bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic structure and electric field gradient calculations for the Zr2Ni intermetallic compound
Authors: Umićević A. , Belošević-Čavor J. , Koteski V. , Cekić B. , Ivanovski V.
Published: September 2009

A detailed theoretical study of the structure and electric field gradients (EFG) of the Zr2Ni compound is presented. Using all-electron augmented plane waves plus local orbitals formalism, the equilibrium volume, bulk modulus, and EFGs at both non-equivalent crystallographic positions, Zr and Ni, are calculated. The possible mechanism of formation of the EFGs at both sites are analyzed and discussed. We have also performed supercell calculations with Cd and Ta impurities. Through the comparison of theoretical and experimental EFGs in these cases, we elucidate the role played by the Cd and Ta probe atoms in the time-differential perturbed angular correlation measurements of this compound.
Solution growth of the Gd–Cu–Al systems in the low-gadolinium concentration range
Authors: Uhlířová Klára , Sechovský Vladimír
Published: September 2009

Solution growth of Gd–Cu–Al resulted in the formation of single crystals of GdCu4Al8 with tetragonal ThMn12-type structure (a = 8.751 Å, c = 5.148 Å), Gd2Cu9.4 – 6.7Al7.6 – 10.3 with hexagonal Th2Zn17-type structure (a = 8.83 Å, c = 1.28 Å), and Gd(Cu, Al)4 with orthorhombic CeNi2+x
Sb2 – x
-type structure. An antiferromagnetic ordering of GdCu4Al8 was found below 35 K, which is in agreement with the previously reported TN = 35 K and TN = 32 K measured on polycrystalline samples. In the temperature range 50 – 320 K the magnetic susceptibility χ follows the Curie–Weiss law with μeff = 7.8 μB/f. u. and θp = – 17 K for B c, μeff = 7.9 μB/f. u. and θp = – 18 K for B ⊥ c. The a-axis is the easy magnetization direction. The Gd(Cu, Al)4 and Gd(Cu, Al)4 compounds order antiferromagnetically below TN = 35 K and TN = 31 K, respectively.
Novel behaviors in rare-earth-filled skutterudites studied by bulk-sensitive photoemission spectroscopy
Authors: Yamasaki Atsushi , Imada Shin , Sekiyama Akira , Fujiwara Hidenori , Yano Masao , Yamaguchi Junichi , Miyamachi Toshio , Sugawara Hitoshi , Kikuchi Daisuke , Sato Hideyuki , Muro Takayuki , Higashiya Atsushi , Yabashi Makina , Tamasaku Kenji , Ishikawa Tetsuya , Harima Hisatomo , Suga Shigemasa
Published: September 2009

The electronic structures of rare-earth-filled skutterudites have been investigated by high-resolution photoemission spectroscopy. In order to reveal their bulk nature, the bulk-sensitive photoemission spectroscopy with soft X-ray (hv∼800 – 1100 eV) and hard X-ray (hv∼8000 eV) is a very powerful tool since the rare-earths' valence and electronic structures on the surface are often different from those in the bulk. Our experimental results clearly show the coexistence of the strongly mixed-valence state and the heavy-fermion state in SmOs4Sb12 and the quasi-particle peak near the Fermi level in PrFe4P12 induced by the hybridization between the rare-earth 4f and conduction electrons.
Enrichment and depletion of alloying elements in surface layers of iron base alloys annealed under different conditions
Authors: Suzuki Shigeru , Yamamoto Takamichi , Fukai Hiroyuki , Shinoda Kozo
Published: September 2009

X-ray photoelectron spectroscopy (XPS), electron microprobe microanalysis (EPMA), and secondary ion mass spectrometry (SIMS) have been used for analyzing the chemical composition in surface layers of iron-base alloys. Samples analyzed in this study were a ferritic Fe–Mn alloy annealed under low partial pressure of oxygen and an austenitic Fe–Mn–Si–Cr alloy annealed under vacuum. The XPS results showed that manganese was enriched and oxidized while iron was metallic in the surface layer of the Fe–Mn alloy annealed under a low partial pressure of oxygen. The EPMA results showed that manganese was depleted while chromium was enriched in the surface layer of the Fe–Mn–Si–Cr alloy annealed under vacuum. The SIMS depth profiles coupled with the EPMA results indicated that the enrichment of chromium in the surface layer improves the oxidation resistance of the alloy. The enrichment and depletion of manganese in the surface layer is discussed on the basis of the thermodynamic properties of the iron–manganese system.
Electrochemical properties of fine-grained AZ31 magnesium alloy
Authors: Hadzima Branislav , Janeček Miloš , Bukovina Michal , Král Robert
Published: September 2009

The influence of equal channel angular pressing (ECAP) on the microstructure changes of magnesium alloy AZ31 was investigated. The microstructure changes were correlated with electrochemical characteristics of the surface. Eight passes of ECAP resulted in significant grain refinement (factor 100) of the initial squeeze-cast (SC) alloy. The influence of microstructure changes on electrochemical properties of the surface was evaluated using electrochemical impedance spectroscopy. The variation of electrochemical characteristics of the surface of the SC and ECAP alloy was determined after 3 and 7-day exposure in the corrosion solution of 0.1 M NaCl. The fine-grained deformed structure after ECAP was found to have significantly higher charge transfer resistance as compared to the squeeze-cast material.
Testing crevasse-depth models: a field study at Breiðamerkurjökull, Iceland
Authors: Mottram Ruth H. , Benn Douglas I.
Published: September 2009

