Academic literature on the topic 'Membrane alto cut off'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Membrane alto cut off.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Membrane alto cut off"
1
Kaplunov, J., L. I. Manevitch, and V. V. Smirnov. "Vibrations of an elastic cylindrical shell near the lowest cut-off frequency." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, no. 2189 (May 2016): 20150753. http://dx.doi.org/10.1098/rspa.2015.0753.
Full textAbstract:
A new asymptotic approximation of the dynamic equations in the two-dimensional classical theory of thin-elastic shells is established for a circular cylindrical shell. It governs long wave vibrations in the vicinity of the lowest cut-off frequency. At a fixed circumferential wavenumber, the latter corresponds to the eigenfrequency of in-plane vibrations of a thin almost inextensible ring. It is stressed that the well-known semi-membrane theory of cylindrical shells is not suitable for tackling a near-cut-off behaviour. The dispersion relation within the framework of the developed formulation coincides with the asymptotic expansion of the dispersion relation originating from full two-dimensional shell equations. Asymptotic analysis also enables refining the geometric hypotheses underlying various ad hoc set-ups, including the assumption on vanishing of shear and circumferential mid-surface deformations used in the semi-membrane theory. The obtained results may be of interest for dynamic modelling of elongated cylindrical thin-walled structures, such as carbon nanotubes.
2
Akbari, Ahmad, Vahid Reza Abbaspour, and Seyed Majid Mojallali Rostami. "Tabas coal preparation plant wastewater treatment with membrane technology." Water Science and Technology 74, no. 2 (April 22, 2016): 333–42. http://dx.doi.org/10.2166/wst.2016.192.
Full textAbstract:
The goal of the present work is the Tabas coal preparation plant wastewater treatment using membrane technology. Polyacrylonitrile membrane was prepared through phase inversion method and then developed by annealing process. Also, high fouling resistance membranes were prepared by the embedding of TiO2 nanoparticles using self-assembling and blending methods. The effect of immersion time and TiO2 nanoparticles concentration was investigated using two techniques. The chemical structure, morphology, hydrophilicity, molecular weight cut-off and antifouling properties of membranes were characterized using energy-dispersive X-ray spectroscopy, scanning electron microscopy, contact angle, polyethylene glycol tracers, and cationic polyacrylamide (C-PAM) filtration, respectively. The optimized self-assembled membrane was shown to have more than 31.2% higher water flux with the best antifouling properties. Improving hydrophilicity leads to excellent antifouling properties for composite membranes and illustrates a promising method for fabrication of high performance membrane for C-PAM separation.
3
Kertész, Szabolcs, T. B. De Freitas, and Cecília Hodúr. "Characterization of polymer membranes by contact angle goniometer." Analecta Technica Szegedinensia 8, no. 2 (May 12, 2014): 18–22. http://dx.doi.org/10.14232/analecta.2014.2.18-22.
Full textAbstract:
The wider applications of all membrane separation processes have a main obstacle, namely the fouling phenomena, which have to be understood in more details. Surface properties, hydrophilic and hydrophobic characteristics of a polymer membrane can be determined by measuring the contact angle. The hydrophilicity of a membrane has an important influence on its performances, like permeate flux, membrane rejection or membrane fouling characteristics. In our work the contact angles of three kinds of typically commercial ultrafiltration (UF-PES-4), nanofiltration (NE-90) and reverse osmosis (LFC-30) membranes were firstly investigated and compared by contact angle goniometer measurements. The relationships between the contact angles were researched by well considering the effects of membrane sample pretreatments by distilled water prewetting and water droplet volume. Furthermore, the effects of prewetting, water droplet contact time on different molecular weight cut-off ultrafiltration membranes’ surface and droplet pH on the contact angle values were also investigated. Moreover, fresh, clean and dry, as well as pretreated, and fouled UF membranes were also measured and compared.
4
Naseer, Danyal, Jang-Hoon Ha, Jongman Lee, Chanhyuk Park, and In-Hyuck Song. "Effect of the Peptization Process and Thermal Treatment on the Sol-Gel Preparation of Mesoporous α-Alumina Membranes." Membranes 12, no. 3 (March 10, 2022): 313. http://dx.doi.org/10.3390/membranes12030313.
Full textAbstract:
Compared to traditional membrane materials, alumina membranes are particularly beneficial for industrial wastewater treatment. However, the development of mesoporous α-alumina membranes for ultrafiltration applications is still a challenge due to uncontrolled pore size. In this study, we optimized the sol-gel method for the fabrication of a high-performance mesoporous α-alumina membrane. The peptization conditions (pH and peptization time) and phase transformation of boehmite were investigated to achieve better properties of the α-alumina membrane. The surface properties of the membrane were observed to be improved by reducing the system pH to 3.5 and increasing the peptization time to 24 h. The effect of sintering temperature on the phase transformation behavior, microstructures and performance of the membranes was also elucidated. An α-alumina ultrafiltration membrane with an average thickness of 2 μm was obtained after sintering at 1100 °C. The molecular weight cut-off of the α-alumina membrane, as obtained by the filtration of aqueous PEG solution, was approximately 163 kDa (12.5 nm). This is the smallest pore size ever reported for pure α-alumina membranes.
