Miracle-dz/UniFAR-FTUs huggingface dataset:
On the observability of chemical and physical aerosol properties by optical observations: Inverse modelling with variational data assimilation

Determining size-resolved chemical composition of aerosols is important for modelling the aerosols’ direct and indirect climate impact, for source–receptor modelling, and for understanding adverse health effects of particulate pollutants. Obtaining this kind of information from optical remote sensing observations is an ill-posed inverse problem. It can be solved by variational data assimilation in conjunction with an aerosol transport model. One important question is how much information about the particles’ physical and chemical properties is contained in the observations. We perform a numerical experiment to test the observability of size-dependent aerosol composition by remote sensing observations. An aerosol transport model is employed to produce a reference and a perturbed aerosol field. The perturbed field is taken as a proxy for a background estimate subject to uncertainties. The reference result represents the ‘true’ state of the system. Optical properties are computed from the reference results and are assimilated into the perturbed model. The assimilation results reveal that inverse modelling of optical observations significantly improves the background estimate. However, the optical observations alone do not contain sufficient information for producing a faithful retrieval of the size-resolved aerosol composition. The total mass mixing ratios, on the other hand, are retrieved with remarkable accuracy.
(Henry B. Linford Award for Distinguished Teaching Address) Low Temperature Plasma Etching of Copper, Silver, and Gold Films

Copper, silver and gold films possess unique electrical and optical properties that render them suitable for various device structures as employed in integrated circuits and plasmonic devices. Traditional etching of these metal films in halogenated plasmas is difficult due to the low vapor pressure of halogenated metal species. Reasonable etch rates of Cu, Ag, and Au films are obtained with hydrogen-based plasmas. Pattern formation with hydrogen and methane plasmas yields excellent selectivity to barrier materials such as Ta and Ti and generates metal wall slopes of ~80 o . This paper describes a plasma-enhanced approach to patterning of Cu, Ag, and Au films that can be employed at room temperature and below, and that may alleviate some limitations in the fabrication of future devices and circuits.
Application of neural network prediction model to full‐scale anaerobic sludge digestion

BACKGROUND: Process modeling is a useful tool for description and prediction of the performance of anaerobic digestion systems under varying operation conditions. The objective of this study was to implement a model to simulate the dynamic behavior of a large-scale anaerobic sewage sludge digestion system. Artificial neural network (ANN) models using algorithms best suited to environmental problems (the Levenberg–Marquardt algorithm and the ‘gradient descent with adaptive learning rate’ back propagation algorithms) were used to model the anaerobic sludge digester of the Ankara Central Wastewater Treatment Plant (ACWTP) using dynamic data. RESULTS: Based on the relatively low mean square error (MSE), mean absolute error (MAE) and mean absolute percentage error (MAPE) and very high r values, ANN models predicted effluent volatile solid (VS) concentration and methane yield satisfactorily. Effluent VS and methane yields were predicted by the ANN using only conventional parameters such as pH, temperature, flow rate, volatile fatty acids, alkalinity, dry matter and organic matter. The best back propagation algorithm was the gradient descent with adaptive learning rate algorithm in both models. In the training of the neural network, four-fold cross-validation was used for validation of the model for better reliability. CONCLUSION: The proposed ANN models were shown to be capable of dynamically predicting the VS and CH4 production rates for real system behavior. Only relatively simple monitoring parameters are needed to build the model for this complex anaerobic digestion process. Copyright © 2011 Society of Chemical Industry
Effects of partial substitution of Ni by Pd on the thermoelectric properties of ZrNiSn-based half-Heusler compounds

We report on the effects of partial substitution of nickel by palladium on the thermoelectric properties of ZrNiSn-based half-Heusler compounds. It is shown that the substitution of palladium for nickel results in a significant, beneficial reduction of the thermal conductivity. The Seebeck coefficient also decreases, but only by a small amount. In the Hf0.5Zr0. 5Ni0.8Pd0. 2Sn0.99Sb0. 01 compound, a power factor of 22.1 μW K−2 cm−1 and a thermal conductivity as low as 4.5 W/m K are measured at room temperature. The dimensionless figure of merit ZT increases with increasing temperature and reaches a maximum value of 0.7 at about 800 K.
Impact of Public Expenditure on Climate Change in Nigeria: Lessons from South Africa

