Search results for: postharvest loss reduction
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 7848

Search results for: postharvest loss reduction

6408 Two-Stage Estimation of Tropical Cyclone Intensity Based on Fusion of Coarse and Fine-Grained Features from Satellite Microwave Data

Authors: Huinan Zhang, Wenjie Jiang

Abstract:

Accurate estimation of tropical cyclone intensity is of great importance for disaster prevention and mitigation. Existing techniques are largely based on satellite imagery data, and research and utilization of the inner thermal core structure characteristics of tropical cyclones still pose challenges. This paper presents a two-stage tropical cyclone intensity estimation network based on the fusion of coarse and fine-grained features from microwave brightness temperature data. The data used in this network are obtained from the thermal core structure of tropical cyclones through the Advanced Technology Microwave Sounder (ATMS) inversion. Firstly, the thermal core information in the pressure direction is comprehensively expressed through the maximal intensity projection (MIP) method, constructing coarse-grained thermal core images that represent the tropical cyclone. These images provide a coarse-grained feature range wind speed estimation result in the first stage. Then, based on this result, fine-grained features are extracted by combining thermal core information from multiple view profiles with a distributed network and fused with coarse-grained features from the first stage to obtain the final two-stage network wind speed estimation. Furthermore, to better capture the long-tail distribution characteristics of tropical cyclones, focal loss is used in the coarse-grained loss function of the first stage, and ordinal regression loss is adopted in the second stage to replace traditional single-value regression. The selection of tropical cyclones spans from 2012 to 2021, distributed in the North Atlantic (NA) regions. The training set includes 2012 to 2017, the validation set includes 2018 to 2019, and the test set includes 2020 to 2021. Based on the Saffir-Simpson Hurricane Wind Scale (SSHS), this paper categorizes tropical cyclone levels into three major categories: pre-hurricane, minor hurricane, and major hurricane, with a classification accuracy rate of 86.18% and an intensity estimation error of 4.01m/s for NA based on this accuracy. The results indicate that thermal core data can effectively represent the level and intensity of tropical cyclones, warranting further exploration of tropical cyclone attributes under this data.

Keywords: Artificial intelligence, deep learning, data mining, remote sensing

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6407 Investigating the Influence of Roof Fairing on Aerodynamic Drag of a Bluff Body

Authors: Kushal Kumar Chode

Abstract:

Increase in demand for fuel saving and demand for faster vehicles with decent fuel economy, researchers around the world started investigating in various passive flow control devices to improve the fuel efficiency of vehicles. In this paper, A roof fairing was investigated for reducing the aerodynamic drag of a bluff body. The bluff body considered for this work is Ahmed model with a rake angle of 25deg was and subjected to flow with a velocity of 40m/s having Reynolds number of 2.68million was analysed using a commercial Computational Fluid Dynamic (CFD) code Star CCM+. It was evident that pressure drag is the main source of drag on an Ahmed body from the initial study. Adding a roof fairing has delayed the flow separation and resulted in delaying wake formation, thus improving the pressure in near weak and reducing the wake region. Adding a roof fairing of height and length equal to 1/7H and 1/3L respectively has shown a drag reduction by 9%. However, an optimised fairing, which was obtained by changing height, length and width by 5% increase, recorded a drag reduction close 12%.

Keywords: Ahmed model, aerodynamic drag, passive flow control, roof fairing, wake formation

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6406 Opportunities for Precision Feed in Apiculture

Authors: John Michael Russo

Abstract:

Honeybees are important to our food system and continue to suffer from high rates of colony loss. Precision feed has brought many benefits to livestock cultivation and these should transfer to apiculture. However, apiculture has unique challenges. The objective of this research is to understand how principles of precision agriculture, applied to apiculture and feed specifically, might effectively improve state-of-the-art cultivation. The methodology surveys apicultural practice to build a model for assessment. First, a review of apicultural motivators is made. Feed method is then evaluated. Finally, precision feed methods are examined as accelerants with potential to advance the effectiveness of feed practice. Six important motivators emerge: colony loss, disease, climate change, site variance, operational costs, and competition. Feed practice itself is used to compensate for environmental variables. The research finds that the current state-of-the-art in apiculture feed focuses on critical challenges in the management of feed schedules which satisfy requirements of the bees, preserve potency, optimize environmental variables, and manage costs. Many of the challenges are most acute when feed is used to dispense medication. Technology such as RNA treatments have even more rigorous demands. Precision feed solutions focus on strategies which accommodate specific needs of individual livestock. A major component is data; they integrate precise data with methods that respond to individual needs. There is enormous opportunity for precision feed to improve apiculture through the integration of precision data with policies to translate data into optimized action in the apiary, particularly through automation.

Keywords: precision agriculture, precision feed, apiculture, honeybees

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6405 Effectiveness of Control Measures for Ambient Fine Particulate Matters Concentration Improvement in Taiwan

Authors: Jiun-Horng Tsai, Shi-Jie, Nieh

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Fine particulate matter (PM₂.₅) has become an important issue all over the world over the last decade. Annual mean PM₂.₅ concentration has been over the ambient air quality standard of PM₂.₅ (annual average concentration as 15μg/m³) which adapted by Taiwan Environmental Protection Administration (TEPA). TEPA, therefore, has developed a number of air pollution control measures to improve the ambient concentration by reducing the emissions of primary fine particulate matter and the precursors of secondary PM₂.₅. This study investigated the potential improvement of ambient PM₂.₅ concentration by the TEPA program and the other scenario for further emission reduction on various sources. Four scenarios had been evaluated in this study, including a basic case and three reduction scenarios (A to C). The ambient PM₂.₅ concentration was evaluated by Community Multi-scale Air Quality modelling system (CMAQ) ver. 4.7.1 along with the Weather Research and Forecasting Model (WRF) ver. 3.4.1. The grid resolutions in the modelling work are 81 km × 81 km for domain 1 (covers East Asia), 27 km × 27 km for domain 2 (covers Southeast China and Taiwan), and 9 km × 9 km for domain 3 (covers Taiwan). The result of PM₂.₅ concentration simulation in different regions of Taiwan shows that the annual average concentration of basic case is 24.9 μg/m³, and are 22.6, 18.8, and 11.3 μg/m³, respectively, for scenarios A to C. The annual average concentration of PM₂.₅ would be reduced by 9-55 % for those control scenarios. The result of scenario C (the emissions of precursors reduce to allowance levels) could improve effectively the airborne PM₂.₅ concentration to attain the air quality standard. According to the results of unit precursor reduction contribution, the allowance emissions of PM₂.₅, SOₓ, and NOₓ are 16.8, 39, and 62 thousand tons per year, respectively. In the Kao-Ping air basin, the priority for reducing precursor emissions is PM₂.₅ > NOₓ > SOₓ, whereas the priority for reducing precursor emissions is PM₂.₅ > SOₓ > NOₓ in others area. The result indicates that the target pollutants that need to be reduced in different air basin are different, and the control measures need to be adapted to local conditions.