5
Akbari, Ahmad, Zahra Fakharshakeri, and Sayed Majid Mojallali Rostami. "A novel positively charged membrane based on polyamide thin-film composite made by cross-linking for nanofiltration." Water Science and Technology 73, no. 4 (October 26, 2015): 776–89. http://dx.doi.org/10.2166/wst.2015.538.
Full textAbstract:
In this paper, a novel positively charged membrane was prepared through interfacial polymerization technique between polyethyleneimine in aqueous phase and trimesoyl chloride in organic phase. Next, cross-linking of polyamide (PA) layer using ρ-xylylene dichloride (XDC) and glutaraldehyde (GA) was studied. The influences of cross-linking concentrations on the separation and permeation performance of membrane were also investigated. Membranes were characterized in terms of their chemical structure, the cross-sectional and surface morphologies, contact angles, molecular weight cut-off (MWCO) and effect of pH feed solution. The salt rejection sequence of CaCl2 >NaCl > Na2SO4 showed a positive charge at the membrane surface after cross-linking reaction. The MWCO of primary PA membrane decreased from 1,135 to 775 and 885 Da for XDC and GA, respectively. XDC membrane shows highest CaCl2 divalent cationic rejection (95.5%) and lowest water flux (21.1 L/m2.h). This study illustrates a promising method for fabrication of positively charged membrane in cation separation.
6
Gomes, Elson Dinis, P. C. R. Pinto, and Alírio E. Rodrigues. "Lignin Valorization: Concentration of Model Phenolic Compounds by Nanofiltration." U.Porto Journal of Engineering 3, no. 1 (March 26, 2018): 72–78. http://dx.doi.org/10.24840/2183-6493_003.001_0007.
Full textAbstract:
Lignin is a biopolymer found in plants which can be valorized as a source of value added compounds by breaking its structure in the constituting monomers. A model solution was prepared with seven phenolic compounds, including vanillin and syringaldehyde, usually found after alkaline lignin oxidation. The model solution was concentrated by nanofiltration membranes with low molecular weight cut-off (MWCO). Two membranes (DOW NF270 and KOCH MPS-34) were tested for permeate fluxes and phenolic compound rejection. Significant reduction of the volume mixture was achieved with high permeate fluxes as well as high rejections (above 90%) for the phenolic compounds studied. The membrane with the best performance was the DOW NF270 with maintained high rejections while having higher permeate fluxes resulting in higher productivity when compared with the other membrane KOCH MPS-34 also tested.
7
et al., Alsayer. "Effect of membrane mean pore diameter on water and solute flux in forward osmosis processes." International Journal of ADVANCED AND APPLIED SCIENCES 9, no. 11 (November 2022): 99–105. http://dx.doi.org/10.21833/ijaas.2022.11.012.
Full textAbstract:
Several forward osmosis (FO) experiments were carried out using aqueous solutions of sodium chloride (NaCl) in different concentrations, as draw solution (DS), and freshwater, as feed water (FW). The experiments were conducted at a constant temperature of ~20°C and using a symmetric cellulosic membrane in two grades different in their values of the molecular weight cut-off (MWCO), which is related to the mean pore diameter. This study investigates the effect of the membrane mean pore diameter on water flux and DS solute diffusional flux across the membrane. The value of water flux indicates the performance of the FO process, while solute flux is an important factor that determines its practicality. A proportionality factor is used to specify the relationship between water flux and solute flux for each membrane type and operational conditions. The results of this study show that water flux and solute flux increase as the solute concentration difference across the membrane increases. It is also found that, in the range of the tested membranes, membranes with larger mean pore diameters have lower water flux and higher solute flux.
8
Chen, Yee-An, Shuo-Ming Ou, and Chih-Ching Lin. "Influence of Dialysis Membranes on Clinical Outcomes: From History to Innovation." Membranes 12, no. 2 (January 26, 2022): 152. http://dx.doi.org/10.3390/membranes12020152.
Full textAbstract:
Dialysis membranes were traditionally classified according to their material compositions (i.e., as cellulosic or synthetic) and on the basis of the new concept of the sieving coefficient (determined by the molecular weight retention onset and molecular weight cut-off). The advantages of synthetic polymer membranes over cellulose membranes are also described on the basis of their physical, chemical, and structural properties. Innovations of dialysis membrane in recent years include the development of medium cutoff membranes; graphene oxide membranes; mixed-matrix membranes; bioartificial kidneys; and membranes modified with vitamin E, lipoic acid, and neutrophil elastase inhibitors. The current state of research on these membranes, their effects on clinical outcomes, the advantages and disadvantages of their use, and their potential for clinical use are outlined and described.
9
Kovpak, A. A., Yu Yu Ivin, A. N. Piniaeva, Yu Kh Khapchaev, S. V. Ozherelkov, A. V. Belyakova, and A. A. Ishmukhametov. "Application of ultrafiltration membranes for purification and concentration of Sabin poliovirus type 1." Journal of microbiology, epidemiology and immunobiology 98, no. 2 (May 5, 2021): 135–43. http://dx.doi.org/10.36233/0372-9311-94.