: This paper examines the role of public expenditure in enhancing climate change adaptation and mitigation in Nigeria. It examines the trend of carbon dioxide (CO 2 ) in Nigeria alongside those of South Africa and Sub Saharan Africa and investigates the statistical relationship between public expenditure and climate change in Nigeria. The paper hinges on the Climate Public Expenditure and Institutional framework of the Oversee Development Institute (ODI), which argues that climate change, has fiscal implications and can be addressed using national plans and annual budgets. Time series data were then collected for emission, public expenditure, human development index and economic growth from the World Bank and the Central Bank of Nigeria for 1970-2008, while trend analysis and lag regression model were used for data analysis. It was found that public expenditure towards economic services could be used to enhance Nigeria’s climate change mitigation and adaptation strategies. Though economic growth and human development index were found to be positively related to emission, results imply that economic growth in Nigeria is not pursued in a sustainable manner that accounts for the future generation. The paper recommends that economic growth that is driven by investment in renewable energy, developing human capacity to adapt to climate change and coordinating public expenditure to economic and community services to develop rural communities and vulnerable sectors like agriculture, would be useful for addressing climate change in Nigeria and ensuring sustainable development. A lesson Nigeria can learn from climate change mitigation and adaptation measures in South Africa is to identify and prioritize short term and medium term adaptation interventions to be addressed in sector plans such as water, agriculture and forestry, health, biodiversity and human settlements. minimum emission year over the sample period was 1961 at 5.694383. Looking at the trend of emission for South Africa and Nigeria, statistics shows that South Africa has made effort to stabilize its CO 2 emission since the adoption of the Kyoto protocol in 1997 by 37 countries 1 while that of Nigeria has remained volatile. Although South Africa ratified 2 the Kyoto protocol on the 31 July 2002, the deduction here is that South Africa compared to Nigeria, has contributed to global efforts to cut down emission than Nigeria. Differencing both trends reveals the volatility in their emission rate over time.
ELECTROCHEMICAL CHARACTERIZATION OF CARBON PASTE ELECTRODES MODIFIED WITH NATURAL ZEOLITE

A comparative study between carbon paste electrodes (CPE) modified with natural zeolite (ZMCPE, 20 and 50 wt.% clinoptilolite as a major phase) and unmodified CPE (UCPE) is reported. The electro-oxidation of reactive azo-dye (C.I. Reactive Blue 69) was used as a probe to evaluate the performance of these materials. In order to understand the electro-catalytic behavior, cyclic voltammetry (CV), linear sweep voltammetry (LSV), and real time (i-t) techniques were performed. It was found that ZMCPE presents different anodic processes in both free and azo-dye based solutions as a function of zeolite concentration, compared to UCPE. According to the i-E characteristic, in a solution containing azo-dye compound, ZMCPE (50 wt.% oz zeolite) presents major catalytic activity in acid conditions, as revealed by UV-vis spectroscopy. Particle size-shape distribution and structural-textural properties in the zeolite framework and onto the CPE bulk, compared to UCPE electrodes, promote this catalytic effect.
Theoretical, Structural, Vibrational, NMR, and Thermal Evidence of the Inter- versus Intramolecular Hydrogen Bonding in Oxamides and Thiooxamides

