OPAC libraries basically have provided complete metadata with various data fields that can be used to contain more detailed collection information. This paper will analyze the potential for ...additional data collections, especially collection abstractions from the point of view of information needs and information dissemination. The study used a literature review analysis by referring to several sources of information such as scientific articles from electronic journals or other online sources as well as books relevant to this study. The data was obtained by observing the OPAC of online-based libraries from several educational institutions. The results of the study showed that the metadata pattern built by the library is still limited to a brief description of the collection so that the benefits of the information are not necessarily obtained by the user. The addition of abstract data to the OPAC, from the point of view of information dissemination is very necessary because the users need more detailed information. Libraries can add abstract data by choosing one of the methods in the summary process, namely abstraction and extraction.
The aerosol species separation algorithm (ASSA) is a method designed to retrieve vertical concentration profiles of individual aerosol species by combining measurements from lidar systems and ...spectrophotometers. The ASSA operates as a forward model, simulating as the first step the attenuated backscatter and volume depolarization ratios at various wavelengths initially measured by lidar systems. Subsequently, it extends these simulations to reproduce radiance spectra obtained from co-located spectrophotometers by integrating a radiative transfer model. Currently, the ASSA relies on a lookup table (LUT) of intensive aerosol properties that correspond to mixtures generated from up to eight pure aerosol species as these are defined in the OPAC database. In this study we are focusing on the first step and investigating the performance of the algorithm when solely fitting nighttime data from the Thessaloniki lidar system are used. The algorithm identifies the ensemble of mixture/mass concentration combinations that best fit the elastic and Raman 4 primary species attenuated backscatter and depolarization ratio profiles.
This article provides an overview of computer-based catalogue systems designed for use by library clients, seeing present day discovery systems on the same trajectory as the older online public ...access catalogues (OPACs) which they are gradually replacing, both in technical development and their approach to client use scenarios. It traces the history of the OPAC/discovery system from its origins in the library automation of the 1960s through to the present and discusses the main technical standards which have formed its development. The article goes on to consider questions relating to the usability of electronic library catalogues and highlights semiotic and ethical issues inherent to their design. It concludes with reflections on the future of the OPAC/discovery system in an information universe apparently dominated by the Internet search engine.
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•Low-cost carbon – adsorbent was prepared from orange peel waste by simple method.•The synthesised orange peel activated carbon surface area was 592.471 m2 g−1.•Adsorption mechanism ...and kinetics studies of highly hazardous chlorophenoxy herbicides from aqueous was studied.•Maximum Langmuir capacity of 574.71 mg g−1 was achieved.
This study presents the orange peel activated carbon (OPAC), derived from biowaste precursor (orange peel) by single step pyrolysis method and its application for the adsorption of chlorophenoxyacetic acid herbicides from the water. The OPAC exhibited the surface area of 592.471 m2 g−1, pore volume and pore diameter of 0.242 cc g−1 and 1.301 nm respectively. The adsorption kinetics and thermodynamic equilibrium modelling for all chlorophenoxyacetic acid herbicides were investigated. The various parametric effects such as pH and temperature were evaluated. A pseudo-second-order kinetic model was well fitted for all the herbicides. The Langmuir isotherm was obeyed for all the herbicides and the maximum Langmuir capacity of 574.71 mg g−1 was achieved. The thermodynamic studies revealed that the adsorption increases with increase in temperature. The results shows that the orange peel derived carbon (OPAC) as effective and efficient adsorbent material for the removal of chlorophenoxyacid herbicides from the water.
•Polluted clouds were detected by a novel method based on Gaofen -5 DPC data.•The composition of polluted clouds in different regions was deduced from the regional aerosol composition.•A new idea was ...provided for detecting pollution sources and types.