Full textAbstract:
Introduction. Since the development of inactivated polio vaccines, different stages of the production process have been changed and improved. Current production of inactivated polio vaccines based on both wild and attenuated strains includes several technological stages, one of which is the concentration of the virus-containing liquid, which ensures poliovirus concentration, and purification of the virus-containing liquid from a significant part of the ballast components.Research objective is to compare the characteristics of ultrafiltration membranes and select the membranes that provide optimal value of purification and concentration of poliovirus type 1 (Sabin strain).Materials and methods. Laboratory ultrafiltration systems from two manufacturers with 50, 100, and 300 kDa membranes were used for the concentration. Results were evaluated by the content of total protein, which is the main stress for the subsequent purification stages, the value of infectious virus titer in the concentrate, and the content of D-antigen as the target product.Results and discussion. Obtained results demonstrated that the content of the target product (the highest D-antigen content) and purification from impurity proteins (the total protein content in the concentrate) were most optimal when a membrane with a cut-off of 300 kDa was used for concentration. The study also evaluated the real cut-off components by various membranes to determine the composition of the protein load on the target product.Conclusion. In terms of quality of the resulting target product and the manufacturability of the production process, the use of a 300 kDa membrane is the most appropriate when working out the technology for manufacturing inactivated polio vaccine based on Sabin strains of poliovirus and the Vero line as a producing culture.
10
Gardiner, James D., Jonathan R. Codd, and Robert L. Nudds. "An association between ear and tail morphologies of bats and their foraging style." Canadian Journal of Zoology 89, no. 2 (February 2011): 90–99. http://dx.doi.org/10.1139/z10-096.
Full textAbstract:
Most studies relating bat morphology to flight ecology have concentrated on the wing membrane. Here, canonical variance analysis showed that the ear and tail morphologies of bats also strongly relate to foraging strategy, which in turn is correlated with flight style. Variations in tail membrane morphology are likely to be a trade-off between increases in the mechanical cost of flight and improvements in foraging and flight performance. Flying with large ears is also potentially energetically expensive, particularly at high flight speeds. Large ears, therefore, are only likely to be affordable for slow foraging gleaning bat species. Bats with faster foraging flight styles tend to have smaller ears, possibly to cut the overall drag produced and reduce the power required for flight. Variations in the size of ears and tail membranes appear to be driven primarily by foraging strategy and not by body size, because the scaling relationships found are either weak or not significant. Ear size in bats may be a result of a trade-off between acoustic and aerodynamic performance.
Dissertations / Theses on the topic "Membrane alto cut off"
1
Gomes, Carlos André Mendonça. "Study of multi-component systems in polybenzimidazole membrane formation and their impact on membrane performance." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10651.
Full textAbstract:
Dissertação para obtenção do Grau de Mestre em
Engenharia Química e BioquímicaIntegrally skinned asymmetric polybenzimidazole (PBI) membranes suitable for organic solvent nanofiltration (OSN) were prepared via phase inversion and several changes were implemented in the dope solutions in order to control their molecular weight cut-off (MWCO). Initially, uncrosslinked membranes with different polymer concentrations were tested to investigate their impact on membrane performance. On a second approach, several co-solvents were added in the dope solutions of PBI membranes. Coupling this methodology with chemical crosslinking, using an aromatic bi-functional crosslinker, provided solvent stable membranes with several MWCOs in the nanofiltration range and high permeance. Further variation of membrane dope parameters was tested in order to study membrane formation impact on membrane performance. Total solubility parameters of the chosen co-solvents were calculated, and a correlation between this tool and membrane performance was studied. Even though it was not possible to withdraw conclusions on a fundamental level, from the correlation of the total solubility parameters with membrane performance, this work demonstrates the possibility of developing PBI OSN membranes using different co-solvents and opens up future possibilities for controlling the MWCO of these membranes. A post-treatment study was also conducted in order to examine its impact in membrane performance.
2
Chu, Jiangtao. "Microdialysis Sampling of Macro Molecules : Fluid Characteristics, Extraction Efficiency and Enhanced Performance." Doctoral thesis, Uppsala universitet, Mikrosystemteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-261068.
Full textAbstract:
In this thesis, fluid characteristics and sampling efficiency of high molecular weight cut-off microdialysis are presented, with the aim of improving the understanding of microdialysis sampling mechanisms and its performance regarding extraction efficiency of biological fluid and biomarkers. Microdialysis is a well-established clinical sampling tool for monitoring small biomarkers such as lactate and glucose. In recent years, interest has raised in using high molecular weight cut-off microdialysis to sample macro molecules such as neuropeptides, cytokines and proteins. However, with the increase of the membrane pore size, high molecular weight cut-off microdialysis exhibits drawbacks such like unstable catheter performance, imbalanced fluid recovery, low and unstable molecule extraction efficiency, etc. But still, the fluid characteristics of high molecular weight cut-off microdialysis is rarely studied, and the clinical or in vitro molecule sampling efficiency from recent studies vary from each other and are difficult to compare. Therefore, in this thesis three aspects of high molecular weight cut-off microdialysis have been explored. The first, the fluid characteristics of large pore microdialysis has been investigated, theoretically and experimentally. The results suggest that the experimental fluid recovery is in consistency with its theoretical formula. The second, the macromolecule transport behaviour has been visualized and semi-quantified, using an in vitro test system and fluorescence imaging. The third, two in vitro tests have been done to mimic in vivo cerebrospinal fluid sampling under pressurization, using native and differently surface modified catheters. As results, individual protein/peptide extraction efficiencies were achieved, using targeted mass spectrometry analysis. In summary, a theory system of the fluid characteristics of high molecular weight cut-off microdialysis has been built and testified; Macromolecular transport of microdialysis catheter has been visualized; In vivo biomolecules sampling has been simulated by well-defined in vitro studies; Individual biomolecular extraction efficiency has been shown; Different surface modifications of microdialysis catheter have been investigated. It was found that, improved sampling performance can be achieved, in terms of balanced fluid recovery and controlled protein extraction efficiency.
