bluuebunny/crossref_metadata_2025 huggingface dataset:
South Cascade Glacier mass balance, 1935–2006
Authors: Rasmussen L.A.
Published: March 2009

A simple model uses daily observations of precipitation and temperature at a nearby weather station to estimate glacier-average seasonal mass-balance components at South Cascade Glacier, Washington, USA, from 1935, 24 years before measurements began at the glacier. This is 13 years earlier than measurements that can be derived using the NCEP–NCAR reanalysis database (begins 1 January 1948). Although the model’s error in estimating winter balance and summer balance over 1959–2006 is greater than that of a model using the reanalysis database, its error in estimating net balance is comparable. The model uses an empirically determined precipitation ratio between the station and the glacier, and a seasonally varying temperature lapse rate determined from 9 years of measurements at the glacier. Temperature is used with a degree-day formulation to estimate ablation and to partition precipitation between rain and snow for estimating accumulation. Both processes are assumed to exist throughout the year, and model results are compared seasonally with adjusted observations of winter and summer balances. The published mass-balance series is adjusted to a constant-topography (1970) series in an attempt to remove the influence of changing topography on the glacier’s response to climate. The reconstructed values prior to 1959 are also with respect to the 1970 glacier topography. Because precipitation is measured at the weather station, rather than being inferred from other meteorological variables, it enables us to distinguish more accurately between wet-day and dry-day conditions, including vertical lapse rates of temperature.
In vitro Regeneration of Aristolochia tagala Champ. A Rare Medicinal Plant of Chittagong Hill Tracts
Authors: Biswas Animesh , Bari MA , Roy Mohashweta , Bhadra SK
Published: March 2009

An efficient regeneration protocol through in vitro direct organogenesis was developed for a valuable medicinal plant Aristolochia tagala Champ. using nodal segments as explants. Multiple shoot buds were induced directly from nodal explants cultured on MS (Murashige and Skoog 1962) basal medium supplemented with 2.0 mg/l BAP (N6- benzylaminopurine) and 0.5 mg/l NAA (a-naphthalenacetic acid). The average number of shoots induced per culture was found to be six. Excised shoot roots were cultured on half-strength MS medium containing 0.5 mg/l IBA. The rooted plantlets were transferred to natural environment after proper acclimatization. Â Key words: Aristolochia tagala, rare medicinal plant, direct organogenesis. doi: 10.3329/jbs.v15i0.2204 J. bio-sci. 15: 63-67, 2007 Â Â  Â Â
Influence of Irrigation, Fertilizer and Variety on Grain Growth of Barley (Hordeum vulgare L.)
Authors: Mollah MSI , Paul NK
Published: March 2009

An experiment was conducted in the experimental field of Rajshahi University Campus (AEZ-11) to study the influence of soil moisture and NPK fertilizers on grain growth of four varieties of barley (Hordeum velgare L.). Spikelet number (SN), spike dry weight (SDW), grain number (GN), grain dry weight (GDW), spike relative growth rate (spike RGR) and grain relative growth rate (grain RGR) were observed highest in the highest level of irrigation (40 mm). The highest amount of fertilizer (120N 75P 45K) produced the highest SN, SDW, GN, GDW, spike RGR and grain RGR. BHL-3 produced the highest SN, BARI Barley -2 produced the highest spike RGR, BARI Barley -1 produced the highest grain RGR and BL-1 produced the highest SDW, GN, and GDW. Key words: Irrigation, soil moisture, fertilizers, barley, grain growth. Â  doi: 10.3329/jbs.v15i0.2205 J. bio-sci. 15: 69-75, 2007
Isolation and Characterization of Rhizosphere Bacteria and their Effect on Germination of Rice Seeds and Growth of Seedlings
Authors: Nasrin Shamima , Rahman MA
Published: March 2009

Rhizosphere bacteria were isolated from root zones from rice fields. These were cultured in laboratory conditions and investigated the effects on germination and growth of rice seedlings. They inhabit around the roots and live on root exude and benefit the plants by altering the solubility and availability of mineral nutrients and protecting the roots from invasion of pathogens by creating an antibiotic barrier around the root. It has been found that rhizosphere bacteria have no effect on germination of rice seeds. Both the rhizosphere bacteria and the Agrobacterium have been found to produce better growth of rice seedlings in pot cultures but later is less effective than the former. Rhizosphere bacteria are mixtures of many e.g. Actimomyces, Proteobacteria, Pseudomonas etc. but Agrobacterium sp is single. Key words: Rhizosphere, Bacteria, Symbiosis, Soil microflora, Non-leguminous plants. doi: 10.3329/jbs.v15i0.2206 J. bio-sci. 15: 77-82, 2007
Dosimetry of cell-monolayers in multiwell plat
Authors: Andreeff M. , Oehme L. , Kotzerke J. , Freudenberg R.
Published: March 2009

