scholarly journals Toxic Metals (As, Cd, Ni, Pb) Impact in the Most Common Medicinal Plant (Mentha piperita)

2021 ◽  
Vol 18 (8) ◽  
pp. 3904
Author(s):  
Cristina Dinu ◽  
Stefania Gheorghe ◽  
Anda Gabriela Tenea ◽  
Catalina Stoica ◽  
Gabriela-Geanina Vasile ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Metal Accumulation ◽  
Mentha Piperita ◽  
Transfer Coefficients ◽  
Metal Mixtures ◽  
Short Period ◽  
Growth Development ◽  
Metal Addition ◽  
Translocation Factors ◽  
Different Parts

This study aimed to evaluate the behavior of Mentha piperita under Cd, Pb, Ni, and As soil contamination and their transfer from soil in plants as well as translocation in the roots/stems/leaves system compared with a control without metal addition. The mint seedlings were exposed for a three-month period using two metal mixtures in the same concentrations such as AsCd and AsCdNiPb (23.7 mg/kg As, 5 mg/kg Cd, 136 mg/kg Ni, and 95 mg/kg Pb). The results of metal concentration in plants showed that Cd, Ni, and Pb were accumulated in different parts of the plant, except for As. In plants organs, the order of metal accumulation was roots > stems > leaves. No significant impact on the growth, development, and chlorophyll content compared to the control was observed in the first month of exposure. After three months of exposure, phytotoxic effects occurred. Generally, the transfer coefficients and translocation factors values were less than 1, indicating that Mentha piperita immobilized the metals in root. The laboratory experiments highlighted that for a short period of time, Mentha piperita has the capacity to stabilize the metals at the root level and was a metal-tolerant plant when using a garden rich-substrate.

Covering of cometary nucleus by refractory crust and its evolution into asteroid-like body

1999 ◽  
Vol 173 ◽  
pp. 365-370
Author(s):  
Kh.I. Ibadinov
Keyword(s):  
Laboratory Experiments ◽  
Cometary Nucleus ◽  
Sublimation Rate ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Brightness Decrease ◽  
Crust Thickness ◽  
Ice Sublimation ◽  
Period Comet

AbstractFrom the established dependence of the brightness decrease of a short-period comet dependence on the perihelion distance of its orbit it follows that part of the surface of these cometary nuclei gradually covers by a refractory crust. The results of cometary nucleus simulation show that at constant insolation energy the crust thickness is proportional to the square root of the insolation time and the ice sublimation rate is inversely proportional to the crust thickness. From laboratory experiments resulted the thermal regime, the gas productivity of the nucleus, covering of the nucleus by the crust, and the tempo of evolution of a short-period comet into the asteroid-like body studied.

The effect of spacecraft descent engine plumes on spore transfer to planetary surfaces: Phoenix as a test case

2011 ◽  
Vol 10 (4) ◽  
pp. 335-340 ◽  
Author(s):  
J.R. Marshall ◽  
R.L. Mancinelli
Keyword(s):  
Atmospheric Pressure ◽  
Laboratory Experiments ◽  
Particle Impact ◽  
Test Case ◽  
Surrounding Area ◽  
Planetary Protection ◽  
Engine Thrust ◽  
Exhaust Plumes ◽  
Microbial Contaminants ◽  
Different Parts

AbstractLaboratory experiments were conducted to determine the effect of descent-engine plumes on the scouring of surface (microbial) contaminants from a spacecraft. A simulated touchdown of a half-scale lander engine and deck configuration was conducted at Mars atmospheric pressure in the NASA Ames Planetary Aeolian Laboratory. Low-density particles were used for the soil simulant to emulate the lower Martian gravity. The underside of the model had small witness plates with controlled microbial surface populations and particle impact detectors. For both steady-state engine thrust (Viking) and pulsed engine thrust (Phoenix), the exhaust plumes from the engines violently excavated the soil and produced particle-laden eddies beneath the lander that sandblasted the lander underside. The result was nearly complete erosion of microbial contaminants from the spacecraft model with their subsequent deposition in the surrounding area. It is concluded that different planetary protection cleanliness levels for different parts of a spacecraft do not necessarily prevent soil contamination because these cleaning strategies evolved without consideration of the effects of the descent engine plumes.

