CHEMICAL ENGINEERING CONGRESS AND EXHIBITION | Year:2010 | دوره:13 |Papers Count:48

PROBLEM OF FORCED CONVECTION HEAT TRANSFER IN ANNULUS UNDER BOTH THERMAL AND HYDRODYNAMIC FULLY DEVELOPED AND LAMINAR CONDITIONS ARE INVESTIGATED FOR FLUIDS OBEYING THE GIESEKUS MODEL. THE CONSTANT HEAT FLUX IMPOSED AT THE WALLS AND THE FLUID PROPERTIES ARE TAKEN AS CONSTANT. AXIAL CONDUCTION IS NEGLIGIBLE BUT THE EFFECT OF VISCOUS DISSIPATION IS INCLUDED BECAUSE OF HIGH VISCOSITY OF THIS TYPE FLUIDS.TEMPERATURE PROFILES AND NUSSELT NUMBER ARE DERIVED FROM DIMENSIONLESS ENERGY EQUATION WITH IMPOSED THERMAL AND HYDRODYNAMIC ASSUMPTIONS. THEREFORE, THE EFFECTS OF ELASTICITY AND INTERNAL HEAT GENERATION THAT PRODUCED FROM VISCOUS DISSIPATION ARE SURVEYED. RESULTS INDICATED THE STRONG EFFECT OF THESE PARAMETERS ON BEHAVIOR OF VISCOELASTIC FLUIDS HEAT TRANSFER.

KNOWLEDGE OF MIXING TIME IS OF FUNDAMENTAL IMPORTANCE FOR INVESTIGATION OF MIXING EFFICIENCY IN AGITATION SYSTEMS. THE OBJECTIVE OF THIS WORK IS THE OPTIMIZATION OF OPERATION CONDITANS TO REDUCE THE MIXING TIME. EXPERIMENTALLY, MIXING TIME CAN BE DETERMINED USING A CONDUCTIVITY METER. IN THIS STUDY THE PARAMETERS AFFECTING THE MIXING TIME IN A FIXED GEOMETRICAL CONDITION BY USING EXPERIMENTAL DESIGN HAS BEEN INVESTIGATED. A SECONDORDER POLYNOMIAL EQUATION WAS DERIVED FOR MIXING TIME BY USING RUSPONCE SURFACE METHODOLOGY, AND INDICATING THAT 96% OF THE VARIABILITY IN THE RESPONSE COULD BE EXPLAINED BY THE MODEL.

THIS PAPER EXAMINES A NOVEL DESIGN OF HELMET COOLING SYSTEM USING PHASE CHANGE MATERIAL (PCM) WHICH ABSORBS AND STORE THE HEAT PRODUCED BY THE RIDER. NO ELECTRICAL POWER SUPPLY IS NEEDED FOR THE COOLING SYSTEM. DURING WEARING HELMET THE TEMPERATURE ON THE RIDER HEAD IS MAINTAINED JUST ABOVE THE PCM TEMPERATURE AND CREATE COMFORTABLE ENVIRONMENT SO THE RIDER WOULD NOT SUFFER FROM AN UNCOMFORTABLE AND DANGEROUS HOT ENVIRONMENT ON THE HEAD WHICH WILL AFFECT THE RIDER ALERTNESS. THE UPGRADED HELMET WERE MODELED AND SOLVED BY A THERMAL RESISTANCE NETWORK AND FINITE DIFFERENCE METHOD UNDER UNSTEADY STATE CONDITIONS, THE EFFECT OF ENVIRONMENTAL CONDITIONS SUCH AS AIR VELOCITY AND AMBIENT TEMPERATURE HAD BEEN STUDIED ON THE THERMAL COMFORT OF THE RIDER. THIS PAPER CONCLUDES THAT DESIGNED HELMET IS VERY EFFECTIVE AND PRACTICAL IN VARIOUS AMBIENT CONDITIONS IN IRAN.

WATER CONING AND PRODUCTION OF EXCESS WATER IS ONE OF THE MOST OCCURING PROBLEMS IN OIL WELLS. IT IS ESTIMATED THAT OVER TWO BILLION DOLLARS IS EXPENDED TO SIOLVE THIS PROBLEM. SCIENTIFIC AND PRACTICAL STUDIES HAVE SHOWN THAT DOWNHOLE OIL – WATER SEPARATION (DHOWS) AND DOWNHLOE WATER SINK (DWS) COULD CONTROL WATER CONING AND IMPROVE RECOVERY WITH INCREASE IN OIL PRODUCTION.IN THIS PAPER AN IRANIAN OIL FIELD HAS BEEN STUDIED. ACCORDING TO THE ABOVE STUDIES, WATER CONING WILL OCCUR IN THIS RESERVOIR, THEREFORE A DWS SYSTEM IS DESIGNED FOR A PRODUCING WELL. TO CONTROL THE QUALITY AND EFFICIENCY OF THE SYSTEM, WELLS WITH DWS SYSTEM ARE SIMULATED. RESULTS SHOW 2 TO 3 FOLD INCREASE IN RECOVERY RATE AND 15% TO 20% INCREASE IN RECOVERY FACTOR. FINALLY, ACCORDING TO THE RESULTS AND TO ACCESS MAXIMUM RECOVERY, MINIMUM TIME AND MINIMUM WATER PRODUCTION, SYSTEM IS OPTIMIZED AND PROPOSED TO BE USED IN PRACTICE.

WE PRESENT PORE SCALE MODELING AND SIMULATION OF SOLUTE TRANSPORT IN HETEROGENEOUS POROUS MEDIA UNDER UNSTEADY STATE CONDITIONS. THE GOAL OF THIS PAPER IS TO INVESTIGATE THE EFFECT OF PORE SPACE MORPHOLOGY AND MOBILITY RATIO ON SOLUTION TRANSPORT PROCESSES. MODELING OF SOLUTE TRANSPORT IS USEFUL IN VARIETY APPLICATIONS INCLUDES SIMULATING CONTAMINANT TRANSPORT IN AQUIFERS, DETERMINING THE POTENTIAL DANGER DERIVED FROM UNDERGROUND NUCLEAR WASTE DISPOSAL AND MODELING MISCIBLE INJECTION TO OBTAIN HIGHER OIL RECOVERY IN HYDROCARBON RESERVOIRS. ONE IDEALIZATION OF A POROUS MEDIUM IS TO CONSIDER IT AS A NETWORK, AND THEN A TWO DIMENSIONAL (2- D) PORE NETWORK OF INTERCONNECTED PORES WITH DISTRIBUTED EFFECTIVE RADII IS USED AS A MODEL OF THE POROUS MEDIA. ALONG EACH BOND ADVECTIVE-DISPERSIVE TRANSPORT OCCURS WITH COMPLETE MIXING OF SOLUTE AT PORES. IN THIS MODEL FIRST THE PRESSURE EQUATION IS SOLVED AND THEN THE CONCENTRATION DISTRIBUTION IS DETERMINED USING THE CONVECTIVE-DIFFUSION EQUATION (CDE) FOR EACH PORE IN THE NETWORK. THE RESULTS SHOW THE EFFECT OF HETEROGENEITY OF THE NETWORK, PORE SIZE DISTRIBUTION (PSD) AND MOBILITY RATIO ON VISCOUS FINGERING FORMATION, BREAKTHROUGH TIME, RECOVERY FACTOR (RF) AND LONGITUDINAL DISPERSION. THE RESULTS OF MONTE CARLO SIMULATION SHOW THAT BY INCREASING THE HETEROGENEITY OF THE NETWORK THE FINGERING FORMATION, BREAKTHROUGH TIME AND LONGITUDINAL DISPERSION WOULD INCREASE WHILE THE RF DECREASE. ACCORDING TO THE RESULTS, THE LONGITUDINAL DISPERSION DEPENDS ON THE NETWORK SIZE AND WILL INCREASE GRADUALLY WITH ITS INCREASE. ALSO THE INCREASE OF THE MOBILITY RATIO WILL DECREASE THE BREAK THROUGH TIME AND INCREASE FINGERING FORMATION.