Aim: Irradiation of cells in-vitro with unsealed radionuclides is often carried out in cylindrical multi-well-plates. For calculation of the absorbed dose using the sphere model is common. This model assumes a spherical distribution of activity. However, by physical aspects a dose reduction in the peripheral area of the activity volume is expected and predicted especially for high-energy beta-emitting radionuclides. The impact on cellular dosimetry shall be depicted in this paper. Methods: The dose-distribution inside a multi-well-plate was calculated by convolving the dose distribution around a point source with a given activity. This was performed for the radionuclides I-131, Re-188 and Y-90 in wells of different sizes. For comparison the sphere dose was also calculated. Results: Depending on the beta-energy differences up to 40% between the mean calculated dose and the mean sphere dose were found, whereby calculated dose was always lower than the sphere model prediction. Furthermore a fall-off was calculated for the bottom-dose compared to dose in the centre. An analytical expression was revealed for the bottom-dose with respect to the filling level for three different wells. Conclusion: The shape of geometry and the influence on dose distribution must be considered especially at in-vitro exposure with low energy and short range beta-emitting radionuclides. There could be a great impact for exact dose estimation, which is especially necessary to know for comparison of different irradiation experiments (e.g. different radionuclides, various irradiation geometries or comparison with x-rays).
Subjective perception of radioactivity
Authors: Müller S. P. , Beyer T. , Bockisch A. , Freudenberg L. S.
Published: March 2009

Aim: We assess the attitude of patients with thyroid disease towards radiation and radioactivity before and after radioiodine therapy by means of a cultural-anthropological approach. We evaluate in patient interviews how their subjective attitude towards radioactivity as an abstract term and towards radioactivity in the medical context on the basis of their personal experiences with radionuclide therapy. Patients, methods: 29 patients with autonomously functioning thyroid lesions (17 women, 12 men, 35–79 years) were included in this study. All patients were interviewed prior to and 22–27 month post radioiodine therapy in an open dialogue with the principal investigator. Patients were asked to describe their attitude towards radioactivity in general and towards radioiodine therapy in particular. Patients were asked to use a scoring system (1: positive, 5: negative) to quantify their perception of radioactivity. Results: The personal perception of radio - activuty as an abstract term does not change significantly (p = 0.15) before and after radioiodine therapy. This perception is linked to mostly negative impressions of radiactivity. However, patients become more positive when assessing the value of radioactivity as part of their therapy regimen. Thus, we observe a significant increase in percepted value of radioactivity post radioiodine therapy (p = 0.03). Conclusion: Patients continue to view radioactivity as something negative despite treatment success following radioiodine therapy. Our results provide useful information for patient information by the nuclear medicine physician prior to a radioiodine therapy.
Grossly apparent cartilage erosion of the patellar articular surface in dogs with congenital medial patellar luxation
Authors: Janssens L.A. , Béosier Y.M. , Daems R.
Published: March 2009

One hundred and forty-five stifles of client-owned dogs that underwent corrective surgery for congenital medial patellar luxation were inspected for cartilage erosion on the articular surface of the patella. The lesions were mapped in surface percentage ranges of 20% and by location. Two-thirds of the patellae had cartilage erosion. Cartilage erosion varied between 0 and 100% of the total patellar articular surface and was localised mainly on the medial and distal side of the patella. Dogs with Grade IV patellar luxations and heavier dogs were more affected. The majority of dogs in our study with congenital medial patellar luxation had grossly apparent cartilage erosion on the articular surface of the patella, which may help to explain why certain patients do not function well clinically after technically successful corrective surgery.
The role of computed tomography in the classification and management of pelvic fractures
Authors: Clements D. , Farrell M. , Heller J. , Bennett D. , Carmichael S. , Draffan D.
Published: March 2009

Computed tomography (CT) imaging is an important component in the pre-operative assessment of pelvic fractures in humans. The value of CT images in the management of small animal pelvic fractures is presently undetermined. The objective of this study was to investigate the benefits of CT images on the management of pelvic fractures. A prospective study of 25 traumatised cases of canine and feline pelvic fractures were evaluated, where CT images and conventional orthogonal radiographic assessments were performed on each case. Three diplomat orthopaedic surgeons independently reviewed the radio-graphs and CT images on separate occasions and determined fracture classification, management plan, estimated recovery time and prognosis. A consensus review of the imaging modalities and surgical reports was used as the definitive fracture description. For all observers, management was not found to differ significantly between radiographic and CT analysis (P< 0.05). There was moderate agreement between observers and between imaging modalities for fracture description. Greatest discrepancy was found as the fracture complexity increased, such as with acetabula and sacral fractures, whereby CT was the most sensitive. Clinically high quality radiography would be recommended for all pelvic fracture cases; CT may be beneficial where there is uncertainty, particularly with acetabula fractures or sacral fractures causing neurological deficits. Experienced orthopaedic surgeons often disagreed on the diagnosis, treatment and prognosis of pelvic trauma.
Radiographic measurement of tibial joint angles in sheep
Authors: Hette K. , Volpi R.S. , Pereira-Junior O.C.M. , Mamprim M.J. , da Silva V. Colombi , Rahal S.C.
Published: March 2009

The aim of this study was to establish normal reference values of anatomic and mechanical joint angles of the tibia in sheep at different age groups. Eighteen clinically healthy Santa Ines sheep were used. The animals were divided into three equal groups according to age: Group I – from six- to eight-months-old, Group II – 2-years-old, Group III – from three- to five-years-old. Anatomic medial proximal and lateral distal tibial angles, mechanical proximal and distal tibial angles, and anatomic caudal proximal and anatomic cranial distal tibial angles were measured from tibiae radiographs (n = 36). In the craniocaudal view, the mean values of the anatomic medial proximal, anatomic lateral distal, mechanical medial proximal, and mechanical lateral distal tibial joint angles were 89.6°, 86.6°, 91.4°, and 85.19° respectively. In mediolateral view, the mean values of the anatomic caudal proximal and anatomic cranial distal tibial angles were 64.55° and 105.69°, respectively. The joint orientation angles of the tibia in sheep showed similar values regardless of animal age for both anatomic and mechanical axes.
Selective iNOS-inhibition does not influence apoptosis in ruptured canine cranial cruciate ligaments
Authors: Hofer D. , Forterre S. , Schweighauser A. , Krayer M. , Doherr M. , Schawalder P. , Zurbriggen A. , Spreng D.
Published: March 2009

