Ion permeability of artificial membranes evaluated by diffusion potential and electrical resistance measurements

2013 ◽  
Vol 37 (4) ◽  
pp. 392-400 ◽  
Author(s):  
Vadim Shlyonsky
Keyword(s):  
Electrical Resistance ◽  
Liquid Mixture ◽  
Low Cost ◽  
Organic Liquid ◽  
Ion Permeability ◽  
Ionic Selectivity ◽  
Artificial Membranes ◽  
A Value ◽  
Diffusion Potentials ◽  
Novel Model

In the present article, a novel model of artificial membranes that provides efficient assistance in teaching the origins of diffusion potentials is proposed. These membranes are made of polycarbonate filters fixed to 12-mm plastic rings and then saturated with a mixture of creosol and n-decane. The electrical resistance and potential difference across these membranes can be easily measured using a low-cost volt-ohm meter and home-made Ag/AgCl electrodes. The advantage of the model is the lack of ionic selectivity of the membrane, which can be modified by the introduction of different ionophores to the organic liquid mixture. A membrane treated with the mixture containing valinomycin generates voltages from −53 to −25 mV in the presence of a 10-fold KCl gradient (in to out) and from −79 to −53 mV in the presence of a bi-ionic KCl/NaCl gradient (in to out). This latter bi-ionic gradient potential reverses to a value from +9 to +20 mV when monensin is present in the organic liquid mixture. Thus, the model can be build stepwise, i.e., all factors leading to the development of diffusion potentials can be introduced sequentially, helping students to understand the quantitative relationships of ionic gradients and differential membrane permeability in the generation of cell electrical signals.

Removal of nutrients from Organic Liquid Agricultural Waste using filamentous algae.

2020 ◽  
Author(s):  
Gonzalo Flores-Morales ◽  
Mónica Díaz ◽  
Patricia Arancibia-Avila ◽  
Michelle Muñoz-Carrasco ◽  
Pamela Jara-Zapata ◽  
...  
Keyword(s):  
Organic Waste ◽  
Low Cost ◽  
Organic Liquid ◽  
Agricultural Waste ◽  
Filamentous Algae ◽  
Tertiary Treatment ◽  
Nutrient Reduction ◽  
Algae Removal ◽  
Algae Growth ◽  
Waste Effluents

Abstract A feasibility analysis of tertiary treatment for Organic Liquid Agricultural Waste is presented using filamentous algae belonging to the genus Cladophora sp. as an alternative to chemical tertiary treatment. The main advantages of tertiary treatments that use biological systems are the low cost investment and the minimal dependence on environmental variables. In this work we demonstrate that filamentous algae reduces the nutrient load of nitrate (circa 75%) and phosphate (circa 86%) from the organic waste effluents coming from dairy farms after nine days of culture, with the added advantage being that after the treatment period, algae removal can be achieved by simple procedures. Currently, the organic wastewater is discarded into fields and local streams. However, the algae can acquire value as a by-product since it has various uses as compost, cellulose, and biogas. A disadvantage of this system is that clean water must be used to achieve enough water transparency to allow algae growth. Even so, the nutrient reduction system of the organic effluents proposed is friendly to the ecosystem, compared to tertiary treatments that use chemicals to precipitate and collect nutrients such as nitrates and phosphates.

Environment-Friendly Design of Lithium Batteries Starting from Biopolymer-Based Electrolyte

NANO ◽  
2021 ◽  
pp. 2130006
Author(s):  
Jiayuan Shi ◽  
Bin Shi
Keyword(s):  
Lithium Batteries ◽  
Lithium Battery ◽  
Water Solubility ◽  
Low Cost ◽  
Organic Liquid ◽  
Adhesive Property ◽  
Environment Friendly ◽  
Battery Materials ◽  
Mild Conditions ◽  
Film Forming

The nondegradable nature and toxicity of organic liquid electrolytes reveal the design deficiency of lithium batteries in environmental protection. Biopolymers can be extracted from biomass under mild conditions, thus they are usually low cost and renewable. The unique characteristics of biopolymers such as water solubility, film-forming capability and adhesive property are of importance for lithium battery. The studies on the biopolymer materials for lithium batteries have been reviewed in this work. Although a lot of work on the biopolymer-based battery materials has been reported, it is still a challenge in the design of lithium battery with zero pollution and zero waste.

