Abstract: A pressure swing adsorption process for the separation of nitrogen from a mixture of same with methane, utilizing two separate PSA stages, one containing a nitrogen selective adsorbent and the second containing a methane-selective adsorbent. In the process, the first PSA unit containing a nitrogen selective adsorbent forms a product methane stream and a waste stream rich in nitrogen which is passed to a second PSA unit containing a methane selective adsorbent which forms a product nitrogen stream and a waste stream rich in methane. The waste stream rich in methane can be treated to remove heavy hydrocarbons therefrom before the methane is recycled to feed.

Abstract: A pressure swing adsorption process for the separation of nitrogen from a mixture of of same with methane, utilizing two separate PSA stages, one containing a nitrogen selective adsorbent and the second containing a methane-selective adsorbent. In the process, the first PSA unit containing a nitrogen selective adsorbent forms a product methane stream and a waste stream rich in nitrogen which is passed to a second PSA unit containing a methane selective adsorbent which forms a product nitrogen stream and a waste stream rich in methane. The waste stream rich in methane can be treated to remove heavy hydrocarbons therefrom before the methane is recycled to feed.

Abstract: A process for adsorbing hydrocarbons from an acid gas stream includes passing the acid gas stream through an adsorbent which selectively removes hydrocarbons, desorbing the hydrocarbons from the adsorbent and contacting the desorbed hydrocarbons with an acid gas removal solution to remove acid gases which have been coadsorbed with the hydrocarbons. The process is particularly useful in removing hydrocarbons from a hydrogen sulfide-containing stream which is being directed to Claus processing for conversion into elemental sulfur. Useful adsorbents include crystalline titanium silicate molecular sieves containing titania octahedral sites such as ETS-10 and similar materials, as well as high silica aluminosilicate zeolite.

Abstract: A pressure swing adsorption process for the separation of nitrogen from natural gas utilizes two separate pressure swing adsorption stages, the first containing a hydrocarbon-selective adsorbent and the second containing a nitrogen-selective adsorbent. In the process, the product stream from the first pressure swing adsorption unit contains a natural gas stream having a reduced hydrocarbon content and the product stream from the second pressure swing adsorption unit is a natural gas stream having a reduced nitrogen concentration. The product from the second pressure swing adsorption unit is used to desorb the hydrocarbons from the first pressure swing adsorption unit so as to add the hydrocarbons, which have heat value to the product natural gas stream. Periodically, heating the nitrogen-selective adsorbent with heated product stream from the second pressure swing adsorption unit has been found to improve the capacity of the nitrogen-selective adsorbent to adsorb nitrogen.

Abstract: An author-oriented document summarizer for a word processor is described. The document summarizer performs a statistical analysis to generate a list of ranked sentences for consideration in the summary. The summarizer counts how frequently content words appear in a document and produces a table correlating the content words with their corresponding frequency counts. Phrase compression techniques are used to produce more accurate counts of repeatedly used phrases. A sentence score for each sentence is derived by summing the frequency counts of the content words in a sentence and dividing that tally by the number of the content words in the sentence. The sentences are then ranked in order of their sentence scores. Concurrent with the statistical analysis, during the same pass through the document the summarizer performs a cue-phrase analysis to weed out sentences with words or phrases that have been pre-identified as potential problem phrases.

Abstract: A process for adsorbing hydrocarbons from an acid gas stream includes passing the acid gas stream through an adsorbent which selectively removes hydrocarbons, desorbing the hydrocarbons from the adsorbent and contacting the desorbed hydrocarbons with an acid gas removal solution to remove acid gases which have been coadsorbed with the hydrocarbons. The process is particularly useful in removing hydrocarbons from a hydrogen sulfide-containing stream which is being directed to Claus processing for conversion into elemental sulfur. Useful adsorbents include crystalline titanium silicate molecular sieves containing titania octahedral sites such as ETS-10 and similar materials, as well as high silica aluminosilicate zeolite.

Abstract: A process for recovering halides from hydrocarbon containing streams is disclosed using a sulfonated hexafluro bis-A-polysulfone membrane of polymers and copolymers having the polymer repeat unit of the formula: in the polymer or copolymer. This process is applicable to recovering and recycling hydrogen chloride, which is used as a catalytic promoter, in hydrocarbon conversion processes such as isomerization and alkylation.

Abstract: A method of computerized searching receives parameters of a search query from a user and adds a restriction to the parameters to require that at least two of the search terms of the search query appear in a same sentence in a document. A representation of a set of documents is then searched based on the parameters of the search query and the added restriction. Documents that meet the search parameters and the added restriction are thus identified.

Abstract: An author-oriented document summarizer for a word processor is described. The document summarizer performs a statistical analysis to generate a list of ranked sentences for consideration in the summary. The summarizer counts how frequently content words appear in a document and produces a table correlating the content words with their corresponding frequency counts. Phrase compression techniques are used to produce more accurate counts of repeatedly used phrases. A sentence score for each sentence is derived by summing the frequency counts of the content words in a sentence and dividing that tally by the number of the content words in the sentence. The sentences are then ranked in order of their sentence scores. Concurrent with the statistical analysis, during the same pass through the document the summarizer performs a cue-phrase analysis to weed out sentences with words or phrases that have been pre-identified as potential problem phrases.

Abstract: A pressure swing adsorption process for the separation of hydrogen from a mixture of the same with methane, utilizing two separate PSA stages, one containing a nitrogen selective crystalline zeolite, and the second containing a methane selective adsorbent.