Abnormal patterns of cell death, including increased apoptosis, can influence homeostasis of ligaments and could be involved in the pathogenesis of cranial cruciate ligament (CCL) rupture. Increased nitric oxide (NO) production has been implicated as a stimulus to increased apoptosis in articular cartilage. This study investigated apoptotic cell death in ruptured canine CCL (CCL group, n = 15), in ruptured CCL of dogs treated with oral L-N6-(1-iminoethyl)-lysine (L-NIL), a selective NO-synthetase(NOS)-inhibitor, (L-NIL group, n = 15) and compared the results with normal canine CCL (control group, n = 10).

Orally administered L-NIL at a dosage of 25 mg/m2 of body surface area was effective in inhibiting NO production in the articular cartilage of dogs in the L-NIL group, but it did not significantly influence the increased quantity of apoptotic cells found in ruptured CCL specimens. The results of this study suggest that apoptosis of ligamentocytes in the canine CCL is not primarily influenced by increased NO production within the stifle joint.
Community-Based Organizations Are Critical Partners in Providing Complete Cancer Care
Authors: Rutledge Rob , Robinson L.
Published: March 2009

In Canada people affected by cancer access psychosocial care and support from two systems. In the conventional medical system, psychosocial professionals focus mainly on screening for and treating those most distressed by their diagnosis. Many patients and family members go beyond this step to find information and support provided by community-based organizations (cbos). This article outlines the components of complete cancer care effectively provided by cbos and why the integration of the two systems of care is critical in delivering seamless high-quality psychosocial care for all.
Fostering Healing through Mindfulness in the Context of Medical Practice
Authors: Dobkin Patricia L.
Published: March 2009

Suffering is an affective experience of unpleasantness and aversion associated with harm or threat of harm. Suffering may be physical or mental (or both), depending on whether it is linked primarily to the body or the mind. [...]
N-acylation of ethanolamine using lipase: a chemoselective catalyst
Authors: Kidwai Mazaahir , Poddar Roona , Mothsra Poonam
Published: March 2009

The N-acylation of ethanolamine (2) with various fatty acids 1a–d and esters of fatty acids 1e–h using Candida antarctica B lipase (Novozym® 435) are described and optimum conditions for selective N-acylation rather than O-acylation are also discussed. Microwave assisted solution phase, solid supported and conventional methods were investigated and results were compared. There is a synergy between the enzyme catalysis and microwave irradiation.
MONOHARMONIC APPROACH TO INVESTIGATION OF THE VIBRATIONS AND SELF‐HEATING OF THIN‐WALL INELASTIC MEMBERS
Authors: Zhuk Yaroslav , Senchenkov Igor
Published: March 2009

An approximate formulation is given to a dynamic coupled thermo‐mechanical problem for physically nonlinear inelastic thin‐walled structural elements within the framework of a geometrically linear theory and the Kirchhoff‐Love hypotheses. A simplified model is used to describe the vibrations and dissipative heating of inhomogeneous physically non‐linear bodies under harmonic loading. Unsteady vibration self‐heating problem is solved. The dissipative function obtained from the solution for steady‐state vibrations is used to simulate internal heat sources. For the partial case of forced vibrations of a beam, the amplitude‐frequency characteristics of the field quantities are studied within a wide frequency range. The temperature characteristics for the first and second resonance modes are compared. Santrauka Naudojant geometrinio tiesiškumo ir Kirchhofo ir Love hipotezes, pateikiama apytikslė jungtinė dinamikos ir disipacinės šilumos uždavinio formuluotė fiziškai netiesiniams konstrukciniams elementams. Apytikslis modelis taikomas harmonine apkrova veikiamo nehomogeninio fiziškai netiesinio kūno svyravimams ir išskiriamai šilumai aprašyti. Sprendžiamas neharmoninių svyravimų disipacinės šilumos uždavinys. Pasitelkus harmoninių svyravimų uždavinį, gaunama disipacijos funkcija, kuri naudojama vidinės šilumos šaltiniams modeliuoti. Esant priverstiniams sijos svyravimams, plačiai nagrinėjamos amplitudės ir dažnio charakteristikos. Lyginamos temperatūros charakteristikos, atitinkančios pirmojo ir antrojo rezonanso formas.
EXPERIMENTAL ANALYSIS OF STEEL DISSIPATIVE BRACING SYSTEMS FOR SEISMIC UPGRADING
Authors: Mazzolani Federico M. , Corte Gaetano Della , D’Aniello Mario
Published: March 2009