Keywords: airborne PM₂.₅, community multi-scale air quality modelling system, control measures, weather research and forecasting model

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6404 The Photocatalytic Approach for the Conversion of Polluted Seawater CO₂ into Renewable Source of Energy

Authors: Yasar N. Kavil, Yasser A. Shaban, Radwan K. Al Farawati, Mohamed I. Orif, Shahed U. M. Khanc

Abstract:

Photocatalytic way of reduction of CO₂ in polluted seawater into chemical fuel, methanol, was successfully gained over Cu/C-co-doped TiO₂ nanoparticles under UV and natural sunlight. A homemade stirred batch annular reactor was used to carry out the photocatalytic reduction experiments. Photocatalysts with various Cu loadings (0, 0.5, 1, 3, 5 and 7 wt.%) were synthesized by the sol-gel procedure and were characterized by XRD, SEM, UV–Vis, FTIR, and XPS. The photocatalytic production of methanol was promoted by the co-doping with C and Cu into TiO₂. This improvement was attributed to the modification of bandgap energy and the hindrance of the charges recombination. The polluted seawater showing the yield depended on its background hydrographic parameters. We assessed two types of polluted seawater system, the observed yield was 2910 and 990 µmol g⁻¹ after 5 h of illumination under UV and natural sunlight respectively in system 1 and the corresponding yield in system 2 was 2250 and 910 µmol g⁻¹ after 5 h of illumination. The production of methanol in the case of oxygen-depleted water was low, this is mainly attributed to the competition of methanogenic bacteria over methanol production. The results indicated that the methanol yield produced by Cu-C/TiO₂ was much higher than those of carbon-modified titanium oxide (C/TiO₂) and Degussa (P25-TiO₂). Under the current experimental condition, the optimum loading was achieved by the doping of 3 wt % of Cu. The highest methanol yield was obtained over 1 g L-1 of 3wt% Cu/C-TiO₂.

Keywords: CO₂ photoreduction, copper, Cu/C-co-doped TiO₂, methanol, seawater

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6403 Effects of Rice Husk Ash on the Properties of Scrap Tyre Steel Fiber Reinforced High Performance Concrete (RHA-STSFRHAC)

Authors: Isyaka Abdulkadir, Egbe-Ngu Ntui Ogork

Abstract:

This research aims to investigate the effect of Rice Husk Ash (RHA) on Scrap Tyre Steel Fiber Reinforced High Performance Concrete (STSFRHPC). RHA was obtained by control burning of rice husk in a kiln to a temperature of 650-700oC and when cooled sieved through 75µm sieve and characterized. The effect of RHA were investigated on grade 50 STSFRHPC of 1:1.28:1.92 with water cement ratio of 0.39 at additions of Scrap Tyre Steel Fiber (STSF) of 1.5% by volume of concrete and partial replacement of cement with RHA at percentages of 0, 5, 10, 15 and 20. The fresh concrete was tested for slump while the hardened concrete was tested for compressive and splitting tensile strengths respectively at curing ages of 3, 7, 28 and 56 days in accordance with standard procedure. Results of RHA-STSFRHPC indicated a reduction in slump and compressive strength with increase in RHA content, while splitting tensile strength increased with RHA replacement up to 10% and reduction in strength above 10% RHA content. The 28 days compressive strength of RHA-STSFRHPC with up to 10% RHA attained the desired characteristic strength of 50N/mm2 and therefore up to 10% RHA is considered as the optimum replacement dosage in STSFRHPC-RHA.

Keywords: compressive strength, high performance concrete, rice husk ash, scrap tyre steel fibers

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6402 Fe₃O₄/SiO₂/TiO₂ Nanoparticles as Catalyst for Recovery of Gold from the Mixture of Au(III) and Cu(II) Ions

Authors: Eko S. Kunarti, Akhmad Syoufian, Indriana Kartini, Agnes

Abstract:

Fe₃O₄/SiO₂/TiO₂ nanoparticles have been synthesized and applied as a photocatalyst for the recovery of gold from the mixture of Au(III) and Cu(II) ions. The synthesis was started by the preparation of magnetite (Fe₃O₄) using coprecipitation and sonication methods, followed by SiO₂ coating on magnetite using sol-gel reactions, and then TiO₂ coating using sol-gel process. Characterization was performed by using infrared spectroscopy, X-ray diffraction, transmission electron microscopy methods. Activity of Fe₃O₄/SiO₂/TiO₂ nanoparticles was evaluated as a photocatalyst for recovery of gold through photoreduction of Au(III) ions in Au(III) and Cu(II) ions mixture with a ratio of 1:1, in a closed reactor equipped with UV lamp. The photoreduction yield was represented as a percentage (%) of reduced Au(III) which was calculated by substraction of initial Au(III) concentration by the unreduced one. The unreduced Au(III) was determined by atomic absorption spectrometry. Results showed that the Fe₃O₄/SiO₂/TiO₂ nanoparticles were successfully synthesised with excellent magnetic and photocatalytic properties. The nanoparticles present optimum activity at a pH of 5 under UV irradiation for 120 minutes. At the optimum condition, the Fe₃O₄/SiO₂/TiO₂ nanoparticles could reduce Au³⁺ to Au⁰ 97.24%. In the mixture of Au(III) and Cu(II) ions, the Au(III) ions are more easily reducible than Cu(II) ions with the reduction results of 96.9% and 45.80% for Au(III) and Cu(II) ions, respectively. In addition, the presence of Cu(II) ions has no significant effect on the amount of gold recovered and its reduction reaction rate.

Keywords: Fe₃O₄/SiO₂/TiO₂, photocatalyst, recovery, gold, Au(III) and Cu(II) mixture

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6401 Recycled Plastic Fibers for Minimizing Plastic Shrinkage Cracking of Cement Based Mortar

Authors: B. S. Al-Tulaian, M. J. Al-Shannag, A. M. Al-Hozaimy

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The development of new construction materials using recycled plastic is important to both the construction and the plastic recycling industries. Manufacturing of fibers from industrial or post-consumer plastic waste is an attractive approach with such benefits as concrete performance enhancement, and reduced needs for land filling. The main objective of this study is to investigate the effect of plastic fibers obtained locally from recycled waste on plastic shrinkage cracking of ordinary cement based mortar. Parameters investigated include: Fiber length ranging from 20 to 50 mm, and fiber volume fraction ranging from 0% to 1.5% by volume. The test results showed significant improvement in crack arresting mechanism and substantial reduction in the surface area of cracks for the mortar reinforced with recycled plastic fibers compared to plain mortar. Furthermore, test results indicated that there was a slight decrease in compressive strength of mortar reinforced with different lengths and contents of recycled fibers compared to plain mortar. This study suggests that adding more than 1% of RP fibers to mortar, can be used effectively for controlling plastic shrinkage cracking of cement based mortar, and thus results in waste reduction and resources conservation.

