scholarly journals Remediation of the Serbian soils contaminated by radionuclides in the function of the sustainable development

2008 ◽  
Vol 14 (4) ◽  
pp. 265-267 ◽  
Author(s):  
M. Stojanovic ◽  
M. Grubisic ◽  
D. Stevanovic ◽  
J. Milojkovic ◽  
D. Iles
Keyword(s):  
Contaminated Soils ◽  
Water Solution ◽  
Solution Concentration ◽  
Large Area ◽  
The Sustainable Development ◽  
Geological Conditions ◽  
Wide Range ◽  
Uranium Phosphate ◽  
Natural Apatite

Phosphate-induced metal stabilization (PIMS) using apatite stabilizes uranium in situ, by chemically binding it into the new low-solubility (Ksp=10-49) phase. Uranium-phosphate-autunite is stable across a wide range of geological conditions for millions of years. A large area of contaminated soil is suitable for in situ remediation that involves minimizing the mobility of the uranium. Laboratory study was conducted to quantify different forms of apatite sequestration of uranium contaminant. The experiment was done with natural phosphate from Lisina deposit (14.43 % P2O5), with non-treated samples, phosphate concentrate samples with 34.95 % P2O5 and mechanochemically activated of natural apatite. Different concentration of P2O5 in apatite, pH, reaction time, solid/liquid ratio was investigated. The concentrate at pH 5.5 for 7 days sorbed around 93,64 % and nature apatite, with 14,43 % P2O5, for 30 days sorbed 94.54 % of the uranium from the water solution, concentration 100 ?g U/ml. The results show that mineral apatite 'Lisina' is very effective for the treatment of contaminated soils in situ immobilization of U. Mechanochemical activation of natural apatite in vibration mill immobilized 85.37 % of uranium in the 7-day period of acting. This research on natural apatite from the deposit 'Lisina' for immobilization of uranium was the first one of this type in our country.

A Preliminary Study on Saving Parking Lot

2011 ◽  
Vol 368-373 ◽  
pp. 3628-3631
Author(s):  
Jun Liu ◽  
Wei Xian Zhang
Keyword(s):  
Sustainable Development ◽  
Large Area ◽  
The Sustainable Development ◽  
Parking Lots ◽  
Wide Range ◽  
Parking Lot ◽  
Preliminary Study

Along with the development of society and the popularity of private cars, more and more parking lots are to be needed. Consequently, large sized parking lots will be built in many cities. But the traditional parking lots were paved by a large area of concrete. So much concrete will be bound to create heat pollution. Meanwhile, a large area of parking lot occupies mass openspace. The existing parking lots lead to a waste of resources. This paper introduces a new term of saving parking lot and presents some key principles that stem from a wide range of contributions. The newfashioned parking lot may also give rise to the sustainable development.

In situ multiphase fluidization ("upflow washing") for the remediation of hydrocarbon contaminated sands

1998 ◽  
Vol 35 (6) ◽  
pp. 938-960 ◽  
Author(s):  
Robert K Niven ◽  
Nasser Khalili
Keyword(s):  
Theoretical Analysis ◽  
Contaminated Soils ◽  
Fixed Bed ◽  
Fine Sand ◽  
In Situ Remediation ◽  
Pump And Treat ◽  
Wide Range ◽  
Phase Liquid ◽  
Regime Map

A new in situ remediation method is described, "upflow washing," in which contaminants are flushed to the surface within an in situ fluidized zone produced by a jet inserted into a granular formation. The suitability of the method for LNAPL (light non-aqueous phase liquid) remediation is examined by experiments on diesel-contaminated soils within column and tank settings. The experiments indicate significant reductions in diesel levels (96-99.9%) may be achieved by fluidization with water and gas (gas-liquid upflow washing, GLUW) for a wide range of initial diesel concentrations (10 000 to 150 000 mg/kg) and for soil fines contents of 0 to at least 10%. Final diesel levels of <1000 mg/kg in a uniform fine sand and <200 mg/kg in clayey sands can be achieved. The efficiency is much higher than that of fixed bed flushing (simulated pump-and-treat), as the method overcomes the trapping of NAPL ganglia. Fludization with water alone (liquid upflow washing, LUW) is less effective than fixed bed flushing in the uniform sand, but approaches that of GLUW in clayey and silty sands. The results are explained by theoretical analysis of the removability of isolated NAPL droplets and mixed solid - NAPL particles from a fluidized bed due to buoyancy and elutriation, which may be represented using a "removability regime map" for the diesel-water-sand system.Key words: fluidization, in situ, remediation, NAPL, diesel.