3
ZAMIDEI, LUCIA. "IL RUOLO DELLA TERAPIA RENALE SOSTITUTIVA CON MEMBRANE AD ALTO CUT-OFF IN PAZIENTI CRITICI CON SEPSI GRAVE/SHOCK SETTICO ASSOCIATI AD INSUFFICIENZA RENALE ACUTA." Doctoral thesis, 2015. http://hdl.handle.net/2158/989010.
Full text
4
Rebêlo, Beatriz Leonor. "Hemodiálise de alto cut-off na nefropatia de cilindros do mieloma múltiplo : a propósito de dois casos clínicos." Master's thesis, 2018. http://hdl.handle.net/10451/41914.
Full textAbstract:
Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2018O mieloma múltiplo (MM) consiste numa doença neoplásica plasmocitária, cujo diagnóstico depende da demonstração da proliferação de uma colónia de plasmócitos, uma forma madura de linfócitos B. O envolvimento renal é frequente, ocorrendo em cerca de 25-50% dos casos, quer na forma de doença renal crónica, quer na forma de lesão renal aguda. A apresentação sob a forma de lesão renal aguda com necessidade de técnica substitutiva renal ocorre em cerca de 10% dos doentes. Nestes doentes, o prognóstico é reservado, com uma taxa de dependência de diálise aos 3 meses de aproximadamente 80%, e uma sobrevivência média de 6 meses. A principal causa de lesão renal aguda com necessidade de diálise é a nefropatia de cilindros, também denominada rim de mieloma, uma consequência direta da presença das cadeias leves livres (CLL). De um ponto de vista fisiopatológico, a nefrotoxicidade das CLL determina a importância da sua redução rápida, podendo a mesma ser conseguida com esquemas de quimioterapia eficazes, nomeadamente, aqueles baseados em bortezomib, associados a técnicas de remoção extracorpórea. Novas técnicas de depuração, como a hemodiálise de alto cut-off (HCO-HD) têm sido apesentadas. O benefício desta técnica tem-se mostrado cada vez mais controverso, à medida que novos estudos, mais robustos, vêm mostrar resultados reservados, comparativamente aos estudos iniciais. Atendendo à evidência atualmente disponível, apresenta-se uma revisão dos métodos de depuração extracorpórea no mieloma múltiplo com indicação na lesão renal aguda e seus resultados e descrevem-se dois casos clínicos acompanhados nesta instituição.
Multiple myeloma consists of plasmocitary neoplastic disease, which diagnosis depends on the demonstration that a proliferation of a plasmocitary mature B cell colony is occurring in the bone marrow. Renal involvement is common, occurring in about 25-50% of cases, being in the form of chronic kidney disease, or acute kidney failure. In the moment of diagnosis, the presentation under the form of acute kidney failure with need of kidney replacement therapy occurs in about 10% of patients. In these, the prognosis is reserved with dialysis dependency at 3 months around 80%, and a median survival of 6 months. The main cause of acute renal failure with dialysis dependency is cast nephropathy, also called myeloma kidney, a direct consequence of the presence of free light chains (FLC) From a physiopathology viewpoint, the FLC determines the importance of its rapid reduction, that being achieved, with effective chemotherapy agents, bortezomib for instance, or resorting to extracorporeal removal technics. New removal technics, such as high cut-of hemodialysis have been presented. The evidence referring the benefits of this technic has been showing to be increasingly controversial, as new, more robust studies show reserved results, comparatively to the original studies. Attending the evidence currently available, is presented a revision of the various methods of extracorporeal removal in multiple myeloma indicated in acute renal failure, and results of two case studies of this institution are presented.
5
Öz, Pýnar. "Theoretical analysis of membrane properties underlying action potential phase-locking in noise-driven cells." Doctoral thesis, 2011. http://hdl.handle.net/11858/00-1735-0000-0006-B5D6-B.
Full textBook chapters on the topic "Membrane alto cut off"
1
Choi, Heechul, Moon Son, Jiyeol Bae, and Hyeon-gyu Choi. "Nanotechnology in Engineered Membranes." In Materials Science and Engineering, 802–24. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1798-6.ch031.
Full textAbstract:
The membrane processes have received extensive attention as comprehensive and interdisciplinary approaches for water-energy nexus. Nanotechnology has induced significant attention in improving membrane performances to mitigate global water and energy scarcity because of its unique characteristics and simple application for membrane fabrication. Nano-sized materials could provide highly enhanced characteristics to a membrane material, resulting in excellent performance enhancement, such as permeability, selectivity, and fouling resistance, of membrane. Carbon Nanotube (CNT), a widely utilized or studied nanomaterial in membrane science, is discussed in this chapter with a focus on its state-of-the-art applications and future prospects. Electrospun nanofiber, which is one of the feasible nano-structured membrane materials, is also discussed as a promising material for water-energy nexus. Therefore, this chapter also describes its application cases and its potential as an innovative membrane for water-energy nexus.
