scholarly journals Continuous Flow Esterification of a H-Phosphinic Acid, and Transesterification of H-Phosphinates and H-Phosphonates under Microwave Conditions

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 719
Author(s):  
Nóra Zsuzsa Kiss ◽  
Réka Henyecz ◽  
György Keglevich
Keyword(s):  
Flow Rate ◽  
Continuous Flow ◽  
Phosphinic Acid ◽  
Optically Active ◽  
Similar Reaction ◽  
Step Process ◽  
Direct Esterification ◽  
Alkoxy Groups ◽  
Acid Transesterification

The microwave (MW)-assisted direct esterification of phenyl-H-phosphinic acid, transesterification of the alkyl phenyl-H-phosphinates so obtained, and the similar reaction of dibenzyl phosphite (DBP) were investigated in detail, and the batch accomplishments were translated into a continuous flow operation that, after optimization of the parameters, such as temperature and flow rate, proved to be more productive. Alcoholysis of DBP is a two-step process involving an intermediate phosphite with two different alkoxy groups. The latter species are of synthetic interest, as precursors for optically active reagents.

Defluoridation of drinking water by magnesium and aluminum electrocoagulation in continuous flow-rate: A response surface design.

2021 ◽  
pp. 1-37
Author(s):  
Ana Gabriela Sierra-Sánchez ◽  
Verónica Martínez-Miranda ◽  
Elia Alejandra Teutli-Sequeira ◽  
Ivonne Linares-Hernández ◽  
Guadalupe Vázquez-Mejía ◽  
...  
Keyword(s):  
Drinking Water ◽  
Response Surface ◽  
Flow Rate ◽  
Continuous Flow ◽  
Response Surface Design ◽  
Surface Design

An Experimental Study on Cryogenic Spray Quenching of a Circular Metal Disk II. Chilldown Efficiency and Effects of Coating and Flow Pulsing

2021 ◽  
Author(s):  
Jun Dong ◽  
Hao Wang ◽  
Samuel Darr ◽  
Jason Hartwig ◽  
Jacob Chung
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Liquid Nitrogen ◽  
Mass Flow ◽  
Flow Rate ◽  
Continuous Flow ◽  
Nucleate Boiling ◽  
Film Boiling ◽  
Teflon Coating ◽  
Bare Surface

Abstract This is the second part of a two-part series that presents the results of liquid nitrogen spray quenching of a Stainless Steel disc. The results of continuous-flow spray chilldown of a bare surface disc are summarized first that serves as the baseline information for evaluating the effects of disc surface coating and pulse flow. We found that for continuous-flow spray chilldown of a bare surface disc, the chilldown efficiency is mainly a function of the average mass flow rate with the trend of decreasing efficiency with increasing mass flow rate. Additional experiments were performed to evaluate the enhancement of cryogenic spray quenching by three techniques: 1. Using intermittent pulse sprays on SS bare surface, 2. Coating the SS surface with a layer of low thermal conductivity Teflon film, and 3. Spraying liquid nitrogen intermittently on the coated SS surface. In general, the results indicate that all three methods effectively produced higher spray thermal efficiencies and reduced liquid nitrogen mass consumption. However, it was also found that the Teflon coating was more effective than the flow pulsing due to that the Teflon coating induced a large surface temperature drop at the beginning of the chilldown that allowed the quenching to move quickly from poor heat transfer film boiling to efficient heat transfer transition and nucleate boiling regimes. This quick transition shortens the film boiling period, thus facilitates the switch to much higher heat transfer transition boiling and nucleate boiling periods earlier to complete the chilldown process faster.

Zeolite/Cerium Oxide Coat-on Activated Alumina Ball for Arsenite Removal via Fixed- Bed Continuous Flow Adsorption Column

2021 ◽  
Author(s):  
Suttikorn Suwannatrai ◽  
Dickson Y. S. Yan ◽  
Pummarin Khamdahsag ◽  
Visanu Tanboonchuy
Keyword(s):  
Cerium Oxide ◽  
Flow Rate ◽  
Continuous Flow ◽  
Human Life ◽  
Fixed Bed ◽  
Point Of Zero Charge ◽  
Contaminated Water ◽  
Activated Alumina ◽  
Initial Flow ◽  
Alumina Ball

