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At least 217 records · Page 12Linked to original sources
PubMed2002

A comparison of liquid hot water and steam pretreatments of sugar cane bagasse for bioconversion to ethanol.

Sugar cane bagasse was pretreated with either liquid hot water (LHW) or steam using the same 25 l reactor. Solids concentration ranged from 1% to 8% for LHW pretreatment and was > or = 50% for steam pretreatment. Reaction temperature and time ranged from 170 to 230 degrees C and 1 to 46 min, respectively. Key performance metrics included fiber reactivity, xylan recovery, and the extent to which pretreatment hydrolyzate inhibited glucose fermentation. In four cases, LHW pretreatment achieved > or = 80% conversion by simultaneous saccharification and fermentation (SSF). > or = 80% xylan recovery, and no hydrolyzate inhibition of glucose fermentation yield. Combined effectiveness was not as good for steam pretreatment due to low xylan recovery. SSF conversion increased and xylan recovery decreased as xylan dissolution increased for both modes. SSF conversion, xylan dissolution. hydrolyzate furfural concentration, and hydrolyzate inhibition increased, while xylan recovery and hydrolyzate pH decreased, as a function of increasing LHW pretreatment solids concentration (1-8%). These results are consistent with the notion that autohydrolysis plays an important. if not exclusive, role in batch hydrothermal pretreatment. Achieving concurrently high (greater than 90%) SSF conversion and xylan recovery will likely require a modified reactor configuration (e.g. continuous percolation or base addition) that better preserves dissolved xylan.

Biodegradation, Environmental↗
PubMed2002

Solid-state production of biopulp by Phanerochaete chrysosporium using steam-exploded wheat straw as substrate.

A novel material for biopulp-making, steam-exploded wheat straw (SEWS), was studied. During the steam explosion process, the hemicellulose was partly degraded and became water-soluble sugar as the carbon resource of the chosen microbe growth, and compared with non-SEWS, the degradation amount of cellulose decreased and the degradation amount of lignin increased for the fermented steam-exploded wheat straw (FSEWS) cultured with Phanerochaete chrysosporium ME-446. Under the optimum conditions of solid-state ferrmentation (SSF), the degradation amount of lignin reached 60% on the 5th day and the fermented straw residue could be used directly as the material for pulp making.

Fermentation↗
PubMed1996

Inhalation of steaming seafood aroma: sudden death in an asthmatic.

A 29-year-old asthmatic with a family history of atopy inhaled a large dose of fumes from sizzling, steaming seafood being served to another client in a restaurant. She immediately developed respiratory distress, loss of consciousness and cyanosis; she also vomited profusely, aspirated and died with 58 min of the onset of symptoms. Autopsy revealed epiglottitis and tracheobronchitis associated with an infiltration by mast cells. The blood IgE was marginally elevated. Death was attributed to upper respiratory airway obstruction due to aspiration of gastric contents, and to bronchospasm following the inhalation of steaming vapour from the seafood dish. The practice of transporting a platter of sizzling, steaming seafood across dining rooms and restaurants with its aroma permeating the entire premises could prove fatal for atopic customers.

Journal Article↗
PubMed2003

Decontamination of polyaromatic hydrocarbons from soil by steam stripping: mathematical modeling of the mass transfer and energy requirement.

For cleaning of contaminated soil from polyaromatic hydrocarbons (PAH), a thermal separation process is applied. The process uses superheated steam that is supplied through a nozzle together with a suspension (approximately 40% soil content) of the contaminated soil into a tube reactor. In the reactor, the soil suspension is vaporized, and the PAH are stripped from the soil at temperatures of 140-300 degrees C. In a cyclone, a solid-vapor separation is carried out, and after going through a condenser, a separation of the condensed water and the PAH is obtained. For improvement of the economical performance, a heat recovery is integrated. This is realized by preheating the water/stream supplied to the evaporator by cooling the vapor steam leaving the reactor. For the mathematical description of the process, the removal of the PAH from the soil is considered to take place by a desorption process. Sorption isotherms are measured by batch experiments and can be described by isotherms of Langmuir type. A dispersion model is used to describe the mass transfer of the process. The process is mathematically modeled for instationary and stationary operation. The simulation predicts the lowest energy consumption at a good cleaning performance at a steam-to-suspension ratio of 5.

Adsorption↗
PubMed2001

Comparison of volatile components in dried scallops (Chlamys farreri and Patinopecten yessoensis) prepared by boiling and steaming methods.