2
Barr, K. M. H., C. W. Berry, and P. J. Barker. "The use of a composite HDPE membrane/bentonite-cement slurry trench cut-off at Broadwood Loch, Cumbernauld." In The prospect for reservoirs in the 21st century, 276–91. Thomas Telford Publishing, 1998. http://dx.doi.org/10.1680/tpfrit21c.27046.0024.
Full text
3
Schindler, Thomas E. "The Lederbergs’ Stanford Years, 1959–1976." In A Hidden Legacy, 117–29. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197531679.003.0014.
Full textAbstract:
This chapter picks up the story of Esther’s life after she and her husband moved to Stanford University in Palo Alto, California, in 1959, and Joshua became chairman of the newly formed Genetics Department. The Lederbergs separated in September 1966, divorced in 1967, and a year later, Joshua married Marguerite Stein, a thirty-year-old divorcee and pediatrician. Esther Lederberg collaborated with her husband less and less after the move to Stanford. When they separated, Esther was suddenly exiled from the laboratory, cut off from research funding, and facing uncertain employment prospects. After winning the Nobel Prize, Joshua began collaborating with new colleagues in chemistry, engineering, and computer science. He became an international proponent of exobiology. In 1976, Esther Lederberg became director of the Plasmid Reference Center of Stanford University. Although it was not a research position, she applied her extensive knowledge of plasmids and bacteria to curating one of the largest collections in the world. She held this position until her retirement in 1985.
4
Sanz, Marta Gonzalez, and Caoimhe Nic Fhogartaigh. "Zoonotic Infections." In Tutorial Topics in Infection for the Combined Infection Training Programme. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198801740.003.0046.
Full textAbstract:
The term zoonosis comes from the Greek: ζῷον (zoon) ‘animal’ and νόσος (nosos) ‘sickness’, and means an infection transmissible from animals to humans. Infected animals can be symptomatic or asymptomatic, and humans usually become accidental hosts through close contact with the reservoir animal. Six out of ten infections in humans globally are spread from animals, and 75% of emerging infections are zoonotic. Some occur worldwide e.g. E. coli O157:H7, whereas some are more restricted geographically, e.g. Ebola virus. The highest burden is in developing countries. There are various classifications of zoonoses. ● Causative pathogen: bacterial (anthrax, non-typhoidal Salmonelloses); viral (rabies, Yellow Fever, hantaviruses); parasitic (hookworm, Giardia, toxoplasmosis); fungal (dermatophytes, histoplasmosis); or prion (new-variant Creutzfeldt-Jakob disease). ● Mode of transmission (see Section 35.3 and Table 35.1 below) ● Distribution: endemic zoonoses are continually present in a population (e.g. leptospirosis, brucellosis); epidemic zoonoses occur intermittently (e.g. anthrax, Rift Valley Fever); emerging zoonoses are new infections, or existing infections that are increasing in incidence or geographical range (e.g. Nipah virus, Middle East Respiratory Syndrome coronavirus). ● Direct contact: infectious particles are present on an infected animal, in its body fluids, and in its excreta. Q fever, caused by Coxiella burnetii, and brucellosis may be acquired by direct contact with infected animals, particularly during parturition; cat-scratch disease caused by Bartonella henselae, and Pasteurella spp. may be acquired by bites or scratches from cats, and rabies from canine bites. Many zoonoses are also transmitted via indirect animal contact through exposure to soil or water contaminated by infectious material, e.g. leptospirosis may be acquired when water contaminated with infected rats’ urine comes into contact with broken skin or mucous membranes. ● Ingestion: infection occurs by ingesting contaminated food or water, e.g. unpasteurized milk, poorly processed or undercooked meat, or by eating/ drinking after handling animals without handwashing. Listeria, bovine tuberculosis, and brucellosis may be transmitted by unpasteurized milk and dairy produce; Hepatitis E through processed pork, and Ebola and Marburg through bushmeat. ● Vector-borne: infection is transmitted through a biting arthropod vector. Examples include West Nile Virus and Japanese encephalitis from mosquitoes, Lyme disease, tick-borne encephalitis, and Rocky Mountain Spotted Fever from ticks, and Rickettsia typhi from rat fleas.
Conference papers on the topic "Membrane alto cut off"
1
Sharma, B., and C. T. Sun. "Design of Acoustic Filters Using Acoustic and Elastic Resonators." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65499.
Full textAbstract:
Recently, investigators have experimentally demonstrated that high transmission loss at low frequencies can be obtained using membrane type resonators. Mass loaded membranes have been shown to produce high transmission loss at the anti-resonance frequency [1], while an array of membranes has been experimentally demonstrated to exhibit a cut-off frequency below which all waves are attenuated [2]. Also, an array of side holes on a cylindrical tube has been shown to exhibit a similar cut-off frequency [3].
2
Zhou, Nina, and A. G. Agwu Nnanna. "Parametric Study of Ultrafiltration." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11696.
Full textAbstract:
The performance of cross flow hollow fiber ultrafiltration (UF) membrane with molecular weight cut off (MWCO) 100 kDaltons was studied in order to effectively remove suspended solids in wastewater. Experiments were carried out to investigate the influence of the several factors such as cross flow velocity, transmembrane pressure (TMP), water temperature, and concentration of suspended solids on the membrane performance. Several cleaning methods were applied to remove the fouling. The experimental results showed that increasing TMP, temperature and cross flow velocity all resulted in increasing permeate flux. It is observed that high TMP aggravated the fouling while high cross flow velocity alleviated the fouling. High concentrations of suspended solids led to the reduction of permeate flux. It is also found that both combination of chemical, back- and forward-washing as well as soaking cleaning methods effectively removed fouling and achieved high flux recovery. The suspended solids were effectively removed by our UF system, and the water quality is significantly improved after ultrafiltration.
