THE ISOPIESTIC METHOD APPLIED TO SORPTION ISOTHERMS

1949 ◽  
Vol 27b (2) ◽  
pp. 87-100 ◽  
Author(s):  
S. Barnartt ◽  
J. B. Ferguson
Keyword(s):  
Carbon Tetrachloride ◽  
Linear Relation ◽  
Sorption Isotherms ◽  
Sorption Process ◽  
The Other ◽  
Isopiestic Method ◽  
Simple Criterion ◽  
Water Vapors ◽  
Linear Sections ◽  
Wide Pressure

The isopiestic method has been applied to the sorption of carbon tetrachloride and water vapors by activated coconut shell charcoals. The isopiestic charges were found to be linearly related over wide pressure ranges. Isotherms formed by plotting the isopiestic charges of two charcoals one against the other consisted of three linear sections for both carbon tetrachloride and water. If the pressure isotherm of one charcoal be known, those of other charcoals may be computed from it by weighing relatively few isopiestic charges. Errors inherent in the measurement of equilibrium pressures, as well as those caused by the drift of the pressure isotherms towards higher sorption capacities at a given pressure, are eliminated in the isopiestic method of comparing charcoals. The linear relation between the isopiestic charges affords a simple criterion of rejection for equations proposed to fit the pressure isotherms. It also throws into relief the structural regularities in activated charcoals. The existence of discontinuities m the sorption process, reported by previous experimenters, is supported by the isopiestic data.

Sorption of Water, Ammonia, Ethyl Chloride, and Methane on Na—X Zeolite and Associated Framework Distortion

1974 ◽  
Vol 52 (22) ◽  
pp. 3699-3706 ◽  
Author(s):  
D. L. Rimmer ◽  
R. McIntosh
Keyword(s):  
Water Sorption ◽  
Room Temperature ◽  
Sorption Isotherms ◽  
Length Change ◽  
Sorption Process ◽  
Ethyl Chloride ◽  
Two Dimensional ◽  
X Zeolite ◽  
Methane Sorption ◽  
Multilayer Formation

Length change and sorption isotherms have been determined for water, ammonia, ethyl chloride, and methane on compacted samples of zeolite NaX. Methane sorption at 0 °C and ethyl chloride sorption at −10°C were accompanied by little or no framework distortion as monitored by length change measurements; sorption of ammonia in the temperature range −50 to −70 °C produced more appreciable distortion; and water sorption at room temperature caused large changes. In each case the framework distortion was correlated with different stages in the sorption process. The sorption isotherms for the ammonia/NaX system indicated the possibility at high uptakes of two-dimensional condensation or multilayer formation. The critical temperature for two-dimensional condensation would be −70 °C.

scholarly journals Efecto de la alternación de fuentes sanguíneas sobre la fecundidad y la fertilidad de Rhodnius prolixus Stal (Heteroptera: Reduviidae).

2009 ◽  
Vol 2 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Elis José Aldana ◽  
David Jácome ◽  
Eliézer Lizano
Keyword(s):  
Human Blood ◽  
Linear Relation ◽  
Rhodnius Prolixus ◽  
The Other ◽  
Insect Species ◽  
Reproductive Parameters ◽  
Other Hand ◽  
Blood Source

