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排序方式: 共有4129条查询结果,搜索用时 15 毫秒
91.
Md Hossain Ali Ismail Abustan Md Ashiqur Rahman Abu Ahmed Mokammel Haque 《Water Resources Management》2012,26(3):623-641
Water is essential for economic, social, and environmental development. Global water resources are vulnerable due to increasing demand related to population growth, pollution potential, and climate change. Competition for water between different sectors is increasing. To meet the increasing demand, the use of groundwater is increasing worldwide. In this paper, the water-table dynamics of the north-eastern region of Bangladesh were studied using the MEKESENS software. This study reveals that the depth to water-table (WT) of almost all the wells is declining slowly. In many cases, the depth will approximately double by the year 2040, and almost all will double by 2060, if the present trend continues. If the decline of the water-table is allowed to continue in the long run, the result could be a serious threat to the ecology and to the sustainability of food production, which is vital for the nation’s food security. Therefore, necessary measures should be taken to sustain water resources and thereby agricultural production. Demand-side management of water and the development of alternative surface water sources seem to be viable strategies for the area. These strategies could be employed to reduce pressure on groundwater and thus maintain the sustainability of the resource. 相似文献
92.
Gene-expression programming for flip-bucket spillway scour 总被引:1,自引:0,他引:1
During the last two decades, researchers have noticed that the use of soft computing techniques as an alternative to conventional statistical methods based on controlled laboratory or field data, gave significantly better results. Gene-expression programming (GEP), which is an extension to genetic programming (GP), has nowadays attracted the attention of researchers in prediction of hydraulic data. This study presents GEP as an alternative tool in the prediction of scour downstream of a flip-bucket spillway. Actual field measurements were used to develop GEP models. The proposed GEP models are compared with the earlier conventional GP results of others (Azamathulla et al. 2008b; RMSE = 2.347, δ = 0.377, R = 0.842) and those of commonly used regression-based formulae. The predictions of GEP models were observed to be in strictly good agreement with measured ones, and quite a bit better than conventional GP and the regression-based formulae. The results are tabulated in terms of statistical error measures (GEP1; RMSE = 1.596, δ = 0.109, R = 0.917) and illustrated via scatter plots. 相似文献
93.
H. Md. Azamathulla Chun Kiat Chang Aminuddin Ab. Ghani Junaidah Ariffin Nor Azazi Zakaria Zorkeflee Abu Hasan 《Journal of Hydro》2009,3(1):35-44
A total of 346 sets of bed-load data obtained from the Kinta River, Pari River, Kerayong River and Langat River were analyzed using four common bed-load equations. These assessments, based on the median sediment size (d50), show that the existing equations were unable to predict the measured bed load accurately. All existing equations over-predicted the measured values, and none of the existing bed-load equations gave satisfactory performance when tested on local river data. Therefore, the present study applies a new soft computing technique, i.e. an adaptive neuro-fuzzy inference system (ANFIS), to better predict measured bed-load data. Validation of the developed network (ANFIS) was performed using a new set of bed-load data collected at Kulim River. The results show that the recommended network can more accurately predict the measured bed-load data when compared to an equation based on a regression method. 相似文献
94.
Combination of NMR and MRI quantitation of moisture and structure changes for convection cooking of fresh chicken meat 总被引:2,自引:0,他引:2
This study demonstrates that a combination of bulk NMR and magnetic resonance imaging measurements of the T(2)-values of water protons can be used to determine the heat-induced changes in the structure and moisture content of fresh chicken meat which had been cooked in a convection oven at 200°C for a range of times. The gravimetric moisture content was also determined for both the raw and cooked meat. Multi-exponential fitting of the bulk NMR T(2) relaxation time data demonstrated three distinct water populations T(21) (39-43ms), T(22) (82-99ms) and T(23) (2-3ms) for raw meat which changed to 18-31ms (T(21)), 61-208ms (T(22)) and 3-7ms (T(23)) after the meat had been cooked. The T(1) and T(2) values obtained by MRI for cooked meat decreased progressively with increased heating time. There are highly significant correlations between the T(2) values from MRI and the T(21) values from bulk NMR measurements of cooked meat (r=0.986; p<0.01), and also between the normalised M(0) values from MRI and the gravimetric moisture content (r=0.953; p<0.01). 相似文献
95.