Convective Heat Transfer Enhancement Due to Intermittency in an Impinging Jet

1993 ◽  
Vol 115 (1) ◽  
pp. 91-98 ◽  
Author(s):  
D. A. Zumbrunnen ◽  
M. Aziz
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Impinging Jets ◽  
Transfer Coefficients ◽  
Stagnation Line ◽  
High Heat Transfer ◽  
Short Period

An experimental investigation has been performed to study the effect of flow intermittency on convective heat transfer to a planar water jet impinging on a constant heat flux surface. Enhanced heat transfer was achieved by periodically restarting an impinging flow and thereby forcing renewal of the hydrodynamic and thermal boundary layers. Although convective heat transfer was less effective during a short period when flow was interrupted, high heat transfer rates, which immediately follow initial wetting, prevailed above a threshold frequency, and a net enhancement occurred. Experiments with intermittent flows yielded enhancements in convective heat transfer coefficients of nearly a factor of two, and theoretical considerations suggest that higher enhancements can be achieved by increasing the frequency of the intermittency. Enhancements need not result in an increased pressure drop within a flow system, since flow interruptions can be induced beyond a nozzle exit. Experimental results are presented for both the steady and intermittent impinging jets at distances up to seven jet widths from the stagnation line. A theoretical model of the transient boundary layer response is used to reveal parameters that govern the measured enhancements. A useful correlation is also provided of local heat transfer results for steadily impinging jets.

The effects of pesticides on life in fresh waters

1972 ◽  
Vol 180 (1061) ◽  
pp. 383-394 ◽  
Keyword(s):  
Laboratory Experiments ◽  
Organophosphorus Compounds ◽  
Analytical Techniques ◽  
Toxicity Tests ◽  
Limited Data ◽  
Fish Kills ◽  
Test Species ◽  
Fresh Waters ◽  
Short Period ◽  
Rivers And Lakes

About sixty pesticides are estimated to be used in Britain in circumstances where some contamination of fresh waters could occur. Apart from major fish kills, most of the evidence of contamination must be obtained from chemical analyses of water or fish, although these are mainly restricted to a few organochlorine and organophosphorus compounds. The potential hazards to fish and invertebrates have been identified in laboratory experiments and toxicity tests, but routine population surveys of susceptible species in rivers and lakes are rarely made. The nature of possible environmental effects of various types of pesticides is described, and the information on toxic levels of some chemicals, obtained from laboratory tests, is compared with the limited data available on levels existing in the environment. The need for more extensive screening of pesticide chemicals, especially the more persistent types, is discussed. Both adult fish and fry of several species should be used in tests, as well as representative invertebrates, which are known to be more susceptible to some pesticides than are fish. Long-period tests are also required, as for some pesticides the lethal concentrations are much lower in extended tests than in the usual short-period tests. Where possible, the test species, whether fish or invertebrates, should be analysed for the chemical under test. Analytical techniques should be developed, for levels existing in the environment, of a wider range of compounds than is currently investigated.

scholarly journals Sufism in Jammu

IJOHMN ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 81-102
Author(s):  
Dr R. Subramony
Keyword(s):  
Thirteenth Century ◽  
Significant Role ◽  
Indian Subcontinent ◽  
Social Response ◽  
Local Resistance ◽  
Jammu And Kashmir ◽  
Muslim Population ◽  
The People ◽  
Short Period ◽  
Different Parts

Sufism entered the Indian subcontinent in the twelfth century as a new socio-religious force.  Within a short period, it mushroomed to different parts of India. Fro Punjab to Rajputana, from Jammu and Kashmir to Kerala, sufism influenced the life and thought of the people. Though on the eve of its advent, Muslim population in most parts of India was virtually negligible, yet the sufis hardly faced any local resistance to their activities. Sufism reviewed enthusiastic social response. It adjusted itself with the indigenous cultural modes in a smooth manner. As a result, it became a catalyst in shaping and consolidating the Indian regional identities from the thirteenth century onwards. In this context, sufi shrines of the different regions-Ajodhan, Sirhins, Delhi, Ajmer and Gulbarga – played a significant role. For example, Richard Maxwell Eaton has shown that the sufis of Bijapur contributed tremendously to the promotion of vernacular idiom and Dakhani language.

scholarly journals Phytoremediation potentials of some wild plants around the chromium mine

2021 ◽  
Author(s):  
Veli Çeliktaş ◽  
Necattin Türkmen
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Plant Species ◽  
Metal Accumulation ◽  
Wild Plants ◽  
Mining Sites ◽  
Rhizosphere Soils ◽  
Different Parts