EFFECTS OF PACKED BED IN THE RISER SECTION OF A SPLIT-CYLINDER AIRLIFT BIOREACTOR ON GAS HOLDUP, LIQUID CIRCULATION RATE, MIXING TIME AND THE GAS-LIQUID MASS TRANSFER WITH DIFFERENT GAS FLOW RATES ARE REPORTED FOR AIR–WATER. PACKING ARE ONE/TWO ROWS OF CYLINDRICAL TYPE THAT WERE SETTING HORIZONTALLY WITH A REGULAR DISTANCES. SUPERFICIAL GAS VELOCITIES WAS USED AS OPERATIONAL PARAMETER.IT WAS OBSERVED FROM EXPERIMENTAL RESULTS THAT GAS HOLD UP, OXYGEN TRANSFER AND MIXING TIME INCREASED WITH INCREASING THE NUMBER OF PACKING ROWS BUT PRESENCE OF PACKING IN THE REACTOR DECREASE THE LIQUID CIRCULATION. IN FACT PACKINGS ACT LIKE A BARRIER SO DECREASE LIQUID CIRCULATION, IN ADDTION, ACCUMULATION OF BUBBLES BEHIND THEM LEAD TO INCREASING BUBBLE COALESCENCE RATE AND INCREASING OF BOUYNCY FORCE THUS BUBBLES EXPORT FROM RECTOR WITH NOT IMPORTING TO DOWN COMER RESULT IN DECREASING OF GAS HOLD-UP IN THE DOWN COMER.

INVESTIGATION OF NON-NEWTONIAN FLUID FLOW THROUGH A TAPERED TUBE IS IMPORTANT FOR ATOMIZATION AND EXTRUSTION OF NON-NEWTONIAN FLUID LIKE POLYMERIC AND PARTICULATE FLUIDS. IN THIS ARTICLE, THE EFFECTS OF VARIATIONS SURFACE GEOMETRY OF THE TAPERED TUBE BY USING OF AN CICULAR RIB SHAPE LIKE O-RING THAT IS VERTICAL TO AXIS OF TUBE HAS BEEN INVESTIGATED. THE NON-NEWTONIAN FLUID OBEYS THE MODIFIED HERSCHEL–BULKLEY BEHAVIOR. THE FINITE VOLUME METHODS HAVE BEEN USED TO DISCRETISE THE PARTIAL DIFFERENTIAL EQUATIONS OF THE MODEL USING THE SIMPLE METHOD FOR PRESSURE–VELOCITY COUPLING AND THE SECOND-ORDER UPWIND SCHEME TO INTERPOLATE THE VARIABLES ON THE SURFACE OF THE CONTROL VOLUME. INFLUENCE OF OPERATIONAL AND GEOMETRICAL PARAMETERS ON APPARENT VISCOSITY OF FLUID AT DIE OUTLET HAVE BEEN DISCUSSED. COMPUTATIONAL RESULTS SHOW THAT ADDITION OF VERTICAL O-RING IN TAPERED TUBE IN SUITABLE POSITIONS CAUSES CONSIDERABLE DECREASE IN APPARENT VISCOSITY AT DIE OUTLET.

A CIRCULATING PHOTOCATALYTIC REACTOR WAS USED FOR REMOVING THE ORGANIC POLLUTANTS IN REFINERY WASTEWATER. THE NANO-TIO2 ADDED WASTEWATER SAMPLES, WHILE SATURATING WITH AIR, WERE IRRADIATED WITH AN IMMERSED MERCURY UV LAMP (400 W, 200–550 NM). OPTIMAL CATALYST CONCENTRATION, FLUID AND TEMPERATURE WERE OBTAINED AT AMOUNTS OF NEAR 100 MG L-1, 3 AND 45OC, RESPECTIVELY. A MAXIMUM REDUCTION IN CHEMICAL OXYGEN DEMAND OF MORE THAN 78% WAS ACHIEVED AFTER ABOUT 120 MIN IRRADIATION AND HENCE, 72% AFTER ABOUT ONLY 90 MIN, SIGNIFICANT POLLUTANT REMOVAL WAS ALSO ACHIEVABLE IN THE OTHER CONDITIONS. THE IDENTIFICATION OF THE ORGANIC POLLUTANTS, PROVIDED BY MEANS OF A GC/MS AND A GC ANALYSIS SYSTEMS, EQUIPPED WITH HEADSPACE INJECTION TECHNIQUE, SHOWED THAT THE MAJOR COMPOUNDS WERE DIFFERENT FRACTIONS OF PETROLEUM ALIPHATIC AND AROMATIC COMPOUNDS. THE RESULTS SHOWED A HIGH EFFICIENCY DEGRADATION OF ALL OF THESE POLLUTANTS.

THIS PAPER REPORTS THE RESULTS OF AN EXPERIMENTAL AND NUMERICAL INVESTIGATION ON THE MIXING TIME IN A TANK WITH AN ASPECT RATIO OF 1 EQUIPPED WITH A TOP ENTRY JET MIXER. FOR THIS PURPOSE, A THREE DIMENSIONAL MODELING WAS CARRIED OUT USING AN IN-HOUSE COMPUTATIONAL FLUID DYNAMICS (CFD) CODE. IN THIS STUDY, THE THEORETICAL MIXING CURVES PREDICTED BY THE CFD WERE VALIDATED BY EXPERIMENTS. THE EXPERIMENTS WERE CARRIED OUT FOR 0O, 10O, 17O, 25O, 35O AND 45O JET ANGLE SETUPS. THE RESULTS SHOWED THAT THE 35OP JET LAYOUT WOULD LEAD IN THE SHORTEST MIXING TIME. THE CFD CODE WAS RUN FOR 0O, 10O, 17O, 25O, 30O, 35O, 40O, 45O AND 60O JET ANGLES AND THE RESULTS CONFIRMED THAT 35O PWOULD RESULT IN THE SHORTEST MIXING TIME. THE CFD CODE WAS ALSO RUN FOR A VARIETY OF JET FLOW RATES. THE RESULTS SHOWED THAT THE MIXING TIME CHANGES ARE MUCH MORE OBVIOUS IN LOW JET FLOW RATES (LOW JET REYNOLDS NUMBERS) AND AS THE FLOW RATE EXCEEDS 0.2 LIT/SEC THESE CHANGES BECOME LESS OBVIOUS. THE EFFECT OF THE MESH SIZE ON THE PREDICTED RESULTS WAS ALSO INVESTIGATED. THE RESULTS SHOWED THAT THE NUMBER OF MESHES IS QUITE EFFECTIVE ON THE OBTAINED THEORETICAL RESULTS IN A WAY THAT THE PREDICTED RESULTS FOR THE LARGEST MESH SIZE WERE FAR AWAY FROM THE RESULTS FOR THE SMALLEST MESH SIZE.

IN THIS WORK EFFECTS OF AERATION AND IMPELLER SPEED ON MIXING TIME IN A STIRRED TANK WITH PBT IMPELLERS IS STUDIED. ALL THE EXPERIMENTS CARRIED OUT IN A STIRRED TANK WITH TWO PBTU30O. CONDUCTIVITY PROBE TECHNIQUE IS USED FOR OBTAINING OF THE MIXING TIME. RESULTS SHOW WITH INCREASING THE IMPELLER SPEED IN BOTH, SINGLE- AND TWO-PHASE SYSTEMS CAUSE DECREASING THE MIXING TIME. WHEREAS, THE AERATION CAN LEAD TO INCREASE OR DECREASE MIXING TIME AND EVEN CREATE NEGLIGIBLE EFFECT. ALSO, IS SHOWN THAT DIFFERENT FLOW REGIMES CAN AFFECT THE FINAL CONCENTRATION OF CONDUCTOMETER.