scholarly journals Catalytic conversion of alcohol-waste vegetable oil mixtures over aluminosilicate catalysts

2018 ◽  
Author(s):  
◽  
Elvis Tinashe Ganda
Keyword(s):  
Surface Area ◽  
Organic Liquid ◽  
Liquid Product ◽  
Catalytic Conversion ◽  
Product Yield ◽  
Waste Cooking Oil ◽  
Relative Crystallinity ◽  
Cooking Oil ◽  
A Value ◽  
Catalyst Systems

Thermochemical catalytic conversion of ethanol-waste cooking oil (eth-WCO) mixtures was studied over synthesised aluminosilicate catalysts HZSM-5, FeHZSM-5 and NiHZSM-5. The thermochemical reactions were carried out at temperatures of 400° and 450°C at a fixed weight hourly space velocity of 2.5 h-1 in a fixed bed reactor system. Successful conversion of the eth-WCO mixtures was carried out over the synthesised catalyst systems and in order to fully understand the influence of the catalysts, several techniques were used to characterise the synthesised materials which include XRD, SEM, EDS, BET techniques. Results of the catalyst characterisation showed that highly crystalline solid material had been formed as evidenced by the high relative crystallinity in comparison with the commercial HZSM-5 catalyst at 2θ peak values of 7°- 9° and 23°- 24°. The introduction of metals decreased the intensity of the peaks leading to lower values of relative crystallinity of 88% and 90% for FeHZSM-5 and NiHZSM-5, respectively. However this was even slightly higher than the commercial sample which had a value of 86% with respect to HZSM-5 synthesised catalyst taken as reference material. There was no significant change in XRD patterns due to the introduction of metal. Elemental analysis done with energy dispersive spectroscopy showed the presence of the metal promoters (Fe, Ni) and the Si/Al ratio obtained from this technique was 38 compared to the target ratio of 50 set out initially in the synthesis. From the SEM micrographs the morphology of the crystals could be described as regular agglomerated sheet like material. Surface area analysis showed that highly microporous crystals had been synthesised with lower external surface area values ranging from 57.23 m2/g - 100.82 m2/g compared to the microporous surface area values ranging from 195.96 m2/g to 212.51 m2/g. For all catalyst employed in this study high conversions were observed with values of over 93 %, almost total conversion was achieved for some samples with values as high as 99.6 % with FeHZSM-5 catalysts. Despite the high level of conversion the extent of deoxygenation varied with lower values recorded for FeHZSM-5 (25%WCO) at 400°C and NiHZSM-5 (75%WCO) at 450°C with oxygenated hydrocarbons of 19.5% and 19.33% respectively. The organic liquid product yield comprised mostly of aromatic hydrocarbon (toluene, p-xylene and naphthalene) decreased with the introduction of metal promoters with NiHZSM-5 producing higher yields than FeHZSM-5. For the pure waste cooking oil (WCO) feedstock the parent catalyst HZSM-5 had a liquid yield of 50% followed by NiHZSM-5 with 44% and lastly FeHZSM-5 had 40% at 400°C which may be seen to follow the pattern of loss of relative crystallinity. An increase in operating temperature to 450°C lowered the quantity of organic liquid product obtained in the same manner with the HZSM-5 parent catalyst still having the highest yield of 38% followed by Ni-HZSM-5 with 36% and Fe-HZSM-5 having a value of 30% for pure waste cooking oil feedstock which may be attributed to thermally induced secondary cracking reactions. For all catalyst systems with an increase in the content of waste cooking oil from 25% to 100% in the feed mixture there was a linearly increasing trend of the liquid product yield. HZSM-5 catalyst increased from 14% to 50% while FeHZSM-5 increased from 16% to 40% and NiHZSM-5 increased from 12% to 44% at a temperature setting of 400°C with lower values observed at 450°C.Results obtained in this study show the potential of producing aromatics for fuel and chemical use with highly microporous zeolite from waste material such as waste cooking oil forming part of the feedstock.