Interest in crevasses and associated ice-fracture processes has recently increased due to recognition of the importance of calving glaciers to the mass balance of the cryosphere, as well as the importance of fractures in glacier hydrology. Recently developed calving criteria make use of models which predict crevasse depth from surface strain rates, but these models have rarely been tested against observations. In this study, we present data on crevasse depth and surface strain rates, and compare the measured values with results of two crevasse-depth models: a simple function proposed by Nye and a linear elastic fracture mechanics (LEFM) model developed by Van der Veen. Our results indicate that both models predict crevasse depths within the correct order of magnitude. The LEFM model, incorporating measured values of crevasse spacing and tuned for fracture toughness, performs better in predicting crevasse depths, but where lack of input data precludes such tuning, the results are similar to Nye’s model predictions. We conclude that both models may be used to calculate crevasse depths in calving models, although the Nye function is undoubtedly much simpler to implement within an ice-dynamics model.
Numerical analysis of rapid water transfer beneath Antarctica
Authors: Peters Nial J. , Willis Ian C. , Arnold Neil S.
Published: September 2009

We use a simple energy-conservation model and a model based on Röthlisberger’s theory for steady-state water flow in a subglacial conduit to model water movement between lakes in the Adventure subglacial trench region of East Antarctica during a 1996–98 jökulhlaup. Using available field evidence to constrain the models suggests that water flow would likely be accommodated in a tunnel with a cross-sectional area of 36 m2 and a value for k (the reciprocal of Manning’s roughness parameter) larger than the 12.5 m1/3 s−1 previously calculated. We also use Nye’s theory for time-dependent conduit water flow to model the temporal evolution of conduit discharge, cross-sectional area, water pressure and lake draining and filling during the flood. We initially assume one source and one sink lake. We perform sensitivity tests on the input parameter set, matching modeled source- and sink-lake depth changes with measured surface elevation data. Using a simple function for vertical ice deformation in which surface deformation scales linearly to the lake depth change, we find the scaling factor is of the order 4 × 10−3 of the ice thickness. The most likely value of k lies in the range 55–68 m1/3 s−1, and the ratio of source to sink-lake radii is approximately 1 : 1.4. Finally, we experiment using Nye’s theory to model water movement between one source and three sink lakes. The model fails to produce the observed patterns of water movement as indicated by the surface deformation data.
A new glacier inventory for the Svartisen region, Norway, from Landsat ETM+ data: challenges and change assessment
Authors: Paul Frank , Andreassen Liss M.
Published: September 2009

Glaciers are widely recognized as key indicators of climate change, and their meltwater plays an important role in hydropower production in Norway. Since the last glacier inventory was compiled in northern Norway in the 1970s, marked fluctuations in glacier length and mass balance have been reported for individual glaciers, and the current overall glacier state is thus not well known. Within the framework of the Global Land Ice Measurements from Space (GLIMS) initiative, we have created a new inventory for 489 glaciers in the Svartisen region, northern Norway, using a Landsat Enhanced Thematic Mapper Plus (ETM+) satellite scene from 7 September 1999 and automated multispectral glacier mapping (thresholded band ratios). In addition, visual inspection and correction of the generated glacier outlines has been applied. Adverse snow conditions and uncertain drainage divides made glacier mapping challenging in some regions of the study site. Glacier outlines from 1968, as digitized from a topographic map, were used for a quantitative change assessment for a selection of 300 glaciers. The overall area change of this sample from 1968 to 1999 was close to zero, but with a strongly increasing scatter towards smaller glaciers, large area gains (>50%) for small glaciers (<1 km2), and an unexpected stronger relative area loss towards the wetter coast. The overall size changes are small (<1%) for the three largest ice masses in the study region (Vestisen, Østisen and Blåmannsisen).
Dermatological Patients at the Outdoor of an Upazila Health Complex
Authors: Kabir M Rizaul , Khan M Abdul Kuddus , Karmakar Ananda Kumar
Published: September 2009

In outdoor of Adamdighi Upazila Health & Family Welfare Complex of Bogra district, the attendance of patients suffering from skin and venereal diseases were observed. Out of total 1,54,843 patients, 23,820 patients were suffering from various forms of dermatological diseases. The percentage of patients suffering from skin and venereal diseases were 15.34 %. Female patients were 13,667 in number (57.38%) and male patients were 10,153 in number (42.62%). Male, female ratio is 1.35:1. Most of the patients were suffering from dermatological diseases attending outdoor of the said health complex belong to 14 years and above age group (67.53%). It was observed that though previously most of the rural people neglected their skin diseases, but now a day, a good number of patients of the rural areas are conscious about their skin conditions and attend outdoor of health and family welfare complex.   doi: 10.3329/taj.v17i2.3453   TAJ 2004; 17(2): 93-94
Interferon to PEG-Interferon: A Review
Authors: Ahad MA , Alim MA , Ekram ARM Saifuddin
Published: September 2009