Usman Ali Shah;Ao Wang;Muhammad Irfan Ullah;Muhammad Ishaq;Imtiaz Alam Shah;Yiyu Zeng;Misbah Sehar Abbasi;Muhammad Ali Umair;Umar Farooq;Guang-Xing Liang;Kaiwen Sun; 《Small (Weinheim an der Bergstrasse, Germany)》2024,20(30):2310584
Renewable energy is crucial for sustainable future, and Cu2ZnSnS4 (CZTS) based solar cells shine as a beacon of hope. CZTS, composed of abundant, low-cost, and non-toxic elements, shares similarities with Cu(In,Ga)Se2 (CIGS). However, despite its promise and appealing properties for solar cells, CZTS-based solar cells faces performance challenges owing to inherent issues with CZTS material, and conventional substrate structure complexities. This review critically examines these roadblocks, explores ongoing efforts and breakthroughs, providing insight into the evolving landscape of CZTS-based solar cells research. Furthermore, as an optimistic turn in the field, the review first highlights the crucial need to transition to a superstrate structure for CZTS-based single junction devices, and summarizes the substantial progress made in this direction. Subsequently, dive into the discussion about the fascinating realm of CZTS-based tandem devices, providing an overview of the existing literature as well as outlining the possible potential strategies for enhancing the efficiency of such devices. Finally, the review provides a useful outlook that outlines the priorities for future research and suggesting where efforts should concentrate to shape the future of CZTS-based solar cells. 相似文献
96.
Mahabub Alam;Animesh Sarkar;A. S. M. Sayem;Rahul Biswas;M. M. Mahdi Hasan; 《Food Science & Nutrition》2024,12(11):9371-9378
Heat-resistant molds (HRM) pose a significant threat to food industries due to their ability to survive in high temperatures (pasteurization range) and grow in a variety of environments. To understand how inhibiting variables affect HRM growth, this study evaluated the impact of high sugar concentration (50–60°Brix), low pH (3.5–4.5), and temperature (5–15) on the time (tv) to develop detectable colonies (colony diameter = 2 mm) of three HRM strains (Byssochlamys nivea, Byssochlamys fulva, Neosartorya fischeri) isolated from mixed fruit products. The study found that all HRM strains had relatively short periods of time to develop detectable colonies at 50°Brix, while no visible growth was observed at 60°Brix. Byssochlamys nivea was found to be the most susceptible to low temperatures, requiring up to 43 days to develop detectable colonies at 10°C and unable to grow at colder temperatures. The tv varied from 6 to 27 days based on pH and isolates. HRM's resistance to high sugar concentrations and ability to grow in cold environments pose a threat to the microbiological safety of fruit products. The evaluated data were fitted to several statistical distribution models to support further research on the quantitative microbiological risk in processed fruit products. This study provides valuable insights into how inhibiting variables affect HRM growth and can inform efforts to minimize their impact on fruit-based product quality and safety. 相似文献
97.
M. Atikur Rahman;Zahid Hasan;Hasan Khaled Rouf;M. Khurshed Alam;A. K. M. Akther Hossain;M. N. I. Khan;M. R. Mohammad;Abdullah Alodhayb;Saikh Mohammad;Rajesh Haldhar;M. Khalid Hossain; 《International Journal of Applied Ceramic Technology》2024,21(5):3632-3644
This study investigates the magnetoelectric coupling effect in dual-phase multiferroic composites prepared using a solid-state reaction method. The composites were fabricated with the formula (1−x)Ba₀.₇₇Ca₀.₂₃TiO₃(BCT) + xNi₀.₆Zn₀.₂₅La₀.₁₅Fe₂O₄(NZLFO), where x varied from 0% to 100% in 10% increments. Ca-doped BaTiO₃ served as the ferroelectric phase, while La-doped Ni–Zn ferrite acted as the ferromagnetic phase. The effects of varying ferrite content (x) on structural, optical, ferroelectric, electrical, and magnetoelectric properties were comprehensively analyzed. X-ray diffraction (XRD) with Rietveld refinement revealed a spinel cubic structure for the ferrite phases and a tetragonal structure for the perovskite phases. The study observed a moderate influence of ferrite concentration on the lattice parameters of BCT and an opposing effect on the lattice parameters of NZLFO. Optical measurements indicated higher light absorption in the visible range compared to the UV region and wide optical bandgap. Magnetic properties, characterized by saturation magnetization, exhibited a dependence on temperature, with a Curie temperature (Tc) of 700 K. Electrical resistivity displayed a maximum at x = 50% and remained constant at high frequencies. The study also confirmed the presence of electric polarization induced by a magnetic field, with the highest magnetoelectric coefficient observed at x = 10%. These findings demonstrate the successful fabrication of dual-phase multiferroic composites with tunable properties through controlled ferrite content. The observed magnetoelectric coupling suggests potential applications in multifunctional devices. 相似文献
98.