En este trabajo se evidencia que si el éxito reproductivo de Rhodnius prolixus Stal está relacionado a la fuente alimentaria, entonces las necesidades biológicas del insecto son satisfechas en modos diferentes según el tipo de alternancia entre dichas fuentes de alimentación; tales diferencias son reveladas mediante los cambios en fertilidad y fecundidad del insecto. Se realizaron nueve alternancias, en cada una se suministraron dos alimentaciones, en unas se alternó la fuente de alimentación y en los controles se suministraron dos alimentaciones con la misma fuente. Las fuentes alimentarias fueron paloma, gallina y humano, esta última mediante un aparato de alimentación artificial; estas fuentes se escogieron en el supuesto que son fuentes alimentarias encontradas en los ecotopos silvestre, peri-domicilio y domicilio respectivamente. En todos los tipos de alternancia se encontró una relación lineal entre la fecundidad y el tiempo de oviposición, que la relación entre cantidad de sangre ingerida y la fecundidad varían, que la tasa de fecundidad aumenta en la segunda alimentación respecto a la primera y que la fertilidad fue superior al 95 %.   Effects of alternating blood sources on fecundity and fertility of Rhodnius prolixus Stal (Heteroptera: Reduviidae) In this work it is argued that if the reproductive parameters of Rhodnius prolixus Stal are related to the blood source upon which it feeds, then the insects biological needs must be satisfied in different ways by the alternation between blood sources, reveled through changes in the fecundity and fertility of individuals of this insect species. Nine experiments were conducted, each one consisting of two feedings, in which the blood source were either alternated or remained the same. The meal sources used were pigeon, hen and human blood, selected according to the resources found in the sylvatic, peri-domestic and domestic ecotopes respectively. It was found that the quantity of blood ingested and the fecundity were differents according to alternation of blood sources offered in each meal. A linear relation was found between the fecundity and the time of oviposition in every alternation of meal sources. On the other hand there was a slope increase in the second feeding of every experiment. The fertility was above 95% in each experiment.   Efeito da alternação de fontes sanguíneas sobre fecundidade e fertilidade de Rhodnius prolixus Stal (Heteroptera Reduviidae) Neste trabalho evidencia-se que o sucesso reprodutivo de Rhodnius prolixus Stal esta relacionado à fonte alimentícia, então as necessidades biológicas do inseto são satisfeitas em modos diferentes segundo o tipo de alternância entre ditas fontes de alimentação; tais diferenças são reveladas mediante mudanças em fertilidade e fecundidade do inseto. Realizaram-se nove testes, em cada um foram subministradas duas alimentações, sendo que em alguns foi alternada a fonte de alimentação e nos controles foram subministradas duas alimentações com a mesma fonte. As fontes alimentícias foram pomba, galinha e humano, esta ultima mediante um aparelho de alimentação artificial; estas fontes foram escolhidas no suposto que são fontes alimentícias encontradas nos ecótopos silvestres, peridomicilio e domicilio respectivamente. Em todos os tipos de alternância foi encontrada uma relação lineal entre a fecundidade e o tempo de oviposição, que a relação entre quantidade de sangue ingerida e a fecundidade variam, que a taxa de fecundidade aumenta na segunda alimentação respeito à primeira e que a fertilidade foi superior ao 95%.

Motor responses of Rhodnius prolixus Stål (Hem., Reduviidae) to volatile drugs

1971 ◽  
Vol 61 (2) ◽  
pp. 309-313 ◽  
Author(s):  
Ian McLure
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Carbon Tetrachloride ◽  
Chloral Hydrate ◽  
Rhodnius Prolixus ◽  
The Other ◽  
Motor Responses ◽  
Normal Feeding ◽  
Insect Central Nervous System ◽  
Differential Action

Fifth-instar nymphs of Rhodnius prolixus Stålwere exposed to the vapours of 11 volatile drugs: acetone, bromobenzene, bromoform, carbon tetrachloride, chloral hydrate, chloroform, dioxane, ethanol, ethyl ether, isopropanol and paraldehyde. Bromobenzene, bromoform, carbon tetrachloride, chloroform and ether induced reversible anaesthesia. For each of these five, the insects exhibited a different andspecific pattern of motor responses before becoming totally immobile; these responses are described. The responses to carbon tetrachloride are similar to the normal feeding responses of this insect. The other six drugs did not induce anaesthesia, but instead, a commonand stereotyped pattern of cleaning responses, suggesting irritation of the sensory organs. It is proposed that the agent-specific responses to the anaesthesiainducing drugs are due to their differential action upon specific portions of the insect central nervous system.

Determination of Small Bone Particles in Meat

1968 ◽  
Vol 51 (6) ◽  
pp. 1175-1177 ◽  
Author(s):  
Robert M Hill ◽  
B D Hites
Keyword(s):  
Carbon Tetrachloride ◽  
Meat Products ◽  
The Other ◽  
Small Particles ◽  
Bone Content ◽  
Bone Particles ◽  
Small Bone ◽  
Good Agreement

Abstract Very small particles of bone can be separated from ground meats and meat products by the following procedure: The bulk of the meat is solubilized by digestion with papain and the bone is separated from the other nondigestible material according to its ability to settle in a carbon tetrachloride: acetone mixture. Turkey samples with widely varying bone content were analyzed, with good agreement between duplicate samples.