3
Li, Junfeng, Fujuan Han, and Jianlong Wang. "Radioactive Waste Water Treatment by Inorganic Membrane System." In 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-30092.
Full textAbstract:
The removal efficiencies of strontium, cesium and cobalt by inorganic membrane with cut-off 8kD were studied. In order to improve the removal efficiency of non-active nuclides, soluble macropolymers sodium poly(acrylic) acid (NaPAA) of different molecule sizes were selected as chemical assistant reagents to make comparative experimental studies. The molecule of 8000,50000 and 100000 D NaPAA were used. The flux and removal rates of different systems were mainly studied. The results show that for inorganic membrane with pore size of 8kD molecule of 50000 Da NaPAA is the best selection for assistant reagents.
4
Mishra, Ashreet, and A. G. Agwu Nnanna. "A Novel Activated Carbon Enabled Steam Generation System Under Simulated Solar Light." In ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipack2018-8387.
Full textAbstract:
A number of studies on CNT, Au and Ag solar enabled steam generation with potential application in water purification, distillation and sterilization of medical equipment. The key challenge with these nanoparticles is cost of production hence limiting its wide application for clean water production. This work for the first time, reports on activated carbon enabled steam generation hence addressing the cost limitations of metallic nanoparticles. Activated carbon has high solar absorptivity at various wavelengths of visible light under low concentration. Experiments were carried out using activated carbon and CNT nanofluids and polyurethane membrane with immobilized activated carbon and CNT. A simulated solar light of 1 KW ∼1 Sun was used. The rate of evaporation, temporal and spatial evolution of bulk temperature in the water were monitored automatically and recorded for further data reductions. Parametric studies of the effect of nanoparticle concentration, water quality and salinity were performed. Experimental evidence showed that activated carbon has potential. We reported for the first time that optimal activated carbon concentration for maximum steam generation is 60 % vol. We also obtained a 160 % increase in steam production rate at 60 % concentration of activated carbon when compared with D.I water.
5
Nnanna, A. G. Agwu, Chenguang Sheng, Kimberly Conrad, and Greg Crowley. "Performance Assessment of Pre-Filtration Strainer of an Ultrafiltration Membrane System by Particle Size Analysis." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-53447.
Full textAbstract:
One of the industrial applications of ultrafiltration membrane system is water purification and wastewater treatment. Membranes act as physical barriers by eliminating particles such as pollen, yeast, bacteria, colloids, viruses, and macromolecules from feed water. The effectiveness of the membrane to separate particles is determined by its molecular weight cut-off and feed water characteristics. Typically, pre-filtration strainers are installed upstream of an ultrafiltration membrane system to separate large particles from the flow stream. The criteria for selection of the strainer pore size is unclear and is often determined by the feed water average particle size distribution. This paper is motivated by the hydraulic loading failure of a 125 μm strainer by average feed water particle size of 1.6 μm when the volumetric flow is at or greater than 40% of the rated design flow capacity. The objective of this paper are to: a) determine if the feed particle size distribution is a sufficient parameter for selection of pre-filtration strainer, b) evaluate the effect of feed flow velocity on strainer performance, and c) enhance strainer performance using vortex generator. In this experimental study, a Single Particle Optical Sensing, Accusizer, was used to analyze particle size distribution of five water samples collected at strainer feed, strainer filtrate, and strainer backwash. All samples were analyzed using a lower detection limit of 0.5 μm. In order to capture more counts of the larger particles present in the sample, a second analysis was done for each sample at a higher detection limit, 5.09 μm for feed sample, and 2.15 μm for the rest of the samples. Particle size data based on individual detection limits were statistically combined to generate comprehensive blended results of total number and total volume. The volume was determined based on assumption that each particle is spherically shaped. The Particle Size Distribution Measurement Accuracy is ±0.035 μm. Results showed that the feed particle size diameter and volume was insufficient to determine strainer size. Particle size distribution is needed at the feed, filtrate, and backwash to evaluate the strainer particle separation efficiency. It was observed that the total particle count in the filtrate (4.4 × 106) was an order of magnitude higher than the feed (3.2 × 105). Specifically, the total count for particles with diameter less than 7.22 μm were higher in the filtrate while larger particle size ≥ 7.22 μm were more in the feed stream. It appears that the large particles in the feed breaks down into smaller particles at the strainer interface and the small particles (≤ 7.22μm) passed through the pore into the filtrate. The particle breakdown, detachment of particles in the strainer pore into the filtrate, and particle to particle interactions are enhanced by increase in flow velocity hence increasing the hydrodynamic shear that acts on attached particles. A vortex generator inserted in to the strainer reduced pore clogging and pressure drop.
Reports on the topic "Membrane alto cut off"
1
Nechushtai, Rachel, and Parag Chitnis. Role of the HSP70 Homologue from Chloroplasts in the Assembly of the Photosynthetic Apparatus. United States Department of Agriculture, July 1993. http://dx.doi.org/10.32747/1993.7568743.bard.