The interferons (IFNs) are group of naturally occurring cytokines that are secreted by cells of mammalian immune system when they are stimulated by viral, bacterial and other antigens. There are number of alpha IFNs available for treatment purposes. The two most commonly used α-2a and α-2b are made by recombinant technology. When interferon Alpha-2a is combined with polyethylene glycol (PEG), it is known as pegylated interferon or PEG interferon. Polyethylene glycol (PEG) is a safe, inert and nontoxic molecule. Therapeutic benefits of altering proteins with PEG include an improvement in half-life due to reduced renal and cellular clearance, enhanced protection from proteolysis and a reduction in toxicity.   doi: 10.3329/taj.v17i2.3460   TAJ 2004; 17(2): 113-116
Chromosomal Location of Traits Associated with Wheat Seedling Water and Phosphorus Use Efficiency under Different Water and Phosphorus Stresses
Authors: Cao Hong-Xing , Zhang Zheng-Bin , Sun Cheng-Xu , Shao Hong-Bo , Song Wei-Yi , Xu Ping
Published: September 2009

The objective of this study was to locate chromosomes for improving water and phosphorus-deficiency tolerance of wheat at the seedling stage. A set of Chinese Spring- Egyptian Red wheat substitution lines and their parent Chinese Spring (recipient) and Egyptian Red (donor) cultivars were measured to determine the chromosomal locations of genes controlling water use efficiency (WUE) and phosphorus use efficiency (PUE) under different water and phosphorus conditions. The results underlined that chromosomes 1A, 7A, 7B, and 3A showed higher leaf water use efficiency (WUEl = Pn/Tr; Pn = photosynthetic rate; Tr = transpiration rate) under W-P (Hoagland solution with1/2P), -W-P (Hoagland solution with 1/2P and 10% PEG). Chromosomes 7A, 3D, 2B, 3B, and 4B may carry genes for positive effects on individual plant water use efficiency (WUEp = biomass/TWC; TWC = total water consumption) under WP (Hoagland solution), W-P and -W-P treatment. Chromosomes 7A and 7D carry genes for PUE enhancement under WP, -WP (Hoagland solution with 10% PEG) and W-P treatment. Chromosome 7A possibly has genes for controlling WUE and PUE simultaneously, which indicates that WUE and PUE may share the same genetic background. Phenotypic and genetic analysis of the investigated traits showed that photosynthetic rate (Pn) and transpiration rate (Tr), Tr and WUEl showed significant positive and negative correlations under WP, W-P, -WP and -W-P, W-P, -WP treatments, respectively. Dry mass (DM), WUEP, PUT (phosphorus uptake) all showed significant positive correlation under WP, W-P and -WP treatment. PUE and phosphorus uptake (PUT = P uptake per plant) showed significant negative correlation under the four treatments. The results might provide useful information for improving WUE and PUE in wheat genetics.
Life-Cycle Assessment and the Environmental Impact of Buildings: A Review
Authors: Khasreen Mohamad  Monkiz , Banfill Phillip F. G. , Menzies Gillian  F.
Published: September 2009

Life-Cycle Assessment (LCA) is one of various management tools for evaluating environmental concerns. This paper reviews LCA from a buildings perspective. It highlights the need for its use within the building sector, and the importance of LCA as a decision making support tool. It discusses LCA methodologies and applications within the building sector, reviewing some of the life-cycle studies applied to buildings or building materials and component combinations within the last fifteen years in Europe and the United States. It highlights the problems of a lack of an internationally comparable and agreed data inventory and assessment methodology which hinder the application of LCA within the building industry. It identifies key areas for future research as (i) the whole process of construction, (ii) the relative weighting of different environmental impacts and (iii) applications in developing countries.
Environmental Strategies for Electrical and Electronic Equipment Supply Chains: Which to Choose?
Authors: Georgiadis Patroklos , Besiou Maria
Published: September 2009

Waste electrical and electronic equipment is one of the major world-wide waste streams triggering the emergence of environmental strategies. Environmental regulations, closed-loop supply chain (CLSC) activities and design-for-environment (DfE) practices are environmental friendly strategies being implemented by governments and industry. In this paper, we apply a System Dynamics model to a CLSC of electrical and electronic equipment in Greece. Extensive numerical investigation provides insights regarding the impact of different legislative measures, CLSC activities and DfE practices on the environmental (availability of natural resources and landfills) and economic sustainability.
Preparation and Diels–Alder/cross coupling reactions of a 2-diethanolaminoboron-substituted 1,3-diene
Authors: Wang Liqiong , Day Cynthia S , Wright Marcus W , Welker Mark E
Published: September 2009

A 2-diethanolamine boronyl substituted 1,3-diene has been synthesized in high yield and characterized spectroscopically as well as by X-ray crystallography. This diene has then subsequently been used in a number of fast, high yielding Diels–Alder/cross coupling reactions.
Questions-Bank System to Enhance E-Learning in School Education
Authors: El-Sofany Hosam Farouk , El-Seoud Samir A. , Ghaleb F. F. M. , Ibrahim Shaima , Al-Jaidah Noor
Published: September 2009