scholarly journals In situ lead stabilization using natural and synthetic apatite

2008 ◽  
Vol 14 (4) ◽  
pp. 269-271 ◽  
Author(s):  
T. Kaludjerovic-Radoicic ◽  
S. Raicevic
Keyword(s):  
Computer Simulation ◽  
Computer Program ◽  
Sorption Capacity ◽  
Water Solution ◽  
Lead Contamination ◽  
Lead Removal ◽  
Visual Minteq ◽  
Experimental Values ◽  
Natural Apatite

In this work, mineral apatite was investigated for the remediation of lead contamination. Two different apatite minerals were used: synthetic apatite, Ca10(PO4)6(OH)2 (hereafter denoted as HAP) and natural apatite from Lisina, near Bosilegrad, Serbia (hereafter denoted as LA). Phosphate ore from Lisina deposit consists of 43.3 % apatite in the form of fluorapatite, Ca10(PO4)6(F)2. Sorption properties of HAP and LA were investigated. The results show that both of these minerals are effective in lead removal from the water solution. Sorption capacity of HAP obtained in this experiment is 0.216 mmol Pb/g HAP, while the value for LA is 0.162 mmol Pb/g LA. Modeling of these systems was conducted using Visual Minteq computer program. The values obtained from the computer simulation were compared to experimental values.

Comparison of in situ DGT measurement with ex situ methods for predicting cadmium bioavailability in soils with combined pollution to biotas

2017 ◽  
Vol 75 (9) ◽  
pp. 2171-2178 ◽  
Author(s):  
Peifang Wang ◽  
Cui Liu ◽  
Yu Yao ◽  
Chao Wang ◽  
Teng Wang ◽  
...  
Keyword(s):  
Soil Solution ◽  
Contaminated Soils ◽  
Pearson Correlation ◽  
Solution Concentration ◽  
Extraction Methods ◽  
Single Step ◽  
Ex Situ ◽  
In Situ Data ◽  
Positive Correlations

To assess the capabilities of the different techniques in predicting Cadmium (Cd) bioavailability in Cd-contaminated soils with the addition of Zn, one in situ technique (diffusive gradients in thin films; DGT) was compared with soil solution concentration and four widely used single-step extraction methods (acetic acid, EDTA, sodium acetate and CaCl2). Wheat and maize were selected as tested species. The results demonstrated that single Cd-polluted soils inhibited the growth of wheat and maize significantly compared with control plants; the shoot and root biomasses of the plants both dropped significantly (P &lt; 0.05). The addition of Zn exhibited a strong antagonism to the physiological toxicity induced by Cd. The Pearson correlation coefficient presented positive correlations (P &lt; 0.01, R &gt; 0.9) between Cd concentrations in two plants and Cd bioavailability indicated by each method in soils. Consequently, the results indicated that the DGT technique could be regarded as a good predictor of Cd bioavailability to plants, comparable to soil solution concentration and the four single-step extraction methods. Because the DGT technique can offer in situ data, it is expected to be widely used in more areas.

scholarly journals In situ epitaxial engineering of graphene and h-BN lateral heterostructure with a tunable morphology comprising h-BN domains

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Dechao Geng ◽  
Jichen Dong ◽  
Lay Kee Ang ◽  
Feng Ding ◽  
Hui Ying Yang
Keyword(s):  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
2D Materials ◽  
Chemical Vapor ◽  
Large Area ◽  
Atomic Lattice ◽  
Cvd Method ◽  
Wide Range ◽  
Tunable Morphology