Full textAbstract:
The major goal of the proposed research was to study the role of a 70-kDa heat shock cognate protein from chloroplasts (ct-HSP70) in the assembly of chlorophyll-protein complexes. The latters are mostly important in allowing photosynthesis to occur. Photosynthesis is at the heart of crop productivity and the knowledge of the biogenesis of the photosynthetic apparatus is essential to manipulate the efficiency of photosynthesis. The characterization of the function of the ct-HSP70 was planned to be studied in vitro by assaying its capability to physically interact with the thylakoid proteins and to assist their assembly into thylakoid membranes. We planned to identify regions in the light-harvesting complex protein (LHCP) that interact with the ct-HSP70 and characterize the interaction between them. We also intended to isolate cDNA clones encoding ct-HSP70, sequence them, express one of them in E. coli and use the purified protein for functional assays. The research in this BARD proposal aimed at providing insights and aid in understanding the mechanism by which plants may respond to the heat stress. Since plants often experience increased temperatures.
2
Warrick, Arthur, Uri Shani, Dani Or, and Muluneh Yitayew. In situ Evaluation of Unsaturated Hydraulic Properties Using Subsurface Points. United States Department of Agriculture, October 1999. http://dx.doi.org/10.32747/1999.7570566.bard.
Full textAbstract:
The primary information for accurately predicting water and solute movement and their impact on water quality is the characterization of soil hydraulic properties. This project was designed to develop methods for rapid and reliable estimates of unsaturated hydraulic properties of the soil. Particularly, in situ methodology is put forth, based on subsurface point sources. Devices were designed to allow introduction of water in subsurface settings at constant negative heads. The ability to operate at a negative head allows a direct method of finding unsaturated soil properties and a mechanism for eliminating extremely rapid preferential flow from the slow matrix flow. The project included field, laboratory and modeling components. By coupling the measurements and the modeling together, a wider range of designs can be examined, while at the same time realistic performance is assured. The developed methodology greatly expands the possibilities for evaluating hydraulic properties in place, especially for measurements in undisturbed soil within plant rooting zones. The objectives of the project were (i) To develop methods for obtaining rapid and reliable estimates of unsaturated hydraulic properties in situ, based on water distribution from subsurface point sources. These can be operated with a constant flow or at a constant head; (ii) To develop methods for distinguishing between matrix and preferential flow using cavities/permeameters under tension; (iii) To evaluate auxiliary measurements such as soil water content or tensions near the operating cavities to improve reliability of results; and (iv: To develop numerical and analytical models for obtaining soil hydraulic properties based on measurements from buried-cavity sources and the auxiliary measurements. The project began in July 1995 and was terminated in November 1998. All of the objectives were pursued. Three new subsurface point sources were designed and tested and two old types were also used. Two of the three new designs used a nylon cloth membrane (30 mm) arranged in a cylindrical geometry and operating at a negative water pressure (tension). A separate bladder arrangement allowed inflation under a positive pressure to maintain contact between the membrane and the soil cavity. The third new design used porous stainless steel (0.5 and 5 mm) arranged in six segments, each with its own water inlet, assembled to form a cylindrical supply surface when inflated in a borehole. The "old" types included an "off-the-shelf" porous cup as well as measurements from a subsurface drip emitter in a small subsurface cavity. Reasonable measurements were made with all systems. Sustained use of the cloth membrane devices were difficult because of leaks and plugging problems. All of the devices require careful consideration to assure contact with the soil system. Steady flow was established which simplified the analysis (except for the drip emitter which used a transient analysis).
3
Shomer, Ilan, Ruth E. Stark, Victor Gaba, and James D. Batteas. Understanding the hardening syndrome of potato (Solanum tuberosum L.) tuber tissue to eliminate textural defects in fresh and fresh-peeled/cut products. United States Department of Agriculture, November 2002. http://dx.doi.org/10.32747/2002.7587238.bard.