Effects of infliximab against carbon tetrachloride-induced intestinal injury via lipid peroxidation and apoptosis

2019 ◽  
Vol 38 (11) ◽  
pp. 1275-1282
Author(s):  
A Pergel ◽  
L Tümkaya ◽  
MK Çolakoğlu ◽  
G Demiral ◽  
S Kalcan ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Caspase 3 ◽  
Inhalation Exposure ◽  
Isotonic Saline ◽  
Neutrophil Infiltration ◽  
Intestinal Injury ◽  
The Other ◽  
Control Group ◽  
Sprague Dawley ◽  
Other Hand

Carbon tetrachloride (CCL4) is often employed in the production of chlorofluorocarbons, petroleum refining, oil and rubber processing, and laboratory applications. Oral, subcutaneous, and inhalation exposure to CCL4 in animal studies have been shown to be capable of leading to various types of cancer (benign and malignant, liver, breast, and adrenal gland tumors). The present study also evaluated the protective role of infliximab (INF) against the deleterious effects of CCL4 on the intestinal system. Twenty-four male Sprague-Dawley rats were randomly assigned into three groups, control ( n = 8), CCL4 ( n = 8), and CCL4 + INF ( n = 8). The control group received 1 mL isotonic saline solution only via intraperitoneal (i.p.) injection. The CCL4 group received a single i.p. dose of 2 mL/kg CCL4. The CCL4 + INF group received a single i.p. dose of 7 mg/kg INF followed 24 h later by a single dose of 2 mL/kg CCL4. All rats were euthanized 2 days following drug administration. CCL4 group samples also exhibited diffuse loss of enterocytes, vascular congestion, neutrophil infiltration, an extension of the subepithelial space and significant epithelial lifting along the length of the villi with a few denuded villous tips. In addition, CCL4 treatment increased intestinal malondialdehyde (MDA) level and caspase-3 positivity. On the other hand, INF decreased MDA levels, caspase-3 positivity, and loss of villous. Our findings suggest that CCL4 appears to exert a highly deleterious effect on the intestinal mucosa. On the other hand, INF is effective in preventing this CCL4-induced intestinal injury by reducing oxidative stress and apoptosis.

An in situ study of the phase transitions among CaCO3 high-pressure polymorphs

2018 ◽  
Vol 83 (02) ◽  
pp. 191-197 ◽  
Author(s):  
Xueyin Yuan ◽  
Chao Gao ◽  
Jing Gao
Keyword(s):  
Phase Transitions ◽  
Intermediate Phase ◽  
The Other ◽  
Three Samples ◽  
Short Period ◽  
Two Samples ◽  
Wide Pressure Range ◽  
Diamond Anvil ◽  
Wide Pressure

AbstractThe phase transitions involving calcite (CaCO3-I), CaCO3-II, CaCO3-III and CaCO3-IIIb were investigated using a diamond anvil cell and micro-Raman spectroscopy. Based on the results obtained from in situ observations and Raman measurements made with six natural calcite crystals, the phase transition from calcite to CaCO3-II took place between 1.56 and 1.67 GPa under ambient temperature. Under a precise pressure of 1.97 ± 0.03 GPa, three CaCO3 samples were observed to transform from CaCO3-II directly to CaCO3-III, while in the other three samples both CaCO3-III and CaCO3-IIIb crystal structures were detected. Transformation from CaCO3-IIIb to CaCO3-III was completed in a short period in one sample, whereas in the other two samples coexistence of CaCO3-III and CaCO3-IIIb was observed over a wide pressure range from 1.97 to 3.38 GPa, with sluggish transformation from CaCO3-IIIb to CaCO3-III being observed after the samples were preserved under 3.38 GPa for 72 h. Hence, it can be concluded that CaCO3-IIIb is a metastable intermediate phase occurring during the reconstructive transformation from CaCO3-II to CaCO3-III. Splitting of the C–O in-plane bending (ν4) and symmetric stretching (ν1) vibrations and appearance of new lattice vibrations in the Raman spectra of CaCO3-III and CaCO3-IIIb suggest a lowering in crystal symmetry during the transformation from CaCO3-II through CaCO3-IIIb to CaCO3-III, which is in good agreement with the observed sequence of phase symmetries.

