Biased Atmospheric, Sub-Atmospheric, and Low-Pressure Air Plasmas for Material Surface Improvements

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Metallic powder injection molding using low pressure

The demand by high performance materials that have to support severe service conditions at a reasonable cost has been forcing the powder metallurgy to improve constantly. The most recent and more important innovation in the area is the process of powder injection.Powder injection molding (PIM) is a technology capable of producing a new range of components from powders. This advanced technology overcomes the existent limitations in the forming of products with complex geometry. The process presents countless variations which are used in the industry today. Invariably, it consists of mixing the powders and a thermo-plastic binder, injecting the mass in the mold in the wanted form, debinding, sintering and making optional secondary operations, as for example, machinery.The purpose of this work is to review the metal injection molding techniques and apply the low pressure injection molding process to family of parts using metallic powder with 10 mum particle size. This work also comments the design and construction of a low pressure injection machine and injection molds. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Application of low-pressure gas chromatography-ion-trap mass spectrometry to the analysis of the essential oil of Turnera diffusa (Ward.) Urb.

Turnera diffusa Willd. var. afrodisiaca (Ward) Urb. (syn. T. aphrodisiaca) belongs to the family of Turneraceae and is an aromatic plant growing wild in the subtropical regions of America and Africa. It is widely used in the traditional medicine as e.g. anti-cough, diuretic, and aphrodisiac agent. This work presents a 3 min chromatographic analysis using low-pressure (LP) gas chromatography (GC)-ion-trap (IT) mass spectrometry (MS). The combination of a deactivated 0.6 m x 0.10 mm i.d., restrictor with a wide-bore CP-Wax 52 capillary column (10 m x 0.53 mm i.d., 1 mum) reduces the analysis time by a factor of 3-7 in comparison to the use of a conventional narrow bore column. Chromatographic conditions have been optimized to achieve the fastest separation with the highest signal/noise ratio in MS detection. These results allow fast and reliable quality control of the essential oil to be achieved. (C) 2003 Elsevier B.V. All rights reserved.

Nitrogen diffusion in niobium under low pressure

The interaction among heavy interstitial atoms present in metals with bcc structure is studied using anelastic spectroscopy. This technique makes it possible to obtain information on interstitial concentration, precipitation, solubility limit, and diffusion. The diffusion coefficients of nitrogen in niobium were obtained using the relaxation parameters obtained from anelastic spectroscopy measurements for different oscillation frequencies of the system. The results showed the interstitial diffusion of nitrogen present in solid solution in niobium when submitted to different charges of nitrogen at a temperature of 1373 K and a partial pressure in the order of 10-4 Torr. The exponential variation of the pressure experimentally in function of the time was thus obtained.

Low pressure support changes the rapid shallow breathing index (RSBI) in critically ill patients on mechanical ventilation

Background: The rapid shallow breathing index (RSBI) is the most widely used index within intensive care units as a predictor of the outcome of weaning, but differences in measurement techniques have generated doubts about its predictive value. Objective: To investigate the influence of low levels of pressure support (PS) on the RSBI value of ill patients. Method: Prospective study including 30 patients on mechanical ventilation (MV) for 72 hours or more, ready for extubation. Prior to extubation, the RSBI was measured with the patient connected to the ventilator (Drager (TM) Evita XL) and receiving pressure support ventilation (PSV) and 5 cmH(2)O of positive end expiratory pressure or PEEP (RSBI_MIN) and then disconnected from the VM and connected to a Wright spirometer in which respiratory rate and exhaled tidal volume were recorded for 1 min (RSBI_ESP). Patients were divided into groups according to the outcome: successful extubation group (SG) and failed extubation group (FG). Results: Of the 30 patients, 11 (37%) failed the extubation process. In the within-group comparison (RSBI_MIN versus RSBI_ESP), the values for RSBI_MIN were lower in both groups: SG (34.79 +/- 4.67 and 60.95 +/- 24.64) and FG (38.64 +/- 12.31 and 80.09 +/- 20.71; p<0.05). In the between-group comparison, there was no difference in RSBI_MIN (34.79 +/- 14.67 and 38.64 +/- 12.31), however RSBI_ESP was higher in patients with extubation failure: SG (60.95 +/- 24.64) and FG (80.09 +/- 20.71; p<0.05). Conclusion: In critically ill patients on MV for more than 72h, low levels of PS overestimate the RSBI, and the index needs to be measured with the patient breathing spontaneously without the aid of pressure support.

