Systematic Precipitation of Magnesium Hydroxide Using NH4OH to Preparing MgO-PSZ Precursor Powder

The wide range of applications of zirconia based ceramics is due to stabilization of its tetragonal and cubic structures at room temperature, by controlled adding of dopants such as yttria, magnesia, calcia, ceria and some rare earth oxides. The advantage of the use of magnesia as dopant is not only due to its low cost, but fact that by controlling its ceramic processing, it is possible to control a specific microstructure for the specific application. The precipitation of magnesium hydroxides, using NH4OH as a precipitant, presents some difficulties due to the formation of a variety of soluble complexes of ammonia with magnesium, which inhibits the total precipitation of magnesium. In the present work, the influence of precipitant and metals concentrations and pH on the magnesium hydroxide precipitation was investigated. Magnesium chloride, zirconium oxychloride and NH4OH were used as starting materials. The precipitation of magnesium hydroxide depends on concentrations of OH-, Cl- and Mg2+. To achieve specific precipitation yield, lower the concentration of Mg2+ high molar ratio of [OH-]/[Cl-] is required. The pH measure is not enough to control Mg (OH)2 precipitation. The use of molar ratio of [OH-]/[Cl-] = 4.4, resulted in 95 % of Mg (OH)2 precipitation. The co-precipitation of Zr and Mg hydroxides, using the optimized molar ratio of [OH-]/[Cl-], the precipitation of Mg (OH)2 achieved in range of 97.6 to 98.3 %.

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μCHILL: a lightweight, modular system for handling crystalline samples at low temperatures under inert conditions

Journal of Applied Crystallography ◽

10.1107/s1600576718003291 ◽

2018 ◽

Vol 51 (2) ◽

pp. 541-548 ◽

Cited By ~ 1

Author(s):

Michael Solar ◽

Nils Trapp

Keyword(s):

Low Temperatures ◽

Room Temperature ◽

Low Cost ◽

Three Dimensional ◽

Modular System ◽

Preparation Time ◽

Stable Conditions ◽

Wide Range ◽

Single Operator ◽

Cold Gas

A procedure for preparing and mounting crystals under inert conditions is demonstrated, using a specialized apparatus (μCHILL) to provide a cold gas stream fed from a liquid nitrogen (LN2) reservoir or an open bath heat exchanger. A second, dry gas stream at room temperature enwraps the cold gas, protecting the sample preparation zone from ambient moisture. The technique is extremely flexible, requiring only a single operator, little practice and almost no preparation time. The device enables operation in a wide temperature range (at least 213 K to room temperature), providing temperature control and very stable conditions with no icing for extended time periods. The flexible, modular and low-cost design is based on three-dimensional-printed parts and readily available standard components, potentially making the device available to a wide range of users and applications not limited to single-crystal studies.

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A Novel Ionic Exchange Membrane Crystallizer to Recover Magnesium Hydroxide from Seawater and Industrial Brines

Membranes ◽

10.3390/membranes10110303 ◽

2020 ◽

Vol 10 (11) ◽

pp. 303

Author(s):

Daniele La Corte ◽

Fabrizio Vassallo ◽

Andrea Cipollina ◽

Marian Turek ◽

Alessandro Tamburini ◽

...

Keyword(s):