Abstract: An apparatus for pressure and temperature swing adsorption processes is described. Such processes include pressure swing adsorption, temperature swing adsorption, and sorption cooling. The apparatus, a spirally wound module, provides high efficiency gas separations by reducing the differential pressure required between the adsorption pressure and the desorption pressure. The apparatus comprises an adsorption zone containing at least one adsorbent paper layer containing a selective adsorbent and an adsorbent spacer spirally wound about a hollow mandrel and in intimate thermal contact with a heat transfer zone. For pressure and temperature swing processes, the adsorption zone is disposed on the outside of the heat transfer zone, and for sorption cooling processes, the heat transfer zone is disposed on the outside of the adsorption zone and the adsorption zone is contained in an envelope-like leaf.

Abstract: A system is utilized for determining a relationship between first and second textual inputs. The system identifies clauses in the first textual input having predetermined characteristics indicative of usefulness in determining the relationship. The relationship is then determined based on the clauses identified. The clauses can be eliminated from the first textual input, weighted in the first textual input, or simply annotated.

Abstract: An author-oriented document summarizer for a word processor is described. The document summarizer performs a statistical analysis to generate a list of ranked sentences for consideration in the summary. The summarizer counts how frequently content words appear in a document and produces a table correlating the content words with their corresponding frequency counts. Phrase compression techniques are used to produce more accurate counts of repeatedly used phrases. A sentence score for each sentence is derived by summing the frequency counts of the content words in a sentence and dividing that tally by the number of the content words in the sentence. The sentences are then ranked in order of their sentence scores. Concurrent with the statistical analysis, during the same pass through the document the summarizer performs a cue-phrase analysis to weed out sentences with words or phrases that have been pre-identified as potential problem phrases.

Abstract: A process for recovering halides from hydrocarbon containing streams is disclosed using a sulfonated hexafluro bis-A-polysulfone membrane of polymers and copolymers having the polymer repeat unit of the formula: in the polymer or copolymer. This process is applicable to recovering and recycling hydrogen chloride, which is used as a catalytic promoter, in hydrocarbon conversion processes such as isomerization and alkylation.

Abstract: The present invention is directed to characterizing the sense of an occurrence of a polysemous word in a representation of a dictionary. In a preferred embodiment, the representation of the dictionary is made up of a plurality of text segments containing word occurrences having a word sense characterization and word occurrences not having a word sense characterization. The embodiment first selects a plurality of the dictionary text segments that each contain a first word. The embodiment then identifies from among the selected text segments a first and a second occurrence of a second word. The identified second occurrence of the second word has a word sense characterization. The embodiment then attributes to the first occurrence of the second word sense characterization of the second occurrence of the second word.

Abstract: The present invention is directed to performing information retrieval utilizing semantic representation of text. In a preferred embodiment, a tokenizer generates from an input string information retrieval tokens that characterize the semantic relationship expressed in the input string. The tokenizer first creates from the input string a primary logical form characterizing a semantic relationship between selected words in the input string. The tokenizer then identifies hypemyms that each have an “is a” relationship with one of the selected words in the input string. The tokenizer then constructs from the primary logical form one or more alternative logical forms. The tokenizer constructs each alternative logical form by, for each of one or more of the selected words in the input string, replacing the selected word in the primary logical form with an identified hypernym of the selected word.

Abstract: A pressure swing adsorption process for the separation of hydrogen from a mixture of the same with methane, utilizing two separate PSA stages, one containing a nitrogen selective crystalline zeolite, and the second containing a methane selective adsorbent.

Abstract: The present invention is directed to performing information retrieval utilizing semantic representation of text. In a preferred embodiment, a tokenizer generates from an input string information retrieval tokens that characterize the semantic relationship expressed in the input string. The tokenizer first creates from the input string a primary logical form characterizing a semantic relationship between selected words in the input string. The tokenizer then identifies hypernyms that each have an "is a" relationship with one of the selected words in the input string. The tokenizer then constructs from the primary logical form one or more alternative logical forms. The tokenizer constructs each alternative logical form by, for each of one or more of the selected words in the input string, replacing the selected word in the primary logical form with an identified hypernym of the selected word. Finally, the tokenizer generates tokens representing both the primary logical form and the alternative logical forms.

Abstract: The present invention provides a facility for determining similarity between two input words utilizing the frequencies with which path patterns occurring between the words occur between words known to be synonyms. A preferred embodiment of the facility utilizes a training phase and a similarity determination phase. In the training phase, the facility first identifies, for a number of pairs of synonyms, the most salient semantic relation paths between each pair of synonyms. The facility then extracts from these semantic relation paths their path patterns, which each comprise a series of directional relation types. The number of times that each path pattern occurs between pairs of synonyms, called the frequency of the path pattern, is counted. In the training phase, the facility identifies the most salient semantic relation paths between the input words, and extracts their path patterns.

Abstract: The present invention is directed to characterizing the sense of an occurrence of a polysemous word in a representation of a dictionary. In a preferred embodiment, the representation of the dictionary is made up of a plurality of text segments containing word occurrences having a word sense characterization and word occurrences not having a word sense characterization. The embodiment first selects a plurality of the dictionary text segments that each contain a first word. The embodiment then identifies from among the selected text segments a first and a second occurrence of a second word. The identified second occurrence of the second word has a word sense characterization. The embodiment then attributes to the first occurrence of the second word sense characterization of the second occurrence of the second word.