Large amounts of fine polluted particles due to anthropogenic activities can enter into the lower atmosphere and may pollute the lower water clouds, especially continental cumulus. Continental polluted cumulus (CPCU) plays an important role in the process of atmospheric radiative transfer and the Earth's environmental change. Based on the sensitivity of polarization to small particles, GF-5 DPC data were used to identify polluted clouds. In addition, dynamic transport and composition of polluted clouds were further analyzed. Firstly, a novel method based on two tests was used to identify polluted clouds in China. The source and transport characteristics of the polluted clouds were analyzed by using wind field and backward trajectory pattern. Secondly, based on the monitoring data from the Sun‐sky radiometer Observation NETwork (SONET), the types of atmospheric aerosol composition in China were classified into ten types by considering influences of the climate types, Digital Elevation Model and social economy, etc. Finally, the composition of polluted clouds in different regions was further identified according to regional aerosol composition, and the results were verified by the Optical Properties of Aerosols and Clouds (OPAC) software.
The identifying results of polluted clouds showed that there were four polluted clouds over China on May 27, 2018 and high concentration of small dust particles. The changes in the component ratios of different polluted clouds respond well to the results of airflow sources and transport. Compared with the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) Vertical Feature Mask (VFM) data, the proposed method is effective and robust. The proposed method of identification and composition analysis based on GF-5 DPC data for polluted clouds can enrich the application of DPC data in the field of atmospheric and environmental detection.
•We studied BCRF in ultraviolet, visible, and near-infrared spectra under haze.•ARF and BCRF increase with the development of haze.•Radiative forcing efficiency is weakened by increased forward ...scattering.
The optical properties and radiative forcing of atmospheric aerosol (ARF) and black carbon (BC) aerosol (BCRF) in ultraviolet (UV), visible (VIS), near-infrared (NIR), and shortwave (SW) spectra were investigated under haze conditions based on the observations of the Aethalometer and sun-sky radiometer and simulations from libRadtran. The results show that the BC concentrations increased greatly from 2.73 μg/m3 under clear-air conditions to 7.95 μg/m3 under severe haze conditions, while BC aerosol optical depth (AOD) increased from 0.025 to 0.092. A high correlation (R2=0.62) was found between BC AOD and absorbing aerosol optical depth (AAOD) derived from the sun-sky radiometer. The BCRF in SW (BCRFSW) varied from -10.20 W/m2 under clear-air conditions to -25.40 W/m2 under severe hazy conditions. However, its fraction in ARF (ARFSW) decreased from 19% to 17% simultaneously, which is mainly related to the decrease of the ratio of BC AOD to AOD. The fraction of ARF in VIS in ARFSW decreased from 56.3% under clear-air conditions to 50.5% under severe haze conditions, while the fraction of BCRF in VIS in BCRFSW was much larger, and increased from 72.9% to 73.8%. The BCRF efficiency (BCRFE) was much larger than ARF efficiency (ARFE), and both of them decreased with the development of haze. The ARFE in SW decreased from -173.84 W/m2 under clear-air conditions to -112.75 W/m2 under severe haze conditions while BCRFESW varied from -482.50 W/m2 to -321.88 W/m2. The decrease of ARFE and BCRFE is related to the increase of aerosol loading and asymmetry factor (ASY). The ASY increased and the forward scattering was enhanced with the development of haze due to the hygroscopic growth of aerosol particles, which reduced the extinction efficiency of aerosols including BC on solar radiation and the cooling effect on the surface.
With observations of black carbon (BC) aerosol concentrations, optical and radiative properties were obtained over the urban city of Karachi during the period of March 2006–December 2008. BC ...concentrations were continuously measured using an Aethalometer, while optical and radiative properties were estimated through the Optical Properties of Aerosols and Clouds (OPAC) and Santa Barbra DISORT Atmospheric Radiative Transfer (SBDART) models, respectively. For the study period, the measured BC concentrations were higher during January, February and November, while lower during May, June, July and August. A maximum peak value was observed during January 2007 while the minimum value was observed during June 2006. The Short Wave (SW) BC Aerosol Radiative Forcing (ARF) both at Top of the Atmosphere (ToA) and within ATMOSphere (ATMOS) were positive during all the months, whereas negative SW BC ARF was found at the SurFaCe (SFC). Overall, SW BC ARF was higher during January, February and November, while relatively lower ARF was found during May, June, July and August. Conversely, the Long Wave (LW) BC ARF at ToA and SFC remained positive, whereas within ATMOS it shifted towards positive values (heating effect) during June–August. Finally, the net (SW+LW) BC ARF were found to be positive at ToA and in ATMOS, while negative at SFC. Moreover, a systematic increase in Atmospheric Heating Rate (AHR) was found during October to January. Additionally, we found highest correlation between Absorption Aerosol Optical Depth (AODabs) and SW BC ARF within ATMOS followed by SFC and ToA. Overall, the contribution of BC to the total ARF was found to greater than 84% for the whole observational period while contributing up to 93% during January 2007.