Energy dissipating devices, such as metallic ductile dampers, could represent one reliable system for seismic performance upgrading of reinforced concrete (RC) structures. This paper illustrates the significant improvement to the seismic response of RC structures equipped with dissipative bracing systems, such as eccentric braces (EBs) and buckling restrained braces (BRBs). In fact, the results of experimental tests carried out on two similar two‐storey one‐bay RC structures, respectively equipped with EBs and BRBs, are described. Referring to EBs, 3 lateral loading tests have been performed. Each test is characterized by shear links with bolted end‐plate connections. Different design criteria have been applied in the design of the connections. In the first test, capacity design criteria have not been considered. In the second test, a capacity design criterion has been applied, with a link shear over‐strength factor equal to 1.5. In the third test, a design criterion similar to the one adopted for the second test has been implemented, but with a larger over‐strength factor. In case of BRBs, two types of ‘only‐steel’ braces have been tested: one type was made using two buckling‐restraining rectangular tubes that are fully welded together with steel plates; the other type is detachable, being made again with two buckling‐restraining rectangular tubes but joined together by means of bolted steel connections. In both cases, the internal yielding core was a rectangular steel plate. The experimental results of both bracing systems are encouraging about the possibility to use these devices for improving the seismic resistance of existing RC structures. Santrauka Didinant gelžbetoninių pastatų atsparumą seisminiams poveikiams, gali būti naudojami energiją sugeriantys metaliniai slopintuvai. Straipsnyje parodoma, kaip tokios slopinančios sistemos, kaip necentriniai ryšiai ir klupimą suvaržantys ryšiai, gali iš esmės gerinti pastato seisminę elgseną. Pateikiami dviejų panašių vienos angos gelžbetoninių pastatų su minėtaisiais ryšiais eksperimentiniai tyrimų rezultatai. Tyrimai parodė, kad abi suvaržymo sistemos gerina eksploatuojamų gelžbetoninių pastatų atsparumą seisminiams poveikiams.
DYNAMIC ANALYSIS OF STRUCTURES WITH MULTIPLE TUNED MASS DAMPERS
Authors: Lewandowski Roman , Grzymisławska Justyna
Published: March 2009

It is the purpose of this paper to analyse the possibility of reducing the vibrations of frame building structures with the help of multiple tuned mass dampers. Structures exposed to strong winds are considered. Excitation forces, which are functions of wind velocity fluctuations, are treated as random forces. The spectral density functions of wind velocity fluctuations are assumed as proposed by Davenport. The correlation theory of random vibration is used and the root mean squares of displacements and accelerations are determined. Several remarks, concerning the effectiveness of multiple tuned or mass dampers, are formulated from the results of calculation. Santrauka Nagrinėjama galimybė sumažinti stipraus vėjo veikiamų rėminių pastatų konstrukcijų svyravimus, taikant masės slopintuvų sistemą. Vibracijas sukeliančios jėgos, priklausančios nuo vėjo greičio svyravimų, laikomos atsitiktiniais dydžiais. Vėjo greičio svyravimo spektro tankio funkcijos nagrinėjamos Davenport metodu. Atlikus atsitiktinių vibracijų regresinę analizę, nustatytos poslinkių ir pagreičių vidutinės kvadratinės paklaidos. Remiantis skaičiavimo rezultatais, padarytos masės slopintuvų efektyvumo išvados.
INVESTIGATION OF STATIC AND DYNAMIC BEHAVIOR OF ANISOTROPIC INHOMOGENEOUS SHALLOW SHELLS BY SPLINE APPROXIMATION METHOD
Authors: Grigorenko Alexander , Yaremchenko Sergiy
Published: March 2009

The present report proposes an efficient approach to solving within the framework of the classic and refined models the stress‐strain problems of shallow shells as well as the problems on free vibrations. In accordance with the approach the initial system of partial differential equations is reduced to one‐dimensional problems by using approximation of the solution in terms of basic splines in one coordinate. The boundary‐value problems obtained and eigenvalue boundary‐value problems for systems of ordinary differential high‐order equations are solved by the stable numerical method of discrete ortogonalization. Santrauka Nagrinėjamas efektyvus lėkštųjų kevalų įtempių, deformacijų ir laisvųjų svyravimų nustatymo algoritmas, pagrįstas klasikiniais ir tobulesniais skaičiavimo modeliais. Algoritme dalinių diferencialinių lygčių sistema yra transformuojama į vienmatį uždavinį, sprendžiamą naudojant pagrindinių splainų aproksimaciją į vieną koordinatę. Gaunamas kraštinis uždavinys, kuris sprendžiamas kaip kraštinis savųjų reikšmių nustatymo uždavinys. Uždavinio sąlygas atitinka įprastų aukštesnės eilės diferencialinių lygčių sistema, kuriai spręsti taikomi patikimi diskrečiosios ortogonalizacijos skaitiniai metodai.
The Influence of Industrial Processing on the Physico-Chemical Characteristics and Lipid and Antioxidant Contents of Rice Bran
Authors: Pestana Vanessa R. , Zambiazi Rui C. , Mendonça Carla R. B. , Bruscatto Mariângela H , Ramis-Ramos Guillermo
Published: March 2009

A comparative study of the physico-chemical characteristics of rice bran during the successive steps of its industrial processing was carried out and included white and parboiled rice brans and pelletized and defatted rice brans. Moisture, acidity and peroxide index were determined. Using extracts in petroleum ether and gas chromatography, the total fat contents and the profiles of the fatty acids were established. The tocopherols and γ-oryzanol were determined using high performance liquid chromatography. The bran of parboiled rice showed the largest fat content and the lowest acidity, indicating that parboiling is the most effective process for bran stabilization. Oleic, linoleic and palmitic acids predominated in all the samples. Pelletization did not produce a loss in lipids, tocopherols or γ-oryzanol. All the samples showed higher contents of α-tocopherol, intermediate contents of γ-tocopherol and much lower concentrations of δ-tocopherol. Nine components of γoryzanol were detected, with a major proportion of the component that eluted in the fourth position, probably ferulate of 24-methylene cycloartenol. Pelletized rice bran showed the highest tocopherol content, whereas parboiled rice bran yielded the largest γ-oryzanol content.
NIR prediction of fruit moisture, free acidity and oil content in intact olives
Authors: Cayuela José Antonio , García José María , García José María , Caliani Nuria , Caliani Nuria
Published: March 2009