Rice Husk-Derived Mesoporous Silica Nanostructure for Supercapacitors Application: A Possible Approach for Recycling Bio-Waste into a Value-Added Product

2021 ◽  
Author(s):  
P. Araichimani ◽  
K.M. Prabu ◽  
G. Suresh Kumar ◽  
Gopalu Karunakaran ◽  
S. Surendhiran ◽  
...  
Keyword(s):  
Rice Husk ◽  
Redox Reactions ◽  
Low Cost ◽  
Combustion Process ◽  
Value Added ◽  
Mesoporous Structure ◽  
Rice Husks ◽  
A Value ◽  
Current Densities ◽  
Thermal Combustion

Abstract We synthesized mesoporous SiO2 nanomatrix using rice husks as a precursor through a facile thermal combustion process. XRD, FTIR, EDX, and TEM analyses were used to validate the produced mesoporous SiO2 nanomatrix. Electrochemical measurements were used to determine the specific capacitance of mesoporous SiO2 nanomatrix, and the results showed that the specific capacitances are 216, 204, 182, 163, 152, 142, 135, 133, 124.4, 124 F/g at current densities of 0.5, 1, 2, 4, 6, 8, 10, 12, 14, and 16 A/g. The benefit of impurities, as well as the large surface area and mesoporous structure of rice husk derived SiO2 nanostructures, allow Faradaic redox reactions at the electrode surface and the resulting supercapacitive behavior. This research might lead to a low-cost technique of producing supercapacitor electrodes using rice husk-derived SiO2 as a precursor.

scholarly journals Minilateralism Revisited: MIKTA as Slender Diplomacy in a Multiplex World

2018 ◽  
Vol 24 (4) ◽  
pp. 475-489 ◽  
Author(s):  
Sung-Mi Kim ◽  
Sebastian Haug ◽  
Susan Harris Rimmer
Keyword(s):  
Ad Hoc ◽  
Resource Constraints ◽  
Low Cost ◽  
Value For Money ◽  
A Value ◽  
Sharing Scheme ◽  
Operational Characteristics ◽  
Member Commitment ◽  
Global Uncertainty ◽  
Foreign Ministries

Abstract Based on over seventy interviews with diplomats and experts from all five MIKTA member countries, we find that MIKTA is used as a value-for-money minilateral mechanism for the world’s lesser powers grappling with the heightened global uncertainty and deepening interdependency. MIKTA foreign ministries have used the group as an ad hoc capacity-building and network-sharing scheme; and as a low-cost toolkit to diversify their traditional diplomatic channels and increase global visibility in various multilateral forums. However, MIKTA’s flexible, but precarious, institutional realities also suggest that minilateral arrangements that share MIKTA’s operational characteristics are likely to be short-lived and suffer from weak member commitment, resource constraints, forum-shopping risks, and a leadership vacuum.

scholarly journals Measurement of leaf lamina moisture with a low-cost electrical humidity sensor: case study on a wheat water-mutant

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Agata Rascio ◽  
Michele Rinaldi ◽  
Giuditta De Santis ◽  
Nicola Pecchioni ◽  
Gabriele Palazzo ◽  
...  
Keyword(s):  
Moisture Content ◽  
Electrical Resistance ◽  
Low Cost ◽  
Bound Water ◽  
Genotypic Differences ◽  
Wild Type ◽  
Leaf Lamina ◽  
Mature Leaves ◽  
Moisture Meter