IN THIS STUDY, SOLUBILITY DATA WERE REGRESSED FOR 2-PROPOXYETHANOL (C3E1) DISSOLVED IN N-HEXANE AND N-HEPTANE AT THE TEMPERATURE RANGE FROM 303.15K TO 323.15K BY NRTL MODEL. NRTL MODEL WAS FOUND TO PROVIDE AN ACCURATE MATHEMATICAL REPRESENTATION OF THE EXPERIMENTAL RESULTS, WITH OVERALL AVERAGE ABSOLUTE RELATIVE DEVIATIONS BETWEEN EXPERIMENTAL AND CALCULATED VALUES AS 9.15%. THE RESULTS SHOWED THAT THE NRTL MODEL IS SUITABLE FOR DESCRIPTION OF THE GAS-LIQUID EQUILIBRIUM CONTAINING 2-PROPOXYETHANOL (C3E1).

OXIDATIVE COUPLING OF METHANE WAS STUDIED OVER TRIMETALLIC CATALYST CONTAINING MN, W AND ALKALI ION OVER SIO2 AS SUPPORT UNDER FIXED BED CONDITION WITH CH4/AIR=1, CH4/O2=5 FEED FLOW RATE OF 140 ML/MIN (STP) AND GHSV=13200 ML/GCAT. THE AIM OF RESERCH IS ATTAINING A CATALYST WITH HIGH ACTIVITY-SELECTIVITY. ROLE OF THE SUPPORT POROSITY ON THE CATALYST PERFORMANCE WAS STUDIED. THIS IS RESEARCHED BY SELECTION OF POROUS SIO2 AND QUARTZ AS SUPPORT.

ADSORPTION OF WATER FROM ETHANOL-WATER MIXTURE IS MODELED UNDER NON-ISOTHERMAL TRANSIENT CONDITIONS. THE MODEL CAN BE USED TO STUDY EFFECT OF DIFFERENT PARAMETERS SUCH AS EQUILIBRIUM ISOTHERM, ADSORPTION VESSEL GEOMETRY, AND MASS TRANSFER AND HEAT TRANSFER COEFFICIENTS ON OPERATIONAL EFFICIENCY. FOUR DIFFERENT OPTIMIZATION ALGORITHMS ARE COUPLED WITH THE MODEL IN ORDER TO DETERMINE CONSTANTS OF EQUILIBRIUM ISOTHERMS AND HEAT OF ADSORPTION USING EXPERIMENTAL DATA. VALIDITY OF MODEL OUTPUTS IS INVESTIGATED BASED ON LOGICAL TESTS. CONCENTRATION AND TEMPERATURE PROFILES AS MODEL OUTPUTS ARE USED AS INPUT DATA TO OPTIMIZATION ALGORITHMS TO STUDY PERFORMANCE OF THESE ALGORITHMS IN ESTIMATING CONSTANTS OF EQUILIBRIUM ISOTHERMS AND HEAT OF ADSORPTION. ESTIMATIONS PROVED TO BE IN GOOD AGREEMENT WITH DATA USED IN MODEL TO GENERATE REQUIRED INPUT PROFILES REGARDLESS OF ERRORS IN INITIAL GUESSES.

EXPERIMENTAL TIE-LINE RESULTS AND PHASE DIAGRAMS WERE OBTAINED FOR THE TERNARY SYSTEMS OF [WATER +CARBOXYLIC ACIDS + ISOBUTYL ACETATE] AT T=298.2 K AND ATMOSPHERIC PRESSURE. THE CARBOXYLIC ACIDS WERE PROPIONIC ACID AND BUTYRIC ACID. THESE TWO TERNARY SYSTEMS EXHIBIT TYPE-1 BEHAVIOR OF LLE. THE EXPERIMENTAL TIE-LINE DATA WERE ALSO COMPARED WITH THOSE CORRELATED BY THE UNIQUAC AND NRTL MODELS. THE CONSISTENCY OF THE VALUES OF THE EXPERIMENTAL TIE-LINES WAS DETERMINED THROUGH THE HAND CORRELATION EQUATION. DISTRIBUTION COEFFICIENTS AND SEPARATION FACTORS WERE EVALUATED OVER THE IMMISCIBILITY REGIONS AND A COMPARISON OF THE EXTRACTING CAPABILITIES OF THE ISOBUTYL ACETATE WAS MADE WITH RESPECT TO DISTRIBUTION COEFFICIENTS AND SEPARATION FACTORS.

THE CATALYTIC REFORMING PROCESS IS ONE OF THE MOST SIGNIFICANT SYSTEMS IN PETROLEUM REFINERIES .IT CONVERTS HEAVY NAPHTHA WITH LOW OCTANE NUMBER TO A LIGHT NAPHTHA (REFORMATE) WITH HIGH OCTANE NUMBER THROUGH A GROUP OF CATALYTIC REACTIONS SUCH AS DEHYDROGENATION, ISOMERIZATION, DEHYDRO-CYCLIZATION AND HYDRO- CRACKING. AT THE SAME TIME, IT PRODUCES HYDROGEN GAS (H2) AND LIQUEFIED PETROLEUM GAS (LPG) AS BY-PRODUCTS.THE PROPOSED MODEL ASSUMES THREE ADIABATIC CATALYTIC REACTORS WITH A CENTRAL FURNACE RELATIVE TO BASRAH REFINERY PLANT IN BASRAH CITY, ONE OF THE LARGEST INDUSTRIAL CITIES IN THE SOUTHERN PART OF IRAQ. THE CATALYTIC REFORMING UNITS ARE OPERATED AT RELATIVELY HIGH OPERATION CONDITIONS WHERE THE TEMPERATURE IS IN THE RANGE OF (470 -500)OC, PRESSURE IS IN THE RANGE OF (30-35 ATM) AND HYDROGEN TO HYDROCARBON MOLAR RATIO IS ABOUT 5.9. THE REACTORS HAVE BEEN PROVIDED WITH PLATINUM- ALUMINA AS A CATALYST AND THE DENSITY OF FEEDSTOCK IS (732.8 -766.7 KG/M3).

IN THE PRESENT STUDY, POLYMER COMPOSITE REINFORCED WITH DIFFERENT RATIOS OF GLASS FIBER WERE PREPARED TO IMPROVE MECHANICAL AND THERMAL CHARACTERISTICS FOR WEAR APPLICATIONS. FIVE SAMPLES WITH PERCENTAGES (5%, 10%, 15%, 20%, 25%) OF GLASS FIBER OF CHOPPES RANGE FROM (0.1-5 MM) LENGTH USED AS ADDITIVES TO A MATRIX OF UNSATURATED POLYESTER WERE TESTED. MECHANICAL TESTS INCLUDE: WEAR, IMPACT, TENSILE AND HARDNESS, WHILE THERMAL TESTS INCLUDE: THERMAL CONDUCTIVITY. THE RESULTS SHOW THAT THE SAMPLE WITH 25% GLASS FIBER INDICATES HIGH WEAR RESISTANCE AND HARDNESS, WHILE 10% IS THE HIGHER IMPACT RESISTANCE AND 5% IS THE HIGHER TENSILE STRENGTH. ALSO THERMAL CONDUCTIVITY DECREASES WITH INCREASING GLASS FIBER PERCENTAGE .TO OBTAIN OPTIMUM POLYMER PROPERTIES, SUITABLE BALANCE BETWEEN MECHANICAL AND THERMAL PROPERTIES MUST BE PERFORMED BY CONTROLLING ON ADDITIVES RATIOS AND SHAPE WHICH MENTIONED ABOVE, THEREFORE 15% PERCENTAGE GLASS FIBER IS INDICATE GOOD AGREEMENT WITH PURPOSE OF THIS WORK.