Analisi comparativa di un circuito low pressure e high pressure EGR per un motore diesel sottostante a normativa americana US LEV III ULEV 125

Questa tesi di laurea nasce dall’esperienza maturata presso la VM Motori S.p.A., ufficio CRM (Centro Ricerca Motori) di ingegneria, divisione del reparto R&D (Research and Development) situato a Cento di Ferrara. Durante tale esperienza sono state affrontate le problematiche inerenti al settore automotive riguardo la ricerca e lo sviluppo dei motori endotermici diesel. Dopo un approccio introduttivo, che definisce l’ambito lavorativo in cui opera VM Motori S.p.A. e l’oggetto della tesi, si passa alla definizione ed alla calibrazione di un circuito low pressure EGR di un propulsore diesel da 200HP@3800rpm di potenza e 500Nm@1600rpm di coppia per uso automobilistico, mediante l’ausilio dei software AδαMO, INCA, Controldesk Next Generation, DoE, DIAdem ed INDICOM, software per lo studio della calibrazione al banco sviluppo. Si analizzano gli aspetti che contraddistinguono la VM Motori S.p.A. dalle altre aziende specializzate nel settore automotive, facendo riferimento ai campi produttivi in cui si applica l’ingegneria meccanica ed analizzandone gli aspetti tecnici, metodici e gestionali. Da notare il ruolo fondamentale delle automotive nell’economia mondiale in riferimento alla produzione dei principali propulsori diesel, primarie fonti produttive della VM.

Twenty years experience with an ileal orthotopic low pressure bladder substitute--lessons to be learned

PURPOSE: We present the long-term results of a large consecutive series of patients undergoing ileal orthotopic bladder substitution following radical cystectomy. MATERIALS AND METHODS: Between April 1985 and 2005 orthotopic bladder substitution with an ileal low pressure reservoir was performed in 482 patients (including 40 women) after radical and, if possible, nerve sparing cystectomy. In 447 cases the procedure was combined with an afferent ileal isoperistaltic tubular segment. The patients were followed prospectively. RESULTS: In the 482 patients 61 early (less than 30 days) diversion related complications requiring prolonged hospital stay or readmission were noted and 115 late complications required treatment. At 1 year continence was good in 92% of patients during the day and in 79% at night. At last followup 93% of patients could void spontaneously. Of 442 evaluable men 99 (22.4%) reported having erections without and 68 (15.4%) with medical assistance. Ureteroileal stenosis was observed in 12 of 447 (2.7%) patients. Urethral recurrence was detected in 25 of 482 (5%) patients. A total of 15 (5%) patients received vitamin B12 substitution. Renal parenchyma decreased only in patients with preoperative or postoperative ureteral obstruction. After 10 years patients with normal renal function had no long-term acidosis and in 20 patients the incidence of osteoporosis resembled that of the normal population. CONCLUSIONS: Ileal orthotopic bladder substitution combined with an afferent ileal tubular segment allows for good long-term functional results provided patients are restrictively selected, postoperative instructions are followed carefully, and typical complications such as outlet obstruction and hernias are treated early.

On the theory of high and low pressure areas: The significance of divergence in pressure areas

This is the edited and translated version of the article by Richard Scherhag “Zur Theorie der Hoch- und Tiefdruckgebiete. Die Bedeutung der Divergenz in Druckfeldern” (On the theory of high and low pressure areas: The significance of divergence in pressure areas), which was published in Meteorologische Zeitschrift 51, 129–138.

Low-pressure melting relations of a basalt from ODP Hole 127-797C

One-atmosphere melting experiments, controlled to approximately the fayalite-magnetite-quartz oxygen buffer, performed on a basalt from Hole 797C crystallized olivine and plagioclase nearly simultaneously from about 1235°C and augite from about 1175°C. The liquid compositions indicate systematic trends of increasing FeO and TiO2 and decreasing Al2O3 with decreasing MgO. Experimental olivine compositions vary from Fo90 to Fo78, plagioclase from An79 to An67, and augite from En49 to En46. The KD value for the Fe2+ and Mg distribution between olivine and liquid is 0.31. The KD value for the distribution of Fetotal and Mg between augite and liquid averages 0.24. These KD values suggest experimental equilibrium. The KD values for Na and Ca distribution between plagioclase and liquid range between 0.55 and 0.99 and are dependent on crystallization temperature. Projected on pseudoternary basaltic phase diagrams, the liquid line of descent moves toward increasing quartz normative compositions, revealing a typical tholeiitic crystallization trend with marked Fe and Ti enrichments. Such enrichments are a reflection of the dominance of plagioclase in the crystallizing assemblage. The experimental results can explain the marked Fe- and Ti-enrichment trends observed for the sills of the lower part of Hole 797C, but have no direct bearing on the origin of the relatively evolved high-Al basalts of Hole 794C.

Test time in low pressure shock tubes.

"SSD-TDR-62-204. Report no TDR-169 (3230-12)TN-5."

Water gravity waves generated by a moving low pressure area /

Mode of access: Internet.

Model study of water gravity waves generated by moving circular low pressure area /

Mode of access: Internet.

Rules and regulations relating to the handling of anhydrous ammonia and low pressure nitrogen solutions, equipment containers and storage facilities /

Cover title.