This contribution describes the study of hydrogen bonding in secondary oxamides, monothiooxamides, and dithiooxamides by ab initio calculations, X-ray diffractions, NMR spectra, thermal analysis, and variable- temperature infrared and Raman spectroscopy. The results can all be interpreted as a function of the change in the strength and the nature of the hydrogen bonding by substituting oxygen for sulfur in the series CH 3- HNCOCONHCH 3 ,C H 3HNCSCONHCH 3 ,C H 3HNCSCSNHCH3 and by changing the steric influence of the alkyl group in a series of oxamides (RHNCOCNHR; R ) CH3 ,C 2H5 ,i C 3H7 ,t C 4H9). In this work, we studied the change in the character of the hydrogen bonding in two series of original compounds. The hydrogen bonding has been studied using different techniques. X-ray structures and ab initio calculations give direct information because the most reliable criterion is based on the van der Waals radii 1 and also the angle involved in the hydrogen bonding. 2 Vibrational spectroscopy has always been the main experimental method in the study of hydrogen bonding, and we obtained very valuable information from the temperature-dependent solid-state spectra, 3-5 especially when solubility problems were encoun- tered. Concentration- and temperature-dependent NMR spectro- scopy 6-23 and especially the enthalpies confirm the trend indicated by X-ray and vibrational spectroscopy between inter- and intramolecular character, as indicated by structural and vibrational spectroscopy. The comparison of these different techniques clearly shows that infrared and Raman spectroscopy are the best techniques for these typical kinds of studies; the other techniques used in this work also give important information throughout the whole study. The compounds under investigation are original oxamides, thiooxamides, and dithiooxamides. These molecules form an important group of ligands in coordination chemistry. 24 A remarkable characteristic of these ligands is their thermal and chemical stability and especially their dissociation constants. 25 The very important role of hydrogen bonding in these various characteristics has been extensively studied. 5,26-32
The adsorption of whey proteins on the surface of emulsified fat.

Whey proteins adsorbed on fat globule surfaces during emulsification with coconut oil at pH 3 ~ 9 were examined. The amount of proteins adsorbed on the fat surface was dependent on the pH during emulsification. At any pH examined here, however, tightly-adsorbed proteins which were not extracted from the fat surface with urea or guanidine-HCl were 2 ~ 3 mg/m2. Marked selectivities in the adsorption of individual whey proteins were observed at any pH. No correlation between the adsorbabilities and the surface hydrophobicities of individual whey proteins was observed. Whey proteins adsorbed on the emulsified fat were much more easily digested with proteases compared to the native whey proteins, indicating that conformational changes of whey proteins occurred at the fat surface. The results suggested that conformational properties, such as flexibility of the structure, of whey proteins are important in the adsorption and possibly affect their emulsifying ability.
Determination of Chromium(VI) by Batch Injection Analysis and Adsorptive Stripping Voltammetry

Abstract A new sensitive voltammetric method is presented for the determination of trace levels of Cr(VI). The method is based on square wave adsorptive stripping voltammetry (AdSV) in conjunction with the electrochemical batch injection analysis technique at mercury thin-film electrodes. The determination of chromium is made in the presence of cupferron as ligand. Relevant experimental parameters are explored and optimized, such as injection mode, cupferron concentration, accumulation potential and time, and square wave parameters. A preconcentration time of 20 s at −0.8 V vs. SCE results in a detection limit of 32 nM. The relative standard deviation for 12 measurements of 0.12 µM was 6.5%. Possible interferences by other trace metals are considered.
Environmental and Medical Assessment of Stevedores Employed in Ferry Operations

Abstract The exposure of stevedores employed in ferry operations to a range of diesel and gasoline exhaust constituents was assessed. The exhaust constituents quantified included total particulate, polycyclic aromatic hydrocarbons (PAH), aldehydes, oxides of nitrogen, sulfur dioxide, and carbon monoxide. In addition, acute and chronic respiratory effects of stevedores relative to a control population of port office workers were assessed. Air sampling was conducted on board the ferry on two successive evenings. The exposure of the control group to these contaminants was also measured. Total particulate was determined gravimetrically, while PAH were determined by high performance liquid chromatographic (HPLC) analysis of the cyclohexane soluble fraction of particulate material. ldehydes were collected on SEP-PAK™ C18 cartridges treated with 2,4-dinitrophenyl-hydrazine and analyzed by HPLC. Exhaust gases were determined by frequent grab sampling using detector tubes. Medical assessment of stevedores and cont.
Molecular simulations of self-assembly processes of amphiphiles in dilute solutions: the challenge for quantitative modelling