Comparison of two types of dried scallops, Chlamys farreri and Patinopecten yessoensis, and effects of preparation methods (boiling and steaming) on the composition of their volatile components were carried out by simultaneous steam distillation and extraction and with analysis by gas chromatography-mass spectrometry. One hundred and seventy-two compounds were identified, three tentatively. Qualitatively, both scallops had similar components. Quantitatively, C. farreri contained more components with higher levels in aldehydes, alkanes, naphthalenes, esters, furans, miscellaneous compounds, alcohols, and ketones, whereas P. yessoensis had more components with higher levels in aromatics, pyrazines, pyridines, sulfur-containing compounds, and terpenes from both boiling and steaming methods. Comparison between methods for the same scallop showed that similar qualities of components were detected. Overall, more compounds with higher levels were detected from the boiling method.

Alcohols↗
PubMed2006

Purification and opening of carbon nanotubes using steam.

Purification and opening of carbon nanotubes has been carried out by treatment of as-made single-wall carbon nanotubes (SWNTs) with pure steam at 1 atm pressure. Treated samples have been characterized by high-resolution transmission electron microscopy and IR and Raman spectroscopy. Comparison between the steam purification and the standard nitric acid purification treatment shows that steam is less aggressive toward damage to the tubular nanotube wall structure and forms fewer functional groups.

Journal Article↗
PubMed2005

Investigation of nitrogen-bearing species in catalytic steam gasification of poultry litter.

The production of broiler chickens has become one of the largest sectors in U.S. agriculture, and the growing demand for poultry has led to an annual production growth rate of 5%. With increased demand for poultry, litter management has become a major challenge in the agriculture industry. Although the catalytic steam gasification has been accepted as a possible and feasible method for litter management, concern has been expressed about the presence of nitrogen and phosphorus containing species in the fuel gas and/or in the final solid residue. The possible release of phosphorus as phosphine gas in the fuel gas can have an adverse impact on the environment. Similarly, possible release of ammonia from the nitrogen containing species is also not acceptable. Hence, under partial U.S. Department of Agriculture support, a study was conducted to examine the fate and the environmental impact of the nitrogen- and phosphorus-containing species released during catalytic steam gasification of poultry litter. From various preliminary tests, it was concluded that most (approximately 100%) of the phosphorus would remain in the residue, and some (20-70%) of the nitrogen would end up as ammonia in the fuel gas. The effects of temperature, catalyst loading, and type of catalyst on ammonia liberation were studied in a muffled furnace setup at atmospheric pressure. The fraction of nitrogen released as ammonia was found to decrease with an increase in temperature during pyrolysis and steam gasification. It also decreased with an increase in catalyst loading.

Animals↗
PubMed1993

Steam press burns of the hand.

Steam presses pose an occupational hazard to workers in the dry cleaning industry. Three patients with thermal burns to the hand from steam press accidents were recently treated at this institution. Each patient sustained deep second and third degree burns to the dorsum of the hand. Two patients required split-thickness skin grafts and have retained full range of motion and returned to full employment. One patient sustained destruction of extensor tendons and required a groin flap for coverage. Late tendon reconstruction will be necessary. Investigation revealed that older steam press models do not have an emergency release lever in case of accidental closure on a worker's hand. Although newer models are equipped with a thigh-activated emergency release lever, a contact burn remains likely if the press closes on the operator's hands. Some of the newest models have an attached safety bar that prevents the press from closing on the operator's hands. It is recommended that older models either be modified with the attachment of a safety bar or replaced entirely.

Accidents, Occupational↗
PubMed1972

Steam versus hot-water scalding in reducing bacterial loads on the skin of commercially processed poultry.

A comparison of two types of scalders was conducted to determine their effectiveness in reducing bacterial contamination of poultry carcasses. A conventional hot-water scalder and a prototype model of a steam scalder were tested under commercial conditions. Total plate counts from steam-scalded birds were significantly lower than the counts of water-scalded birds immediately after scalding and again after picking. No differences in the two methods could be found after chilling. Coliform counts from steam-scalded birds were significantly lower than the counts from water-scalded birds immediately after scalding. No significant differences in coliform counts were detected when the two scald methods were compared after defeathering and chilling.

Bacteria↗
PubMed2003

Optimization of SO2-catalyzed steam pretreatment of corn fiber for ethanol production.