The assessment process in an educational system is an important and essential part of its success to assure the correct way of knowledge transmission and to ensure that students are working correctly and succeed to acquire the needed knowledge. This paper describes the analysis, design, and implementation of the Questions-Bank system, that allows the students of primary, preparatory, and secondary schools to take web-based quizzes and exams, to download course reviews, and previous exams. "Questions-Bank", means that each question has a weight and area of knowledge deals with it. The system facilitates generation of automatic, balanced, and different exam sheets, that containing different types of questions, covering the entire curriculum, and displaying gradually from easiness to difficulty. The exam sheet produced by the system, takes into account the different levels of the students from excellent, good, to fair, and avoids any mistakes of language and non-clear terminologies. The system allows the schools to create a Questions-Bank database, that stores the previous exams, the model answers, the reviews, and useful exercises for each course. Our system is used successfully in distance learning as well as in self-training. We have tested the system with different type of courses taught in Qatari schools, ranged from primary to secondary levels. The feedbacks of both teachers and students were highly promising.
Preferential fluid flow pathways in embankment dams imaged by self‐potential tomography
Authors: Bolèkve J. , Revil A. , Janod F. , Mattiuzzo J.L. , Fry J.‐J.
Published: September 2009

We invert self‐potential data in order to locate anomalous water flow pathways in dams and embankments and to estimate the seepage velocity. The inversion of the self‐potential data is performed using the modified singular value decomposition for the inverse problem using a linear formulation of the forward problem. The kernel is solved numerically accounting for the topography of the system and the resistivity distribution, which is independently obtained through electrical resistance tomography. A prior constraint based on finite element modelling of ground water flow can also be used to provide a prior source current density model if needed. This self‐potential tomography approach is first validated with a synthetic case study showing how the position of a preferential fluid flow pathway can be retrieved from self‐potential and resistivity data and how the seepage velocity can be obtained inside one order of magnitude. This methodology is then applied to a test site corresponding to a portion of an embankment dam along the Rhône River in France. Two self‐potential maps (with 1169 and 2076 measurements, respectively) and four resistivity tomograms are used to locate a leak. One self‐potential profile and one resistivity profile are used together to perform the 2D inversion of the self‐potential data to locate the anomalous leakage at depth and to estimate the flow rate. The depth at which the preferential fluid flow pathway is located, according to self‐potential tomography, agrees with an independent geotechnical test using the Perméafor. This demonstrates the usefulness of this methodology to detect preferential water channels inside the body of a dam.
Monitoring the hydrologic behaviour of a mountain slope via time‐lapse electrical resistivity tomography
Authors: Cassiani G. , Godio A. , Stocco S. , Villa A. , Deiana R. , Frattini P. , Rossi M.
Published: September 2009

Catchment and hillslope hydrology is a major research area in geoscience and the understanding of its underlying processes is still poor. Direct investigation of steep hillslopes via drilling is often infeasible. In this paper, we present the results of non‐invasive time‐lapse monitoring of a controlled infiltration test at a site in the Italian Central Alps. The hillslope considered is steep (30–35°), covered with grass and a soil layer 1–1.5 m thick above a variably fractured metamorphic bedrock. The key hydrologic question is whether rainfall infiltrates mainly into the underlying fractured bedrock, thus recharging a deeper hydraulic system, or flows in the soil layer as interflow towards the stream channel a few hundred metres downhill. In order to respond to this question, we applied 2200 mm of artificial rain on a 2 m × 2 m slope box over about 18 hours. We estimated the effective infiltration by subtracting the measured runoff (7% of total). Due to the limited irrigation time and the climate conditions, the evapotranspiration was considered as negligible. The soil moisture variation and the underlying bedrock were monitored via a combination of electrical resistivity tomography (ERT), TDR probes and tensiometers. A small‐scale 3D cross‐hole ERT experiment was performed using 2 m deep boreholes purposely drilled and completed with electrodes in the irrigated plot. A larger scale (35 m long) 2D surface ERT survey was also continuously acquired across the irrigated area. Monitoring continued up to 10 days after the experiment. As a result, we observed a very fast vertical infiltration through the soil cover, also favoured by preferential flow patterns, immediately followed by infiltration into the fractured bedrock. The surface layer showed a fast recovery of initial moisture condition nearly completed in the first 12 hours after the end of irrigation. The lateral transmission of infiltrating water and runoff were negligible as compared to the vertical infiltration. These experiment results confirm that the fractured bedrock has a key role in controlling the fast hydrological dynamics of the small catchment system under study. We concluded that deep water circulation is the key pathway to hillslope processes at this site.
Automated monitoring of coastal aquifers with electrical resistivity tomography
Authors: Ogilvy R.D. , Meldrum P.I. , Kuras O. , Wilkinson P.B. , Chambers J.E. , Sen M. , Pulido‐Bosch A. , Gisbert J. , Jorreto S. , Frances I. , Tsourlos P.
Published: September 2009