Keywords: mortar, plastic, shrinkage cracking, compressive strength, RF recycled fibers

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6400 The Practice of Low Flow Anesthesia to Reduce Carbon Footprints Sustainability Project

Authors: Ahmed Eid, Amita Gupta

Abstract:

Abstract: Background: Background Medical gases are estimated to contribute to 5% of the carbon footprints produced by hospitals, Desflurane has the largest impact, but all increase significantly when used with N2O admixture. Climate Change Act 2008, we must reduce our carbon emission by 80% of the 1990 baseline by 2050.NHS carbon emissions have reduced by 18.5% (2007-2017). The NHS Long Term Plan has outlined measures to achieve this objective, including a 2% reduction by transforming anaesthetic practices. FGF is an important variable that determines the utilization of inhalational agents and can be tightly controlled by the anaesthetist. Aims and Objectives Environmental safety, Identification of areas of high N20 and different anaesthetic agents used across the St Helier operating theatres and consider improvising on the current practice. Methods: Data was collected from St Helier operating theatres and retrieved daily from Care Station 650 anaesthetic machines. 60 cases were included in the sample. Collected data (average flow rate, amount and type of agent used, duration of surgery, type of surgery, duration, and the total amount of Air, O2 and N2O used. AAGBI impact anaesthesia calculator was used to identify the amount of CO2 produced and also the cost per hour for every pt. Communication via reminder emails to staff emphasized the significance of low-flow anaesthesia and departmental meeting presentations aimed at heightening awareness of LFA, Distribution of AAGBI calculator QR codes in all theatres enables the calculation of volatile anaesthetic consumption and CO2e post each case, facilitating informed environmental impact assessment. Results: A significant reduction in the flow rate use in the 2nd sample was observed, flow rate usage between 0-1L was 60% which means a great reduction of the consumption of volatile anaesthetics and also Co2e. By using LFA we can save money but most importantly we can make our lives much greener and save the planet.

Keywords: low flow anesthesia, sustainability project, N₂0, Co2e

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6399 Performance of a Lytic Bacteriophage Cocktail against Pseudomonas aeruginosa in Conditions That Simulate the Cystic Fibrosis Lung Environment

Authors: Isaac Martin, Abigail Lark, Sandra Morales, Eric W. Alton, Jane C. Davies

Abstract:

Objectives: The cystic fibrosis (CF) lung is a unique microbiological niche, wherein harmful bacteria persist for many years despite antibiotic therapy. Pseudomonas aeruginosa (Pa), the major culprit leading to lung decline and increased mortality, thrives in the lungs of patients with CF due to several factors that have been linked with poor antibiotic performance. Our group is investigating alternative therapies including bacteriophage cocktails with which we have previously demonstrated efficacy against planktonic organisms. In this study, we explored the effects of a 4-phage cocktail on Pa grown in two different conditions, intended to mirror the CF lung: a) alongside standard antibiotic treatment in pre-formed biofilms (structures formed by Pa-secreted exopolysaccharides which provide both physical and cell division barriers to antimicrobials and host defenses and b) in an acidic environment postulated to be present in the CF airway due both to the primary defect in bicarbonate secretion and secondary effects of inflammation. Methods: 16 Pa strains from CF patients at the Royal Brompton Hospital were selected based on sensitivity to a) ceftazidime/ tobramycin and b) the phage cocktail in a conventional plaque assay. To assess efficacy of phage in biofilms, 96 well plates with Pa (5x10⁷ CFU/ ml) were incubated in static conditions, allowing adherent bacterial colonies to form for 24 hr. Ceftazidime and tobramycin (both at 2 × MIC) were added, +/- bacteriophage (4x10⁸ PFU/mL) for a further 24 hr. Cell viability and biomass were estimated using fluorescent resazurin and crystal violet assays, respectively. To evaluate the effect of pH, strains were grown planktonically in shaking 96 well plates at pH 6.0, 6.6, 7.0 and 7.5 with tobramycin or phage, at varying concentrations. Cell viability was quantified by fluorescent resazurin assay. Results: For the biofilm assay, treatment groups were compared with untreated controls and expressed as percent reduction in cell viability and biomass. Addition of the 4-phage cocktail resulted in a 1.3-fold reduction in cell viability and 1.7-fold reduction in biomass (p < 0.001) when compared to standard antibiotic treatment alone. Notably, there was a 50 ± 15% reduction in cell viability and 60 ± 12% reduction in biomass (95% CI) for the 4 biofilms demonstrating the most resistance to antibiotic treatment. 83% of strains tested (n=6) showed decreased bacterial killing by tobramycin at acidic pHs (p < 0.01). However, 25% of strains (n=12) showed improved phage killing at acidic pHs (p < 0.05), with none showing the pattern of reduced efficacy at acidic pH demonstrated by tobramycin. Conclusion: The 4-phage anti-Pa cocktail tested against Pa performs well in pre-formed biofilms and in acidic environments; two conditions intended to mimic the CF lung. To our knowledge, these are the first data looking at the effects of subtle pH changes on phage-mediated bacterial killing in the context of Pa infection. These findings contribute to a growing body of evidence supporting the use of nebulised lytic bacteriophage as a treatment in the context of lung infection.

Keywords: biofilm, cystic fibrosis, pH, Pseudomonas aeruginosa, lytic bacteriophage

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6398 Elaboration and Characterization of Self-Compacting Mortar Based Biopolymer

Authors: I. Djefour, M. Saidi, I. Tlemsani, S. Toubal

Abstract:

Lignin is a molecule derived from wood and also generated as waste from the paper industry. With a view to its valorization and protection of the environment, we are interested in its use as a superplasticizer-type adjuvant in mortars and concretes to improve their mechanical strengths. The additives of the concrete have a very strong influence on the properties of the fresh and / or hardened concrete. This study examines the development and use of industrial waste and lignin extracted from a renewable natural source (wood) in cementitious materials. The use of these resources is known at present as a definite resurgence of interest in the development of building materials. Physicomechanical characteristics of mortars are determined by optimization quantity of the natural superplasticizer. The results show that the mechanical strengths of mortars based on natural adjuvant have improved by 20% (64 MPa) for a W/C ratio = 0.4, and the amount of natural adjuvant of dry extract needed is 40 times smaller than commercial adjuvant. This study has a scientific impact (improving the performance of the mortar with an increase in compactness and reduction of the quantity of water), ecological use of the lignin waste generated by the paper industry) and economic reduction of the cost price necessary to elaboration of self-compacting mortars and concretes).