LABORATORY INVESTIGATION HAS BEEN CARRIED OUT ON MIXING POWER CONSUMPTION AND FLOW REGIME TRANSITION IN A FULLY BAFFLED STIRRED TANK REACTOR EQUIPPED WITH DUAL SIX-BLADE RUSHTON TURBINES BY ELECTRICAL MEASUREMENT TECHNIQUE. AN EMPIRICAL CORRELATION HAS BEEN DERIVED USING PREDICTED EXPERIMENTAL DATA, WHICH PRESENTS A NEW RELATION IN ESTIMATION OF POWER CONSUMPTION IN STIRRED TANKS WITH DUAL RUSHTON IMPELLERS. RESULTS HAVE BEEN COMPARED WITH DATA AVAILABLE IN TECHNICAL LITERATURE. A REASONABLE AGREEMENT BETWEEN THE EXPERIMENTAL AND TECHNICAL LITERATURE RESULTS HAS BEEN OBSERVED.

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THIS PAPER PRESENTED THE CHARACTERISTIC OF LIQUID DESICCANT DEHUMIDIFICATION. LIQUID DESICCANT COOLING SYSTEM WAS DESIGNED AND MADE IN SEPARATION PROCESS LABORATORY OF TARBIAT MODARES UNIVERSITY. LITHIUM CHLORIDE (LICL) AS LIQUID DESICCANT AND A PACKED BED COLUMN WAS USED FOR DEHUMIDIFICATION. THE DESCRIBED SYSTEM INCLUDES ONE PART FOR PROCESS AIR SIMULATION WITH VARIOUS TEMPERATURES AND HUMIDITY. A METHOD WAS DEVELOPED FOR DETERMINING COUPLED HEAT AND MASS TRANSFER COEFFICIENTS BETWEEN AIR AND LIQUID DESICCANT, THROUGH WHICH THE HEAT AND MASS TRANSFER COEFFICIENTS BETWEEN AIR AND LIQUID DESICCANT WERE CALCULATED TO OBTAIN FROM EXPERIMENTAL INLET AND OUTLET PARAMETERS OF AIR AND DESICCANT SOLUTION. BASED ON THE COMPUTATION RESULTS, IT WAS CONCLUDED THAT THE LEWIS NUMBER GREATLY DEPENDED ON THE OPERATION PARAMETERS AND CONDITIONS OF THE AIR AND DESICCANT.

ONE OF THE EFFECTIVE PARAMETERS EFFECTIVE IN DESIGNING OF PULSED PACKED COLUMNS IS HOLD UP. THIS PARAMETER IS USED TO MEASURE THE SLIP VELOCITY AND OF COURSE TO ESTIMATE THE HEIGHT AND DIAMETER OF THE EXTRACTION COLUMN. THE MAIN OBJECTIVE OF THIS ARTICLE IS STUDY ON THE INFLUENCE OF PULSE INTENSITY ON THE HOLDUP AMOUNTS IN A PILOT PLANT PULSED PACKED COLUMN. ACCORDING TO THE INTERFACIAL TENSION EFFECT ON THE DROPS DIAMETER AND HOLD UP AMOUNTS ALONG THE PULSED PACKED COLUMN, THE LIQUID-LIQUID SYSTEMS USED WERE TOLUENE-WATER (HIGH INTERFACIAL TENSION) AND N-BUTYL ACETATE-WATER (MEDIUM INTERFACIAL TENSION). ALL EXPERIMENTS HAVE BEEN CARRIED OUT WITHOUT MASS TRANSFER. THE COMPARISON BETWEEN TWO SYSTEMS RESULTS SHOW THAT BY INCREASING THE PULSE INTENSITY VALUES, THE HOLDUP AMOUNTS FOR THE BOTH OF THE SYSTEMS INCREASE TOO, AND THE EFFECT OF PULSE INTENSITY ON THE HOLD UP FOR N-BUTYL ACETATE-WATER SYSTEM WHICH HAS LOWER INTEFACIAL TENSION, IS MORE THAN TOLUENE-WATER.

KNOWLEDGE OF MIXING TIME IS OF FUNDAMENTAL IMPORTANCE FOR INVESTIGATION OF MIXING EFFICIENCY IN AGITATION SYSTEMS. THE MIXING TIME OBTAINED BY USING THE CORRELATION AND FORMULA AT LARGE SCALE OF MIXING SYSTEMS WAS INCORRECT. AGAIN NUMBER OF AVAILABLE CORRELATION IN THIS SCALE OF MIXING SYSTEMS IS LIMITED. TO PREDICT THE MIXING TIME OF STIRRED TANKS WITH DUAL IMPELLERS, COMMONLY USED IN INDUSTRY, A THIRD- COMPARTMENT MIXING MODEL WAS USED. THE TIME OF HOMOGENIZATION OF THECHARGE (MIXING TIME) WAS CALCULATED FROM THE TIME DEPENDENCY OF THE LOCAL CONCENTRATION OF TRACER MEASURED AT VARIOUS LOCATIONS. EXPERIMENTAL DATA ON MIXING TIME WERE OBTAINED WITH A CONDUCTIVITY TECHNIQUE. IN THE PRESENT STUDY DISTRIBUTION OF TRACER IN THE BULK OF LIQUID DESCRIBED BY COMPARTMENT MODEL(CM) AS WELL AS FOR STIRRED VESSEL WITH DUAL RUSHTON IMPELLERS. AS FOR THE MODEL, A GOOD AGREEMENT BETWEEN THE EXPERIMENTAL DATA AND THE CALCULATED VALUES WAS APPARENT.

A NEW TYPE OF AIR CONDITIONING SYSTEM, THE LIQUID DESICCANT EVAPORATION COOLING AIR CONDITIONING SYSTEM (LDCS) IS INTRODUCED IN THIS PAPER. DESICCANT EVAPORATION COOLING TECHNOLOGY IS ENVIRONMENTAL FRIENDLY AND CAN BE USED TO CONDITION THE INDOOR ENVIRONMENT OF BUILDINGS. THIS SYSTEM WAS DESIGNED AND MADE IN SEPARATION PROCESS LABORATORY OF TARBIAT MODARES UNIVERSITY. LITHIUM CHLORIDE (LICL) AS LIQUID DESICCANT AND A PACKED BED COLUMN WAS USED FOR DEHUMIDIFICATION. THE DESCRIBED SYSTEM INCLUDES ONE PART FOR PROCESS AIR SIMULATION WITH VARIOUS TEMPERATURES AND HUMIDITY. THEN A MODEL BASED ON MASS AND HEAT TRANSFER EQUATIONS WAS WRITTEN FOR THE DEHUMIDIFICATION PACKED COLUMN LIQUID DESICCANT. THIS EQUATIONS WAS SOLVED WITH MATLAB SOFTWARE. EXPERIMENTAL DATA WERE COMPARED WITH THE RESULTS OF THIS MODEL. THE RESULTS SHOW THAT OBTAINED EXPERIMENTAL DATA FROM THIS SYSTEM HAVE VERY GOOD AGREEMENT WITH THIS MODEL. THE RESULTS ARE PRESENTED IN THIS PAPER.

AN EFFICIENT METHOD CALLED ULTRASONIC-ASSISTED SYNTHESIS HAS BEEN REPORTED FOR THE ADDING NI TO CERIA-ZIRCONIA SUPPORT. CERIA-ZIRCONIA SOLID SOLUTION ITSELF WAS PREPARED BY THE CO-PRECIPITATION METHOD. SYNTHESIZED NANO CATALYST CHARACTERIZED BY XRAY DIFFRACTION (XRD), N2 ADSORPTION (BET), FTIR SPECTRA AND SCANNING ELECTRON MICROSCOPE (SEM) TECHNIQUES. THE APPARENT CRYSTALLITE SIZES OF THE ZIRCONIA, CERIA AND NICKEL PHASES WERE DETERMINED USING SCHERER'S EQUATION WHICH ARE ESTIMATED AS 48, 15 AND 22 NM, RESPECTIVELY.