An Automated time‐Lapse Electrical Resistivity Tomography (ALERT) system has been developed for the long‐term monitoring of coastal aquifers. This ALERT system has been permanently installed in the River Andarax, Almeria, Spain to monitor and manage the impact of climatic change and land‐use practice on the underlying Quaternary aquifer. An electrode array, nearly 1.6 km long, has been buried below the normally dry riverbed with electrode take‐outs at regular intervals of 10 m. The maximum depth of investigation is about 160 m below ground level. An unmanned, permanent control station, in a secure location, allows the aquifer to be interrogated remotely from the BGS office in the UK. Volumetric geoelectric images of the subsurface can be obtained ‘on demand’ or at regular intervals; thereby eliminating the need for expensive repeat surveys. The entire process from data capture to image on the office PC is fully automated and seamless. The ALERT technology can provide early warning of potential threats to vulnerable water systems such as over‐exploitation, rising sea levels, anthropogenic pollutants and seawater intrusion. The electrical images obtained (in space and time) are interpreted in terms of the hydrogeologic features including the seawater‐freshwater interface. The timely detection and imaging of groundwater changes can help to regulate pumping and irrigation schemes.
Aquifer investigations in the León‐Chinandega plains, Nicaragua, using electromagnetic and electrical methods
Authors: Corriols Marvin , Ryom Nielsen Mette , Dahlin Torleif , Christensen Niels B.
Published: September 2009

The Leon‐Chinandega plains are located in the north‐western part of Nicaragua and represent the most important groundwater reservoir of the country. The aquifer is comprised of three hydrogeological units. The top unit is an unconfined alluvial and below a more consolidated volcanic aquifer is found. These aquifers rest on an ignimbrite unit that acts as the basement of the aquifer. The plains are mainly used for agricultural purposes and most of the irrigation comes from upper aquifer wells (not deeper than 70 m) allocated within the shallow unconfined aquifer.

Transient electromagnetic soundings (TEM) and continuous vertical electrical soundings (CVES) were carried out in order to obtain information regarding the geology of the study area. Two TEM profiles extending from the Pacific coast towards the volcanic chain were carried out with an approximate separation between soundings of 250 metres. A grid of TEM soundings was also performed in an area located between the towns of Posoltega and Quezalguaque. CVES were carried out in different areas of the plains in order to obtain detailed information on the geology and distribution of the shallow aquifer. This information was later correlated with information available from wells in the area.

One of the objectives of this investigation was to test and evaluate the applicability of the TEMfast48 equipment in the study area. In the plains area the TEM method shows very good results where a general geophysical model of mostly a three‐layered earth can be obtained. In the coastal areas the models are more irregular and complex. The results from the CVES generally agree with the TEM models but present more details, especially in areas of complex geology. The penetration depth for the TEM soundings reached almost 100 m at most, depending on the depth to a low resistivity layer. In some areas the depth to the basement was estimated with long‐layout CVES.

In general, it was possible to obtain consistent geoelectrical models of the area and the methods complement each other well. The geoelectrical models are an excellent addition to other investigation methods as they provide an overview of the aquifer system and can serve as a basis for refining the conceptual and numerical models of the aquifer system. This information is expected to become very valuable for the exploration, management and protection of the groundwater resources in the León‐Chinandega plains to ensure sustainability of the resource.
Hydrogeologic structure underlying a recharge pond delineated with shear‐wave seismic reflection and cone penetrometer data
Authors: Haines Seth S. , Pidlisecky Adam , Knight Rosemary
Published: September 2009

With the goal of improving the understanding of the subsurface structure beneath the Harkins Slough recharge pond in Pajaro Valley, California, USA, we have undertaken a multimodal approach to develop a robust velocity model to yield an accurate seismic reflection section. Our shear‐wave reflection section helps us identify and map an important and previously unknown flow barrier at depth; it also helps us map other relevant structure within the surficial aquifer. Development of an accurate velocity model is essential for depth conversion and interpretation of the reflection section. We incorporate information provided by shear‐wave seismic methods along with cone penetrometer testing and seismic cone penetrometer testing measurements. One velocity model is based on reflected and refracted arrivals and provides reliable velocity estimates for the full depth range of interest when anchored on interface depths determined from cone data and borehole drillers’ logs. A second velocity model is based on seismic cone penetrometer testing data that provide higher‐resolution 1D velocity columns with error estimates within the depth range of the cone penetrometer testing. Comparison of the reflection/refraction model with the seismic cone penetrometer testing model also suggests that the mass of the cone truck can influence velocity with the equivalent effect of approximately one metre of extra overburden stress. Together, these velocity models and the depth‐converted reflection section result in a better constrained hydrologic model of the subsurface and illustrate the pivotal role that cone data can provide in the reflection processing workflow.
Estimating the depth of fresh and brackish groundwater in a predominantly saline region using geophysical and hydrological methods, Zeeland, the Netherlands
Authors: Goes B.J.M. , Oude Essink G.H.P. , Vernes R.W. , Sergi F.
Published: September 2009

The province of Zeeland is situated in the coastal zone of the Netherlands. The ground surface level is around or below mean sea level. Therefore seepage of brackish to saline groundwater is very common. Sea level rise as a result of climate change will very likely increase the pressure on the coastal groundwater system, leading to an increased salinization of the groundwater and surface water system. Still, freshwater agriculture is being practiced in large parts of the province. The vegetation extracts its fresh water from the unsaturated zone and thin rainwater lenses that ‘float’ on top of brackish and saline groundwater. Geophysical and hydrogeological data have been combined on two spatial scales to obtain a better insight into this fresh‐brackish‐saline groundwater distribution. This information is being used to: assess groundwater abstractions, plan landuse and improve the input of variable‐density groundwater flow and coupled solute transport models.