In this work, the prediction of olive fruit and virgin olive oil quality parameters through the direct measuring of the fruit using near infrared spectrometry (NIRS) has been investigated and the effectiveness of a portable spectrometer has been assessed. Models and calibration tests were developed using both the hexane-isopropanol extraction of individual olive fruits, and the Soxhlet extraction of olive paste. The parameters analyzed were the free acidity in olive oil, oil yield from physical extraction, oil content referring to fresh weight, oil content referring to dry matter and fruit moisture. The results indicate a good predictive potential with both methodologies and serve to encourage improvement in the obtained models through the enlargement of the calibrations. Fruit moisture prediction models showed high accuracy.
The relationship between total phenol concentration and the perceived style of extra virgin olive oil
Authors: Gawel Richard , Rogers Deborah A.G.
Published: March 2009

The degree of bitterness and pungency of a virgin olive oil largely defines its style, and therefore how it is most appropriately used by consumers. In order to assess how Australian olive oil producers interpret the style of their oils, 920 Australian virgin olive oils were classified by their producers as either being mild, medium or robust in style. Although in general, the classifications by producers were associated with the oils’ total phenol concentration, significant variability in phenol concentration within each style category was observed. The perceived styles of a subset of these oils were further assessed by panels of expert tasters. The expert panels were more discriminating when assigning oils to style categories based on total phenol levels. The producers and the expert panels were in moderate agreement with respect to oil style, with the interpretation of what constitutes a mild oil being the most contentious.
EVALUATION OF CHITOSAN/CaSO4/PLATELET-RICH PLASMA MICROSPHERE COMPOSITES AS ALVEOLUS OSTEOGENESIS MATERIAL
Authors: Chang Shwu Jen , Kuo Shyh Ming , Lan Cheng-Wen , Manousakas Ioannis , Tsai Pei Hua
Published: March 2009

Periodontal disease is the manifestation of serious bacteria infection that may extend to the gingival, periodontal ligaments, and alveolus bone. One commonly administrated treatment is the debridement therapy with the removal of infected area including the soft and hard lesion tissues. In some critical case, osteogenetic materials are being filled into the defective voids to improve the regeneration of slow-growing bony tissues. In attempt to improve bone regeneration, chitosan microsphere composites embedded with two osteogenesis beneficial ingredients, CaSO 4 and platelet-rich plasma (PRP), were fabricated by using a high voltage electrostatic field system. Three groups, chitosan/ CaSO 4 microspheres (Group A), chitosan/ CaSO 4 microspheres mixed with thrombin (Group B), and chitosan/ CaSO 4/PRP microspheres mixed with thrombin (Group C) were prepared. And, these chitosan-based composites were evaluated together with a control group in pig oral model for the bone regeneration study. The chitosan/ CaSO 4/PRP microsphere composites, exhibiting good sphericity, were in the range of 457.5 ± 59.3 μ m in diameter. Defects filled with Group B and Group C showed increases in new bone formation along with fibrous tissue regeneration as compared to that filled with Group A. The Masson's Trichrome stain observations suggested more abundant presence of fibrous collagen matrices around the defects after implanted with Group B over that of Group C microsphere composites. The preparation of chitosan/ CaSO 4-based microspheres was straight forward by using high voltage electrostatic field system. Furthermore, Chitosan/ CaSO 4-based microspheres with thrombin could be used successfully in regenerating new bone around the alveolus bone area.
Challenge and opportunity: Rethinking the role and function of developmental education in community college
Authors: Bailey Thomas
Published: March 2009

This chapter provides a national context about how students progress in community colleges across the country. It includes data about students who take developmental education courses, how they move through the developmental course sequence, the obstacles they face when completing their intended course of study, and programs and practices that appear to help students meet their goals.
Intensification of a vortex during free draining
Authors: Ramamurthi K. , Tharakan T. John
Published: March 2009

Three regimes of air‐core vortex formation are demonstrated to exist for the free draining of liquids containing angular momentum. These comprise of a rapidly intensifying air‐core vortex, a quasisteady vortex and a decaying vortex. The regimes are shown to be strongly influenced by the size of the drain‐port used in relation to the tank diameter. The influence of Froude number on air‐core vortex is discussed.
Characterization studies of calcined, promoted and non‐promoted methanol‐steam reforming catalysts
Authors: Idem Raphael O. , Bakhshi Narendra N.
Published: March 2009

Various promoted methanol‐steam reforming catalysts were prepared by incorporating Mn, Cr and Zn promoters into two dried corprecipitated Cu‐Al catalyst precursors containing 24.1 and 27.8 mass% Cu, calcined at 700°C, and then subjected to various activation treatments. Both the calcined and activated catalysts were thoroughly characterized using reaction studies, ICP—AES, XRD and TPR techniques.

Results showed that in addition to Cu2O, CuO, Al2O3 and CuAl2O4 species present in all calcined catalysts, calcined Zn‐promoted catalysts contained ZnO and ZnAl2O4 species, whereas calcined Mn‐ and Cr‐promoted catalysts contained CuMnO2 and Mn2O3, and Cu2Cr2O4 and Cr2O3 species, respectively. The nature and amounts of active sites generated on activated catalysts for the methanol‐steam reforming reaction strongly depended not only on the promoter type and concentration but also on the activation method.
Experimental investigation of phosphate dust collection in impinging streams (IS)
Authors: Berman Yuli , Tamir Abraham
Published: March 2009

An experimental study on collection of dry phosphate dust and coalescence of moistened phosphate dust in an Impinging‐stream (IS) collector has been conducted in the presence and in the absence of a water spray.