THERMO SYPHON IS AN EFFECTIVE SYSTEM IN HEAT TRANSFER. ACCORDING TO THE APPLICATIONS, THERE ARE TWO IMPORTANT TYPES: OPEN THERMO SYPHON AND CLOSED THERMO SYPHON. IN THIS PAPER, AFTER A REVIEW ON THEORETICAL AND EXPERIMENTAL ARTICLES ABOUT SINGLE-PHASE LOOP THERMO SYPHON, CONSIDERING A SINGLE PHASE THERMO SYPHON, THE INFLUENCE OF DIAMETER ON THE MEAN VELOCITY INSIDE THE LOOP IS STUDIED USING ANSYS CFX SOFTWARE.

IN THIS WORK, A KINETIC MODEL WAS PROPOSED FOR SIMULATION OF CATALYTIC REFORMING PROCESS. THE FEED OF CATALYTIC REFORMING UNITS IS HEAVY NAPHTHA INCLUDING PARAFFIN, NAPHTHENIC COMPOUNDS AND AROMATICS WITH 6-9 CARBONS. MAJOR REACTIONS OCCURRED IN THE CATALYTIC REACTOR INCLUDE DEHYDROGENATION, DEHYDROCYCLISATION, ISOMERISATION, HYDROCRACKING AND RING OPENING WHICH REACT SIMULTANEOUSLY. A CYLINDRICAL ELEMENT OF CATALYST IS CONSIDERED TO OBTAIN CONSERVATION EQUATIONS INCLUDING MASS AND ENERGY BALANCES. THE DERIVED EQUATIONS ARE SOLVED BY NUMERICAL METHOD USING MATLAB SOFTWARE TO SIMULATE CATALYTIC REFORMING REACTORS OF TEHRAN REFINERY. MODELING FINDINGS INVOLVING CONCENTRATION, TEMPERATURE AND OCTANE NUMBER VARIATIONS WERE EVALUATED. FURTHERMORE, SIMULATION RESULTS WERE COMPARED WITH EXPERIMENTAL DATA AND CONFIRMED THE ACCURACY OF THE PROPOSED MODEL.

SPRAY DRYING IS A CONVENTIONAL AND OLD METHOD IN DETERGENT PROCESSING. THERE ARE MANY PROBLEMS INVOLVED WITH THIS PROCESS, SUCH AS, HIGH ENERGY CONSUMPTION, ENVIRONMENTAL RISKS DUE TO SPREADING OF FINE PARTICLES, AND LOW DENSITY MATERIALS LEADING TO LARGE VOLUME PRODUCTS. IN THIS REGARD, CONSOLIDATION OF SOLID DETERGENT MATERIALS IN A HIGH SHEAR MIXER GRANULATOR BY A LIQUID BINDER LOOKS TO BE A SUITABLE ALTERNATIVE METHOD. NOWADAYS IN DEVELOPED COUNTRIES, GRANULATIONS OF POWDERED MATERIALS, FOLLOWED BY TABLETING OF SOFT GRANULES, PLAY THE MAIN ROLE IN THE DETERGENT MANUFACTURING. THE GRANULATION OF FINE AND COHESIVE POWDERS (I.E. BUILDERS IN DETERGENT) BY VISCOUS ANIONIC SURFACTANT BINDERS SUCH AS LAS IN A HIGH SHEAR MIXING GRANULATOR MAY IMPROVE THE PROPERTIES FOR COMPACTED GRANULES. THE MAIN OBJECTIVE OF THIS STUDY WAS TO INVESTIGATE PARAMETERS AFFECTING THE GRANULATION OF ZEOLITE POWDERS WITH LAS IN A LABORATORY HIGH SHEAR MIXER GRANULATOR. THE PAPER PRESENTS THE EFFECTS OF MIXING TIME, IMPELLER ROTATIONAL SPEED AND LIQUID TO SOLID RATIO ON THE GRANULES PROPERTIES SUCH AS SIZE DISTRIBUTION, MOISTURE CONTENT AND BULK DENSITY OF GRANULES. THE RESULTS SHOWED THAT THE DESIRABLE SIZE AND BINDER CONTENT OF THE GRANULES WERE OBTAINED UNDER THE SPEED OF 150 RPM AND MIXING TIME OF 6 MIN. IN THESE CONDITIONS, THE BULK DENSITY AND MOISTURE CONTENT OF GRANULES WERE IN THE PROPER FIGURE SUITABLE FOR COMPACTED DETERGENTS.

IN THIS PAPER, RESULTS OBTAINED FROM INVESTIGATIONS ON A POLYAMIDE REVERSE OSMOSIS MEMBRANE FOULED BY PRECIPITATION OF MATERIALS, WHICH EXIST IN SEAWATER, ARE PRESENTED. IN THESE STUDIES, EFFECT OF DIFFERENT HYDRODYNAMIC FACTORS ON FOULING OF THE MEMBRANE HAS BEEN INVESTIGATED. OPERATING CONDITIONS SUCH AS TEMPERATURE, PRESSURE, CROSS FLOW VELOCITY AND PH, WHICH COULD PLAY AN IMPORTANT ROLE IN THE FOULING PROCESSES, WERE SELECTED FOR THE STUDIES. THE RESULTS SHOW THAT INCREASING TEMPERATURE, PRESSURE AND CROSS FLOW VELOCITY ENHANCES FOULING OF THE MEMBRANE; ON THE OTHER HAND, INCREASES PERMEATE FLUX. THUS, OPTIMIZATION OF THE PARAMETERS WAS FOUND TO BE NECESSARY AND OPTIMUM VALUES OF THEM AND PH WERE DETERMINED.

THE AIM OF THIS ARTICLE IS THE SIMULATION OF THE BAFFLED STIRRED TANK WITH 6 BLADES RUSHTON TURBINE THROUGH DIFFERENT TURBULENT MODELS TO INVESTIGATE THEIR PERFORMANCE AND ACCURACY IN PREDICTING THE FLUIDS HYDRODYNAMICS IN TURBULENT FLOW FIELDS. IN ALL SIMULATIONS PISO PRESSURE-VELOCITY COUPLE, PRESTO DISCRETIZATION SCHEME FOR PRESSURE AND THE SLIDING MESH METHOD TO IMPELLER ROTATION MODEL WAS USED. THE EXPERIMENTAL VELOCITY DISTRIBUTION AND TURBULENT KINETIC ENERGY CURVES WERE COMPARED WITH THE NUMERICAL ONES. THE RESULTS CONFIRMED THAT THE LES MODEL IS MORE CAPABLE IN PREDICTING THE FLUID HYDRODYNAMICS IN TURBULENT FLOW FIELDS THAN THE OTHER TURBULENT MODELS USED IN THIS WORK.

THIS WORK PRESENTS AN EXPERIMENTAL AND THEORETICAL INVESTIGATION OF CO2 ABSORPTION INTO AQUEOUS OF 2-AMINO-2-METHYL-1-PROPANOL (AMP) .THE SOLUBILITY OF CO2 IS STUDIED IN TEMPERATURE RANGE OF (303 TO 323)K AND AT AMP SOLUTION COMPOSITIONS (2.0 M, 2.8 M, AND 3.4 M) ON SAMPLES OF FLUE GASES FROM THERMAL AND CENTRAL POWER PLANTS OF ESFAHAN STEEL COMPANY USING SOLUBILITY MEASURING APPARATUS.. THE DESHMAKH-MATHER MODEL WAS USED TO CORRELATE AND PREDICT THE VAPOR-LIQUID EQUILIBRIA OF THE (CO2 + AMP + H2O) SYSTEM. DATA ON CO2 LOADING IN AQUEOUS SOLUTIONS OF AMP WAS FITTED TO GENERATE THE DIFFERENT INTERACTION PARAMETERS REQUIRED TO CALCULATE THE ACTIVITY COEFFICIENTS IN THEMODEL THE MODEL PREDICTED RESULTS ARE IN GOOD AGREEMENT WITH THE EXPERIMENTAL VAPOR-LIQUID EQUILIBRIUM MEASUREMENTS IN THIS RESEARCH.

POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) ARE TOXIC POLLUTANTS WHICH ARE WIDESPREAD IN THE ENVIRONMENT. THESE COMPOUNDS SHOWED CARCINOGENIC AND MUTAGENIC PROPERTIES AND ARE LISTED BY THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY (USEPA) AS PRIORITY POLLUTANTS. IN THIS STUDY 13 BACTERIAL STRAINS WERE ISOLATED FROM THREE CONTAMINATED SITES OF TEHRAN OIL REFINERY. PAH BIODEGRADATION EXPERIMENTS WERE CONDUCTED IN AQUEOUS PHASE AND GC ANALYSIS WAS USED FOR MEASURING PAHS CONCENTRATIONS.BIODEGRADATION RATES OF THREE PAHS, PHENANTHRENE, ANTHRACENE AND PYRENE WITH 50 MG/L INITIAL CONCENTRATION WERE OBTAINED ALONG 30 DAYS. THE DEGRADATION OF INDIVIDUAL PAHS (PHENANTHRENE, ANTHRACENE AND PYRENE) WAS IN THE RANGE OF 34.5-65.7%, 21.4-92% AND 27.2- 90.1%, RESPECTIVELY. IN THE NEXT STEP AND IN THE SAME CONDITIONS, THE BIODEGRADATION RATES OF HE THREE PAHS WERE INVESTIGATED IN MIXTURE. DECREASE IN DEGRADATION RATE OF THREE RING PAHS AND INCREASE IN PYRENE DEGRADATION, A FOUR RING PAH, SHOWED THAT PYRENE WAS DEGRADED BY CO-METABOLISM. THE USE OF COMETABOLISM IN BIOREMEDIATION TECHNIQUES INCREASES THE BIODEGRADATION RATE OF HIGH MOLECULAR WEIGHT PAHS.

IN THIS PAPER THE PRESSURE DECAY METHOD APPLIED TO MEASURE DIFFUSION COEFFICIENTS OF GASES IN ONE OF IRANIAN HEAVY CRUDE OIL USING VISUAL PVT CELL AT DIFFERENT CONDITIONS OF TEMPERATURE. NUMERICAL AS WELL AS GRAPHICAL SOLUTION WERE UTILIZED TO DETERMINE DIFFUSION COEFFICIENTS OF N2 AND CO2 IN CRUDE OIL AT INITIAL PRESSURE OF 54.6 BAR AND THREE DIFFERENT TEMPERATURES, 25, 40, 50OC FOR CO2 AND 25OC FOR N2. THE RESULTS SHOWED THAT DIFFUSIVITY OF CO2 IS LARGER THAN N2 AT SAME CONDITIONS OF TEMPERATURE AND INITIAL PRESSURE. ALSO, THE MEASURED DIFFUSION COEFFICIENT AT EARLY TIMES IS GREATER THAN THAT OF AT LATE TIMES. THE MEASURED DATA WERE USED AND THE CONSTANTS OF TWO TEMPERATURE DEPENDENT DIFFUSION COEFFICIENT CORRELATIONS FOR CO2-HEAVY OIL SYSTEM WERE MODIFIED. THE MEASURED DIFFUSION COEFFICIENTS ARE IN THE RANGE OF AVAILABLE DATA IN THE LITERATURE FOR DIFFERENT CRUDE OILS.

THREE-DIMENSIONAL STEADY-STATE TURBULENT ROTATING SINGLE-PHASE FLOW WERE SIMULATED IN A ROTATING PACKED BED (RPB) AND WERE VALIDATED USING OVERALL DRY PRESSURE DROP MEASUREMENTS FOR A NOVEL RPB DESIGN. VECTOR PLOTS OF VELOCITY IN THE RPB REPRESENTED THAT CIRCUMFERENTIAL COMPONENTS OF VELOCITY IN THE PACKED BED SECTION AND AXIAL COMPONENTS IN THE HOUSING SECTION WERE MAJOR CONTRIBUTIONS OF VELOCITY. BY THE WAY, SIMULATION RESULTS SHOWED THAT PRESSURE DROP INCREASES WITH INCREASING GAS FLOW RATE. ACCORDING TO THE VALUES OF PRESSURE DROP EARNED FROM CFD SIMULATION AND EXPERIMENTAL WORK, AVERAGE RELATIVE ERROR CALCULATED AND A VALUE EQUAL TO 30.42% EARNED. THE MAIN REASON FOR THIS ERROR, DIFFERENCE BETWEEN POROUS PLATE PACKING DESIGNS IN CFD AND EXPERIMENTAL WORK, APPRAISED.

AS CHARACTERISTIC VELOCITY AND SLIP VELOCITY ARE THE IMPORTANT PARAMETERS IN THE DESIGN OF LIQUID-LIQUID EXTRACTION COLUMNS, THE EFFECT OF THE OPERATING PARAMETERS ON CHARACTERISTIC AND SLIP VELOCITY IN A PILOT PLANT PULSED PACKED COLUMN, IS MAIN OBJECTIVE IN PAPER. REFER TO THE INTERFACIAL TENSION INFLUENCE ON THE DROPS DIAMETERS AND ITS FINAL EFFECT ON THE VELOCITY OF DISPERSED PHASE DROPS DURING THE COLUMN LENGTH, SO THE LIQUID-LIQUID SYSTEM WHICH HAS BEEN USED IN THE EXPERIMENTS IS TOLUENE-WATER THAT HAS GOT HIGH INTERFACIAL TENSION WITH NO MASS TRANSFER. IN THIS WORK, AT FIRST THE DISPERSED PHASE HOLD UP WAS MEASURED IN DIFFERENCE OPERATING CONDITIONS, AND THEN THE EFFECT OF THE OPERATING PARAMETERS ON THE CHARACTERISTIC VELOCITY AND SLIP VELOCITY WILL BE STUDIED. THESE VARIABLE PARAMETERS INCLUDE PULSE INTENSITY, FLOW RATE OF DISPERSED PHASE AND FLOW RATE OF CONTINUOUS PHASE.

FORCED CONVECTION HEAT TRANSFER COEFFICIENTS OF PURE WATER AND PURE ETHYLENE GLYCOL (EG) AND THEIR MIXTURES HAVE BEEN MEASURED IN THE CROSS FLOW HEAT EXCHANGER APPARATUS. THESE TWO CONVENTIONAL HEAT TRANSFER WORKING FLUIDS HAVE MANY APPLICATIONS IN THE INDUSTRIES AND KNOWLEDGE OF THEIR HEAT TRANSFER COEFFICIENTS IS VERY CRUCIAL IN THE DESIGN AND OPTIMIZATION OF THE HEAT EXCHANGERS. HEAT TRANSFER COEFFICIENTS WERE MEASURED AT DIFFERENT FLOW RATES (2-6 LITER PER MINUTE), DIFFERENT INLET TEMPERATURES (41, 47 AND 51OC) AND DIFFERENT CONCENTRATIONS (ZERO TO 100 VOL.% EG) OF THE TEST LIQUIDS. RESULTS DEMONSTRATED THAT INCREASING FLOW RATE AND INLET TEMPERATURE CAN ENHANCE HEAT TRANSFER COEFFICIENT FOR THE TWO PURE FLUIDS. ALSO, IT WAS SHOWN THAT ETHYLENE GLYCOL HAS HEAT TRANSFER COEFFICIENT LOWER THAN THAT OF WATER IN ALL THE CONDITIONS. IT SHOULD ALSO BE MENTIONED THAT THE ADDITION OF ETHYLENE GLYCOL TO PURE WATER CAN CONSIDERABLY DECREASE THE HEAT TRANSFER PERFORMANCE AT CONSTANT FLOW RATE.