For over 6000 locations various types of data have been used to estimate the depth of the brackish‐saline groundwater interface of 1000 mg [Cl‐]/L. These types of data are both of geophysical (vertical electrical soundings, EM34, geoelectrical well logs and electrical cone penetration tests) and of hydrological origin (water samples and abstraction wells). These data have been interpreted and combined with knowledge on the distribution of geological units to make an estimation of the depth of the brackish‐saline water transition for the whole province (~66 km × 63 km).

In addition to the regional brackish‐saline interface map, continuous vertical electrical soundings (CVES) have been executed to map the fresh‐brackish‐saline distribution on a local scale. The CVES profiles were made at eight different plots where brackish‐saline water is occurring at shallow depths (<5 m below the surface) according to the regional map and where freshwater agriculture is still being practised. Six of the eight sites have thin (0–3 m) brackish to slightly saline water lenses. At two sites up to 15 m thick brackish water lenses have been observed with CVES. The thickness of the brackish water lenses varies laterally over short distances. Sandy sediment and a higher topography are favourable factors for the development of such lenses.
Photo-Oxidative Stress on Model Membranes – Studies by Optical Methods
Authors: Bărbînţă Pătraşcu Marcela Elisabeta , Badea Nicoleta Maria , Ţugulea Laura , Meghea Aurelia
Published: September 2009

Photophysical studies on oxidative stress induced by illumination with ultraviolet (UV) light from artificial light sources, were performed on small unilamellar liposomes (SUVs) as models of biomembranes. Different liposoluble antioxidants were incorporated in the liposome bilayer during the lipid film preparation. The quercetin containing bilayers exhibited a high tolerance to photooxidative stress. The light-driven reactive oxygen species (ROS) effects on liposomal membranes were monitored by optical methods: UV-VIS absorption, fluorescence and chemiluminescence (CL), exploiting the spectral properties of chlorophyll a (Chla) embedded into some liposome bilayers (Chla/lipid molar ratio = 1/100). The interaction between Chla and the other liposome components resulted in changes in their absorption and emission fluorescence properties.
Dynamics of Dental Pellicle Formation - In Vitro Analysis of Time Dependant Binding Behavior by Surface Plasmon Resonance and the Influence of Oral Therapeutics
Authors: Vornicescu Doru , Solanska Katerina , Demetrescu Ioana , Frentzen Matthias , Keusgen Michael
Published: September 2009

: The pellicle on oral surfaces represents a central interface for the formation of biofilms. Among other things it causes the first adsorption of bacteria. The dynamics of pellicle formation, on tooth surfaces and the influence of oral therapeutics on the pellicle structure are fairly unknown. With the method of surface plasmon resonance (SPR), the formation of salivary pellicle structures on hydroxylapatite (HAP) surfaces covering a very thin (~50nm) layer gold on a glass prism was recorded in real time without labeling or destruction. As pellicle forming substrates natural pooled human saliva (NS) and artificial saliva (AS) were used. To simulate the influence of therapeutic additives on the dynamic of the pellicle forming process, a chlorhexidine preparate (Chlorhexamed Fluid® CHX) on two different concentrations was selected. The binding behavior of a NS and a preparation in terms of an AS were compared. The layer was largely stable against rinsing with buffer. The application of CHX preparations in two different concentrations as an example of an oral therapeutic additive revealed a complex dynamic of adsorption. CHX did not lead to any visible destruction of the pellicle. The introduced method is an excellent tool to illustrate the dynamic effects of pellicle formation or pellicle reorganization by measuring the increase or decrease of the SPR signal in real time.
Research on Uniform Surface Roughness in Grinding of Revolving Curved Surface
Authors: Kong Ling Ye , Yan Qiu Sheng , Song Jun Hui , Song Ya Nan
Published: September 2009

When grinding the revolving curved surface with Arc Envelope Grinding Method, the different curvatures in the convex and concave surfaces make a great difference in the surface roughness. In order to solve this problem, the relationship among envelope height, feeding rate, rotational speed and curvature of workpiece was analyzed based on equal-envelope-height grinding method. The results presented that, low feeding rate of grinding wheel and high rotational speed of workpiece were helpful to obtain smaller envelope height. And the smaller the radius of workpiece curvature, the more different the surface roughness. Besides, it was an effective method to solve this problem by changing feeding rate. The feeding rate should be changed directly proportionally to radius of workpiece curvature. Then, the experimental results indicate that, the fluctuation ratio of surface roughness with variable feeding rate is reduced to 4.896% from 26.17% with constant feeding rate. It proves the validity of hypothesis.
Processing Experiment Research of the Swirling Airflow Finishing
Authors: Li Xiu Hong , Yang Shi Chun , Yang Sheng Qiang , Gao Yong Ning
Published: September 2009

A new swirling airflow finishing process is put forward mainly for hole surface. Flows field analysis is done through computational fluid dynamics (CFD) software. Abrasive velocity along axis length according to nozzle elevation and abrasive diameter are shown. Unthreaded hole is experimented on the basis of simulation. Experiment results are consistent with simulation research and it provides credible theoretic basis for process improvement. The successful application of this technology may meet deburring and finishing of complicated parts as crossed holes, stepped holes and winding pipe as well as unthreaded holes.
Experimental Investigation of Tool Wear in Rotary Ultrasonic Machining of Alumina
Authors: Zeng Wei Ming , Xu Xi Peng , Pei Zhi Jian
Published: September 2009