Keywords: biopolymer (lignin), industrial waste, mechanical resistances, self compacting mortars (SCM)

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6397 Surgical Planning for the Removal of Cranial Spheno-orbital Meningioma by Using Personalized Polymeric Prototypes Obtained with Additive Manufacturing Techniques

Authors: Freddy Patricio Moncayo-Matute, Pablo Gerardo Peña-Tapia, Vázquez-Silva Efrén, Paúl Bolívar Torres-Jara, Diana Patricia Moya-Loaiza, Gabriela Abad-Farfán

Abstract:

This study describes a clinical case and the results on the application of additive manufacturing for the surgical planning in the removal of a cranial spheno-orbital meningioma. It is verified that the use of personalized anatomical models and cutting guides helps to manage the cranial anomalies approach. The application of additive manufacturing technology: Fused Deposition Modeling (FDM), as a low-cost alternative, enables the printing of the test anatomical model, which in turn favors the reduction of surgery time, as well the morbidity rate reduction too. And the printing of the personalized cutting guide, which constitutes a valuable aid to the surgeon in terms of improving the intervention precision and reducing the invasive effect during the craniotomy. As part of the results, post-surgical follow-up is included as an instrument to verify the patient's recovery and the validity of the procedure.

Keywords: surgical planning, additive manufacturing, rapid prototyping, fused deposition modeling, custom anatomical model

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6396 90-Day Strength Training Intervention Decreases Incidence of Sarcopenia: A Pre- and Posttest Pilot Study of Older Adults in a Skilled Nursing Facility

Authors: Donna-Marie Phyllis Lanton

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Sarcopenia is a well-known geriatric syndrome characterized by the progressive and generalized loss of muscle quantity or quality. The incidence of sarcopenia increases with age and is associated with adverse outcomes such as the increased risk of falls, cognitive impairment, loss of independence, diminished quality of life, increased health costs, need for care in a skilled nursing facility, and increased mortality. Physical activity, including resistance training, is the most prevalent recommendation for treating and preventing sarcopenia. Residents (N = 23) of a skilled nursing facility in East Orlando, Florida, participated in a 90-day strength training program designed using the PARIHS framework to improve measures of muscle mass, muscle strength, physical performance, and quality of life. Residents engaged in both resistance and balance exercises for 1 hour two times a week. Baseline data were collected and compared to data at Days 30, 60, and 90. T tests indicated significant gains on all measures from baseline to 90 days: muscle mass increased by 1.2 (t[22] = 2.85, p = .009), grip strength increased by 4.02 (t[22] = 8.15, p < .001), balance increased by 2.13 (t[22] = 18.64, p < .001), gait speed increased by 1.83 (t[22] = 17.84, p < .001), chair speed increased 1.87 (t[22] = 16.36, p < .001), and quality of life score increased by 17.5 (t[22] = 19.26, p < .001). For residents with sarcopenia in skilled nursing facilities, a 90-day strength training program with resistance and balance exercises may provide an option for decreasing the incidence of sarcopenia among that population

Keywords: muscle mass, muscle strength, older adults, PARIHS framework

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6395 A Review on Aviation Emissions and Their Role in Climate Change Scenarios

Authors: J. Niemisto, A. Nissinen, S. Soimakallio

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Aviation causes carbon dioxide (CO2) emissions and other climate forcers which increase the contribution of aviation on climate change. Aviation industry and number of air travellers are constantly increasing. Aviation industry has an ambitious goal to strongly cut net CO2 emissions. Modern fleet, alternative jet fuels technologies and route optimisation are important technological tools in the emission reduction. Faster approaches are needed as well. Emission trade systems, voluntary carbon offset compensation schemes and taxation are already in operation. Global scenarios of aviation industry and its greenhouse gas emissions and other climate forcers are discussed in this review study based on literature and other published data. The focus is on the aviation in Nordic countries, but also European and global situation are considered. Different emission reduction technologies and compensation modes are examined. In addition, the role of aviation in a single passenger’s (a Finnish consumer) annual carbon footprint is analysed and a comparison of available emission calculators and carbon offset systems is performed. Long-haul fights have a significant role in a single consumer´s and company´s carbon footprint, but remarkable change in global emission level would need a huge change in attitudes towards flying.

Keywords: aviation, climate change, emissions, environment

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6394 Multi-Stakeholder Engagement in the Food Waste Ecosystem: Opportunities and Policy Initiatives in Nigeria

Authors: Victor Oyewumi Ogunbiyi

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Food waste is a global sustainability issue that demands that multiple stakeholders participate in solving it. This article examines how different food system stakeholders are held responsible in the policy debate related to food waste reduction. The study adopts a qualitative approach, paying attention to the views of both public and private policymakers and constructing their views relating to opportunities and policy initiatives towards waste reduction. The data consists of a list of opportunities and food policy initiatives in the development process in Nigeria. The authors identify three emerging opportunities: sectoral growth, technological demands in food service, and sustainable collaborative behaviour. The findings also revealed key policy initiatives for development: law and regulations, multi-stakeholder collaboration, economic incentives, research, and new knowledge. The study extends the marketing literature on food sustainability by investigating several stakeholders’ roles beyond the practical management of the food services sector. Additionally, considering policy initiative development for food waste mitigation sheds light on how stakeholders’ policy initiatives can sustain the food service sector. Finally, the authors outline policy implications.

Keywords: multistakeholder engagement, food services, food waste, policy initiatives, Nigeria

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6393 The Effects of Applying Wash and Green-A Syrups as Substitution of Sugar on Dough and Cake Properties

Authors: Banafsheh Aghamohammadi, Masoud Honarvar, Babak Ghiassi Tarzi

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Usage of different components has been considered to improve the quality and nutritional properties of cakes in recent years. The effects of applying some sweeteners, instead of sugar, have been evaluated in cakes and many bread formulas up to now; but there has not been any research about the usage of by-products of sugar factories such as Wash and Green-A Syrups in cake formulas. In this research, the effects of substituting 25%, 50%, 75% and 100% of sugar with Wash and Green-A Syrups on some dough and cake properties, such as pH, viscosity, density, volume, weight loss, moisture, water activity, texture, staling, color and sensory evaluations, are studied. The results of these experiments showed that the pH values were not significantly different among any of the all cake batters and also most of the cake samples. Although differences among viscosity and specific gravity of all treatments were both significant and insignificant, these two parameters resulted in higher volume in all samples than the blank one. The differences in weight loss, moisture content and water activity of samples were insignificant. Evaluating of texture showed that the softness of most of samples is increased and the staling is decreased. Crumb color and sensory evaluations of samples were also affected by the replacement of sucrose with Wash and Green-A Syrups. According to the results, we can increase the shelf life and improve the quality and nutritional values of cake by using these kinds of syrups in the formulation.

