development and further refinement of the existing applications considering not only the revealed objectives and their associated functionalities, but also revealed design characteristics such as reliability, performance, usefulness, supportive, security, privacy, flexibility, responsiveness, ease of use, and cultural sensitivity.Comment: 11 pages, 3 figures, 4 table

Design of composite rectangular tubes for optimum crashworthiness performance via experimental and ANN techniques

This paper examines the crashworthiness performance of composite rectangular tubes using experimental and artificial neural network (ANN) techniques. Based on experimentally obtained values of different crashworthiness parameters under various loading conditions, ANN models are constructed to identify the optimum cross-sectional aspect ratio of cotton fiber/epoxy laminated composite to achieve the targeted mechanical properties such as load carrying and energy absorption capability. Experimental findings show that axially and laterally loaded rectangular tubes were significantly affected by their aspect ratio. Furthermore, the predictions obtained from the ANN models showed consistency with the experimental data. In addition, the developed ANN captured the complicated nonlinear relationship among crashworthiness parameters to obtain insight into the practical design of the composite materials. 2021 The Author(s)This paper was made possible by NPRP grant No 10-0205-170347 from the Qatar National Research Fund (a member of the Qatar Foundation).Scopu

Creek`s Aquaculture Techniques in Rangamati Hill Tracts of Bangladesh

An experiment was conducted in nine suitable (average .10±2 ha) creeks of Rangamati hill tracts Bangladesh viz., of Langadu, Naniarchar and Sadar Upazila for evaluating growth, survival and production performance of Indian major carps (Labeo rohita, Catla catla, Cirrhinus mrigala) in a completely randomized design into three different treatments with three replications for a period of one year. Stocking density, growth, survival was checked periodically and total yield calculated from stocking and harvesting data. A significant spatial variation in specific growth rate (SGR) and yields was found despite uniform stocking densities, attributable to variation in environmental parameters. Among the results rohu was found to have comparatively higher SGR of 1.51±0.55 in Naniarchar where as langadu creek was reported with higher SGR of 1.46±0.94, 1.57±0.41 and 1.46 ±.64 for rohu catla, and mrigal. Rangamati sadar Upazilla creek was found to be conducive to Catla with a SGR of 1.55±.78. In general, higher gross and net productions were reported from Sadar Upazilla, Langadu and Naniarchar creeks, suggestive of its suitability for developing creeks aquaculture technology. However research findings will help the community of Chittagong hill tracts by giving appropriate technology for sustainable fish production in creeks