As one of the cost-effective machining methods for advanced ceramics, rotary ultrasonic machining (RUM) has attracted much attention and there exist numerous publications on the process. However, few investigations on tool wear in the RUM process have been reported. This paper, for the first time in literature, presents an experimental observation on tool wear in RUM of alumina. it presents and discusses the results on tool wear in RUM of alumina. It also discusses some practical implications of the findings from this study.
Motion Analysis of Ball Grinder with Dual-Rotating Plates Lapping Mode
Authors: Jin Yang Fu , Lv Xun , Hu Xiao Dong , Li Wei
Published: September 2009

Dual-rotating plates lapping method is a new type of ball machining technology, in which the spin axis angle of the ball could wiggle up to 180°. An investigation was made to verify the motion model of the dual-rotating plates lapping. The ball motion parameters, such as revolution speed, spin speed and spin axis angle were detected experimentally. The results show that the calculated values and the measured ones of the ball motion parameters are almost identical. The motion model of the dual-rotating plates lapping method is thus verified valid.
Development of Resin Bonded Diamond Wire Saw and Slicing Experiments
Authors: Ge Pei Qi , Hou Zhi Jian , Li Shao Jie
Published: September 2009

Because its advantages of lower manufacture cost and higher slicing quality, the resin bonded diamond wire saw is supposed to be used widely in the future for slicing hard-brittle materials such as silicon crystal. In this paper, based on the research of the resin bonded diamond wire saw manufacturing technology and slicing process, we select Φ0.2mm SWPB piano string as core wire, 20-30m (800#) diamond grain as abrasive, liquid phenolic resin mixed with epoxy resin as adhesive, the nanometer powders as additive to improve the adhesive holding strength of abrasive grains and heat resistance. By orthogonal experiment, we find the resin bonded diamond wire saw has optimizing performance as the additives is 10% in adhesive, the epoxy resin is 30% in resin, the diamond is 50% in whole mixed material. Slicing experiments proves that the resin bonded diamond wire saw manufactured in this study has better slicing performance. The failure forms of the resin bonded diamond wire saw are wear out of resin adhesive, falling off of diamond grains and the partial peeling off of the resin bond.
Design and Research of Embedded Internal Grinding NC System Based on μC/OS-II
Authors: Xie Ou , Li Hua , Li Yan
Published: September 2009

According to the requirement for high-precision and processing features of the internal grinding, the hardware and software of an internal grinding NC system based on embedded system were presented. The classification and implementation of several key system tasks controlled by real-time operating system uc/os-ii were given, and the control process of the machine switch by soft PLC technology was elaborated on in the system. According to the real-time requirements of internal grinding NC system, the tasks of the system were prioritized reasonably, and some methods for enhancing the capability of real-time and improving the accuracy of the system were presented with software technology.
Research on Adaptive Control of Grinding Force of CNC Cams Grinder
Authors: Hu Zhan Qi , Xie Ming Li , Li Yu Kun , Zhang Yi Tong
Published: September 2009

In view of the special characteristics of cams grinding, some key technologies of grinding force adaptive control system are researched, including selection of inspecting parameter, modeling of grinding feed system, and design of controller. Results of simulation indicate that this system can ensure circular grinding force steady and enhance the machining quality of cams when the grinding allowance is of variety.
Research on the Basic Properties of the Bamboo Charcoal Bonded Grinding Wheel
Authors: Li Wei , Song Zhi Yang , Yu Tian Ming , Geng Bao Gong
Published: September 2009

A new BCB (Bamboo Charcoal Bonded) grinding wheel was developed by bamboo charcoal-phenolic resin composite under vacuum for ELID grinding technology. The pyrolysis behavior of the new bamboo charcoal-phenolic resin material was studied by thermo gravimetric analysis (TGA), and structural characterization of the new material was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), the friction characteristics was also investigated in this paper.
Research on the Material Removal Mechanism in Deliquescent Polishing of KDP Crystals
Authors: Zhang Fei Hu , Guo Shao Long , Zhang Yong , Luan Dian Rong
Published: September 2009

A new ultraprecision machining technology for KDP crystals, deliquescent polishing technology for KDP crystals, is presented. On the basis of analyzing the definitions of deliquescence, the dissolution experiment of KDP crystal’s surface was conducted. Through the experiment, the material removal mechanism in deliquescent polishing of KDP crystals is proposed, and the deliquescent polishing device for KDP crystals is described. Based on the material removal mechanism in deliquescent polishing of KDP crystals, the deliquescent polishing experiment of KDP crystal was carried out, the experimental result has verified the validity, feasibility and effectiveness of the material removal mechanism.
Analysis on Centerless Grinding of Titanium Alloy
Authors: Ming Wei Wei , An Qing Long , Chen Ming
Published: September 2009