We report on two recent developments in molecular simulations of self-assembly processes of amphiphilic solutions. We focus on the determination of micelle formation of ionic surfactants which exhibit the archetype of self-assembling compounds in solution. The first approach is centred on the challenge in predicting micellisation properties through explicit solvent molecular dynamics simulations. Even with a coarse-grained (CG) approach and the use of highly optimised software packages run on graphics processing unit hardware, it remains in many cases computationally infeasible to directly extract the critical micelle concentration (cmc). However, combined with a recently presented theoretical mean-field model this task becomes resolved. An alternative approach to study self-assembly is through implicit solvent modelling of the surfactants. Here we review some latest results and present new ones regarding capabilities of such a modelling approach in determining the cmc, and the aggregate structures in the dilute regime, that is currently not accessible through explicit solvent simulations, neither through atomistic nor through CG approaches. A special focus is put on surfactant concentration effects and surfactant correlations quantified by scattering intensities that are compared to recently published small-angle X-ray scattering data.
Hollow Metallic Microspheres: Fabrication and Characterization

Hollow metallic nickel spheres with an average diameter of 1.8 μm have been successfully synthesized via a decomposition and reduction route by using hollow nickel hydroxide spheres as precursor. Microsized hollow bimetallic (Ni/Au, Ni/Ag, Ni/Pt, and Ni/Pd) and noble metal (Pt and Pd) spheres have also been selectively synthesized by adjusting the amount of reactants of replacement reaction in which corresponding noble metal compound and hollow metallic nickel spheres were used as starting materials. The magnetic properties of hollow metallic nickel spheres have been investigated. It is found that the coercivity of hollow Ni spheres is much enhanced compared with their bulk counterparts. The study on catalytic activities of the as-prepared hollow noble metal spheres for hydrogen generation reveals that Ni/Pt hollow bimetallic spheres exhibit favorable catalytic activities which have potential applications in portable hydrogen generation systems.
Solid‐state NMR of bisphosphonates adsorbed on hydroxyapatite

Solid‐state 31P and 13C magic angle spinning (MAS) NMR spectra were used to characterize pure bisphosphonates and also bisphosphonates adsorbed on hydroxyapatite. Four geminal bisphosphonates, including the clinically used compounds ethane‐1‐hydroxy‐1,1‐diphosphonic acid, 3‐amino‐1‐hydroxypropane‐1,1‐diphosphonic acid and 4‐amino‐1‐hydroxybutane‐1,1‐diphosphonic acid, five α,ω‐bisphosphonates and phosphonoacetic acid were investigated. NMR spectra of pure and adsorbed bisphosphonates differ in the observed linewidths and in the isotropic chemical shifts. The broad lines reflect mainly the poor crystallinity of the adsorbed compounds. Shifts of δiso in both directions do not reveal a correlation with the molecular structures. The molar ratio of phosphonates adsorbed on hydroxyapatite determined by 31P spectra without cross‐polarization (CP) is approximately two times larger for geminal bisphosphonates than for α,ω‐bisphosphonates and phosphonoacetic acid. 13C CP/MAS spectra of pure and adsorbed bisphosphonates recorded in two cases for identification of adsorbed compounds give additional information about the state of adsorbed compounds. Disodium α,ω‐dihydroxypolymethylene‐α,ω‐bisphosphonates in the solid state show characteristic 13C chemical shifts which are indicative of either odd or even numbers of CH2 groups. Copyright © 2000 John Wiley & Sons, Ltd.
Complete dissolution and partial delignification of wood in the ionic liquid 1-ethyl-3-methylimidazolium acetate

Both softwood (southern yellow pine) and hardwood (red oak) can be completely dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim]OAc) after mild grinding. Complete dissolution was achieved by heating the sample in an oil bath, although wood dissolution can be accelerated by microwave pulses or ultrasound irradiation. It has been shown that [C2mim]OAc is a better solvent for wood than 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) and that variables such as type of wood, initial wood load, particle size, etc. affect dissolution and dissolution rates; for example, red oak dissolves better and faster than southern yellow pine. Carbohydrate-free lignin and cellulose-rich materials can be obtained by using the proper reconstitution solvents (e.g., acetone/water 1 : 1 v/v) and approximately 26.1% and 34.9% reductions of lignin content in the reconstituted cellulose-rich materials (from pine and oak, respectively) have been achieved in one dissolution/reconstitution cycle. The regenerated cellulose-rich materials and lignin fractions were characterized and compared with the original wood samples and biopolymer standards. For pine, 59% of the holocellulose (i.e., the sum of cellulose and hemicellulose) in the original wood can be recovered in the cellulose-rich reconstituted material; whereas 31% and 38% of the original lignin is recovered, respectively, as carbohydrate-free lignin and as carbohydrate-bonded lignin in the cellulose-rich material.
An HPLC/ICPMS study of the stability of selenosugars in human urine: implications for quantification, sample handling, and storage

