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241.
Md. Imran H. Khan Hasan M. M. Afroz M. A. Karim 《International Journal of Green Energy》2017,14(4):379-384
Temperature fluctuation inside the cabinet of a household refrigerator significantly affects the quality of preserved food. Phase change material (PCM) is a latent heat storage system that can store and release the heat energy by changing its phase from liquid to solid and solid to liquid respectively. Therefore, use of PCM inside the refrigerator cabinet has the potential for minimizing the temperature fluctuation during the door opening and the power failure. However, very few studies in the literature were dedicated to investigating the role of PCM to reduce the temperature fluctuation. The aim of this work is to experimentally investigate the effects of PCM on temperature fluctuation inside the cabinet of a household refrigerator during the door opening and power failure. The results found that a significantly lower temperature fluctuation can be obtained using PCM. It was found that during the door opening condition the air temperature in the cabinet rose rapidly. However, when a PCM container was used, temperature variation was reduced to 3–5°C. During the power failure, the system with PCM maintained a lower temperature inside the storage chamber for a long period of time (about 2 hours). Moreover, the test results indicate that PCM maintains more stable temperature in the foodstuffs inside the refrigerator. This reduction of temperature fluctuation ultimately improves the quality of preserved food. 相似文献
242.
Pretty Mori Budiman Ta Yeong Wu Ramakrishnan Nagasundara Ramanan Jamaliah Md. Jahim 《Environmental science and pollution research international》2017,24(19):15870-15881
One-time ultrasonication pre-treatment of Rhodobacter sphaeroides was evaluated for improving biohydrogen production via photofermentation. Batch experiments were performed by varying ultrasonication amplitude (15, 30, and 45%) and duration (5, 10, and 15 min) using combined effluents from palm oil as well as pulp and paper mill as a single substrate. Experimental data showed that ultrasonication at amplitude 30% for 10 min (256.33 J/mL) achieved the highest biohydrogen yield of 9.982 mL H2/mLmedium with 5.125% of light efficiency. A maximum CODtotal removal of 44.7% was also obtained. However, when higher ultrasonication energy inputs (>256.33 J/mL) were transmitted to the cells, biohydrogen production did not improve further. In fact, 20.6% decrease of biohydrogen yield (as compared to the highest biohydrogen yield) was observed using the most intense ultrasonicated inoculum (472.59 J/mL). Field emission scanning electron microscope images revealed the occurrence of cell damages and biomass losses if ultrasonication at 472.59 J/mL was used. The present results suggested that moderate ultrasonication pre-treatment was an effective technique to improve biohydrogen production performances of R. sphaeroides. 相似文献
243.
Shah Md.Atiqul Haq 《中国人口.资源与环境(英文版)》2009,7(3):83-88
Now environment is an important topic in academic field. Many researches focus on the negative outcomes of nature which are being continually created by human and much attention has been paid to how the environment is protected through integrated research, movement and policy. But few studies are concentrated on population and environment and are to find out the interconnectivity and underlying mechanism that have an effect on people's preferring additional children and perception to environment. Many researchers claim that population growth is a great problem for environment but they do not provide the indepth integrated knowledge and mechanism that influence fertility trend and environmental problems. It is very crucial to develop practical and concrete initiatives to confirm a transition to reduce population growth and redirect the perception on population and environment. 相似文献
244.
Md. Tamez Uddin Md. Rukanuzzaman Md. Maksudur Rahman Khan Md. Akhtarul Islam 《Journal of environmental management》2009,90(11):3443-3450
Continuous fixed-bed studies were undertaken to evaluate the efficiency of jackfruit leaf powder (JLP) as an adsorbent for the removal of methylene blue (MB) from aqueous solution under the effect of various process parameters like bed depth (5–10 cm), flow rate (30–50 mL/min) and initial MB concentrations (100–300 mg/L). The pH at point of zero charge (pHPZC) of the adsorbent was determined by the titration method and a value of 3.9 was obtained. A FTIR of the adsorbent was done before and after the adsorption to find the potential adsorption sites for interaction with methylene blue molecules. The results showed that the total adsorbed quantities and equilibrium uptake decreased with increasing flow rate and increased with increasing initial MB concentration. The longest breakthrough time and maximum MB adsorption were obtained at pH 10. The results showed that the column performed well at low flow rate. Also, breakthrough time and exhaustion time increased with increasing bed depth. The bed-depth service time (BDST) model and the Thomas model were applied to the adsorption of MB at different bed depths, flow rates, influent concentrations and pH to predict the breakthrough curves and to determine the characteristic parameters of the column that are useful for process design. The two model predictions were in very good agreement with the experimental results at all the process parameters studied indicating that they were very suitable for JLP column design. 相似文献
245.
Tariq Bin Yousuf Md. Mostafizur Rahman 《Journal of Material Cycles and Waste Management》2009,11(3):277-283
Upgrading a crude dump site into a sanitary landfill is a very challenging task; Matuail landfill site in Dhaka posed just
such a challenge. From the very beginning, the existing disposal site had been used for the crude dumping of solid wastes.
All types of solid wastes were haphazardly disposed of all over the site. The existing drainage channels of the dumping ground
were not operational due to blockage by indiscriminate waste dumping. A large amount of leachate oozing out from the waste
mixed with storm water and made the site esthetically very displeasing and environmentally unsound. This adverse situation
sometimes caused disruption of the waste vehicular movement. Step-by-step improvement measures have been taken in the open
dump to make it controlled and sanitary by adopting simple and locally available materials, technical guidelines, and construction
techniques. 相似文献
246.