A batch reactor was employed to steam explode corn fiber at various degrees of severity to evaluate the potential of using this feedstock as part of an enzymatically mediated cellulose-to-ethanol process. Severity was controlled by altering temperature (150-230 degrees C), residence time (1-9 min), and SO2 concentration (0-6% [w/w] dry matter). The effects of varying the different parameters were assessed by response surface modeling. The results indicated that maximum sugar yields (hemicellulose-derived water soluble, and cellulose-derived following enzymatic hydrolysis) were recovered from corn fiber pretreated at 190 degrees C for 5 minutes after exposure to 3% SO2. Sequential SO2-catalyzed steam explosion and enzymatic hydrolysis resulted in a conversion efficiency of 81% of the combined original hemicellulose and cellulose in the corn fiber to monomeric sugars. An additional posthydrolysis step performed on water soluble hemicellulose stream increased the concentration of sugars available for fermentation by 10%, resulting in the high conversion efficiency of 91%. Saccharomyces cerevisiae was able to ferment the resultant corn fiber hydrolysates, perhydrolysate, and liquid fraction from the posthydrolysis steps to 89, 94, and 85% of theoretical ethanol conversion, respectively. It was apparent that all of the parameters investigated during the steam explosion pretreatment had a significant effect on sugar recovery, inhibitory formation, enzymatic conversion efficiency, and fermentation capacity of the yeast.

Bioreactors↗
PubMedDate not supplied

Comparison of the volatile composition of Stachys persica Gmel. and Stachys byzantina C. Koch. oils obtained by hydrodistillation and steam distillation.

The oils obtained by hydrodistillation and steam distillation of the aerial parts of Stachys persica Gmel. and Stachys byzantina C. Koch grown in Iran were analyzed by GC/MS. The essential oil obtained by hydrodistillation of the aerial parts of S. persica was characterized by a high amount of non-terpenoid components of which methyllinoleate (27.7%), hexadecanoic acid (9.8%) and 6,10,14-trimethyl-2-pentadecanone (9.2%) were the major constituents, whereas the steam distilled oil of the plant contained hexadecanoic acid (27.2%), carvacrol (9.4%) and eugenol (5.2%). Both hydrodistilled and steam distilled essential oils of the aerial parts of S. byzantina were rich in sesquiterpenes such as a-copaene (16.6% and 10.4%), spathulenol (16.1% and 18.5%) and beta-caryophyllene (14.3% and 13.5%), respectively.

Gas Chromatography-Mass Spectrometry↗
PubMed1990

Steam-rolled wheat diets for finishing cattle: effects of dietary roughage and feed intake on finishing steer performance and ruminal metabolism.

Two experiments were conducted to determine the influence of dietary roughage concentration and feed intake on finishing steer performance and ruminal metabolism. In Exp. 1, 126 steers (334 kg) were used in a completely randomized design and fed (120 d) diets of steam-rolled wheat without roughage or containing 5, 10 or 15% roughage (50% alfalfa hay:50% corn silage). Steers fed 5 or 10% roughage gained faster (quadratic, P less than .05) and were more efficient (quadratic, P less than .05) than steers fed 15% or no roughage. In Exp. 2, six ruminally cannulated steers (447 kg) were used in a 6 x 6 latin square design and fed (twice daily) diets of steam-rolled wheat without roughage or containing 5 or 15% alfalfa hay at twice or three times NE required for maintenance. Increasing dietary roughage increased (linear, P less than .01) ruminal liquid passage 38%, indigestible ADF passage 63%, Yb-labeled wheat passage 75% and fiber fill 31%. The rate of in situ starch digestion tended to increase (linear, P = .16), and ruminal VFA concentration was 40 mM higher (P less than .01) at 4 h after feeding with increased roughage. Increased feed intake increased (P less than .05) ruminal starch fill, fiber fill, liquid fill and liquid passage 23%, Yb-labeled wheat passage 50% and Dry-labeled hay passage 20%. It reduced protozoa five- to sixfold (P less than .01) but doubled total bacterial counts (P less than .01). Ruminal NH3N was lower (P less than .01) and total VFA concentration was 50 mM higher (P less than .01) at 4 h after feeding. The acetate:propionate ratio was reduced from 2.3 to 1.3 (P less than .01) with increased intake. Adding roughage to a steam-rolled wheat diet increased passage and tended to increase rate of starch digestion; increased feed intake with its associated effects on ruminal fill and passage dramatically shifted the microbial population and fermentation end products.

Animal Feed↗
PubMed2003

Influence of dietary urea level on digestive function and growth performance of cattle fed steam-flaked barley-based finishing diets.