NACL DIFFUSION IN CHEESE GENERALLY DESCRIBED USING SECOND FICK’S LAW WITH AN EFFECTIVE MASS TRANSFER COEFFICIENT. THERE ARE DIFFERENT METHODS TO DETERMINATION OF THE MASS DIFFUSIVITY THAT IN THIS STUDY, THEY ARE BRIEFLY PRESENTED AND DISCUSSED. IN THIS WORK, CONSTANT AND VARIABLE SALT DIFFUSION COEFFICIENTS WERE ESTIMATED IN UF–FETA CHEESE BY USING EXPERIMENTAL SALT TIME–DEPENDENT CONCENTRATION-DISTANCE PROFILES. THESE EXPERIMENTAL PROFILES FOR UF-FETA CHEESE WERE DETERMINED WITH RECTANGULAR SAMPLES ENSURING SEMI-INFINITE UNIDIRECTIONAL MASS TRANSFER WITH SATURATED BRINING AQUEOUS SOLUTIONS AT THE DIFFERENT TEMPERATURES (3, 11, 19 AND 27OC) AND BRINING TIMES (6, 12, 24, 48 H).CONSIDERING A BINARY DIFFUSION SYSTEM CONSTITUTED BY THE CHEESE WATER AND THE NACL SOLUTE, THE NACL DIFFUSION KINETICS WERE ANALYZED AT EACH INVESTIGATED TEMPERATURE BY TWO DIFFERENT APPROACHES: FIRSTLY, USING THE SECOND FICK’S LAW WITH A CONSTANT NACL DIFFUSIVITY, WHICH GAVE A POOR INTERPRETATION OF THE EXPERIMENTAL DATA, SECONDLY, USING THE BOLTZMANN’S METHOD WITH A CONCENTRATION DEPENDENT DIFFUSION COEFFICIENT, WHICH GAVE A GOOD AGREEMENT WITH THE EXPERIMENTAL DATA. FINALLY THE VARIATION OF THE SALT EFFECTIVE DIFFUSIVITY AS A FUNCTION OF TEMPERATURE WAS REPRESENTED BY THE ARRHENIUS’S RELATION. CONSTANT SALT DIFFUSIVITY VARIED FROM 0.614×10-11 TO 12.773×10-10 M2/S IN THE TEMPERATURE RANGE OF 3–27OC. IT CAN BE CONCLUDED THAT THE SALT DIFFUSIVITY VALUES DECREASED WITH THE SALT CONCENTRATION AND INCREASED WITH THE TEMPERATURE. AROUND 11OC, ABNORMALLY, VARIABLE DIFFUSIVITY DECREASED WITH TEMPERATURE INCREASING.

XYLENE WAS USED AS CARBON SOURCE FOR SYNTHESIS OF CARBON NANOTUBES (CNTS) IN A FLOATING CATALYST REACTOR. NITROGEN AND FERROCENE WERE USED AS CARRIER GAS AND CATALYST, RESPECTIVELY. CNTS PURIFICATION WAS PERFORMED BY OXIDATION AND ACID TREATMENT. CHARACTERIZATION OF CNTS BEFORE AND AFTER PURIFICATION WAS CARRIED OUT USING SEM, TEM AND RAMAN SPECTROSCOPY. THE RESULTS DEMONSTRATED THAT CNTS WITH HIGH DENSITY, LENGTH AND PURITY WERE OBTAINED AFTER HNO TREATMENT.

PHASE EQUILIBRIUM PLAYS AN IMPORTANT ROLE IN THE PROCESSING AND APPLICATION OF POLYMER. IN PREVIOUS WORKS OF THIS AUTHOR, BASED ON HARD – SPHERE LIMIT A NEW THEORY HAS BEEN DEVELOPED FOR ACTIVITY OF SOLVENTS (ORGANIC SOLVENT) IN POLYMER/ SOLVENT MIXTURES. IN THIS WORK, OTHER SEVEN SYSTEMS, BOTH OF ORGANIC AND AQUEOUS SOLVENT/POLYMER MIXTURES HAVE BEEN EVALUATED AND COMPARED WITH EXPERIMENTAL DATA AT VARIOUS TEMPERATURES AND VARYING RANGE OF MOLECULAR WEIGHTS (MW) OF POLYMERS. THE RESULTS SHOW REASONABLY GOOD AGREEMENT BETWEEN CALCULATED AND EXPERIMENTAL ACTIVITY DATA. IT IS ARGUED THAT THIS NEW THEORY PROPERLY FITS THE EXPERIMENTAL DATA AND IS RELIABLE FOR A LARGE DIAMETER RATIO OF TWO COMPONENTS, WHERE ONLY ONE ADJUSTABLE PARAMETER S22 (POLYMER DIAMETER 2.97 0A<S22<60 0A) IS INTRODUCED FOR ACTIVITY CALCULATIONS. AN OBJECTIVE ERROR FUNCTION [ROOT MEAN SQUARE DIFFERENCE (R.M.S.D)] WAS DEFINED. THE CALCULATED ACTIVITY (ACAL) WAS DETERMINED BY NUMERICAL METHOD (NONLINEAR REGRESSION) AND OPTIMIZATION (MINIMIZATION THE ERROR FUNCTION).THE ACTIVITIES OF POLYMER ARE IN AGREEMENT WITH THE EXPERIMENTAL DATA AND THUS THE CONSISTENCY IN THE RESULTS IS CONFIRMED CALCULATIONS.

IN THIS STUDY, EXPERIMENTAL KINETIC DATA WERE OBTAINED FOR DETERMINATION OF THE EFFECTIVE DRIVING FORCE IN THE PROCESS OF ETHANE HYDRATE FORMATION IN CONSTANT VOLUME USING A SIMPLE LABORATORY. FOR EVALUATION OF THE EFFECTIVE DRIVING FORCE OF HYDRATE FORMATION, SEVERAL EXPERIMENTS WERE CONDUCTED IN TWO SERIES, CONSTANT PRESSURE GRADIENT AND CONSTANT SUB COOLING, IN TEMPERATURE RANGE 273-283 K AND PRESSURE RANGE 60-400 PSIG. THEN TO DETERMINE THE APPROPRIATE DRIVING FORCE, PRESSURE CHANGES WITH TIME, WHICH IS THE CRITERION OF CONSUMPTION RATE OF GAS IN HYDRATE FORMATION PROCESS, WAS CALCULATED. FINALLY IT WAS CONCLUDED THAT PRESSURE GRADIENT IS EFFECTIVE DRIVING FORCE IN HYDRATE FORMATION PROCESS. ACCORDING TO THIS CONCLUSION, AN INDEPENDENT TEMPERATURE EQUATION WAS OBTAINED FOR THE PRESSURE WHICH ENABLES US TO CALCULATE THE INSTANTANEOUS PRESSURE WITH USING THE INITIAL PRESSURE.

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FOOD PROCESSING INCLUDES SOME PHYSICAL OR CHEMICAL REACTIONS CREATING THE MICROSTRUCTURE AND TEXTURE OF FOOD PRODUCTS. THE TEXTURE HAS AN IMPORTANT FUNDAMENTAL ROLE IN CONSUMER ACCEPTANCE. IN THIS STUDY FAT FREE YOGHURT SAMPLES WERE PRODUCED USING SEVERAL KINDS OF HYDROCOLLOIDS AND THE CORRESPONDING MICROSTRUCTURE OF THE SAMPLES WERE INVESTIGATED BY EPIFLUORESCENCE MICROSCOPE. DIFFERENT PROBES, LABELING METHODS AND SPECIAL MICROSCOPY TECHNIQUES WERE EMPLOYED TO IDENTIFY THE PROTEIN – POLYSACCHARIDE IN THE MICROSTRUCTURE OF YOGHURT GELS. WE FINALLY DEVELOPED A NEW OBSERVATION METHOD IN ORDER TO LOCALIZE MICROSTRUCTURE COMPOUNDS.