Keywords: cake, green-A syrup, quality tests, sensory evaluation, wash syrup

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6392 Tuning Nanomechanical Properties of Stimuli-Responsive Hydrogel Nanocomposite Thin Films for Biomedical Applications

Authors: Mallikarjunachari Gangapuram

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The design of stimuli-responsive hydrogel nanocomposite thin films is gaining significant attention in these days due to its wide variety of applications. Soft microrobots, drug delivery, biosensors, regenerative medicine, bacterial adhesion, energy storage and wound dressing are few advanced applications in different fields. In this research work, the nanomechanical properties of composite thin films of 20 microns were tuned by applying homogeneous external DC, and AC magnetic fields of magnitudes 0.05 T and 0.1 T. Polyvinyl alcohol (PVA) used as a matrix material and elliptical hematite nanoparticles (ratio of the length of the major axis to the length of the minor axis is 140.59 ± 1.072 nm/52.84 ± 1.072 nm) used as filler materials to prepare the nanocomposite thin films. Both quasi-static nanoindentation, Nano Dynamic Mechanical Analysis (Nano-DMA) tests were performed to characterize the viscoelastic properties of PVA, PVA+Hematite (0.1% wt, 2% wt and 4% wt) nanocomposites. Different properties such as storage modulus, loss modulus, hardness, and Er/H were carefully analyzed. The increase in storage modulus, hardness, Er/H and a decrease in loss modulus were observed with increasing concentration and DC magnetic field followed by AC magnetic field. Contact angle and ATR-FTIR experiments were conducted to understand the molecular mechanisms such as hydrogen bond formation, crosslinking density, and particle-particle interactions. This systematic study is helpful in design and modeling of magnetic responsive hydrogel nanocomposite thin films for biomedical applications.

Keywords: hematite, hydrogel, nanoindentation, nano-DMA

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6391 Design and Performance Comparison of Metamaterial Based Antenna for 4G/5G Mobile Devices

Authors: Jalal Khan, Daniyal Ali Sehrai, Shakeel Ahmad

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This paper presents the design and performance evaluation of multiband metamaterial based antenna operating in the 3.6 GHz (4G), 14.33 GHz, and 28.86 GHz (5G) frequency bands, for future mobile and handheld devices. The radiating element of the proposed design is made up of a conductive material supported by a 1.524 mm thicker Rogers-4003 substrate, having a relative dielectric constant and loss tangent of 3.55 and 0.0027, respectively. The substrate is backed by truncated ground plane. The future mobile communication system is based on higher frequencies, which are highly affected by the atmospheric conditions. Therefore, to overcome the path loss problem, essential enhancements and improvements must be made in the overall performance of the antenna. The traditional ground plane does not provide the in-phase reflection and surface wave suppression due to which side and back lobes are produced. This will affect the antenna performance in terms of gain and efficiency. To enhance the overall performance of the antenna, a metamaterial acting as a high impedance surface (HIS) is used as a reflector in the proposed design. The simulated gain of the metamaterial based antenna is enhanced from {2.76-6.47, 4.83-6.71 and 7.52-7.73} dB at 3.6, 14.33 and 28.89 GHz, respectively relative to the gain of the antenna backed by a traditional ground plane. The proposed antenna radiated efficiently with a radiated efficiency (>85 %) in all the three frequency bands with and without metamaterial surface. The total volume of the antenna is (L x W x h=45 x 40 x 1.524) mm3. The antenna can be potentially used for wireless handheld devices and mobile terminal. All the simulations have been performed using the Computer Simulation Technology (CST) software.

Keywords: CST MWS, fourth generation/fifth generation, 4G/5G, high gain, multiband, metamaterial

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6390 A Study of Seismic Design Approaches for Steel Sheet Piles: Hydrodynamic Pressures and Reduction Factors Using CFD and Dynamic Calculations

Authors: Helena Pera, Arcadi Sanmartin, Albert Falques, Rafael Rebolo, Xavier Ametller, Heiko Zillgen, Cecile Prum, Boris Even, Eric Kapornyai

Abstract:

Sheet piles system can be an interesting solution when dealing with harbors or quays designs. However, current design methods lead to conservative approaches due to the lack of specific basis of design. For instance, some design features still deal with pseudo-static approaches, although being a dynamic problem. Under this concern, the study particularly focuses on hydrodynamic water pressure definition and stability analysis of sheet pile system under seismic loads. During a seismic event, seawater produces hydrodynamic pressures on structures. Currently, design methods introduce hydrodynamic forces by means of Westergaard formulation and Eurocodes recommendations. They apply constant hydrodynamic pressure on the front sheet pile during the entire earthquake. As a result, the hydrodynamic load may represent 20% of the total forces produced on the sheet pile. Nonetheless, some studies question that approach. Hence, this study assesses the soil-structure-fluid interaction of sheet piles under seismic action in order to evaluate if current design strategies overestimate hydrodynamic pressures. For that purpose, this study performs various simulations by Plaxis 2D, a well-known geotechnical software, and CFD models, which treat fluid dynamic behaviours. Knowing that neither Plaxis nor CFD can resolve a soil-fluid coupled problem, the investigation imposes sheet pile displacements from Plaxis as input data for the CFD model. Then, it provides hydrodynamic pressures under seismic action, which fit theoretical Westergaard pressures if calculated using the acceleration at each moment of the earthquake. Thus, hydrodynamic pressures fluctuate during seismic action instead of remaining constant, as design recommendations propose. Additionally, these findings detect that hydrodynamic pressure contributes a 5% to the total load applied on sheet pile due to its instantaneous nature. These results are in line with other studies that use added masses methods for hydrodynamic pressures. Another important feature in sheet pile design is the assessment of the geotechnical overall stability. It uses pseudo-static analysis since the dynamic analysis cannot provide a safety calculation. Consequently, it estimates the seismic action. One of its relevant factors is the selection of the seismic reduction factor. A huge amount of studies discusses the importance of it but also about all its uncertainties. Moreover, current European standards do not propose a clear statement on that, and they recommend using a reduction factor equal to 1. This leads to conservative requirements when compared with more advanced methods. Under this situation, the study calibrates seismic reduction factor by fitting results from pseudo-static to dynamic analysis. The investigation concludes that pseudo-static analyses could reduce seismic action by 40-50%. These results are in line with some studies from Japanese and European working groups. In addition, it seems suitable to account for the flexibility of the sheet pile-soil system. Nevertheless, the calibrated reduction factor is subjected to particular conditions of each design case. Further research would contribute to specifying recommendations for selecting reduction factor values in the early stages of the design. In conclusion, sheet pile design still has chances for improving its design methodologies and approaches. Consequently, design could propose better seismic solutions thanks to advanced methods such as findings of this study.

