1,263 research outputs found
Optimization of nanostructured/nano sized rice husk ash preparation
تم تطوير إجراء لإنتاج رماد قشر الأرز. وقد تم دراسة تأثير العوامل المؤثرة على إنتاجية وخصائص السيليكا غير المتبلورة وهذه العوامل هى الكمية الابتدائية لقشر الأرز و ظروف الاحتراق و التقليب . تم التوصل إلى أن أفضل كمية كانت 20 غراما في الدقيقة في صحن تبخر خزفي بحجم 125 مل يحترق لمدة ساعتين عند درجة حرارة 700 درجة مئوية ، مع تبريد على ثلاث فترات أثناء الاحتراق لإنتاج السليكا عند أقل فقد عند الاشتعال وقد وجد أيضا أن فترات التبريد تلعب دوراَ هاماَ فى تباين حجم الهيكل النانوي وتوزيع شكل الجسيمات. بالاضافة إلى أنه لم يتم العثور على مراحل بلورية في رماد قشر الأرز في جميع الحالات.The objective of the study is developing a procedure for production and characterization of rice husk ash (RHA). The effects of rice husk (RH) amount, burning/cooling conditions combined with stirring on producing of RHA with amorphous silica, highest SiO2, lowest loss on ignition (LOI), uniform particle shape distribution and nano structured size have been studied. It is concluded that the best amount is 20 g RH in 125 ml evaporating dish Porcelain with burning for 2 h at temperature 700 °C combined with cooling three times during burning to produce RHA with amorphous silica, SiO2 90.78% and LOI 1.73%. On the other hand, cooling and stirring times affect the variation of nano structured size and particle shape distribution. However, no crystalline phases were found in RHA in all cases. Results proved that the Attritor ball mill was more suitable than vibration disk mill for pulverizing nano structured RHA with 50% of particle size (D50) lower than 45 mm and 99 % of particle size (D99) lower than 144 mm to nanosized RHA with D50 lower than 36 nm and D99 lower than 57 nm by grinding time 8.16 min to every 1 g RHA without changes in morphousity of silica
MAT-762: BUILDING SUSTAINABLE CONTINUOUSLY REINFORCED CONCRETE PAVEMENT USING GFRP BARS: CASE STUDY-HIGHWAY 40 WEST-MONTREAL, CANADA
Continuously reinforced concrete pavement designs (CRCP) are premium pavement designs that are often used on heavily-trafficked roadways and urban corridors. Although CRCP typically is an effective, long-lasting pavement design, it can develop performance problems when the aggregate-interlock load transfer at the transverse cracks is degraded. The prevalence of wide cracks in CRCP has frequently been associated with ruptured steel and significant levels of corrosion. Because of that, there has been recent interest in identifying new reinforcing materials that can prevent or minimize corrosion-related issues in CRCP. Glass fibre-reinforced polymer (GFRP) bars are one product being investigated for use in CRCP in place of traditional steel bars. This paper summarizes the construction details, material properties, early-age behaviour, and preliminary monitoring results of GFRP CRCP after 12 months in service. The project is located westbound HW-40 in Montreal, Qc, Canada, and presents a collaboration between the Ministry of Transportation of Quebec (MTQ) and the University of Sherbrooke. Varieties of sensors were installed in this project in order to monitor the early-age behaviour and the effects of repeated traffic loads and environmental conditions on the performance of CRCP slabs
Prevention and management of type 2 diabetes: dietary components and nutritional strategies
In the past couple of decades, evidence from prospective observational studies and clinical trials has converged to support the importance of individual nutrients, foods, and dietary patterns in the prevention and management of type 2 diabetes. The quality of dietary fats and carbohydrates consumed is more crucial than is the quantity of these macronutrients. Diets rich in wholegrains, fruits, vegetables, legumes, and nuts; moderate in alcohol consumption; and lower in refined grains, red or processed meats, and sugar-sweetened beverages have been shown to reduce the risk of diabetes and improve glycaemic control and blood lipids in patients with diabetes. With an emphasis on overall diet quality, several dietary patterns such as Mediterranean, low glycaemic index, moderately low carbohydrate, and vegetarian diets can be tailored to personal and cultural food preferences and appropriate calorie needs for weight control and diabetes prevention and management. Although much progress has been made in development and implementation of evidence-based nutrition recommendations in developed countries, concerted worldwide efforts and policies are warranted to alleviate regional disparities
MaaSim: A Liveability Simulation for Improving the Quality of Life in Cities
Urbanism is no longer planned on paper thanks to powerful models and 3D
simulation platforms. However, current work is not open to the public and lacks
an optimisation agent that could help in decision making. This paper describes
the creation of an open-source simulation based on an existing Dutch
liveability score with a built-in AI module. Features are selected using
feature engineering and Random Forests. Then, a modified scoring function is
built based on the former liveability classes. The score is predicted using
Random Forest for regression and achieved a recall of 0.83 with 10-fold
cross-validation. Afterwards, Exploratory Factor Analysis is applied to select
the actions present in the model. The resulting indicators are divided into 5
groups, and 12 actions are generated. The performance of four optimisation
algorithms is compared, namely NSGA-II, PAES, SPEA2 and eps-MOEA, on three
established criteria of quality: cardinality, the spread of the solutions,
spacing, and the resulting score and number of turns. Although all four
algorithms show different strengths, eps-MOEA is selected to be the most
suitable for this problem. Ultimately, the simulation incorporates the model
and the selected AI module in a GUI written in the Kivy framework for Python.