The total collection efficiency with a water spray of specific consumption of 0.3 kg water/kg dust was 95–97%. Air velocity at the inlet pipes varied between 10–30 m/s and the inclination angle with respect to the horizontal, a, of the IS was 40−60°. The water spray increased the collection efficiency by 5–20% in comparison to dry collection.

In the coaxial configuration, α = 0°, it has been obtained that in the presence of a water spray, up to 55–85% of the dust accumulated on the walls of the collector, which was undesirable. Applying the inclined IS decreased the above quantities up to 5–15% with an optimal inclination angle of α = 40°.

A simple model for collection of the particles has been established, showing a satisfactory agreement with experimental results.
Diffusion coefficients of propane and butane in peace river bitumen
Authors: Das Swapan K. , Butler Roger M.
Published: March 2009

Diffusion plays a vital role in the “Vapex” process. In the present work the results of experiments on “Vapex” using a Hele‐Shaw cell have been used to obtain empirical correlations for the diffusivities of propane and butane in Peace River bitumen. Additional data required for the estimation of diffusivities from these experiments are the solubilities of solvent in bitumen and a correlation for the viscosity of solvent bitumen mixture. Diffusivities are assumed to decline exponentially with viscosity. Computed values of diffusion coefficients fall within the range of the published data for similar systems. This simple experiment can be used to estimate the diffusivities of gaseous solvents in highly viscous fluids.
Recovery, characterization and conceptual modelling of Non‐Bituminous organic materials from oil sands
Authors: Sengupta Susmita , Tollefson Eric L. , Dalai Ajay K.
Published: March 2009

The hot water process has recovered approximately 90% of the bitumen in oil sands, but the remaining 10% of bitumen and naphtha has been lost to the tailings pond. Recovery of bitumen and non‐bituminous combustibles (NBC) from centrifuge, scroll and final tailings has been considered. The effects of four sequestering agents, and of chemical additives such as CaCl2 and FeCl3 on the flotation behavior of bitumen, NBC and minerals in these tailings have been investigated. A simple method of isolating NBC materials has been developed. The flotation of both bitumen and NBC was enhanced by phosphate treatment and depressed by EDTA. NBC was characterized by its physical properties, energy content, functionality and chemical analysis. A conceptual model explains the interactions between the bitumen, minerals and NBC fractions present in tailings slurries.
Conversion of canola oil to various hydrocarbons over Pt/HZSM‐5 bifunctional catalyst
Authors: Katikaneni Sai P. R. , Adjaye John D. , Bakhshi Narendra N.
Published: March 2009

Canola oil conversion was studied at atmospheric pressure over Pt/HZSM‐5 catalyst (0.5 mass% Pt) in a fixed bed micro‐reactor. The operating conditions were: temperature range of 400−500°C, weight hourly space velocity (WHSV) of 1.8 and 3.6 h−1 and steam/oil ratio of 4. The objective was to optimize the amount of gasoline range hydrocarbons in the organic liquid product (OLP) and the selectivity towards olefins and isohydrocarbons in the gas product. The gas yields varied between 22–65 mass% and were higher in the presence of steam compared to the operation without steam. The olefin/paraffin mass ratio of C2‐C4 hydrocarbon gases varied between 0.31–0.79. The isohydrocarbons/n‐hydrocarbons ratio was higher with Pt/HZSM‐5 (1.6–4.8) compared with pure HZSM‐5 catalyst (0.2–1.0). The OLP yields with Pt/HZSM‐5 (20–55 mass% of canola oil) were slightly lower compared to HZSM‐5 (40–63 mass% of canola oil) under similar conditions. The major components of OLP were aliphatic and aromatic hydrocarbons. A scheme postulating the reaction pathways for the conversion of canola oil over Pt/HZSM‐5 catalyst is also presented.
Preparation of supported La0.66Sr0.34Ni0.3Co0.7O3 perovskite catalysts and their performance in methane and odorized natural gas combustion
Authors: Klvana D. , Kirchnerova J. , Gauthier P. , Delval J. , Chaouki J.
Published: March 2009

Three industrially applicable forms of supported La0.66Sr0.34Ni0.3Co0.7O3 perovskite combustion catalyst were prepared: alumina pellets coated with perovskite powder, perovskite formed in situ on ceramic fibers, and perovskite formed in situ in fluidizable particles. Kinetics of methane combustion over these catalysts was determined in a plug‐flow reactor. For the fiber supported catalyst as the representative one, the effects of various operational conditions on the performance were evaluated in a CSTR Berty reactor. The combustion was inhibited by carbon dioxide, but water had no effect. No carbon monoxide was detected in the effluents even when combusting a methane‐rich mixture. No measurable effect of combusting commercial natural gas odorized by ∼10 mL/m3 methyl mercaptan was observed, although the catalyst was slowly deactivated by 150 mL/m3 mercaptan in the feed. A simple kinetic model which takes CO2 inhibition into account is proposed: r = k2 P/(1 + Kinh P).
Treatment of gases and dust using “droplet columns”
Authors: Botton R. , Benadda B. , Bressat R. , Otterbein M.
Published: March 2009