Gonca Alak;Rabia Nur Yavas; 《Journal of Food Safety》2024,44(6):e13173
Information on the microplastic (MPs) migration, particularly phthalate acid esters (PAEs) in packaged seafood, is limited to a few studies. The aim of this study is to follow the possible migration potential and speed of phthalates in rainbow trout (Oncorhynchus mykiss) fillets stored in vacuum packaging depending on the storage temperature, as well as to determine the polyethylene polymer detection. For this purpose, the fillets were randomly distributed as three pieces in each bag, vacuum-packed, and stored at commonly used temperatures (+4°C and −20°C) for 3 months. On the first day of storage in fillet and packaging materials, in certain periods of storage, the phthalate content in the fillet of each temperature group was determined. It has been determined that the chemical composition of the bag used in the vacuum packaging process is affected by the temperature depending on the storage period, and different polymer types are formed in the packaged material. Ten types of PAEs including diisobutyl phthalate (DIBP), dibutylphthalate (DBP), di-n-pentyl phthalate (DPENP), di-n-hexyl phthalate (DHEXP), butylbenzylphthalate (BBP), di-(2-ethylhexyl)-phthalate (DEHP), dicyclohexyl phthalate (DCHP), di-n-octylphthalate (DNOP), di-iso-nonylphthalate (DINP), and di-isodecylphthalate (DIDP) were recorded in the packaging material and stored fillets. It was determined that the dominant PAE in the fillets were DPENP, and DEHP in the package at all temperature applications and storage periods. The findings help monitor the presence and migration of PAEs in foods and provide a motivating model for adopting the right technologies. 相似文献
99.
Won-Chun Oh Yin Liu Kwang Youn Cho Md Rokon Ud Dowla Biswas 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(11):945-958
AbstractPolyaniline/Bismuth Vanadate/Graphene Oxide (PANI-BiVO4-GO) or BGPA composite was prepared by sonochemical deposition of bismuth vanadate-graphene oxide (BiVO4) nanoparticles on the surface of polyaniline (PANI). The best photocatalytic degradation performance was obtained by 5wt% BGPA composites for MB, RhB, and SO dyes, which is approximately 4 times higher than that of 1% BGPA. Meanwhile, the photocatalytic stability of BiVO4 was significantly improved by introducing PANI into the PANI-BiVO4-GO composite. The dramatic promotion of the photocatalytic degradation performance and the photocatalytic stability can be attributed to the formation of a heterojunction free electron between PANI and BiVO4-GO. The existence of those extra free electrons can dramatically enhance the efficiency of the photogenerated electrons, which accelerate the transfer of photogenerated holes from BiVO4-GO to PANI, and therefore inhibit the self-oxidation of BiVO4. 相似文献
100.
Metal oxide nanostructures are the most promising materials for the fabrication of advanced gas sensors over two decades. Especially, reliable responsivity and selectivity for various harmful gases are the main requirements for the future chemiresistive‐type gas sensors. Here, a 3D nanocone (NC) of WO3 for a real‐time ethane (C2H6) gas sensor is reported. A compact WO3 nanoparticles thin film deposited on the sensor interdigitate electrodes (IDEs) by using radio frequency (RF) sputter and subsequently, WO3 thin film is converted into highly ordered 3D NC with simple monolayer of polystyrene. An in‐plane microheater integrated with a temperature sensor is also developed here in which the heater, temperature sensor, and the gas sensor share the same plane instead of a conventional vertical structure where the microheater and the sensor IDE are placed one above the other. Prior to the fabrication, COMSOL simulations are carried away to predict the heater performance and surface charge densities of the NC structures. A comparative study between the planar WO3 and highly ordered 3D NC WO3 in sensor response has been conducted. The fabricated sensors (planar WO3) and 3D NC WO3 show a high response ΔR/R (%) of 44% and 52% to 100 ppm of ethane at 200 °C respectively. 相似文献