Arsenite (As(III)) has threatened human life for ages. It is a necessity to remove As(III) from the contaminated water before general use. With the improvement of adsorption, higher As(III) removal can be achieved. This study aimed to develop zeolite/cerium oxide coat-on activated alumina ball adsorbent (CeZ-ball) with the aid of PVA binder and apply it to a fixed-bed continuous flow column for As(III) adsorption. The coating percentage of CeZ-ball was studied. Cerium ions leaching from CeZ-ball were monitored throughout the 2,880-min-column run to confirm the stability of CeZ attached to an activated alumina ball. Surface area, pH point of zero charge, and structural property of CeZ-ball were characterized. An average CeZ coating of 83.3% and rare leaching of cerium proved the coating method. The models proposed by Yoon-Nelson provided the most satisfactory fit with the breakthrough curve (r2 = 0.985, MPSD = 2.547, and q0 = 3.481 mg·g–1) under experimental conditions of the flow rate of 5 mL·min–1, As(III) influent concentration of 1 mg·L–1, and CeZ-ball weight of 40 g. The half-time of breakthrough (τ) was 1,228.739 min. The effects of the key parameters, including initial adsorbent weight, initial flow rate, and initial As(III) concentration, were investigated for the performance of As(III) adsorption. Simulated from the Yoon-Nelson model, the τ increased as well as the adsorbent weight but decreased as the flow rate increased, thus impacting the As(III) concentration. With the optimal condition, the fixed-bed continuous column with CeZ-ball could be used in As(III) removal from contaminated water.

scholarly journals Calcium Phosphate Nanoparticle Precipitation by a Continuous Flow Process: A Design of an Experiment Approach

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 953
Author(s):  
Lorenzo Degli Esposti ◽  
Alessandro Dotti ◽  
Alessio Adamiano ◽  
Claudia Fabbi ◽  
Eride Quarta ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Flow Rate ◽  
Continuous Flow ◽  
Scale Up ◽  
Chemical Properties ◽  
Chemical Precipitation ◽  
Water Remediation ◽  
Scale Production ◽  
Flow Process ◽  
Process Factors

Calcium phosphate nanoparticles (CaP NPs) are an efficient class of nanomaterials mainly used for biomedical applications but also very promising in other sectors such as cosmetics, catalysis, water remediation, and agriculture. Unfortunately, as in the case of other nanomaterials, their wide application is hindered by the difficulty to control size, morphology, purity and degree of particle aggregation in the translation from laboratory to industrial scale production that is usually carried out in batch or semi-batch systems. In this regard, the use of continuous flow synthesis can help to solve this problem, providing more homogenous reaction conditions and highly reproducible synthesis. In this paper, we have studied with a design of experiment approach the precipitation of citrate functionalized CaP NPs aided by sonication using a continuous flow wet chemical precipitation, and the effect of some of the most relevant process factors (i.e., reactant flow rate, sonication amplitude, and maturation time) on the physico-chemical properties of the NPs were evaluated. From the statistical data analysis, we have found that CaP NP dimensions are influenced by the reactor flow rate, while the crystalline domain dimensions and product purity are influenced by the maturation process. This work provides a deeper understanding of the relationships between reaction process factors and CaP NP properties, and is a relevant contribution for the scale-up production of CaP NPs for nanomedical or other applications.

scholarly journals Effects of Hydrocortisone on the Yield and Bactericidal Function of Granulocytes Collected by Continuous-flow Centrifugation

Blood ◽  
1974 ◽  
Vol 44 (3) ◽  
pp. 435-443 ◽  
Author(s):  
Mamoru Shoji ◽  
William R. Vogler
Keyword(s):  
Single Dose ◽  
Flow Rate ◽  
Continuous Flow ◽  
Treated Group ◽  
Flow Cell ◽  
Controlled Study ◽  
Single Intravenous Injection ◽  
Cell Separator ◽  
Bactericidal Function

Abstract The usefulness of granulocyte transfusions is in part dependent upon the number of granulocytes transfused. The invention of the continuous-flow cell separator has made it possible to obtain granulocytes from normal donors. Efforts to improve the yield are under study. This controlled study was undertaken to determine the effect of a single dose of hydrocortisone on granulocyte yield from volunteer donors and on granulocyte bactericidal function. Twenty-two normal volunteers were randomized between no therapy or a single intravenous injection of 120 mg/sq m of hydrocortisone 2 hr prior to initiation of a 4-hr leukapheresis using the Aminco cell separator operated at 750 rpm and a flow rate of 41 ml/min. Significant increases in granulocyte yield and reductions in lymphocyte and monocyte yields were obtained in the hydrocortisone-treated group. Granulocytes from each group were equally effective in the phagocytosis of yeast particles and in vitro bactericidal activity.

scholarly journals Understanding Dissolution Rates via Continuous Flow Systems with Physiologically Relevant Metal Ion Saturation in Lysosome

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 311 ◽  
Author(s):  
Johannes Keller ◽  
Willie Peijnenburg ◽  
Kai Werle ◽  
Robert Landsiedel ◽  
Wendel Wohlleben
Keyword(s):  
Flow Rate ◽  
Continuous Flow ◽  
Metal Ion ◽  
Volume Flow Rate ◽  
Particle Surface ◽  
Volume Flow ◽  
High Similarity ◽  
Dissolution Rates ◽  
Wide Range ◽  
Flow Systems