The properties of the air‐water state diagram, representing the liquid holdups according to gas velocities, in a 0.075 m diameter column are restated. After measurement of the interfacial areas and mass‐transfer coefficients, the part of the diagram corresponding to high gas velocities and low liquid contents (10 < UG < 14 m/s and 0.005 < UL < 0.04 m/s) was chosen for the treatment of polluted gas streams. Under these conditions, it was shown that a “droplet column” is very efficient for the treatment of gases polluted by acid vapors (SO2, HCl) and dust (iron oxide, talc, etc.). The cost of energy appeared more favorable than for classical bubble columns.
Critical impeller speed for solid suspension in gas inducing type mechanically agitated contactors
Authors: Saravanan K. , Patwardhan A. W. , Joshi J. B.
Published: March 2009

Critical impeller speed for solid suspension (NCS), has been measured in gas inducing mechanically agitated contactors (GIMAC) fitted with two impellers. Five different impeller designs were employed. It was found that the multiple impeller system having both pitched blade downflow turbines was the most energy efficient for the suspension of solid particles. The interimpeller clearance (C3), and the impeller bottom clearance (C1) were found to be important parameters. Further, for this optimum combination, the design of the lower impeller was optimized in terms of impeller diameter (D), blade width (W), blade angle (A), and the number of blades (nb). An empirical model has been proposed based on the mechanism of fluidization.
Condensation en film entre deux plaques planes verticales: Comparaison des performances thermiques du R134a et du R12
Authors: Louahlia H. , Panday P. K.
Published: March 2009

Cet article présente les résultats d'une étude numérique sur la condensation par convection forcée du R134A entre deux plaques verticales. Le modèle physique est basé sur la résolution des équations de la couche limite en tenant compte des paramètres souvent négligés dans les études théoriques de la condensation, à savoir le gradient de pression, les termes d'inertie et de convection d'enthalpie, la variation des propriétés physiques ainsi que la viscosité et la conductivité turbulentes. Les résultats du présent calcul sont confrontés aux valeurs expérimentaux de Shao et Granryd (1995). Les performances thermiques du R12 et du R134a sont comparées. Les effets de la turbulence, de la pesanteur, de la vitesse de la vapeur, du nombre de Jakob, des forces de pression ainsi que des contraintes tangentielles sont également analysés.
Characterisation of three different impellers using the LDV‐technique
Authors: Tiljander Pia , Rönnmark Björn , Theliander Hans
Published: March 2009

A characterisation of three commonly used impellers was made in this study by measuring local mean velocities and the fluctuations of these velocities with the LDV technique. The data was used to estimate volumetric flow, velocity fluctuations and turbulent intensity in the impeller region of the tank. The impellers investigated were a high flow impeller, a pitched blade turbine and a Rushton turbine. The cylindrical vessel used was made of Perspex, had a dished bottom (DIN 28013), was equipped with four baffles and had an inner diameter of 0.45 m.

It was found that the bulk velocities could be scaled with the tip‐speed of the impeller (ND). The flow rate at constant impeller speed increased in the order high flow impeller — Rushton turbine — pitched blade turbine. The corresponding order for the turbulence fluctuation is: high flow impeller — pitched blade turbine — Rushton turbine. The velocity profile of the flow out from the high flow impeller was furthermore, not as smooth as could be expected.
The solubility of mixtures of H2S and CO2 in an mdea solution
Authors: Jou Fang‐Yuan , Otto Frederick D. , Mather Alan E.
Published: March 2009

The solubility of mixtures of hydrogen sulfide and carbon dioxide in a 50 mass per cent aqueous solution of methyldiethanolamine (MDEA) solution has been measured at 40°, 70° and 100°C. Partial pressures of the acid gases ranged from 0.08 to 10 450 kPa.
Électrodes poreuses percolées constituées de métal fritté: Hydrodynamique et transfert de matière
Authors: Vilar Eudésio Oliveira , Coeuret FrançOis
Published: March 2009

On a étudié des électrodes poreuses percolées constituées de nickel fritté du commerce, suivant différentes configurations (plaque percolée perpendiculairement; tube percolé radialement; tube traversé par un écoulement longitudinal, avec percolation radiale des parois). Après avoir caractérisé ces matériaux partir de mesures de pérmeamétrie, on a utilisé la méthode électrochimique de mesure des coefficients de transfert de matière pour atteindre la valeur des coefficients volumétriques de transfert de matière. Des correlations empiriques sont obtenues dans le cas des électrodes unidimensionnelles (électrode axiale, électrode radiale), et comparées à d'autres corrélations de la litérature. Les résultats obtenus dans le cas d'un écoulement axial combiné à une aspiration au travers de la paroi sont discutés.
Theoretical and experimental investigations of molecular migration and diffusion kinetics of organic esters into tetrafluoroethylene/propylene copolymer membranes
Authors: Aminabhavi Tejraj M. , Harlapur Sujata F. , Balundgi Ramachandra H. , Dale Ortego J.
Published: March 2009

A theoretical analysis of the experimental results on the migration and diffusion kinetics of methyl acetate, ethyl acetate, n‐propyl acetate, n‐butyl acetate and iso‐amylacetate into tetrafluoroethylene/propylene copolymer membranes has been made. Diffusion and permeability coefficients have been calculated from Fick's equation. The concentration profiles of the liquids have been calculated from a solution of Fick's equation as well as using an empirical relation for the esters into the varying penetration depths of the membranes at different time intervals. The diffusion coefficients show a systematic decrease with increasing size of esters and the results are discussed in terms of the membrane‐solvent interactions.
A soft sensor for flotation plants
Authors: Bazin Claude , Trusiak Andrew
Published: March 2009

