Matrix acidizing evaluation

The success of the PVA crosslinking, as well as the success of the dispersion of Co(acac)2 and Co(acac)2trien NaY in the polymeric matrix, were evaluated by FTIR spectroscopy, using a Bio-Rad FTS 155 FT-IR spectrometer. The amount of acid groups in the PVA/SSA matrix was measured by using a classic titration with 0.1 MNaOH... 

There are methods for evaluation of pressure responses during acidizing. They are based on interpretation of recorded wellhead pressure values (or the subsequently derived values for bottom-hole pressure) and corresponding injection rates as treatment progresses. This is done to derive the evolution (hopefully, reduction) of the skin factor during matrix acidizing. Methods... 

Prouvost, L., andM. J. Economides. 1987. Real-time evaluation of matrix acidizing treatments. Petroleum Science and Engineering. November. 

Montgomery, C. T, Y.-M. Jan, and B. L. Niemeyer. 1995. Development of a matrix acidizing stimulation treatment evaluation and recording system. 

It is important to evaluate the effectiveness of every stimulation treatment. Evaluations of matrix addizing and add fracturing treatments are usually based on production increases or comparison with other wells. With matrix acidizing, comprehensive pretreatment and posttreatment well testing and interpretation are usually not economically justified. Comprehensive evaluation can be justified most of the time with acid fracturing and propped fracturing. 

Subsequent to satisfactory evaluation of catalyst and small electrode samples, it is required to test the matrix coated electrode assemblies. Several physical tests are carried out on the matrix, to evaluate its integrity, thickness, uniformity, porosity etc. Simple tests like bubble pressure check is done in a wet matrix (pre-wetted with water or acid). The wet matrix side is pressurized with a gas. The pressure at which the first bubble appears on the top of the other side (i.e. the electrode substrate side) kept under a pool of water, indicates the extent of differential pressure that the matrix can withstand. As the electrode layers are... 

More recently, liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) have been evaluated as possible alternative methods for carfentrazone-ethyl compounds in crop matrices. The LC/MS methods allow the chemical derivatization step for the acid metabolites to be avoided, reducing the analysis time. These new methods provide excellent sensitivity and method recovery for carfentrazone-ethyl. However, the final sample extracts, after being cleaned up extensively using three SPE cartridges, still exhibited ionization suppression due to the matrix background for the acid metabolites. Acceptable method recoveries (70-120%) of carfentrazone-ethyl metabolites have not yet been obtained. 

Barry, J. J., Ph.D Thesis, Evaluation and Characterization of the Degradation and Silver Release From a Poly (d,l- Lactic Acid) - Silver Matrix, Department of Chemistry, University of Lowell, 1988, Bl-1,92. 

Stuer et al. [46] evaluated the presence of the 25 most used pharmaceuticals in the primary health sector in Denmark (e.g., paracetamol, acetyl salicylic acid, diazepam, and ibuprofen). They compared PECs with experimental determinations and they conclude that measured concentrations were in general within a factor of 2-5 of PECs. Carballa et al. [45] also determined PECs for pharmaceuticals (17), musk fragrances (2) and hormones (2) in sewage sludge matrix. For that purpose they used three different approaches (1) extrapolation of the per capita use in Europe to the number of Spanish inhabitants for musk fragrances (2) annual prescription items multiplied by the average daily dose for pharmaceuticals and (3) excretion rates of different groups of population for hormones. They indicated that these PECs fitted with the measured values for half of them (carbamazepine, diazepam, ibuprofen, naproxen, diclofenac, sulfamethoxazole, roxithromycin, erythromycin, and 17a-ethiny I e strad iol). 

Much less work has been focused on the effect of polymer structure on the resist performance in these systems. This paper will describe and evaluate the chemistry and resist performance of several systems based on three matrix polymers poly(4-t-butoxycarbonyloxy-a-methylstyrene) (TBMS) (12), poly(4-t-butoxycarbonyloxystyrene-sulfone) (TBSS) (13) and TBS (14) when used in conjunction with the dinitrobenzyl tosylate (Ts), triphenylsulfonium hexafluoroarsenate (As) and triphenylsulfonium triflate (Tf) acid generators. Gas chromatography coupled with mass spectroscopy (GC/MS) has been used to study the detailed chemical reactions of these systems in both solution and the solid-state. These results are used to understand the lithographic performance of several systems. 

A photosensitive composition, consisting of an aromatic azide compound (4,4 -diazidodi-phenyl methane) and a resin matrix (poly (styrene-co-maleic acid half ester)), has been developed and evaluated as a negative deep UV resist for high resolution KrF excimer laser lithography. Solubility of this resist in aqueous alkaline developer decreases upon exposure to KrF excimer laser irradiation. The alkaline developer removes the unexposed areas of this resist. 

Fig. 1. An overview of the DCLD tier/triage flow chart Boxes 1, 2, and 3 are taken from the Office of Device Evaluation decision tree, which is routinely used to determine whether a product can be reviewed as a 510(k) and found substantially equivalent to a predicate (currently marked) device or whether the product must be handled as a fundamentally new product and submitted to a PMA review. Box 4 determines the novelty of the product in terms of analyte, matrix, and/or technology. If new issues of safety and effectiveness are raised, a highly novel product might require review as a PMA. If the issues of safety and effectiveness are not new but require high-level scrutiny, then a tier III review is warranted. Examples of products requiring a tier III review would include 1. Analyte troponin for diagnosis of MI (with creatinine kinase as the predicate) 2. Matrix sweat patches for drugs of abuse (with urine drugs of abuse tests as the predicate) and 3. Technology nucleic acid...

To demonstrate the use of binary substructure descriptors and Tanimoto indices for cluster analysis of chemical structures we consider the 20 standard amino acids (Figure 6.3) and characterize each molecular structure by eight binary variables describing presence/absence of eight substructures (Figure 6.4). Note that in most practical applications—for instance, evaluation of results from searches in structure databases—more diverse molecular structures have to be handled and usually several hundred different substructures are considered. Table 6.1 contains the binary substructure descriptors (variables) with value 0 if the substructure is absent and 1 if the substructure is present in the amino acid these numbers form the A-matrix. Binary substructure descriptors have been calculated by the software SubMat (Scsibrany and Varmuza 2004), which requires as input the molecular structures in one file and the substructures in another file, all structures are in Molfile format (Gasteiger and Engel 2003) output is an ASCII file with the binary descriptors. 

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