Abstract Phytoremediation is the general name of techniques that uses plants to remediate polluted environments. Heavy metals are one of the pollution resources caused by anthropogenic or natural ways. In this study, it was aimed to find new plant species for phytoremediation of heavy metals. For this purpose, field researches were done in chromium mining sites. After that, plants were selected, which were relatively abundant in the mining sites. Aethionema spicatum, Alyssum alyssoides, Alyssum floribundum, Alyssum oxycarpum, Thlaspi oxyceras, Convolvulus compactus, Onosma cappadocica and Salvia multicaulis were researched. For understanding phytoremediation potentials of plants, heavy metal analyses (Cr, Ni, Co, Pb, Zn, Mn, Cu and Fe) were done in rhizosphere soils and different parts of plants. Then plants were evaluated for accumulation and translocation of heavy metals by using BCF and TF calculations. Aethionema spicatum, Alyssum floribundum, Alyssum oxycarpum and Thlaspi oxyceras were found as hyperaccumulators for Ni because of their metal accumulation abilities.

scholarly journals Short-period fluctuations in the numbers of bacterial cells in soil

1936 ◽  
Vol 119 (814) ◽  
pp. 269-295 ◽  
Keyword(s):  
Room Temperature ◽  
Short Interval ◽  
Bacterial Cells ◽  
Intensive Study ◽  
Natural Conditions ◽  
Short Period ◽  
Initial Decrease ◽  
Plate Counts ◽  
Micro Organisms ◽  
Different Parts

Seasonal changes in the numbers of micro-organisms in fresh soil were first reported at the beginning of the present century; their existence has since been confirmed by workers in many different parts of the world. (For references, see below .) More recently, short-period fluctuations in bacterial numbers were found to exist. Such fluctuations were found in plate counts from daily samples of field soil by Cutler, Crump, and Sandon (1922) and from 2-hourly samples by Thornton and Gray (1930). Periodic determinations of bacterial numbers in soils other than those taken from natural conditions have been few in number and have usually been made as checks on work of some other nature. In earlier work of Russell and Hutchinson (1909), soil incubated at room temperature showed fluctuations in microbial content over such a short interval as 8 hours and over as long a period as 60 days. In their later work, Russell and Hutchinson (1913) working with three soils of different moisture contents, dry, moist, and saturated, incubated at constant temperature, found changes in numbers between samples taken at from 5- to 8-day intervals. Such changes in numbers were not related to temperature, nor necessarily to moisture changes. A more intensive study was made by Allison (1917). He brought soil samples into the laboratory and made bacterial and fungal counts at short intervals of time. Samples taken during the winter showed a drop in numbers of as much as 40% during the first 1½ hours’ storage, followed by a large rise after some hours; in summer the initial decrease was less pronounced, this being attributed to the fact that at that season outdoor temperatures more nearly approached indoor temperatures. Cutler and Dixon (1927) found that, with soil stored at laboratory temperatures in deep narrow bottles, bacterial numbers decreased steadily over a period of 5 weeks. In soil stored in pots with a large surface area, fluctuations in bacterial numbers of as much as 100% were obtained from week to week, and the soil in general behaved as fresh soil.

scholarly journals An apparatus for the direct determination of accelerations

1919 ◽  
Vol 95 (673) ◽  
pp. 492-507 ◽  
Keyword(s):  
Practical Interest ◽  
Direct Determination ◽  
Mechanical Forces ◽  
Artificial Structures ◽  
True Motion ◽  
Short Period ◽  
Different Parts ◽  
Three Components

The question of the determination of the acceleration of the true motion of the ground in various seismic phenomena, or of the motion in different parts of buildings, bridges, and all kinds of artificial structures, due to explosions, shocks, or oscillations of the ground, has a considerable theoretical and practical interest, since the investigation of these accelerations serves as a guide in the study of the mechanical forces by which these movements are caused. The knowledge of these forces is particularly important in the design of buildings of all kinds in seismological areas, and also for the calculation of various elements (ties or reinforcements) of structures which are often subjected to vibrations caused by the action of powerful engines by shifting of large' masses (in the case of bridges or buildings on yielding foundations), by sudden shocks (in the case of ships armed with heavy guns), and so on. The problem of the determination of the true magnitude of the acceleration, however, presents great practical difficulties, especially in the case where the amplitudes of the motion are small and the oscillations of short period. The apparatus generally used for this purpose consists mainly of a pendulum—whether simple, horizontal, or elastic—according to the anticipated magnitude of the period and of the three components (two horizontal and one vertical) of the movement under investigation.

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