Four Holstein steers (282 kg) with cannulas in the rumen and proximal duodenum were used in a 4 x 4 Latin square experiment to evaluate the influence of dietary urea level (0, 0.4, 0.8, and 1.2%, DM basis) in a steam-flaked barley-based finishing diet on digestive function. There were no treatment effects (P > 0.20) on ruminal digestion of OM and ADF. Increasing dietary urea level increased (linear, P < 0.01) ruminal starch digestion. Ruminal degradability of protein in the basal diet (no supplemental urea) was 60%. Increasing dietary urea level did not increase (P > 0.20) ruminal microbial protein synthesis or nonammonia N flow to the small intestine. There were no treatment effects (P > 0.20) on total-tract ADF digestion. Total tract digestion of OM (quadratic, P < 0.01) and starch (linear, P < 0.05) increased slightly with increasing urea level. Urea supplementation increased (linear, P < 0.01) ruminal pH 1 h after feeding; however, by 3 h after feeding, ruminal pH was lower (cubic, P < 0.05) with urea-supplemented diets. Urea supplementation did not affect (P > 0.20) ruminal molar proportions of acetate and propionate. One hundred twenty crossbred steers (252 kg; approximately 25% Brahman breeding) were used in an 84-d feeding trial (five pens per treatment) to evaluate treatment effects on growth performance. Daily weight gain increased (linear, P = 0.01) with increasing urea level, tending to be maximal (1.53 kg/d; quadratic, P = 0.13) at the 0.8% level of urea supplementation. Improvements in ADG were due to treatment effects (linear, P < 0.01) on DMI. Urea supplementation did not affect (P > 0.20) the NE value of the diet for maintenance and gain. Observed dietary NE values, based on growth performance, were in close agreement with expected based on tabular values for individual feed ingredients, averaging 100.4%. We conclude that with steam-flaked barely-based finishing diets, ruminal and total-tract digestion of OM and ruminal microbial protein synthesis may not be increased by urea supplementation. In contrast, ADG was optimized by dietary inclusion of 0.8% urea. Urea supplementation may not enhance the net energy value of steam-flaked barely-based finishing diets when degradable intake protein is greater than 85% of microbial protein synthesis.

Animal Feed↗
PubMed2004

Effects of concentration and composition of wet corn gluten feed in steam-flaked corn-based finishing diets.

Two finishing experiments were conducted to determine the effects of concentration (Exp. 1) and composition of wet corn gluten feed (Exp. 2) in steam-flaked corn-based diets on feedlot steer performance. In Exp. 1, 192 English x Continental crossbred steer calves (299 +/- 0.6 kg) were used in a completely randomized design with six dietary treatments (four pens per treatment). Treatments were six concentrations of wet corn gluten feed (Sweet Bran, Cargill Inc., Blair, NE; 0, 10, 20, 25, 30, and 35%) replacing steam-flaked corn (DM basis). All diets contained 10% corn silage, 5% supplement, and 3.5% tallow (DM basis). Gain efficiency and ADG were similar (P > 0.25) among treatments. Dry matter intake was lower (P < 0.10) with 0% wet corn gluten feed than with concentrations of 20, 25, and 35% WCGF. Dry matter intake did not differ among treatments containing wet corn gluten feed. In Exp. 2, 160 English x Continental crossbred steer calves (315 +/- 0.6 kg) were used in a completely randomized design with five dietary treatments (four pens/treatment). Treatments were assigned based on four ratios of steep to corn bran/germ meal mix in wet corn gluten feed plus a negative control (CON). Wet corn gluten feed was fed at 25% of the dietary DM and was made by mixing steep and corn bran/germ meal into the diet. The four concentrations of steep in wet corn gluten feed that comprised the ratios were 37.5, 41.7, 45.8, and 50% (DM basis), with the remaining proportion being the bran/germ meal mix. Bran/germ meal mix was comprised of 60% dry corn bran, 24% germ meal, and 16% fine-cracked corn (DM basis). All diets contained 10% corn silage, 5% supplement, and 3.5% tallow (DM basis). Daily gain did not differ (P = 0.18) among treatments. Gain efficiency did not differ between CON and 50% steep; however, G:F was decreased (P < 0.05) for concentrations of 37.5, 41.7, and 45.8% steep compared with CON. A linear improvement (P < 0.05) was observed for G:F as concentration of steep increased as a proportion of wet corn gluten feed. These data suggest that wet corn gluten feed can be used at concentrations up to 35% of the dietary DM without adversely affecting performance, and that steep has more energy than bran/germ meal in steam-flaked corn-based diets.