Abstract Graphene and hexagonal boron nitride (h-BN), as typical two-dimensional (2D) materials, have long attracted substantial attention due to their unique properties and promise in a wide range of applications. Although they have a rather large difference in their intrinsic bandgaps, they share a very similar atomic lattice; thus, there is great potential in constructing heterostructures by lateral stitching. Herein, we present the in situ growth of graphene and h-BN lateral heterostructures with tunable morphologies that range from a regular hexagon to highly symmetrical star-like structure on the surface of liquid Cu. The chemical vapor deposition (CVD) method is used, where the growth of the h-BN is demonstrated to be highly templated by the graphene. Furthermore, large-area production of lateral G-h-BN heterostructures at the centimeter scale with uniform orientation is realized by precisely tuning the CVD conditions. We found that the growth of h-BN is determined by the initial graphene and symmetrical features are produced that demonstrate heteroepitaxy. Simulations based on the phase field and density functional theories are carried out to elucidate the growth processes of G-h-BN flakes with various morphologies, and they have a striking consistency with experimental observations. The growth of a lateral G-h-BN heterostructure and an understanding of the growth mechanism can accelerate the construction of various heterostructures based on 2D materials.

scholarly journals Realization of 2D crystalline metal nitrides via selective atomic substitution

2020 ◽  
Vol 6 (2) ◽  
pp. eaax8784 ◽  
Author(s):  
Jun Cao ◽  
Tianshu Li ◽  
Hongze Gao ◽  
Yuxuan Lin ◽  
Xingzhi Wang ◽  
...  
Keyword(s):  
Chemical Conversion ◽  
Metal Nitrides ◽  
Transition Metal Nitrides ◽  
Large Area ◽  
Fundamental Physics ◽  
New Members ◽  
Wide Range ◽  
Atomic Substitution ◽  
Crystalline Metal

Two-dimensional (2D) transition metal nitrides (TMNs) are new members in the 2D materials family with a wide range of applications. Particularly, highly crystalline and large area thin films of TMNs are desirable for applications in electronic and optoelectronic devices; however, the synthesis of these TMNs has not yet been achieved. Here, we report the synthesis of few-nanometer thin Mo5N6 crystals with large area and high quality via in situ chemical conversion of layered MoS2 crystals. The versatility of this general approach is demonstrated by expanding the method to synthesize W5N6 and TiN. Our strategy offers a new direction for preparing 2D TMNs with desirable characteristics, opening a door for studying fundamental physics and facilitating the development of next-generation electronics.

Noncontact Surface-Hardness Measurement Using Laser-Based Ultrasound

MRS Bulletin ◽  
1996 ◽  
Vol 21 (10) ◽  
pp. 53-57 ◽  
Author(s):  
A. Safaeinili ◽  
A.D.W. McKie ◽  
R.C. Addison
Keyword(s):  
Composite Structures ◽  
Elevated Temperatures ◽  
Surface Hardness ◽  
Case Depth ◽  
Ultrasonic Waves ◽  
Inspection System ◽  
Large Area ◽  
Science Center ◽  
Wide Range

A noncontact inspection system that uses lasers to both generate and detect ultrasonic waves has been developed at the Rockwell Science Center for the purpose of nondestructively inspecting metallic and composite structures. The laser-based ultrasound (LBU) system was initially developed to inspect large-area composite airframe structures, including the automated inspection of integrally stiffened and complexly curved composite structures. Furthermore the benefits offered by LBU, such as its noncontacting nature and ability to operate at elevated temperatures, have extended its usefulness to a wide range of applications—for example, in situ process monitoring where the capability to monitor a fabrication process or possibly inspect a part while still in a mold or autoclave could lead to significant cost benefits. Two manufacturing techniques that have shown promise and are presently under investigation are resin-transfer molding and compression molding. Since both of these processes typically occur at elevated temperatures, the noncontacting nature of LBU makes it an ideal candidate for an in situ sensor. More recently, measurement of the case depth in ground vehicle components has been investigated. This article describes current research that uses the LBU technique to determine surface hardness in steel-axle shafts.

