Determination of Essential Parameters for Quality Control in Fabrication of Piezoelectric Micropumps

Quality control of piezoelectric micropumps is presented through design, fabrication process, operation, and characterization. The presented study resulted in the extraction of a minimal set of monitored parameters, which is a prerequisite for reliable and stable micropump operation. Micropump fabrication process steps, especially bonding process quality, in correlation with quality control of micropump constituent components (housing, elastomer, and piezoelectric actuator) provided an explanation for deterioration of common micropump characteristics, such as flow vs. backpressure, suction pressure, and excitation signal. These characteristics also manifested in deterioration of other important micropump properties, such as self-priming ability, bubble tolerance, long-term stability, heat dissipation, and temperature operating range. Besides air and DI water pumping, chemical compatibility of constituent materials was confirmed during successful long-term testing of micropumps by pumping media with different viscosity and aggressive media with low pH value. The extracted set of parameters defines input control for micropump fabrication process while at the same time establishes safe operating area of fabricated micropumps. The presented set of parameters provides quality control guidelines and enables a direct comparison from pump-to-pump or run-to-run variations and extraction of influencing design or fabrication parameters

Influence of Piezoelectric Actuator Properties on Design of Micropump Driving Modules

The chapter will briefly present three distinctive concepts of the micropump actuator driving module, each with its waveform specifics and their impact on particular micropump performance (pumping media, flow rate and backpressure). First presented concept is based on two mutually-exclusive boost switched-mode power supply modules. Characterization of this module identified output voltage asymmetry to be the limiting factor of micropump performance. To assure driving symmetry, an alternative driving module, based on independent high-voltage stages and optocouplers, was implemented. This design is capable of driving a piezoelectric micropump with a rectangular waveform of programmable frequency, positive and negative amplitudes, slew rates and dead time. While this design provides maximum flow and backpressure characteristics, it does not offer minimal current consumption and long-term operation. To overcome this difficulty, our current design is based on an embedded arbitrary waveform generator, which offers an efficient trade-off between high pumping performance and low current consumption

Sistem za suho jedkanje silicija s ksenonovim difluoridom

En 2003, la Wallonie a mis en place un système de certificats verts échangeables pour soutenir la génération d’énergie électrique « verte ». Dans cet article, nous estimons que ce mécanisme de soutien a coûté 1,871 milliard € pour la période 2003-2012, soit un soutien de 107 €/MWh produit, avec de fortes différences entre filières de production, le photovoltaïque recevant jusqu’à 588 €/MWh. Les comparaisons internationales indiquent que le mécanisme wallon est particulièrement généreux. Nous montrons également que les économies induites de carbone sont extrêmement coûteuses avec un prix implicite pour la tonne de CO2 évitée de 425 €

The effect of dent versus flint maize genotype on site and the extent of starch and protein digestion, ruminal fermentation and microbial protein synthesis in the rumen of sheep