Keywords: computational fluid dynamics, hydrodynamic pressures, pseudo-static analysis, quays, seismic design, steel sheet pile

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6389 Systematic Literature Review of Therapeutic Use of Autonomous Sensory Meridian Response (ASMR) and Short-Term ASMR Auditory Training Trial

Authors: Christine H. Cubelo

Abstract:

This study consists of 2-parts: a systematic review of current publications on the therapeutic use of autonomous sensory meridian response (ASMR) and a within-subjects auditory training trial using ASMR videos. The main intent is to explore ASMR as potentially therapeutically beneficial for those with atypical sensory processing. Many hearing-related disorders and mood or anxiety symptoms overlap with symptoms of sensory processing issues. For this reason, inclusion and exclusion criteria of the systematic review were generated in an effort to produce optimal search outcomes and avoid overly confined criteria that would limit yielded results. Criteria for inclusion in the review for Part 1 are (1) adult participants diagnosed with hearing loss or atypical sensory processing, (2) inclusion of measures related to ASMR as a treatment method, and (3) published between 2000 and 2022. A total of 1,088 publications were found in the preliminary search, and a total of 13 articles met the inclusion criteria. A total of 14 participants completed the trial and post-trial questionnaire. Of all responses, 64.29% agreed that the duration of auditory training sessions was reasonable. In addition, 71.43% agreed that the training improved their perception of music. Lastly, 64.29% agreed that the training improved their perception of a primary talker when there are other talkers or background noises present.

Keywords: autonomous sensory meridian response, auditory training, atypical sensory processing, hearing loss, hearing aids

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6388 Disaster Risk Reduction (DRR) through Harvesting Encosternum delegorguei Insect (Harurwa) in Nerumedzo, Bikita District, Zimbabwe

Authors: Mkhokheli Sithole, Brenda N. Muchapondwa

Abstract:

Food security is becoming a critical issue for people residing mainly in the rural areas where frequent droughts interrupt food production, reduce income, compromise the ability to save and erode livelihoods. This tends to increase the vulnerability of poor households to food and income insecurity, hence, malnutrition. There is an emerging need for DRR strategies to complement the existing rain fed crop production based livelihoods. One of such strategies employed by the community of Nerumedzo in Bikita district is the harvesting of Encosternum delegorguei insect. This article analyses the livelihood impacts of Encosternum delegorguei insect as a DRR strategy. The research used a combination of qualitative and quantitative approaches. The insect samples were tested in the laboratory for their nutritional composition while surveys were done on a sample of 40 community members. Participatory observations and 5 focus group discussions were also done. The results revealed that harvesting the Encosternum delegorguei insects provides a livelihood for the locals by complementing crop production thereby mitigating potential negative effects of frequent droughts. The insects are now a significant source of income to poor households in the community.

Keywords: disaster risk reduction, livelihoods, human, social sciences

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6387 NANCY: Combining Adversarial Networks with Cycle-Consistency for Robust Multi-Modal Image Registration

Authors: Mirjana Ruppel, Rajendra Persad, Amit Bahl, Sanja Dogramadzi, Chris Melhuish, Lyndon Smith

Abstract:

Multimodal image registration is a profoundly complex task which is why deep learning has been used widely to address it in recent years. However, two main challenges remain: Firstly, the lack of ground truth data calls for an unsupervised learning approach, which leads to the second challenge of defining a feasible loss function that can compare two images of different modalities to judge their level of alignment. To avoid this issue altogether we implement a generative adversarial network consisting of two registration networks GAB, GBA and two discrimination networks DA, DB connected by spatial transformation layers. GAB learns to generate a deformation field which registers an image of the modality B to an image of the modality A. To do that, it uses the feedback of the discriminator DB which is learning to judge the quality of alignment of the registered image B. GBA and DA learn a mapping from modality A to modality B. Additionally, a cycle-consistency loss is implemented. For this, both registration networks are employed twice, therefore resulting in images ˆA, ˆB which were registered to ˜B, ˜A which were registered to the initial image pair A, B. Thus the resulting and initial images of the same modality can be easily compared. A dataset of liver CT and MRI was used to evaluate the quality of our approach and to compare it against learning and non-learning based registration algorithms. Our approach leads to dice scores of up to 0.80 ± 0.01 and is therefore comparable to and slightly more successful than algorithms like SimpleElastix and VoxelMorph.

Keywords: cycle consistency, deformable multimodal image registration, deep learning, GAN

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6386 Surface Passivation of Multicrystalline Silicon Solar Cell via Combination of LiBr/Porous Silicon and Grain Boundaies Grooving

Authors: Dimassi Wissem

Abstract:

In this work, we investigate the effect of combination between the porous silicon (PS) layer passivized with Lithium Bromide (LiBr) and grooving of grain boundaries (GB) in multi crystalline silicon. The grain boundaries were grooved in order to reduce the area of these highly recombining regions. Using optimized conditions, grooved GB's enable deep phosphorus diffusion and deep metallic contacts. We have evaluated the effects of LiBr on the surface properties of porous silicon on the performance of silicon solar cells. The results show a significant improvement of the internal quantum efficiency, which is strongly related to the photo-generated current. We have also shown a reduction of the surface recombination velocity and an improvement of the diffusion length after the LiBr process. As a result, the I–V characteristics under the dark and AM1.5 illumination were improved. It was also observed a reduction of the GB recombination velocity, which was deduced from light-beam-induced-current (LBIC) measurements. Such grooving in multi crystalline silicon enables passivization of GB-related defects. These results are discussed and compared to solar cells based on untreated multi crystalline silicon wafers.