Centerless grinding is a widely used manufacturing process in the mass production of precision parts. However, its productivity and precision is largely determined by the grinder set-up conditions, process stability and workpiece surface integrity. Grinding titanium alloys encounters difficulties due to its low thermal conductivity, high shear strength and extreme chemical reactivity. Therefore, the grindability of titanium alloy should be improved in order to increase the productivity for the sake of workpiece quality. In this paper, centerless grinding process was introduced initially and the research of impact factors on centerless grinding performance was reviewed. The problems occurred in the centerless grinding of titanium alloy were studied and optimum guidelines were proposed.
Analysis of Grinding Force Influence on HIPSN Ceramic Grinding Surface
Authors: Zhang Ke , Wang He , Wu Yu Hou , Li Song Hua
Published: September 2009

In ceramic machining field, the ultimate goal is to keep material surface integrity, dimension precision and max material removal rate synchronously. HIPSN ceramic ring high speed grinding experiments and researches have been performed, by testing and analyzing grinding force, combining grinding motorized spindle dynamic performance with grinding surface roughness, the influences on ceramic machining quality have been discussed. The grinding parameter can be chose in precondition promising machining quality. It possesses guidance significance in low cost, high efficiency precise ceramic parts machining.
A Methodology for the Simulation of Surface-Contact Grinding Tool Topography
Authors: Zhang Guo Zhi , Zhang Xian Hua , Liu Li Li , Wei Zeng Ju
Published: September 2009

Study on the effect of the surface manufacturing quality (roughness) to the friction between the surfaces. Based on the plastic theory of mechanism-based strain gradient (MSG) of the micro-plastic-mechanics and the contact theory, the theoretical model of the coefficient of friction between the rough surfaces and the non-linear finite element model between the grinding samples were established. Moreover, the surface stress distribution and the coefficient of friction were obtained through the sub-structure finite element method. The established model of static friction theoretical model and the accuracy of the finite element model were verified through comparing with the result of the static friction experiments between the grinding samples with different surface manufacturing quality. The study in the paper is important to the study on the surface friction mechanism.
Experimental Temperature Studies on Two Dimensional Ultrasonic Vibration Grinding the Nano-ZrO2 Ceramics
Authors: Bian Ping Yan , Zhao Bo , Li Yu
Published: September 2009

In processing of engineering ceramics materials with diamond grinding wheel, grinding heat is one of vital factors influencing workpiece surface quality. Grinding parameters have important influences on workpiece surface temperature distributions. Contrast experiments on grinding temperature of nanoZrO2 under common and two dimensional ultrasonic vibration grinding(TDUVG) were carried out in this paper by manual thermocouple method. The relationship between grinding parameters and grinding temperature was clarified through theoretical analysis and experiment confirmation. The research results show that with the increases of grinding depth, grinding speed, and decrease of working table speed, the workpiece’s surface temperature would heighten accordingly. Furthermore, comparing with high surface layer temperature in common grinding, which often results in grinding burn, TDUVG can reduce grinding temperature effectively.
An Investigation to Semi-Fixed Abrasives Plate Characteristics
Authors: Deng Qian Fa , Yuan Ju Long , Wang Zhi Wei , Wen Dong Hui , Lv Xun
Published: September 2009

The most typical example of hard and brittle material is advanced ceramics, for its ultra-precision machining difficulty and wide applications, now it becomes a focus of attention. Semi-fixed abrasive plate (SFAP) is newly developed for preventing larger particles from doing workpiece surface damage in machining advanced ceramics, for larger particles from grain size dispersion or from outside of processing area could bring uneven load distribution on processing region of advanced ceramics. In this paper, Shearing strength, surface hardness and Young’s modulus as characteristics of SFAP are investigated. They were influenced by Grain size and abrasive weight ratio are analyzed and discussed, as well as the qualitative estimation of these influences on the characteristics of SFAP are deduced.
Online Wear Evaluation of Grinding Wheel in Machining WC-Co Coating
Authors: Jiang Ke Wan , Wu Qi , Hu De Jin
Published: September 2009

This paper presented a new technique, which was the online wear evaluation of wheel in grinding WC-Co coating by using wavelet packet decomposition. Based on the measurement method, theory of online wear evaluation of wheel was introduced. The selection principle of characteristic signals was brought up, and the grinding acceleration signal was the best choice among many characteristic signals. The time domain signal analysis method of wavelet packet decomposition was analyzed. Lastly, experiments on the wear of wheel were performed, and experimental results showed the validity of the method.
Magnetorheological Flexible Gasbag Polishing Technique
Authors: Ji Shi Ming , Jin Ming Sheng , Zhang Li , Yuan Qiao Ling , Zhang Xian , Chen Guo Da
Published: September 2009

Combining the advantages of rheological behavior of magnetorheological fluid (MRF) and flexibility adjustability of rubber gasbag, a magnetorheological flexible gasbag polishing technique applied to free-form mould is proposed. With the development of robotic gasbag polishing technique, the flexibility of rubber gasbag can be adjusted by three methods of changing its internal pressure controlled through a pressure control unit, its own material property and structural parameter, and the rheological behavior of MRF inside of it in response to the application of an alterable magnetic field. Effect of rheological behavior to the flexibility of rubber gasbag and surface quality of mould is the single most important focus in this paper. The magnetorheological flexible gasbag polishing system is established and rheological behavior of MRF with magnetic field is described. Through polishing experiment focusing on the relationship between the surface roughness and current around electromagnetic coil, it can be obtained that magnetorheological flexible gasbag polishing technique is effective to improve surface quality when increasing current around coil in certain extent.