A soft‐sensor was developed to estimate the solids flow rates in the streams of a flotation circuit. The algorithm uses metal assays and mass flow rate measurements to perform the estimation. The method performs a recursive least squares estimation of the mass flow rates based on the assumption of mass conservation over a specified time window. The soft‐sensor is programmed into a Vax computer system interfaced with a DCS and is currently used for process control and instrument tuning.
Autofluidization: The fluidization of solid particles by gases evolving from the particles
Authors: Lawrence A. David , Gogolek Peter E. , Kuang James
Published: March 2009

An experimental procedure was developed to study the autofluidization (i.e. the fluidization of solid particles by gases evolving from the particles) of green coke. It was found that the best method was to heat a 30 cm deep bed of 178 μm quartz sand to 800°C while fluidizing it with air and then adding a small batch of ˜1 mm coke particles to the surface of the bed. After allowing the coke to mix with the sand for 20 s, the fluidizing air was reduced to a lower rate. Pressure is then measured as a function of height in the bed and time. The result is a series of pressure measurements which decay smoothly from the fluidized state to a new steady state once all the coke's volatiles have been released. From these measurements it is possible to calculate gas velocities in the bed as well as bed voidage and apparent density. It was found that the upper sections of the bed would remain fluidized for up to nearly 2 min after the coke was added to the sand while the lower parts of the bed were never fluidized. Simple theory, in the form of the Blake‐Kozeny equation, does a good job of predicting when autofluidization will occur and what the changes in bed height and pressure are within the bed.
Non‐uniformity of gas dispersion in turbine‐generated viscoelastic circulation flow
Authors: Vlaev Serafim D. , Martinov Martin
Published: March 2009

Gas dispersion has been analysed experimentally by measuring local gas hold‐up in two lab‐scale conventional turbine‐agitated vessels loaded with viscoelastic fluids. The gas hold‐up radial profiles obtained in various axial positions close and far from the impeller reveal high non‐uniformity of gas dispersion. Non‐uniformity is quantified and related to elasticity, shear dependent viscosity, shear rate, first normal stress difference coefficient and type of fluid. The low values of gas hold‐up obtained for the vessel central area are interpreted as hindered gas dispersion caused by the flow pattern specific for the viscoelastic properties of the circulating fluid. The paper is complementary to the effort for collecting up data for benchmarking numerical CFD simulations (Kumar et al., 1997).
Demixing effects in laminar shearing flows: A practically useful approach
Authors: Agarwal Sushant , Gupta Rakesh K. , Doraiswamy Deepak
Published: March 2009

The phenomena of shear‐induced agglomeration and shear‐induced migration in a non‐ colloidal particulate suspension were examined in different flow fields. The shear flow of a model suspension consisting of spherical glass beads in an aqueous corn syrup with added surfactant was studied in homogeneous and non‐homogeneous flow fields (cone‐and‐plate, parallel plate and laminar flow in a tube). It was found that there was a rapid increase in the average agglomerate size followed by leveling off at long times resulting in an equilibrium particle size. This equilibrium particle size was found to be a strong function of the applied shear rate. It was further found that agglomerate data from the different flow fields superposed well, and, at least in the range of solid volume fractions considered, particle migration was negligible. This work provides a simple technique for quantifying demixing in laboratory experiments and applying the results to industrially relevant situations.
Experimental and numerical characterization of viscous flow and mixing in an impinging jet contactor
Authors: Unger David R. , Muzzio Fernando J. , Brodkey Robert S.
Published: March 2009

The laminar flow in an impinging jet contactor is examined as a first step toward the development of new technology for fast mixing of viscous fluids. The flow, velocity, and stretching fields in an impinging jet contactor are quantified for low Reynolds number flow using three‐dimensional numerical simulations and particle image velocimetry measurements. Computational and experimental velocity fields are in close agreement, as quantified by the velocity probability density functions. Two steady‐state flow regimes are found to exist: for jet Reynolds numbers (Rej) < 10, the jets do not impinge and the velocity field scales linearly with Reynolds number; for Rej > 10, the jets begin to impinge and recirculation regions form above and below the impingement point. The magnitude of the rate‐of‐strain tensor is calculated as a function of Rej. While areas of essentially zero stretching occupy most of the flow domain, very high rates of stretching occur at specific locations in the flow. The maximum and average rates of stretching in the contactor increase roughly linearly as a function of Reynolds number. Mixing simulations show that no mixing occurs for the steady flow in a symmetric‐jet contactor. However, mixing is improved substantially by a slight modification of the impinging jet geometry that disrupts geometric symmetry.
Experimental measurements and simulation of mixing and chemical reaction in a stirred tank
Authors: Zipp Robert P. , Patterson Gary K.
Published: March 2009

Effects of mixing on the rate of second‐order chemical reactions have been studied by measuring the time‐average degree of conversion at enough points in a steady‐state, continuous‐flow stirred reactor to provide comparisons with numerical simulations of the same reactions using a standard Reynolds‐averaged turbulence simulation code with an added closure. The reactants were introduced in widely separated feed streams in order to provide a difficult test for the measurements and simulations. Concentration and segregation measurements were made with two fluorescence based methods ‐ one remote and one using a fiber optic probe. The rates of mixing and reaction were simulated using the Corrsin mixing term and the Spalding segregation production term with the Paired‐Interaction reaction closure term.