Tests performed on users show positive responses and encourage further
initiatives towards joining technology and public applications.Comment: 16 page
Epoxy-cross-linked Polyamine CO2 Sorbents Enhanced via Hydrophobic Functionalization
Optimizing sorption capacity and amine efficiency are among the major challenges in developing solid carbon dioxide sorbents. Such materials frequently feature polyamines impregnated onto supports adding weight to the sorbents. This work presents the cross-linking of polyethyleneimine (PEI) by the industrially available epoxy resin, bisphenol-A diglycidyl ether (DER) to form support-free sorbent materials. Prior to cross-linking, the polyamine chain is functionalized with hydrophobic additives; one material modified with the branched chain hydrocarbon 2-ethylhexyl glycidyl ether displays CO2 uptake of 0.195 g/g, 4.43 mmol CO2/g (1 atm single component CO2, 90 °C). The additive loading affects the cross-linking, with the lesser cross-linked materials showing more favorable sorption capacities and higher amine efficiencies. The type of additive also influences sorption, with the larger, longer and bulkier additives better able to free the amine from their hydrogen bonding network, generally promoting better sorption. As well as increasing CO2 uptake, the additives also reduce the optimum sorption temperature, offering a handle to tune sorbents for specific working conditions. The best performing material shows high selectivity for CO2 sorption, and under sorption cycles in a 10% CO2/90% N2 mixture, utilizing temperature swing desorption, demonstrates a good working capacity of 9.5% CO2 uptake over the course of 29 cycles. Furthermore, humidity has been found to promote CO2 sorption at lower temperatures with a CO2 uptake of 0.235 g/g, 5.34 mmol/g (1 atm single component CO2, 25 °C) using a pre-hydrated sample. Overall, these findings confirm the value of our approach where cross-linking emerges as a valid and practical alternative to loading polyamines onto solid supports. This work demonstrates the versatility of these types of materials and their potential for use in large scale carbon capture systems
Diverse exact solutions to Davey–Stewartson model using modified extended mapping method
In this study, we obtain solitary wave solutions and other exact wave solutions for Davey–Stewartson equation (DSE), which explains how waves move through water with a finite depth while being affected by gravity and surface tension. The study is conducted with the aid of the modified extended mapping method (MEMM). A variety of distinct traveling wave solutions are furnished. The obtained solutions comprise dark, bright, and singular solitary wave solutions. Additionally, Jacobi elliptic function solutions, exponential wave solutions, singular periodic wave solutions, rational wave solutions, and periodic wave solutions are also offered. To help readers physically grasp the acquired solutions, graphical representations of some of the extracted solutions are provided
Stellar parameters of Be stars observed with X-shooter
Aims. The X-shooter archive of several thousand telluric star spectra was
skimmed for Be and Be-shell stars to derive the stellar fundamental parameters
and statistical properties, in particular for the less investigated late type
Be stars, and the extension of the Be phenomenon into early A stars. Methods.
An adapted version of the BCD method is used, utilizing the Balmer
discontinuity parameters to determine effective temperature and surface
gravity. This method is optimally suited for late B stars. The projected
rotational velocity was obtained by profile fitting to the Mg ii lines of the
targets, and the spectra were inspected visually for the presence of peculiar
features such as the infrared Ca ii triplet or the presence of a double Balmer
discontinuity. The Balmer line equivalent widths were measured, but due to
uncertainties in determining the photospheric contribution are useful only in a
subsample of Be stars for determining the pure emission contribution. Results.
A total of 78 Be stars, mostly late type ones, were identified in the X-shooter
telluric standard star archive, out of which 48 had not been reported before.
The general trend of late type Be stars having more tenuous disks and being
less variable than early type ones is confirmed. The relatively large number
(48) of relatively bright (V > 8.5) additional Be stars casts some doubt on the
statistics of late type Be stars; they are more common than currently thought:
The Be/B star fraction may not strongly depend on spectral subtype.Comment: Accepted for publication in A&
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