Dissolution rates of nanomaterials can be decisive for acute in vivo toxicity (via the released ions) and for biopersistence (of the remaining particles). Continuous flow systems (CFSs) can screen for both aspects, but operational parameters need to be adjusted to the specific physiological compartment, including local metal ion saturation. CFSs have two adjustable parameters: the volume flow-rate and the initial particle loading. Here we explore the pulmonary lysosomal dissolution of nanomaterials containing the metals Al, Ba, Zn, Cu over a wide range of volume flow-rates in a single experiment. We identify the ratio of particle surface area (SA) per volume flow-rate (SA/V) as critical parameter that superimposes all dissolution rates of the same material. Three complementary benchmark materials—ZnO (quick dissolution), TiO2 (very slow dissolution), and BaSO4 (partial dissolution)—consistently identify the SA/V range of 0.01 to 0.03 h/μm as predictive for lysosomal pulmonary biodissolution. We then apply the identified method to compare against non-nanoforms of the same substances and test aluminosilicates. For BaSO4 and TiO2, we find high similarity of the dissolution rates of their respective nanoform and non-nanoform, governed by the local ion solubility limit at relevant SA/V ranges. For aluminosilicates, we find high similarity of the dissolution rates of two Kaolin nanoforms but significant dissimilarity against Bentonite despite the similar composition.

Continuous Flow Peritoneal Dialysis: Assessment of Fluid and Solute Removal in a High-Flow Model of “Fresh Dialysate Single Pass”

2003 ◽  
Vol 23 (4) ◽  
pp. 348-355
Author(s):  
Philippe Freida ◽  
Belkacem Issad
Keyword(s):  
Peritoneal Dialysis ◽  
Flow Rate ◽  
Continuous Flow ◽  
Historical Data ◽  
High Flow ◽  
Single Pass ◽  
Peritoneal Transport ◽  
Baxter Healthcare ◽  
Lumen Catheter ◽  
The Impact

♦ Background Growing concern over the limited capacity of the peritoneal dialysis (PD) system has revived interest in continuous flow peritoneal dialysis (CFPD), a modality in which continuous circulation of PD fluid is maintained at a high flow rate using two separate catheters or one dual-lumen catheter. The CFPD regimen contrasts the “inflow/outflow” regimen, which requires specific times devoted to filling and draining the peritoneum via a single-lumen catheter. Historical data established CFPD capabilities in providing higher solute clearance and ultrafiltration rate (UFR) using either an open loop system with a single pass of fresh PD fluid, or various external purifications of the spent dialysate. ♦ Objective To compare, in patients with various peritoneal transport patterns, fluid and solute removal achieved during a standardized program of CFPD versus two control schedules: nightly intermittent peritoneal dialysis (NIPD) and nightly tidal peritoneal dialysis (NTPD). This study focused on small solute clearances and UFR using only isotonic PD solution (Dianeal PD1 1.36%; Baxter Healthcare, Castlebar, Ireland). The model of fresh dialysate, single pass, was used to optimize solute gradients and to characterize the impact of a continuous flow regimen on peritoneal transport characteristics. ♦ Methods In a crossover trial, 4-hour CFPD sessions were performed at a fixed dialysate flow rate (100 mL/minute) in 5 patients being treated with automated PD. A hemofiltration monitor (BM25; Baxter Healthcare, Brussels, Belgium) was adapted to the CFPD technique. The peritoneal cavity was filled through a temporary second catheter and simultaneously drained using the permanent peritoneal access. Fluid and solute removal were compared to data obtained from a control period based on 8-hour sessions of NIPD or NTPD using 13 L of isotonic dialysate. ♦ Results High-flow CFPD enhanced the diffusive transport coefficient compared with the alternative flow regimen in patients ranging from low to high transporters. Weekly creatinine clearance increased from 36.9 L (22.3 – 49.6 L) and 37.3 L (27.5 – 45.0 L) with NIPD and NTPD respectively, to 74.9 L (42.3–107.5 L) with CFPD. Mean UFR was 2.44 mL/min with CFPD versus 0.92 and 0.89 mL/min with NIPD and NTPD respectively. The mass transfer area coefficient (MTAC) of creatinine with CFPD was 2.5-fold that obtained from the peritoneal equilibration test data. ♦ Conclusion Our results confirm that CFPD is highly effective in increasing fluid and solute removal. Furthermore, consistent with historical data, our findings indicate that the enhanced solute transfer is not due only to steeper solute gradients, but also depends on increased MTAC in a wide range of peritoneum transport characteristics.

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