Full textAbstract:
The project sought to understand factors and mechanisms involved in the hardening of potato tubers. This syndrome inhibits heat softening due to intercellular adhesion (ICA) strengthening, compromising the marketing of industrially processed potatoes, particularly fresh peeled-cut or frozen tubers. However, ICA strengthening occurs under conditions which are inconsistent with the current ideas that relate it to Ca-pectate following pectin methyl esterase (PME) activity or to formation of rhamnogalacturonan (RG)-II-borate. First, it was necessary to induce strengthening of the middle lamellar complex (MLX) and the ICA as a stress response in some plant parenchyma. As normally this syndrome does not occur uniformly enough to study it, we devised an efficient model in which ICA-strengthening is induced consistently under simulated stress by short-chain, linear, mono-carboxylic acid molecules (OAM), at 65 oC [appendix 1 (Shomer&Kaaber, 2006)]. This rapid strengthening was insufficient for allowing the involved agents assembly to be identifiable; but it enabled us to develop an efficient in vitro system on potato tuber parenchyma slices at 25 ºC for 7 days, whereas unified stress was reliably simulated by OAMs in all the tissue cells. Such consistent ICA-strengthening in vitro was found to be induced according to the unique physicochemical features of each OAM as related to its lipophilicity (Ko/w), pKa, protonated proportion, and carbon chain length by the following parameters: OAM dissociation constant (Kdiss), adsorption affinity constant (KA), number of adsorbed OAMs required for ICA response (cooperativity factor) and the water-induced ICA (ICAwater). Notably, ICA-strengthening is accompanied by cell sap leakage, reflecting cell membrane rupture. In vitro, stress simulation by OAMs at pH<pKa facilitated the consistent assembly of ICAstrengthening agents, which we were able to characterize for the first time at the molecular level within purified insoluble cell wall of ICA-strengthened tissue. (a) With solid-state NMR, we established the chemical structure and covalent binding to cell walls of suberin-like agents associated exclusively with ICA strengthening [appendix 3 (Yu et al., 2006)]; (b) Using proteomics, 8 isoforms of cell wall-bound patatin (a soluble vacuolar 42-kDa protein) were identified exclusively in ICA-strengthened tissue; (c) With light/electron microscopy, ultrastructural characterization, histochemistry and immunolabeling, we co-localized patatin and pectin in the primary cell wall and prominently in the MLX; (d) determination of cell wall composition (pectin, neutral sugars, Ca-pectate) yielded similar results in both controls and ICA-strengthened tissue, implicating factors other than PME activity, Ca2+ or borate ions; (e) X-ray powder diffraction experiments revealed that the cellulose crystallinity in the cell wall is masked by pectin and neutral sugars (mainly galactan), whereas heat or enzymatic pectin degradation exposed the crystalline cellulose structure. Thus, we found that exclusively in ICA-strengthened tissue, heat-resistant pectin is evident in the presence of patatin and suberinlike agents, where the cellulose crystallinity was more hidden than in fresh control tissue. Conclusions: Stress response ICA-strengthening is simulated consistently by OAMs at pH< pKa, although PME and formation of Ca-pectate and RG-II-borate are inhibited. By contrast, at pH>pKa and particularly at pH 7, ICA-strengthening is mostly inhibited, although PME activity and formation of Ca-pectate or RG-II-borate are known to be facilitated. We found that upon stress, vacuolar patatin is released with cell sap leakage, allowing the patatin to associate with the pectin in both the primary cell wall and the MLX. The stress response also includes formation of covalently bound suberin-like polyesters within the insoluble cell wall. The experiments validated the hypotheses, thus led to a novel picture of the structural and molecular alterations responsible for the textural behavior of potato tuber. These findings represent a breakthrough towards understanding of the hardening syndrome, laying the groundwork for potato-handling strategies that assure textural quality of industrially processed particularly in fresh peeled cut tubers, ready-to-prepare and frozen preserved products.
4
Yermiyahu, Uri, Thomas Kinraide, and Uri Mingelgrin. Role of Binding to the Root Surface and Electrostatic Attraction in the Uptake of Heavy Metal by Plants. United States Department of Agriculture, 2000. http://dx.doi.org/10.32747/2000.7586482.bard.
Full textAbstract:
The principal accomplishment of the research supported by BARD was progress toward a comprehensive view of cell-surface electrical effects (both in cell walls [CWs] and at plasma membrane [PM] surfaces) upon ion uptake, intoxication, and amelioration. The research confirmed that electrostatic models (e.g., Gouy-Chapman-Stern [G-C-S]), with parameter values contributed by us, successfully predict ion behavior at cell surfaces. Specific research objectives 1. To characterize the sorption of selected heavy metals (Cu, Zn, Pb, Cd) to the root PM in the presence of other cations and organic ligands (citric and humic acids). 2. To compute the parameters of a G-C-S model for heavy-metal sorption to the root PM. 3. To characterize the accumulation of selected heavy metals in various plant parts. 4. To determine whether model-computed ion binding or ion activities at root PM surfaces predict heavy-metal accumulation in whole roots, root tips, or plant shoots. 5. To determine whether measured ion binding by protoplast-free roots (i.e., root CWs) predicts heavy-metal accumulation in whole roots, root tips, or plant shoots. 6. To correlate growth inhibition, and other toxic responses, with the measured and computed factors mentioned above. 7. To determine whether genotypic differences in heavy-metal accumulation and toxic responses correlate with genotypic differences in parameters of the G-C-S model. Of the original objectives, all except for objective 7 were met. Work performed to meet the other objectives, and necessitated on the basis of experimental findings, took the time that would have been required to meet objective 7. In addition, work with Pb was unsuccessful due to experimental complications and work on Cd is still in progress. On the other hand, the uptake and toxicity of the anion, selenate was characterized with respect to electrostatic effects and the influences of metal cations. In addition, the project included more theoretical work, supported by experimentation, than was originally planned. This included transmembrane ion fluxes considered in terms of PM-surface electrical potentials and the influence of CWs upon ion concentrations at PM surfaces. A important feature of the biogeochemistry of trace elements in the rhizosphere is the interaction between plant-root surfaces and the ions present in the soil solution. The ions, especially the cations, of the soil solution may be accumulated in the aqueous phases of cell surfaces external to the PMs, sometimes referred to as the "water free space" and the "Donnan free space". In addition, ions may bind to the CW components or to the PM surface with variable binding strength. Accumulation at the cell surface often leads to accumulation in other plant parts with implications for the safety and quality of foods. A G-C-S model for PMs and a Donnan-plus-binding model for CWs were used successfully to compute electrical potentials, ion binding, and ion concentration at root-cell surfaces. With these electrical potentials, corresponding values for ion activities may be computed that are at least proportional to actual values also. The computed cell-surface ion activities predict and explain ion uptake, intoxication, and amelioration of intoxication much more accurately than ion activities in the bulk-phase rooting medium.