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•Net BC ARF at ToA and in ATMOS were positive while negative at SUR in all months.•Significant correlations between AODabs and BC ARF were observed.•Contribution of BC to the total ARF was found to be greater than 84%.
The concentrations, optical and radiative effects of carbonaceous aerosols were essential to studies of the climatic, environmental and health effects. The previous studies less combined numerical ...simulation with in-situ observations, especially for the aerosol vertical profiles. In this study, we off-line measured vertical profiles of submicron black carbon (BC) aerosols and on-line obtained aerosol optical properties over urban Lanzhou during 26 December 2017 to 11 January 2018. The BC optical properties and radiative effects were evaluated using Optical Properties of Aerosols and Clouds (OPAC) and Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) models. The absorption and scattering coefficients and optical depth of BC aerosols ranged from 9 to 83 M m−1, 3–24 M m−1 and 0.02 to 0.2 respectively, which in average accounted for 50%, 3% and 11% of the optical properties of total aerosols during the study period. BC aerosol radiative forcing (ARF) within ATMOS (top-surface) varying from 16.6 to 108.8 W m−2 accounted for 17.3%–97.4% of total aerosols ARF with an average of 66.6%, and the percentages increased significantly as BC concentrations increased during the period. The mean atmospheric heating rate (AHR) induced by BC aerosols was 1.94 K day−1 ranging from 0.46 to 3.03 K day−1 during the study period. This study contributes to understanding the impacts of light-absorbing aerosols on climate and haze pollution in an urban valley.
•BC optical properties were evaluated using OPAC model.•BC radiative forcing was evaluated using SBDART model.•Besides BC, other light-absorbing aerosols increased during high pollution episodes.•The mean heating rate induced by BC aerosols was 1.9 K day−1 over urban Lanzhou.
3,4-Dihydroxyphenylacetic acid (DOPAC) and 3-hydroxyphenylacetic acid (OPAC) are the predominant catabolites of quercetin glycosides, such as quercetin 4′-O-β-glucoside from the onion, produced by ...intestinal microbiota. Although each catabolite has been reported to protect the cells from acetaldehyde-induced cytotoxicity, the effect of their combination remains to be clarified. The purpose of this study was to determine whether the combination of DOPAC and OPAC enhances the resistance against the acetaldehyde-induced oxidative stress in the cultured hepatocytes. The pretreatment of the combination of DOPAC (5 μM) and OPAC (5 μM) showed significant protection against the acetaldehyde- and hydrogen peroxide-induced cytotoxicity, even though each compound at the same concentration did not. This combination also significantly inhibited the intracellular dichlorofluorescin diacetate-detectable reactive oxygen species (ROS) level, whereas the solo treatment did slightly, suggesting that reducing mechanisms of ROS or compounds that enhance ROS production are involved in the cytoprotective effect. The combinatory treatment significantly enhanced the gene expression of not only the aldehyde dehydrogenases (ALDHs), but also glutamate-cysteine ligase, catalytic subunit, the first rate-limiting enzyme of glutathione (GSH) synthesis. Accordingly, both the intracellular GSH level and the total ALDH activity were enhanced by DOPAC plus OPAC. Involvement of GSH in the cytoprotection as well as ALDH up-regulation by the combination was confirmed by the experiments using a GSH biosynthesis inhibitor, buthionine sulfoximine. Taken together, the present results suggested that the quercetin microbiota catabolites concertedly protect the cells from acetaldehyde through a pre-enhanced resistance against oxidative stress by the GSH-dependent up-regulation of ALDHs.
