The Bureau of Mines estimated the cost for a uranium ion-exchange recovery system using five grades of U/sub 3/O/sub 8/ leach solution producing 815,570 pounds of U/sub 3/O/sub 8/ per year from an ammonium bicarbonate in situ leach solution. The system flowsheet consisted of four unit operations: (1) Multiple-compartment ion-exchange (MCIX) absorption; (2) MCIX elution; (3) precipitation of the uranium as yellow cake, filtering, calcining, and packaging; and (4) waste disposal. The total fixed capital cost of a system treating 2,000 gallons per minute of 0.1-gram-per-liter-U/sub 3/O/sub 8/ leach solution was estimated as $6,888,000. For a basic case of an MCIX system depreciating in 9 years, unit production cost of U/sub 3/O/sub 8/ was $3.51 per pound. A decrease in feed solution grade from 0.4 to 0.03 gram per liter increased the production cost exponentially. Shorter depreciating periods significantly increased the production cost particularly for the lower grade feed solutions.
In the preceeding papers (Mem. Ryojun Coll. Eng., 2, 1929, 205, 3, 1930, 87.3, 1931, 285 and 295.), one of the present writers pointed out, that the intermediate metastab'e phase β' exists during the course of the eutectoid-transformation of this alloy.Thereafter, the existence of another metastable phase β1, was additionaly detected by Wassermann in the same alloy.In the present paper, the crystal structure of various phases taking part in the said transformation is re-examined, and the change in structure due to the transformation is studied by means of X-ray, electrical resistivity and microscopic methods. Using the "Vacuumheitztisch nach Esser", the alloy containing 12·66% of Al is heated or cooled rapidly under the microscope, and the change in microstructure due to the metastable transformation β1 β', was photographed with a cinekodak on 16-mm. film. From the micro-cinema thus obtained, it is found that the well-known needle structure of the quenched alloys grows at first at about 300°C on cooling and disappears gradually at about 410°C on re-heating, and further that the needle itself has no phasic meaning; it would probablly be regarded as beeing due to the slip or shear of the lattice plane.
Gas Separation In their Communication on page 16390 ff., K. Eum, M. Tsapatsis et al. describe the separation of oxygen from air by modified ZIF membranes. The permeation properties of the membranes are reversible and can be tailored to suit their application.
Abstract Vapor‐phase treatment of ZIF‐8 membranes with manganese(II) acetylacetonate (Mn(acac) 2 ) allows permselectivity tuning. Propylene/propane selectivity increases from 31 to 210 after the Mn(acac) 2 treatment at 165 °C for 30 min, while selectivities increase from 14.6 to 242 for H 2 /CH 4 , from 2.9 to 38 for CO 2 /CH 4 , from 2.4 to 29 for CO 2 /N 2 , and from 2.9 to 7.5 for O 2 /N 2 , after Mn(acac) 2 treatment at 175 °C for 30 min. Stable equimolar propylene/propane mixture selectivity of 165 at ambient temperature and 4 bar equimolar feed with a propylene flux of 8.3×10 −4 mol m −2 s −1 is established. A control experiment excludes thermal treatment alone causing these changes. XPS analysis reveals the presence of Mn(acac) 2 on the outer surface of the vapor‐treated ZIF‐8 membranes while no other changes are detectable by X‐ray diffraction and infrared spectroscopy.
Immunoelectrodiffusion is a sensitive technique in measuring micro-quantities of proteins. In this method antigen is forced to flow into the gel containing antibody by electrophoresis.Agar gel antibody plates (7.5×7.5×0.1cm) containing 0.75ml of anti-γ chain rabbit serum were used in the present study to quantitate IgG globulin. Electrophoresis was carried out for 2 to 3 hours at 150V. The length of precipitate line thus formed was in proportion to the concentration of applied IgG in the range between 1.18 and 9.5mg/dl.The reported immunological technique is suitable for measuring micro-quantities of IgG in dilute solutions such as cerebrospinal fluid, urine and saliva without concentrating procedure.
Abstract Vapor phase ligand treatment (VPLT) of 2‐aminobenzimidazole (2abIm) for 2‐methylimidazole (2mIm) in ZIF‐8 membranes prepared by two different methods (LIPS: ligand induced permselectivation and RTD: rapid thermal deposition) results in a notable shift of the molecular level cut‐off to smaller molecules establishing selectivity improvements from ca. 1.8 to 5 for O 2 /N 2 ; 2.2 to 32 for CO 2 /CH 4 ; 2.4 to 24 for CO 2 /N 2 ; 4.8 to 140 for H 2 /CH 4 and 5.2 to 126 for H 2 /N 2 . Stable (based on a one‐week test) oxygen‐selective air separation performance at ambient temperature, 7 bar(a) feed, and 1 bar(a) sweep‐free permeate with a mixture separation factor of 4.5 and oxygen flux of 2.6×10 −3 mol m −2 s −1 is established. LIPS and RTD membranes exhibit fast and gradual evolution upon a 2abIm‐VPLT, respectively, reflecting differences in their thickness and microstructure. Functional reversibility is demonstrated by showing that the original permeation properties of the VPLT‐LIPS membranes can be recovered upon 2mIm‐VPLT.
'%3e%3cg id='b'%3e%3cpath id='a' stroke='%23000' stroke-width='2' d='M-6-25H6m-12 3H6m-12 3H6'/%3e%3cuse xlink:href='%23a' y='44'/%3e%3c/g%3e%3cpath stroke='%23fff' d='M0 17v10'/%3e%3ccircle r='12' fill='%23cd2e3a'/%3e%3cpath fill='%230047a0' d='M0-12A6 6 0 0 0 0 0a6 6 0 0 1 0 12 12 12 0 0 1 0-24z'/%3e%3c/g%3e%3cg transform='rotate(-123.69)'%3e%3cuse xlink:href='%23b'/%3e%3cpath stroke='%23fff' d='M0-23.5v3M0 17v3.5m0 3v3'/%3e%3c/g%3e%3c/svg%3e)