We report a study with HPLC/ICPMS on the long-term stability of the major selenium metabolite in human urine, namely methyl 2-acetamido-2-deoxy-1-seleno-β-D-galactopyranoside (selenosugar 1). Three separate experiments were performed of 4–28 weeks duration and incorporating various storage conditions: room temperature, 4 °C, −20 °C, −80 °C, lyophilisation, deoxygenation, or addition of a bactericide (NaN3). Triplicate samples of urine or water, spiked with selenosugar 1 at 200 μg Se L−1, were processed in each case. Selenosugar 1 was stable in water under all investigated conditions. For the urine samples, no significant degradation (<2%) was observed after 17 weeks frozen storage at −80 °C, or after lyophilisation and frozen storage at −20 °C, whereas small quantities of degradation products (ca. 3%) were recorded for frozen storage of wet samples at −20 °C. At 4 °C, the selenosugar was essentially unchanged after storage for up to 2 weeks, but clear losses were observed thereafter ranging up to 75% loss after 28 weeks. Several decomposition products were detected by HPLC/ICPMS, one of which was identified as dimethyl diselenide. Although present as only a trace constituent in the urine, dimethyl diselenide was recorded as a large HPLC peak, presumably because of a marked vapour enhancement effect due to more efficient transfer of volatile analytes to the plasma. In addition, total Se analyses revealed that Se was lost from the solutions during storage/handling, presumably as volatile species. Qualitative analysis of volatile species using head space sampling with solid phase microextraction followed by GC/MIP-AES and GC/MS revealed the presence of dimethyl selenide and dimethyl diselenide, based on comparison with standard compounds, and indicated the presence of dimethyl selenylsulfide based on comparison with literature data. The stability of selenosugar 1 and its isomer methyl 2-acetamido-2-deoxy-1-seleno-β-D-glucopyranoside (selenosugar 2), which occurs as a minor species in urine, was also investigated under room temperature storage in the presence and absence of light. Although both species were moderately stable when stored in the dark, their degradation was rapid in the light with clear losses recorded within three days. The work indicates that urine samples should be cooled immediately after collection, and that they may be stored at 4 °C (often the easiest way) for up to 2 weeks before analysis with no appreciable loss of selenosugar. For longer-term storage, urine samples should be kept at −80 °C or, when such facilities are not available, at −20 °C after lyophilisation. The study has also revealed potential quantification problems in Se speciation analysis resulting from different responses for Se species during ICPMS analysis.
Antibiotic resistance profiles of Escherichia coli isolated from rural and urban environments

Abstract Sludge and waste water samples from a variety of locations (in the United States and from one location in Mexico) were evaluated to determine whether multiple antibiotic resistant resistance patterns correlated with location and type of waste. The occurrence of antibiotic resistant strains of Escherichia coli was dependent upon site among the eleven locations sampled (P < 0.001). The E. coli strains from digested municipal sewage sludge from El Paso, Texas and those from an El Paso army hospital were resistant to the widest range of antibiotics and were resistant to a greater number of antibiotics than any other site (P < 0.01). When isolates from undigested waste water samples were analyzed, there was no significant difference (P ≥ 0.05) between those obtained from two neighboring cities located on either side of the US‐Mexico border. There was no significant difference in the number of antibiotics to which isolates were resistant when comparing digested sewage sludge samples from rural and urba.
Numerical Modeling of Wire and Tube Condenser Used in Domestic Refrigerators

This paper present modeling of wire and tube condensers that are commonly used in vapour compression cycle based domestic refrigeration. A simulation model was developed by using the finite element with a combination of thermodynamic correlations. The application of this model used in the design of condenser in vapour compression cycle with new refrigerant.