Magnesium Hydroxide ◽

Saline Solution ◽

Low Cost ◽

Feed Solution ◽

Ionic Exchange ◽

The North ◽

Novel Technology ◽

Co Precipitation ◽

Exchange Membrane ◽

By Products

A novel technology, the ion exchange membrane crystallizer (CrIEM), that combines reactive and membrane crystallization, was investigated in order to recover high purity magnesium hydroxide from multi-component artificial and natural solutions. In particular, in a CrIEM reactor, the presence of an anion exchange membrane (AEM), which separates two-compartment containing a saline solution and an alkaline solution, allows the passage of hydroxyl ions from the alkaline to the saline solution compartment, where crystallization of magnesium hydroxide occurs, yet avoiding a direct mixing between the solutions feeding the reactor. This enables the use of low-cost reactants (e.g., Ca(OH)2) without the risk of co-precipitation of by-products and contamination of the final crystals. An experimental campaign was carried out treating two types of feed solution, namely: (1) a waste industrial brine from the Bolesław Śmiały coal mine in Łaziska Górne (Poland) and (2) Mediterranean seawater, collected from the North Sicilian coast (Italy). The CrIEM was tested in a feed and bleed modality in order to operate in a continuous mode. The Mg2+ concentration in the feed solutions ranges from 0.7 to 3.2 g/L. Magnesium recovery efficiencies from 89 up to 100% were reached, while magnesium hydroxide purity between 94% and 98.8% was obtained.

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‘On-water’ organic synthesis: a green, highly efficient, low cost and reusable catalyst system for biaryl synthesis under aerobic conditions at room temperature

RSC Advances ◽

10.1039/c5ra09102k ◽

2015 ◽

Vol 5 (63) ◽

pp. 50655-50659 ◽

Cited By ~ 11

Author(s):

Bishwajit Saikia ◽

Preeti Rekha Boruah ◽

Abdul Aziz Ali ◽

Diganta Sarma

Keyword(s):

Organic Synthesis ◽

Room Temperature ◽

Low Cost ◽

Suzuki Reaction ◽

Catalyst System ◽

Reusable Catalyst ◽

Wide Range ◽

Biaryl Synthesis ◽

Phenylboronic Acids ◽

Operational Simplicity

The PdCl2/sucrose/K2CO3/H2O system showed the superb catalytic activity towards the Suzuki reaction of a wide range of aryl/heteroaryl halides with diverse phenylboronic acids at room temperature with operational simplicity and shorter reaction time.

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An investigation on the synthesis of nickel aluminate

Pigment & Resin Technology ◽

10.1108/prt-12-2018-0126 ◽

2019 ◽

Vol 48 (6) ◽

pp. 487-492

Author(s):

Liliya Frolova

Keyword(s):

Electrical Conductivity ◽

Single Phase ◽

Molar Ratio ◽

Precipitation Process ◽

Complex Method ◽

Nickel Aluminate ◽

Content Type ◽

Wide Range ◽

Co Precipitation ◽

Derivatographic Analysis

Purpose The purpose of this paper is to study the process of coprecipitation of polyhydroxocomplexes of nickel and aluminum from solutions of nickel (Ni) (II) sulfate and aluminum (Al) (III) sulfate with caustic soda and to study the conversion process to nickel aluminate and to check its properties. Design/methodology/approach For the thermodynamic analysis of the precipitation process, the software package MEDUSA was used. The dependences of the electrical conductivity, pH and residual concentrations as functions of the OH/Me ratio were obtained. Using X-ray phase analysis, spectroscopic analysis and derivatographic analysis, the properties of the products obtained were studied. The effects of OH/Me ratio and molar ratio cation of reagents on the physicochemical properties of the products were analyzed. Findings The paper deals with the results of theoretical and experimental research on the synthesis pigments of blue and green colors based on Ni-Al spinel. The influence of the molar ratio cation content on optical and color characterise of pigments were studied. Originality/value The original complex method of studying the processes of co-precipitation of cations in the form of hydroxides is proposed. pH precipitation of aluminum hydroxide and nickel are different. It is interesting to study their co-precipitation. The resulting single-phase product is a precursor of nickel aluminate over a wide range of cation ratios. The dependences of the electrical conductivity, pH and residual concentrations as functions of the OH/Me ratio were obtained.