Ruminal and whole tract digestibility of protein and starch, microbial protein yield in the rumen and molar proportions of volatile fatty acids (VFA) in the rumen fluid and faeces were determined in sheep that were given either maize silage derived from the dent (DTS) or flint type hybrid (FTS). Degradabilities in the rumen were determined by means of the in sacco method using three sheep and microbial protein yield in the rumen by means of urinary purine derivative excretion using four sheep. The extent of starch and protein degradation was significantly (P < 0.001) lower in FTS than in DTS (718 vs. 913 and 704 vs. 767 g·kg–1 respectively). Differences in whole tract starch and protein digestibility were small (986 vs. 997, P < 0.01 and 939 vs. 931 g·kg–1, P < 0.05 in FTS and DTS respectively). The concentration of VFA in the rumen fluid was not affected by the type of silage (94.5 and 94.7 mmol·L–1); however, FTS induced a higher molar proportion of propionate (22.6% vs. 20.7%, P < 0.05) than DTS. The proportion of butyrate was higher in DTS (13.5% vs. 10.8%, P < 0.05). Microbial protein supply in FTS was significantly higher than in DTS (109.7 vs. 96.0 g·kg–1 DM intake, P < 0.05). When expressed in relation to fermentable organic matter (FOM) intake, the differences between hybrids were greater (215.6 vs. 158.6 g of microbial protein per kg FOM, P < 0.01). Lower efficiency of microbial protein synthesis in DTS was probably due to a lower pH value of rumen liquor (6.21 vs. 6.33, P < 0.05). FTS offered better conditions for the degradation of the fibre fraction in the rumen than DTS. The faeces of sheep that were given FTS contained less DM (304 vs. 371 g·kg–1, P < 0.05) and tended to have a higher concentration of VFA (383 and 235 mmol·kg–1 DM, P < 0.1) indicating that in FTS at least one part of the starch which escaped digestion in the rumen passed through the small intestine undigested and was fermented in the large intestine. It was concluded that FTS could provide about three times more postruminally digested starch and about 20% more metabolisable protein than DTS.Effet du génotype de maïs (denté vs. corné) sur le site et le volume de la digestion de l’amidon et des protéines, sur la fermentation ruminale, et sur la synthèse des protéines microbiennes dans le rumen chez les ovins. La digestibilité des protéines, de l’amidon et des constituants pariétaux dans l’ensemble du tractus digestif, le rendement de synthèse des protéines microbiennes dans le rumen et les proportions molaires des acides gras volatils (AGV) dans le jus de rumen et dans les fèces ont été déterminées sur des ovins qui ont reçu de l’ensilage de maïs de type denté (DTS) ou corné (FTS). Les dégradabilités dans le rumen ont été mesurées par la méthode in sacco sur trois ovins alors que le rendement de synthèse des protéines microbiennes a été déterminé à partir de l’excrétion urinaire des dérivés de purines en utilisant quatre ovins. L’importance de la dégradation de l’amidon et des protéines a été significativement (P < 0,001) plus faible pour FTS que pour DTS (respectivement, 718 vs. 913 et 704 vs. 767 g·kg–1). Les différences entre les digestibilités de l’amidon et des protéines dans l’ensemble du tractus digestif ont été faibles (respectivement, 986 vs. 997 g·kg–1, P < 0,01 et 939 vs. 931 g·kg–1, P < 0,05 pour FTS et DTS). La concentration en AGV totaux dans le jus de rumen n’a pas été affectée par le type d’ensilage (94,5 et 94,7 mmol·L–1), pourtant, FTS a induit des proportions molaires plus élevées de propionate (22,6 vs. 20,7 %, P < 0,05) et DTS des proportions de butyrate supérieures (13,5 vs. 10,8 %, P < 0,05). La synthèse des protéines microbiennes pour FTS a été significativement plus élevée que pour DTS (109,7 vs. 96,0 g·kg–1 de MS ingérée, P < 0,05). Quand elles sont exprimées par rapport à l’ingestion de la matière organique fermentescible (MOF), les différences entre les hybrides sont plus importantes (215,6 vs. 158,6 g de protéines microbiennes par kg MOF, P < 0,01). L’efficacité plus faible de la synthèse de protéines microbiennes pour DTS est probablement due à la valeur plus faible du pH ruminal (6,21 vs. 6,33, P < 0,05). Les FTS ont présenté les conditions les plus favorables pour la dégradation de la fraction fibreuse dans le rumen. Les fèces des ovins qui ont reçu FTS étaient moins riches en MS (304 vs. 371 g·kg–1, P < 0,05) et tendaient à être plus riche en AGV (383 et 235 mmol·kg–1 DM, P < 0,1) ; ce qui laisse supposer que, pour FTS, une partie de l’amidon, non dégradé dans le rumen, n’a pas été digéré dans l’intestin grêle et a été fermenté dans le gros intestin. En conclusion, FTS semble fournir approximativement trois fois plus d’amidon digéré dans l’intestin et 20 % de protéines métabolisables en plus que DTS

In Vivo Experimental Study of Noninvasive Insulin Microinjection through Hollow Si Microneedle Array

An experimental study of in vivo insulin delivery through microinjection by using hollow silicon microneedle array is presented. A case study was carried out on a healthy human subject in vivo to determine the influence of delivery parameters on drug transfer efficiency. As a microinjection device, a hollow microneedle array (13 × 13 mm2) having 100 microneedles (220 µm high, 130 µm-outer diameter and 50 µm-inner diameter) was designed and fabricated using classical microfabrication techniques. The efficiency of the delivery process was first characterized using methylene blue and a saline solution. Based on these results, the transfer efficiency was found to be predominantly limited by the inability of viable epidermis to absorb and allow higher drug transport toward the capillary-rich region. Two types of fast-acting insulin were used to provide evidence of efficient delivery by hollow MNA to a human subject. By performing blood analyses, infusion of more-concentrated insulin (200 IU/mL, international units (IU)) exhibited similar blood glucose level drop (5–7%) compared to insulin of standard concentration (100 IU/mL), however, significant increase of serum insulin (40–50%) with respect to the preinfusion values was determined. This was additionally confirmed by a distinctive increase of insulin to C-peptide ratio as compared to preinfusion ratio. Moreover, we noticed that this route of administration mimics a multiple dose regimen, able to get a “steady state” for insulin plasma concentration