In-situ electrical-resistivity measurements in the high-voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 68-69
Author(s):  
W. E. King
Keyword(s):  
Electrical Resistivity ◽  
Electron Microscope ◽  
High Voltage ◽  
Resistivity Measurements ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Wide Range ◽  
Helium Gas

A side-entry type, helium-temperature specimen stage that has the capability of in-situ electrical-resistivity measurements has been designed and developed for use in the AEI-EM7 1200-kV electron microscope at Argonne National Laboratory. The electrical-resistivity measurements complement the high-voltage electron microscope (HVEM) to yield a unique opportunity to investigate defect production in metals by electron irradiation over a wide range of defect concentrations.A flow cryostat that uses helium gas as a coolant is employed to attain and maintain any specified temperature between 10 and 300 K. The helium gas coolant eliminates the vibrations that arise from boiling liquid helium and the temperature instabilities due to alternating heat-transfer mechanisms in the two-phase temperature regime (4.215 K). Figure 1 shows a schematic view of the liquid/gaseous helium transfer system. A liquid-gas mixture can be used for fast cooldown. The cold tip of the transfer tube is inserted coincident with the tilt axis of the specimen stage, and the end of the coolant flow tube is positioned without contact within the heat exchanger of the copper specimen block (Fig. 2).

Site specific agricultural soil management with the use of new technologies

2013 ◽  
Vol 16 (1) ◽  
pp. 59-67
Keyword(s):  
New Technologies ◽  
Digital Interface ◽  
Appropriate Treatment ◽  
Wide Range ◽  
Soil Variation ◽  
Soil Information ◽  
Remote Sensing Techniques ◽  
Agricultural Areas

<p>The Soil Science Institute of Thessaloniki produces new digitized Soil Maps that provide a useful electronic database for the spatial representation of the soil variation within a region, based on in situ soil sampling, laboratory analyses, GIS techniques and plant nutrition mathematical models, coupled with the local land cadastre. The novelty of these studies is that local agronomists have immediate access to a wide range of soil information by clicking on a field parcel shown in this digital interface and, therefore, can suggest an appropriate treatment (e.g. liming, manure incorporation, desalination, application of proper type and quantity of fertilizer) depending on the field conditions and cultivated crops. A specific case study is presented in the current work with regards to the construction of the digitized Soil Map of the regional unit of Kastoria. The potential of this map can easily be realized by the fact that the mapping of the physicochemical properties of the soils in this region provided delineation zones for differential fertilization management. An experiment was also conducted using remote sensing techniques for the enhancement of the fertilization advisory software database, which is a component of the digitized map, and the optimization of nitrogen management in agricultural areas.</p>

Indium Bromide-catalyzed Unprecedented Hydrogenolysis: A Novel One-Pot Synthesis of Per-O-Acetylated β-carboxymethyl O and S-glycosides

2020 ◽  
Vol 24 (8) ◽  
pp. 900-908
Author(s):  
Ram Naresh Yadav ◽  
Amrendra K Singh ◽  
Bimal Banik
Keyword(s):  
Asymmetric Synthesis ◽  
Chiral Auxiliary ◽  
Bioactive Molecules ◽  
One Pot ◽  
Enantiomerically Pure ◽  
Stereoselective Glycosylation ◽  
One Pot Synthesis ◽  
Wide Range

Numerous O (oxa)- and S (thia)-glycosyl esters and their analogous glycosyl acids have been accomplished through stereoselective glycosylation of various peracetylated bromo sugar with benzyl glycolate using InBr3 as a glycosyl promotor followed by in situ hydrogenolysis of resulting glycosyl ester. A tandem glycosylating and hydrogenolytic activity of InBr3 has been successfully investigated in a one-pot procedure. The resulting synthetically valuable and virtually unexplored class of β-CMGL (glycosyl acids) could serve as an excellent potential chiral auxiliary in the asymmetric synthesis of a wide range of enantiomerically pure medicinally prevalent β-lactams and other bioactive molecules of diverse medicinal interest.

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