Keywords: Multicrystalline silicon, LiBr, porous silicon, passivation

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6385 Evaluation of Raw Diatomaceous Earth and Plant Powders in the Control of Callosobruchus subinnotatus (Pic.) on Stored Bambara Groundnut (Vigna subterranea (L.) (Verdc.) Seeds

Authors: Ibrahim Nasiru Dole, Audu Abdullahi, Dike Michiel Chidozie, Lawal Mansur

Abstract:

Bambara groundnut is an important grain legume and the seeds in storage suffer infestation by Callosobruchus subinnotatus. Laboratory study was conducted to evaluate the efficacy of raw diatomaceous earth (RDE) and plant powders (Jatropha curcas (L.), Eucalyptus camaldulensis (Dehnh.) and Melia azedarach (L.) against C. subinnotatus infesting stored bambara groundnut seeds. Rearing of the insects and the experiments were conducted in Agricultural Biology Laboratory of the Usmanu Danfodiyo University, Sokoto - Nigeria under ambient conditions (29-33oC and a relative humidity of 44-56%). Four treatments at three levels: RDE at 0.5, 1.0 and 1.5 g while plant powders at 0.5, 1.0 and 2.0 g, standard/check (2.0 g of Actellic dust), and a control. These were separately admixed with 100 g of sterilized seeds in glass jars. Each jar was later infested with thirty, 1-2-days old C. subinnotatus of mixed sexes. Adult mortality was assessed 24, 48, 72 and 96 hours, F1 and F2 progenies, seed damage, weight loss and viability were also assessed after 90 days. Eighty-nine (89%) percent adult mortality was recorded in the highest dose of RDE after 96 hours of exposure. These treatments significantly (P < 0.05) suppressed F1 and F2 progenies emergence in relation to the control. The control suffered significantly (P < 0.05) higher seed damage (51.0 %) and weight loss (40.8%) thereby recording lower seed germination. Therefore, RDE and plant powders could be used against C. subinnotatus on stored bambara groundnut seeds.

Keywords: bambara, callosobruchus subinnotatus, plant powders, raw diatomaceous earth,

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6384 Direct Cost of Anesthesia in Traumatic Patients with Massive Bleeding: A Prospective Micro-Costing Study

Authors: Asamaporn Puetpaiboon, Sunisa Chatmongkolchart, Nalinee Kovitwanawong, Osaree Akaraborworn

Abstract:

Traumatic patients with massive bleeding require intensive resuscitation. The actual cost of anesthesia per case has never been clarified, so our study aimed to quantify the direct cost, and cost-to-charge ratio of anesthetic care in traumatic patients with intraoperative massive bleeding. This study was a prospective, observational, cost analysis study, conducted in Prince of Songkla University hospital, Thailand, with traumatic patients, of any mechanisms being recruited. Massive bleeding was defined as estimated blood loss of at least one blood volume in 24 hours, or a half of blood volume in 3 hours. The cost components were identified by the micro-costing method, and valued by the bottom-up approach. The direct cost was divided into 4 categories: the labor cost, the capital cost, the material cost and the cost of drugs. From September 2017 to August 2018, 10 patients with multiple injuries were included. Seven patients had motorcycle accidents, two patients fell from a height and another one was in a minibus accident. Two patients died on the operating table, and another two died within 48 hours. The median Sequential Organ Failure Assessment (SOFA) score was 8. The median intraoperative blood loss was 3,500 ml. The median direct cost, per case, was 250 United States Dollars (2017 exchange rate), and the cost-to-charge ratio was 0.53. In summary, the direct cost was nearly half of the hospital charge, for these traumatic patients with massive bleeding. However, our study did not analyze the indirect cost.

Keywords: cost, cost-to-charge ratio, micro-costing, trauma

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6383 Bituminous Geomembranes: Sustainable Products for Road Construction and Maintenance

Authors: Ines Antunes, Andrea Massari, Concetta Bartucca

Abstract:

Greenhouse gasses (GHG) role in the atmosphere has been well known since the 19th century; however, researchers have begun to relate them to climate changes only in the second half of the following century. From this moment, scientists started to correlate the presence of GHG such as CO₂ with the global warming phenomena. This has raised the awareness not only of those who were experts in this field but also of public opinion, which is becoming more and more sensitive to environmental pollution and sustainability issues. Nowadays the reduction of GHG emissions is one of the principal objectives of EU nations. The target is an 80% reduction of emissions in 2050 and to reach the important goal of carbon neutrality. Road sector is responsible for an important amount of those emissions (about 20%). The most part is due to traffic, but a good contribution is also given directly or indirectly from road construction and maintenance. Raw material choice and reuse of post-consumer plastic rather than a cleverer design of roads have an important contribution to reducing carbon footprint. Bituminous membranes can be successfully used as reinforcement systems in asphalt layers to improve road pavement performance against cracking. Composite materials coupling membranes with grids and/or fabrics should be able to combine improved tensile properties of the reinforcement with stress absorbing and waterproofing effects of membranes. Polyglass, with its brand dedicated to road construction and maintenance called Polystrada, has done more than this. The company's target was not only to focus sustainability on the final application but also to implement a greener mentality from the cradle to the grave. Starting from production, Polyglass has made important improvements finalized to increase efficiency and minimize waste. The installation of a trigeneration plant and the usage of selected production scraps inside the products as well as the reduction of emissions into the environment, are one of the main efforts of the company to reduce impact during final product build-up. Moreover, the benefit given by installing Polystrada products brings a significant improvement in road lifetime. This has an impact not only on the number of maintenance or renewal that needs to be done (build less) but also on traffic density due to works and road deviation in case of operations. During the end of the life of a road, Polystrada products can be 100% recycled and milled with classical systems used without changing the normal maintenance procedures. In this work, all these contributions were quantified in terms of CO₂ emission thanks to an LCA analysis. The data obtained were compared with a classical system or a standard production of a membrane. What it is possible to see is that the usage of Polyglass products for street maintenance and building gives a significant reduction of emissions in case of membrane installation under the road wearing course.