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Acetate Facilitated Nickel Catalyzed Coupling of Aryl Chlorides and Alkyl Thiols

10.33774/chemrxiv-2021-tgvjk ◽

2021 ◽

Author(s):

Regina M. Oechsner ◽

J. Philipp Wagner ◽

Ivana Fleischer

Keyword(s):

Catalytic System ◽

Room Temperature ◽

Low Cost ◽

Potassium Acetate ◽

Addition Product ◽

Catalytic Cycle ◽

Nmr Studies ◽

Aryl Chlorides ◽

Wide Range ◽

Tertiary Alkyl

We report a mild, fast and convenient catalytic system for the coupling of aryl chlorides with primary, secondary, as well as previously challenging tertiary alkyl thiols using an air-stable nickel(II) precatayst in combination with the low-cost base potassium acetate at room temperature. This new catalytic system tolerates a variety of functional groups and enables the generation of thioethers for a wide range of substrates, including pharmaceutical compounds in excellent yields. Chemoselec-tive functionalization of disubstituted substrates was demonstrated. Kinetic and NMR-studies, as well as DFT computations support a Ni(0)/Ni(II) catalytic cycle and identify the oxidative addition product as the resting state. Acetate coordination and subsequent acetate facilitated formation of a thiolate complex via internal deprotonation play a key role in the catalytic cycle.

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A Novel Seedless TSV Process Based on Room Temperature Curing Silver Nanowires ECAs for MEMS Packaging

Micromachines ◽

10.3390/mi10060351 ◽

2019 ◽

Vol 10 (6) ◽

pp. 351 ◽

Cited By ~ 2

Author(s):

Meng ◽

Cheng ◽

Yang ◽

Sun ◽

Luo

Keyword(s):

Room Temperature ◽

Microelectromechanical Systems ◽

Silver Nanowires ◽

Low Cost ◽

Mems Devices ◽

Filling Process ◽

Conductive Adhesives ◽

Mems Packaging ◽

Wide Range ◽

High Efficient

The through-silicon-vias (TSVs) process is a vital technology in microelectromechanical systems (MEMS) packaging. The current via filling technique based on copper electroplating has many shortcomings, such as involving multi-step processes, requiring sophisticated equipment, low through-put and probably damaging the MEMS devices susceptible to mechanical polishing. Herein, a room temperature treatable, high-efficient and low-cost seedless TSV process was developed with a one-step filling process by using novel electrically conductive adhesives (ECAs) filled with silver nanowires. The as-prepared ECAs could be fully cured at room temperature and exhibited excellent conductivity due to combining the benefits of both polymethyl methacrylate (PMMA) and silver nanowires. Complete filling of TSVs with the as-prepared 30 wt% silver nanowires ECAs was realized, and the resistivity of a fully filled TSV was as low as 10−3 Ω·cm. Furthermore, the application of such novel TSV filling process could also be extended to a wide range of different substrates, showing great potential in MEMS packaging, flexible microsystems and many other applications.

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Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009292x ◽

1976 ◽

Vol 34 ◽

pp. 592-593

Author(s):

Ernest L. Hall ◽

J. B. Vander Sande

Keyword(s):

Mechanical Properties ◽

Single Crystal ◽

Dislocation Structure ◽

Room Temperature ◽

Elevated Temperatures ◽

Strain Curve ◽

Optical Devices ◽

Semiconductor Compound ◽

Wide Range ◽

Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

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Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

Nuklearmedizin ◽

10.1055/s-0038-1629552 ◽

1991 ◽

Vol 30 (01) ◽

pp. 35-39 ◽

Cited By ~ 1

Author(s):

H. S. Durak ◽

M. Kitapgi ◽

B. E. Caner ◽

R. Senekowitsch ◽

M. T. Ercan

Keyword(s):

Soft Tissue ◽

Room Temperature ◽

Normal Subjects ◽

Left Testis ◽

Wide Range ◽

Activity Ratios ◽

The Right ◽

Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

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Graphene Modified Molecular Imprinting Electrochemical Sensor for Determining the Content of Dopamine

Current Analytical Chemistry ◽

10.2174/1573411014666180730112304 ◽

2019 ◽

Vol 15 (6) ◽

pp. 628-634

Author(s):

Rong Liu ◽

Jie Li ◽

Tongsheng Zhong ◽

Liping Long

Keyword(s):

Electrochemical Sensor ◽

Molecular Imprinting ◽

Neurological Disorders ◽

Room Temperature ◽

Low Cost ◽

Differential Pulse ◽

Current Response ◽

Specific Selectivity ◽

Pulse Voltammetry

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.

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