Md. Aynul Bari Günter Baumbach Leire Sarachage-Ruiz Savvas Kleanthous 《Water, Air, & Soil Pollution: Focus》2009,9(1-2):39-53
Due to the dry Mediterranean climate in Cyprus, particulate matter is resuspended from soils and other surfaces. From November 2002 to August 2003, gravimetric PM10 measurements were carried out at three characteristic sites (traffic, residential and rural). A significant seasonal trend with high winter concentrations was observed at the traffic site. Special events, e.g. long-range transport of Sahara dust storms, were recorded over traffic, residential and rural areas in the order of six to eight events per year, with a major frequency in summer and spring periods. This contributes to the increase of 24-h EU limit value exceedances for PM10 at the three investigated sites. The origin of the PM10 load was determined by enrichment factors based on analyses of the local soil deposition at the investigated sites. Furthermore, positive matrix factorisation modelling was applied to find the sources of PM10. Results indicate that the major emission sources affecting the PM10 load were mineral soil, sea salt, road dust, oil combustion, secondary pollutants and gasoline vehicles. The natural contribution (local mineral soil and sea salt) at the three sites was in the range of 7–9 μg m?3 in PM10. Besides the Sahara dust storms and natural background concentrations, the vehicular pollution was found as the largest contributor (12–14 μg m?3) to PM10 load at the traffic site. 相似文献
247.
Ashok Kumar Chakraborty Md Emran Hossain Md Masudur Rhaman K M A Sobahan 《环境科学学报(英文版)》2014,26(2):458-465
A nanoheterojunction composite photocatalyst Bi2O3/TiO2working under visible-light(λ 420 nm) was prepared by combining two semiconductors Bi2O3 and TiO2 varying the Bi2O3/TiO2molar ratio. Maleic acid was employed as an organic binder to unite Bi2O3 and TiO2 nanoparticles. The SEM, TEM, XRD and diffuse reflectance spectra were utilized to characterize the prepared Bi2O3/TiO2nanoheterojunction. The nanocomposite exhibited unusual high photocatalytic activity in decomposing 2-propanol in gas phase and phenol in aqueous phase and, evolution of CO2 under visible light irradiation while the end members exhibited low photocatalytic activity. The composite was optimized to 5 mol% Bi2O3/TiO2. The remarkable high photocatalytic efficiency originates from the unique relative energy band position of Bi2O3 and TiO2 as well as the absorption of visible light by Bi2O3. 相似文献
248.
Determination of volatile organic compounds pollution sources in malaysian drinking water using multivariate analysis 总被引:1,自引:0,他引:1
A field investigation was conducted at all water treatment plants throughout 11 states and Federal Territory in Peninsular
Malaysia. The sampling points in this study include treatment plant operation, service reservoir outlet and auxiliary outlet
point at the water pipelines. Analysis was performed by solid phase micro-extraction technique with a 100 μm polydimethylsiloxane
fibre using gas chromatography with mass spectrometry detection to analyse 54 volatile organic compounds (VOCs) of different
chemical families in drinking water. The concentration of VOCs ranged from undetectable to 230.2 μg/l. Among all of the VOCs
species, chloroform has the highest concentration and was detected in all drinking water samples. Average concentrations of
total trihalomethanes (THMs) were almost similar among all states which were in the range of 28.4--33.0 μg/l. Apart from THMs,
other abundant compounds detected were cis and trans-1,2-dichloroethylene, trichloroethylene, 1,2-dibromoethane, benzene, toluene, ethylbenzene, chlorobenzene, 1,4-dichlorobenzene
and 1,2-dichloro - benzene. Principal component analysis (PCA) with the aid of varimax rotation, and parallel factor analysis
(PARAFAC) method were used to statistically verify the correlation between VOCs and the source of pollution. The multivariate
analysis pointed out that the maintenance of auxiliary pipelines in the distribution systems is vital as it can become significant
point source pollution to Malaysian drinking water. 相似文献
249.
250.
Study of harmful algal blooms in a eutrophic pond, Bangladesh 总被引:2,自引:0,他引:2
Roksana Jahan Saleha Khan Md. Mahfuzul Haque Joong Ki Choi 《Environmental monitoring and assessment》2010,170(1-4):7-21
The purpose of this research was to analyze the underlying mechanisms and contributing factors related to the seasonal dynamic of harmful algal blooms in a shallow eutrophic pond, Bangladesh during September 2005–July 2006. Two conspicuous events were noted simultaneously throughout the study period: high concentration of phosphate–phosphorus (>3.03; SD 1.29 mg l???1) and permanent cyanobacterial blooms {>3,981.88 × 103 cells l???1 (SD 508.73)}. Cyanobacterial blooms were characterized by three abundance phases, each of which was associated with different ecological processes. High nitrate–nitrogen (>2.35; SD 0.83 mg l???1), for example, was associated with high cyanobacterial abundance, while low nitrate–nitrogen (0.36; SD 0.2 mg l???1) was recorded during moderate abundance phase. Extremely low NO3–N/PO4–P ratio (>3.55, SD 2.31) was recorded, and all blooming taxa were negatively correlated with this ratio. Cyanobacterial blooms were positively correlated with temperature (r?=?0.345) and pH (0.833; p?=?0.05) and negatively correlated with transparency (r?=???0.956; p?=?0.01). Although Anabaena showed similar relationship with water quality parameters as cyanobacteria, the co-dominant Microcystis exhibited negative relationship with temperature (r?=???0.386) and nitrate–nitrogen (r?=???0.172). This was attributed to excessive growth of Anabaena that suppressed Microcystis’s growth. Planktothrix was the third most dominant taxa, while Euglena was regarded as opportunistic. 相似文献