Animal Feed↗
PubMed1998

Milk yield and composition of lactating cows fed steam-flaked sorghum and graded concentrations of ruminally degradable protein.

To determine the effect of various amounts of ruminally undegradable protein in the diets of lactating cows fed steam-flaked sorghum, 24 Holstein cows (90 +/- 50 d in milk) were assigned to three treatments: 0.8% urea, 6% soybean meal, or 5% fish meal. Respective percentages of ruminally undegradable protein in the diets (as a percentage of crude protein) were 30, 35, and 39%. All diets contained 37% alfalfa hay; 3 to 5% cottonseed hulls; 10 to 13% whole cottonseed; 39% steam-flaked sorghum (360 g/L); 5% of a molasses, mineral, and vitamin supplement; and the different protein supplements. Intake of dry matter was higher for cows fed urea than for cows fed soybean meal or fish meal diets. In cows that yielded more than 40 kg/d of milk (4 cows per treatment), the soybean meal and fish meal diets resulted in higher yields of milk and 3.5% fat-corrected milk and a greater efficiency of conversion of feed to milk than did the urea diet. Cows that yielded less than 40 kg/d of milk (4 cows per treatment) at the beginning of treatment tended to yield more milk when fed urea than when fed the protein supplements. Nutrient digestibilities were not greatly affected by source of N, suggesting a beneficial effect of urea supplementation on nutrient digestibilities because replacement of protein supplements with cottonseed products caused the neutral detergent fiber content of the urea diet to be about 7% higher than that of the other diets. These data show that response to ruminally undegradable protein in diets of lactating cows fed steam-flaked sorghum was related to milk yield.

Animal Nutritional Physiological Phenomena↗
PubMed2004

Repellency of aromatic medicinal plant extracts and a steam distillate to Aedes aegypti.

The repellent activity of methanol extracts from 23 aromatic medicinal plant species and a steam distillate against female blood-starved Aedes aegypti was examined in the laboratory by skin test and compared with that of N,N-diethyl-m-toluamide (deet). Responses varied according to plant species. At a dose of 0.1 mg/cm2, the repellency of extracts of Cinnamomum cassia bark (91%), Nardostachys chinensis rhizome (81%), Paeonia suffruticosa root bark (80%), and Cinnamomum camphora steam distillate (94%) was comparable to deet (82%). The duration of the effectiveness for extracts from C. cassia bark and N. chinensis rhizome was comparable to deet and lasted for approximately 1 h. Relatively short duration of repellency was observed in P. suffruticosa root bark extract and C. camphora steam distillate. The plants described merit further study as potential mosquito repellent agents.

Aedes↗
PubMed1992

A Comparison of Skin Interface Temperature Response Between the ProHeat Instant Reusable Hot Pack and the Standard Hydrocollator Steam Pack.

The ProHeat(trade mark) reusable hot pack is being used increasingly as a substitute for the standard hydrocollator steam pack. This study evaluated the effects of these two modalities on skin temperature. Seventeen subjects were studied during separate 30-minute applications of a ProHeat pack with a wet barrier, a ProHeat pack with a dry barrier, a hydrocollator pack, and a control pack on their nondominant calf. We measured the skin interface temperature and pack surface temperature during each application with surface thermocouples. The skin interface temperature rise time to the minimum therapeutic temperature (104 degrees F) and the total time at and above the minimum therapeutic temperature, for each application, were analyzed using an analysis of variance (ANOVA) with repeated measures (p<.05). The ProHeat pack application, with one layer of wet toweling as a barrier, was not significantly different from the hydrocollator steam pack application. We conclude that the ProHeat pack, prepared with a wet barrier, can be considered a viable alternative to the standard hydrocollator steam pack.

Journal Article↗
PubMed2006

[Study on ingredients of essential oils of Curcuma wenyujin extracted by supercritical-CO2 fluid extraction and steam distillation].

OBJECTIVE: To compare the ingredients of essential oils of Curcuma wenyujin extracted by supercritical-CO2 fluid extraction and by steam distillation. METHOD: GC-MS was applied in this experiment. RESULT: The ingredients and physical and chemical properties of essential oils of C. wenyujin extracted by supercritical-CO2 fluid extraction and by steam distillation are similar. CONCLUSION: Supercritical-CO2 fluid extraction is better than steam distillation in extraction time, power consumption, recovery and purity.

Carbon Dioxide↗