Investigation of Titania Addition into Tar Sands for Removal of Phenol from Aqueous Solutions

2006 ◽  
Vol 41 (1) ◽  
pp. 94-99 ◽  
Author(s):  
Lua'y Zeatoun ◽  
Munjed Al-Sharif ◽  
Abeer Al-Bsoul
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Sorption Process ◽  
The Other ◽  
Solution Temperature ◽  
Equilibrium Isotherm ◽  
Activation Temperature ◽  
Tar Sands ◽  
Initial Concentration ◽  
Initial Phenol Concentration

Abstract Tar sands were found to remove significant amounts of phenol from aqueous solution in the presence of titania; about 70% at an initial concentration of 10 ppm. Batch sorption experiments showed that phenol uptake was increased with either an increase in initial phenol concentration, percentage of titania in the sorbent or pre-activation temperature. On the other hand, the presence of soft ions such as sodium, Na+, or potassium, K+, or the increase of solution temperature suppressed the uptake of phenol. Physical pre-activation of the tar sands influenced the adsorption process positively. The sorption process appears to be exothermic and relatively fast; the equilibrium isotherm data were well represented by either Langmuir or Freundlich models.

scholarly journals The Physiological Basis for Yield Differences between Four Genotypes of Groundnut (Arachis Hypogaea) in Response to Drought. III. Developmental Processes

1988 ◽  
Vol 24 (2) ◽  
pp. 215-226 ◽  
Author(s):  
D. Harris ◽  
R. B. Matthews ◽  
R. C. Nageswara Rao ◽  
J.H. Williams
Keyword(s):  
Arachis Hypogaea ◽  
Linear Relation ◽  
Leaf Development ◽  
Harvest Index ◽  
Water Status ◽  
The Other ◽  
Physiological Basis ◽  
Pod Yield ◽  
Effects Of Temperature ◽  
Pod Number

SUMMARYRates of leaf development in four groundnut genotypes were found to depend primarily on temperature, although there was a linear relation between the thermal time to produce one leaf and mean leaf water potential below −0.6 MPa. Flower, peg and pod production was analysed in relation to leaf number, since this integrated effects of temperature and water status.When water was not limited, the ratio of pod number: peg number was about 0.8 for all four genotypes. During drought only one genotype (TMV 2) maintained this value, while for the other genotypes the ratio was approximately 0.15. Genotypes also showed different patterns of development during recovery from drought. TMV 2 maintained relatively high values of partitioning factor throughout the pod-filling period, resulting in the largest harvest index and pod yield. Kadiri 3 achieved the second largest harvest index and pod yield by maintaining production of pegs during drought and only forming pods when stress was relieved.

scholarly journals The significance of abrupt transitions in Lineweaver–Burk plots with particular reference to glutamate dehydrogenase. Negative and positive co-operativity in catalytic rate constants

1973 ◽  
Vol 131 (1) ◽  
pp. 97-105 ◽  
Author(s):  
Paul C. Engel ◽  
William Ferdinand
Keyword(s):  
Glutamate Dehydrogenase ◽  
Rate Equation ◽  
Rate Constants ◽  
Initial Rate ◽  
Current Knowledge ◽  
The Other ◽  
Catalytic Rate Constant ◽  
Catalytic Rate ◽  
Linear Sections ◽  
Glucose 6 Phosphate Dehydrogenase

1. Lineweaver–Burk plots for glutamate dehydrogenase, glucose 6-phosphate dehydrogenase and several other enzymes show one or more abrupt transitions between apparently linear sections. These transitions correspond to abrupt increases in the apparent Km and Vmax. with increasing concentration of the varied substrate. 2. The generalized reciprocal initial-rate equation for a multi-site enzyme requires several restrictions to be put on it in order to generate such plots. These mathematical conditions are explored. 3. It is shown that the effective omission of a term in the denominator of the reciprocal initial-rate equation represents a minimal requirement for generation of abrupt transitions. This corresponds in physical terms to negative co-operativity followed by positive co-operativity affecting the catalytic rate constant for the reaction. 4. Previous models for glutamate dehydrogenase cannot adequately account for the results. On the other hand, the model based on both negative and positive co-operativity gives a good fit to the experimental points. 5. The conclusions are discussed in relation to current knowledge of the structure and mechanism of glutamate dehydrogenase.

The estimation of the critical load of a braced framework

1955 ◽  
Vol 231 (1184) ◽  
pp. 25-36 ◽  
Keyword(s):  
Critical Load ◽  
Critical Loads ◽  
The Other ◽  
Simple Criterion ◽  
Relaxation Methods ◽  
The Stability

With present methods of estimating the critical loads of triangulated frameworks by relaxation methods it is difficult to decide near the critical load whether the process is converging and the structure is stable, or whether the process is diverging and the structure unstable. This difficulty does not arise in the method presented here. Each triangle of the framework in turn is replaced by a hypothetical member until finally only one member of the truss remains, and this member has been modified in such a way as to take into account the stiffnesses of all the other members of the truss. A simple criterion for the stability of this final equivalent member is established and an example of the application of the method given.

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