Abstract Background The presence and persistence of water on the leaf can affect crop performance and thus might be a relevant trait to select for or against in breeding programmes. Low-cost, rapid and relatively simple methods are of significant importance for screening of large populations of plants for moisture analysis of detached leaves. Leaf moisture can be detected using an electric circuit, where the resistance changes are proportional to the moisture of the measured surface. In this study, we present a protocol to analyse genotypic differences through the electrical properties of living or stored tissues, performed using a commercial device. Expanded and non-expanded leaves were compared to determine the effects of leaf maturity on these data. Two wheat genotypes that differ in tissue affinity for bound water were used to define the influence of water status. Results The device indirectly estimates leaf moisture content using two electrodes applied to the leaf lamina of fresh and stored samples. Single moisture readings using this moisture meter had mean execution time of ~ 1.0 min. Exponential associations provided good fits for relationships between the moisture meter reading (MMR) and the electrical resistance applied to the electrodes. MMR normalised for the water/ dry matter ratio (MMRnorm) was lower for mature leaves of the water-mutant than those of wild-type, for the fully hydrated fresh leaves. MMR of fully mature leaves when partially dehydrated and measured after 10 min at 27 °C and 40% relative humidity was greater for the water-mutant than the wild-type. Conclusions This case study provides a low-cost tool to compare electrical-resistance estimates of leaf moisture content, together with a promising and rapid phenotyping protocol for genotypic screening of wheat under standard environmental conditions. Measurement of changes in MMR with time, of fresh and partially dehydrated leaves, or of MMR normalised to tissue water content allowed for differentiation between the genotypes. Furthermore, the differences observed between genotypes that here relate particular to tissue affinity for bound water suggest that not only the free-water fraction, but also other water fractions, can affect these electrically estimated leaf moisture measures.

scholarly journals Development and calibration of a rainfall simulator for hydrological studies

RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Silvio Fagundes de Sousa Júnior ◽  
Thiago Augusto Mendes ◽  
Eduardo Queija de Siqueira
Keyword(s):  
Kinetic Energy ◽  
Low Cost ◽  
Local Environment ◽  
Experimental Conditions ◽  
Rainfall Events ◽  
Uniformity Coefficient ◽  
Hydrological Data ◽  
Natural Rainfall ◽  
A Value ◽  
Median Diameter

ABSTRACT Rainfall Simulators (RS) have been used as tools for researches involving the estimation of runoff and infiltration on permeable pavements as well as in evaluating storm build-up and wash-off processes on pavements and roofs. Data obtained with the use of RS allows building a database with parameters which are useful in the implementation of BMPs taking local environment conditions into consideration. The purpose of this study was to develop and calibrate a handy and low-cost RS for hydrological researches. The developed RS can reproduce rainfall with intensities from 40 mm h-1 to 182 mm h-1. The RS is able to simulate rainfall events with drops of median diameter (D50) of 2.12 mm and kinetic energy of 22.53 J mm-1m-2, which represent 90.12% of the kinetic energy produced by a natural rainfall. Spatial distribution of simulated rainfall, which is expressed by the Christiansen's Uniformity Coefficient, was considered satisfactory with a value of up to 87.80%. The developed RS can be used as an alternative for the acquisition of hydrological data in a reduced period of time, under standardized experimental conditions and independently of natural rainfall events. The RS is also capable to simulate rainfall events with varying intensity.

HfZnO/ZnO Heterostructures Fabricated Using Low-Cost Large-Area Compatible Sputtering Processes

2015 ◽  
Vol 1731 ◽  
Author(s):  
Chih-Hung Li ◽  
Jian-Zhang Chen ◽  
I-Chun Cheng
Keyword(s):  
Thin Film ◽  
Electrical Resistance ◽  
Thin Film Transistors ◽  
Carrier Mobility ◽  
Annealing Temperature ◽  
Low Cost ◽  
Zno Thin Films ◽  
Zno Thin Film ◽  
Large Area ◽  
Apparent Decrease

ABSTRACTWe investigated the electrical properties of the rf-sputtered HfxZn1-xO/ZnO heterostructures. The thermal annealing on ZnO prior to the HfxZn1-xO deposition greatly influences the properties of the heterostructures. A highly conductive interface formed at the interface between HfxZn1-xO and ZnO thin films as the ZnO annealing temperature exceeded 500°C, leading to the apparent decrease of the electrical resistance. The resistance decreased with an increase of either thickness or Hf content of the HfxZn1-xO capping layer. The Hf0.05Zn0.95O/ZnO heterostructure with a 200-nm-thick 600°C-annealed ZnO exhibits a carrier mobility of 14.3 cm2V-1s-1 and a sheet carrier concentration of 1.93×1013 cm-2; the corresponding values for the bare ZnO thin film are 0.47 cm2V-1s-1 and 2.27×1012 cm-2, respectively. Rf-sputtered HfZnO/ZnO heterostructures can potentially be used to increase the carrier mobility of thin-film transistors in large-area electronics.

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