Keywords: CO₂ emission, LCA, maintenance, sustainability

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6382 High Temperature Oxidation of Additively Manufactured Silicon Carbide/Carbon Fiber Nanocomposites

Authors: Saja M. Nabat Al-Ajrash, Charles Browning, Rose Eckerle, Li Cao, Robyn L. Bradford, Donald Klosterman

Abstract:

An additive manufacturing process and subsequent pyrolysis cycle were used to fabricate SiC matrix/carbon fiber hybrid composites. The matrix was fabricated using a mixture of preceramic polymer and acrylate monomers, while polyacrylonitrile (PAN) precursor was used to fabricate fibers via electrospinning. The precursor matrix and reinforcing fibers at 0, 2, 5, or 10 wt% were printed using digital light processing, and both were simultaneously pyrolyzed to yield the final ceramic matrix composite structure. After pyrolysis, XRD and SEAD analysis proved the existence of SiC nanocrystals and turbostratic carbon structure in the matrix, while the reinforcement phase was shown to have a turbostratic carbon structure similar to commercial carbon fibers. Thermogravimetric analysis (TGA) in the air up to 1400 °C was used to evaluate the oxidation resistance of this material. TGA results showed some weight loss due to oxidation of SiC and/or carbon up to about 900 °C, followed by weight gain to about 1200 °C due to the formation of a protective SiO2 layer. Although increasing carbon fiber content negatively impacted the total mass loss for the first heating cycle, exposure of the composite to second-run air revealed negligible weight chance. This is explained by SiO2 layer formation, which acts as a protective film that prevents oxygen diffusion. Oxidation of SiC and the formation of a glassy layer has been proven to protect the sample from further oxidation, as well as provide healing of surface cracks and defects, as revealed by SEM analysis.

Keywords: silicon carbide, carbon fibers, additive manufacturing, composite

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6381 New Challenge: Reduction of Aflatoxin M1 Residues in Cow’s Milk by MilBond Dietary Hydrated Sodium Calcium Aluminosilicate (HSCAS) and Its Effect on Milk Composition

Authors: A. Aly Salwa, H. Diekmann, S. Hafiz Ragaa, DG Abo Elhassan

Abstract:

This study was aimed to evaluate the effect of Milbond (HSCAS) on aflatoxin M1 in artificially contaminated cows milk. Chemisorption compounds used in this experiment were MIlBond, hydrated sodium calcium aluminosilicate (HSCAS). Raw cow milk were artificially exposed to aflatoxin M1 in a concentration of 100 ppb) with addition of Nilbond at 0.5, 1, 2 and 3 % at room temperature for 30 minutes. Aflatoxin M1 was decreased more than 95% by HSCAS at 2%. Milk composition consist of protein, fat, lactose, solid non fat and total solid were affected by addition of some adsorbents were not significantly affected (p 0.05). Tthis method did not involve degrading the toxin, milk may be free from toxin degradation products and is safe for consumption. In addition, the added material may be easily separated from milk after the substance adsorbs the toxin. Thus, this method should be developed by further researches for determining effects of these compounds on functional properties of milk. The ability of hydrated sodium calcium aluminosilicate to prevent or reduce the level of aflatoxin MI residues in milk is critically needed. This finding has important implications, because milk is ultimately consumed by humans and animals, and the reduction of aflatoxin contamination in the milk could have an important impact on their health.

Keywords: aflatoxin M1, Hydrated sodium calcium aluminium silicate, detoxification, raw cow milk

Procedia PDF Downloads 423
6380 Stray Light Reduction Methodology by a Sinusoidal Light Modulation and Three-Parameter Sine Curve Fitting Algorithm for a Reflectance Spectrometer

Authors: Hung Chih Hsieh, Cheng Hao Chang, Yun Hsiang Chang, Yu Lin Chang

Abstract:

In the applications of the spectrometer, the stray light that comes from the environment affects the measurement results a lot. Hence, environment and instrument quality control for the stray reduction is critical for the spectral reflectance measurement. In this paper, a simple and practical method has been developed to correct a spectrometer's response for measurement errors arising from the environment's and instrument's stray light. A sinusoidal modulated light intensity signal was incident on a tested sample, and then the reflected light was collected by the spectrometer. Since a sinusoidal signal modulated the incident light, the reflected light also had a modulated frequency which was the same as the incident signal. Using the three-parameter sine curve fitting algorithm, we can extract the primary reflectance signal from the total measured signal, which contained the primary reflectance signal and the stray light from the environment. The spectra similarity between the extracted spectra by this proposed method with extreme environment stray light is 99.98% similar to the spectra without the environment's stray light. This result shows that we can measure the reflectance spectra without the affection of the environment's stray light.

Keywords: spectrometer, stray light, three-parameter sine curve fitting, spectra extraction

Procedia PDF Downloads 233
6379 A Comparative Analysis of an All-Optical Switch Using Chalcogenide Glass and Gallium Arsenide Based on Nonlinear Photonic Crystal

Authors: Priyanka Kumari Gupta, Punya Prasanna Paltani, Shrivishal Tripathi

Abstract:

This paper proposes a nonlinear photonic crystal ring resonator-based all-optical 2 × 2 switch. The nonlinear Kerr effect is used to evaluate the essential 2 x 2 components of the photonic crystal-based optical switch, including the bar and cross states. The photonic crystal comprises a two-dimensional square lattice of dielectric rods in an air background. In the background air, two different dielectric materials are used for this comparison study separately. Initially with chalcogenide glass rods, then with GaAs rods. For both materials, the operating wavelength, bandgap diagram, operating power intensities, and performance parameters, such as the extinction ratio, insertion loss, and cross-talk of an optical switch, have also been estimated using the plane wave expansion and the finite-difference time-domain method. The chalcogenide glass material (Ag20As32Se48) has a high refractive index of 3.1 which is highly suitable for switching operations. This dielectric material is immersed in an air background with a nonlinear Kerr coefficient of 9.1 x 10-17 m2/W. The resonance wavelength is at 1552 nm, with the operating power intensities at the cross-state and bar state around 60 W/μm2 and 690 W/μm2. The extinction ratio, insertion loss, and cross-talk value for the chalcogenide glass at the cross-state are 17.19 dB, 0.051 dB, and -17.14 dB, and the bar state, the values are 11.32 dB, 0.025 dB, and -11.35 dB respectively. The gallium arsenide (GaAs) dielectric material has a high refractive index of 3.4, a direct bandgap semiconductor material highly preferred nowadays for switching operations. This dielectric material is immersed in an air background with a nonlinear Kerr coefficient of 3.1 x 10-16 m2/W. The resonance wavelength is at 1558 nm, with the operating power intensities at the cross-state and bar state around 110 W/μm2 and 200 W/μm2. The extinction ratio, insertion loss, and cross-talk value for the chalcogenide glass at the cross-state are found to be 3.36.19 dB, 2.436 dB, and -5.8 dB, and for the bar state, the values are 15.60 dB, 0.985 dB, and -16.59 dB respectively. This paper proposes an all-optical 2 × 2 switch based on a nonlinear photonic crystal using a ring resonator. The two-dimensional photonic crystal comprises a square lattice of dielectric rods in an air background. The resonance wavelength is in the range of photonic bandgap. Later, another widely used material, GaAs, is also considered, and its performance is compared with the chalcogenide glass. Our presented structure can be potentially applicable in optical integration circuits and information processing.

Keywords: photonic crystal, FDTD, ring resonator, optical switch

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