HOT ASH CORROSION OF HIGH TEMPERATURE COMBUSTION EQUIPMENT FROM BURNING PETROLEUM FUELS CONTAINING NA, S AND V, AND RECOMMENDATIONS FOR PREVENTING OR CONTROLLING FUEL OIL MAY RESULT IN SEVERE DAMAGE TO METAL SURFACES. THE USE OF MGO AS A FUEL ADDITIVE TO COMBACT VANNDIC CORROSION IS WIDELY ACCEPTED PRACTICE FOR BOILERS OPERATING ON RESIDUAL OR LOW GRADE FUELS. MGO HAS THE ABILITY TO FORM HIGH MELTING STABLE VANADATE BUT THE PRESENCE OF NA2SO4 CAN REACT WITH THE MAGNESIUM AND REDUCE ITS EFFECTIVENESS. THIS PAPER AIMS TO QUANTIFY THE EFFECTIVENESS OF MGO AS AN INHIBITOR IN THE PRESENCE OF INCREASING AMOUNTS OF NA2SO4. A METHOD OF DETERMINING PERMISSIBLE LEVELS OF NA2SO4 TO SATISFY PREDICT REMIND CORROSION RATES OR ADDITIVE EFFICIENCIES IS DESCRIBED. EXAMPLES OF THE LOSS OF ADDITIVE EFFICIENCY WITH WEIGHT OF NA2SO4 AT TEMPERATURE OF 750 AND 850OC ARE GIVEN FOR BOTH 209 T1 AND 213 T11 ALLOYS.

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GAS HYDRATES ARE ICE-LIKE CRYSTALLINE STRUCTURES WHICH MAY FORM IN HIGH PRESSURES AND TEMPERATURES ABOVE WATER FREEZING POINT.HYDRATE FORMATION IN THE GAS TRANSMISSION PIPELINES MAY LEAD TO INTERRUPT IN GAS TRANSMISSION AND PIPELINE BLOCKAGE. SO THE HYDRATE FORMATION MUST BE INHIBITED AS THE BLOCKAGE REMOVAL IS COSTLY AND TIME CONSUMING OPERATION.CHEMICAL INHIBITORS ARE COMMONLY USED IN ORDER TO PREVENT THE HYDRATE FORMATION IN GAS PIPELINES. THESE INHIBITORS ARE DIVIDED INTO THERMODYNAMIC AND KINETIC INHIBITORS. THERMODYNAMIC HYDRATE INHIBITORS EFFECTS ON WATER CHEMICAL ACTIVITY AND CAUSES THE HYDRATES TO FORM AT HIGHER PRESSURE AND LOWER TEMPERATURES. KINETIC HYDRATE INHIBITORS WITH LOW CONCENTRATION PREVENTS THE NUCLEATION AND GROWTH OF CRYSTAL HYDRATE.IN THIS PAPER THE KINETIC OF HYDRATE FORMATION WITH KINETIC HYDRATE INHIBITORS AND WITHOUT THEM HAS BEEN DESCRIBED. THEN THE RATE PROFILE VERSUS TIME WHEN KINETIC HYDRATE INHIBITORS WERE INJECTED AND WEREN'T INJECTED HAS BEEN DRAWN BY USING OF EXPERIMENTAL DATA IN GAS PIPELINE AND THE MODEL OF KASHCHIEV.AT THE END THE INDUCTION TIME OF HYDRATE FORMATION WHEN KINETIC HYDRATE INHIBITORS WERE INJECTED AND WEREN'T INJECTED HAS BEEN CALCULATED BY USING THE MODEL OF KASHCHIEV AND FIROOZABADI.

THE AIM OF THIS ARTICLE IS THE SIMULATION OF THE BAFFLED STIRRED TANK WITH 6 BLADES RUSHTON TURBINE THROUGH DIFFERENT INTERFACE LOCATIONS TO INVESTIGATE THEIR EFFECTS IN PREDICTING THE FLUIDS HYDRODYNAMICS IN TURBULENT FLOW FIELDS. IN ALL SIMULATIONS PISO PRESSURE-VELOCITY COUPLE, PRESTO DISCRETIZATION SCHEME FOR PRESSURE AND THE LES FOR TURBULENT MODEL WAS USED. ALSO WE USED MRF’S RESULTS AS A INITIAL GUESS FOR SM MODEL. THE EXPERIMENTAL VELOCITY DISTRIBUTIONS WERE COMPARED WITH THE NUMERICAL ONES. RESULTS INDICATED THAT THE INTERFACE LOCATION HAVE TO BE BETWEEN 7 TO 10 CM FROM CENTER OF THE TANK. AND IT IS IN GOOD AGREEMENT WITH PREVIOUS WORK BY LEE AND YIANNESKIS.

IN THIS STUDY, AN ENHANCED LUMPED HEAT CAPACITY MODEL WAS DEVELOPED FOR UNSTEADY STATE ONE-DIMENTIONAL HEAT CONDUCTION WITH HEAT SOURCE, USING THE POLYNOMIAL APPROXIMATION METHOD. RESULTS OF THIS MODEL WERE COMPARED WITH THE CLASSICAL LUMPED CAPACITY METHOD USING A MATLAB PROGRAM AND FINITE DIFFERENCE METHOD. RESULTS SHOWED THAT ENHANCED LUMPED HEAT CAPACITY MODEL PREDICTED TEMPERATURE MORE ACCURATELY THAN CLASSICAL LUMPED MODEL AND COULD BE USED IN HIGHER BIOT NUMBERS THAN THOSE FOR THE CLASSICAL LUMPED MODEL.

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IN THIS PAPER, AN EXPERIMENTAL STUDY HAS BEEN PERFORMED TO EVALUATE TURBULENT FORCED CONVECTIVE HEAT TRANSFER ENHANCEMENT OF WATER BASED NANO-FLUID IN COMPARE TO PURE WATER. NANO-FLUID CONSISTED OF LOW CONCENTRATIONS OF ALUMINA NANO-PARTICLE FROM 0.1 TO 1 VOL.% IN DISTILLED WATER. THE TEST LIQUID FLOWS THROUGH A CROSS FLOW HEAT EXCHANGER CONSISTED OF 34 VERTICAL TUBES WITH ELLIPTICAL CROSS SECTION. AIR FLOWS OVER THE TUBE BUNDLE BY A FORCED DRAFT FAN WITH CONSTANT SPEED. ADDITIONALLY, LIQUID FLOW RATE WAS CHANGED IN THE RANGE OF 2-5 LITER PER MINUTE TO BE IN THE FULLY TURBULENT REGIME (2×104<RE<5×104). RESULTS DEMONSTRATED THAT INCREASING FLUID VELOCITY CAN IMPROVE HEAT TRANSFER. MEANWHILE, APPLICATION OF NANO-FLUID WITH SMALL CONCENTRATION CAN ENHANCE HEAT TRANSFER EFFICIENCY UP TO 60% IN COMPARE TO DISTILLED WATER.

FURFURAL IS ONE OF THE ENVIRONMENTAL POLLUTANTS THAT IS USEFULL IN OIL INDUSTRY AND OTHER INDUSTRY.BUT IT IS HARMFULL FOR HUMANBODY AND ENVIRONMENT TOO. IN THIS RESEARCH BIOSORBTION OF FORFOURAL ON SAWDUST WAS STUDIED AND REVISED THE IMPRESSIVE PARAMETERS, PH, INITIAL CONCENTRATION OF FOROURAL(C0), AMOUNT OF BIOSORBENT, TIME(T). EXPERIMENTS WERE DONE IN BATCH REACTOR IN CONSTANT MIXING 150 RPM. EQUILIBRIUM ISOTHERMS OF FRENDLICH, TEMKIN, LANGMUIR ARE APPLIED. TEMKIN MODEL WITH REGRESSION 96% WAS BEST MODEL THAT FIT EXPERIMENTAL DATA. OPTIMUM CONDITIONS WERE OBTAIND IN PH=6, C0=250 MG/L, AMOUNT OF BIOSORBENT 10 GR AND T=60 MIN.