scholarly journals An inter-comparison of autonomous in situ instruments for ocean CO2 measurements under laboratory-controlled conditions

2022 ◽  
pp. 104085
Author(s):  
Qipei Shangguan ◽  
Adam Prody ◽  
Taylor S. Wirth ◽  
Ellen M. Briggs ◽  
Todd R. Martz ◽  
...  
Keyword(s):  
Controlled Conditions

An inexpensive portable freezer for in situ freezing in the field

2002 ◽  
Vol 32 (12) ◽  
pp. 2160-2168 ◽  
Author(s):  
Yves Dubuc ◽  
Jean Dubuc ◽  
Francine J Bigras
Keyword(s):  
Picea Glauca ◽  
White Spruce ◽  
Field Conditions ◽  
Natural Conditions ◽  
Dry Ice ◽  
Ambient Temperatures ◽  
Programmable Controller ◽  
Controlled Conditions ◽  
Large Trees

A portable freezer was developed to apply frost to branches of large trees to study their growth and recuperation after frost application under natural conditions. The freezer measures 37.5 × 63.5 × 31.5 cm and weighs approximately 3 kg. It consists of two compartments, a freezing compartment and a dry ice compartment. The portable freezer provides a ramp-and-soak freezing pattern using a programmable controller. The nonfreezing temperature plateaus can be set from 1 to 6°C and maintained for 0 to 12 h. The cooling and warming rates can be programmed from 1 to 12°C·h–1. Test temperatures can be maintained for a period of time ranging from 0 to 12 h at set temperatures. Freezers were tested without samples under controlled conditions at ambient temperatures of 0, –5, –10, 5, 15, 20, and 25°C. Under these conditions, the cooling and warming rates showed a deviation of less than ±1°C·h–1 at a set rate of 2°C·h–1. The freezer provides test temperatures as low as –38°C and –47°C at ambient temperatures of 20 and –10°C, respectively. Freezers were also tested under field conditions on attached branches in mature white spruce (Picea glauca (Moench) Voss) trees under hardening conditions.

scholarly journals Differential Interpretation of Mountain Temperatures by Endospermic Seeds of Three Endemic Species Impacts the Timing of In Situ Germination

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1382
Author(s):  
Marco Porceddu ◽  
Hugh W. Pritchard ◽  
Efisio Mattana ◽  
Gianluigi Bacchetta
Keyword(s):  
Climate Change ◽  
Seed Germination ◽  
Tree Canopy ◽  
Environmental Niche ◽  
Intergovernmental Panel ◽  
Thermal Thresholds ◽  
Controlled Conditions ◽  
The Impact ◽  
Embryo Length

Predicting seed germination in the field is a critical part of anticipating the impact of climate change on the timing of wild species regeneration. We combined thermal time and soil heat sum models of seed germination for three endemic Mediterranean mountain species with endospermic seeds and morphophysiological dormancy: Aquilegia barbaricina, Paeonia corsica, and Ribes sandalioticum. Seeds were buried in the soil within the respective collection sites, both underneath and outside the tree canopy, and their growth was assessed regularly and related to soil temperatures and estimates of the thermal characteristics of the seeds. The thermal thresholds for embryo growth and seed germination of A. barbaricina assessed in previous studies under controlled conditions were used to calculate soil heat sum accumulation of this species in the field. Thermal thresholds of seed germination for P. corsica and R. sandalioticum were not previously known and were estimated for the first time in this field study, based on findings of previous works carried out under controlled conditions. Critical embryo length and maximum germination for A. barbaricina were reached in April, and in December for R. sandalioticum. Seeds of P. corsica stay dormant in the ground until the following summer, and the critical embryo length and highest germination were detected from September to December. Soil heat sum models predicted earlier germination by one month for all three species under two Intergovernmental Panel on Climate Change (IPCC) scenarios, based on the assumption that the estimated thermal thresholds will remain constant through climate changes. This phenological shift may increase the risk of mortality for young seedlings. The models developed provide important means of connecting the micro-environmental niche for in situ seed germination and the macro-environmental parameters under a global warming scenario.

Bioremediation of a Cyanide-Contaminated Site Using EH-/PH-Controlled Conditions (ENA)

2009 ◽  
Vol 71-73 ◽  
pp. 717-720
Author(s):  
P. Harborth ◽  
M. Thieme ◽  
K. Fricke
Keyword(s):  
Field Studies ◽  
Contaminated Site ◽  
H2o2 Treatment ◽  
Iron Cyanide ◽  
Controlled Conditions ◽  
In Situ Conditions ◽  
Cyanide Complexes ◽  
First Time ◽  
Ph Controlled

In the course of remedial investigations for a former gasworks site, high cyanide pollution of the soil (74.6 - 101.7 mg/kgDS total cyanide) and of the groundwater (3,840 µg/l total cyanide /approx. 300 µg/l free cyanides) were particularly problematic. Extensive investigations in the laboratory as well as in field studies finally resulted in a 2-step oxic/anoxic concept. Both the free cyanides as well as the complex bound cyanides could be biodegraded at more than 90% through a combination of H2O2-treatment (ISCO) and denitrification by in situ conditions. Furthermore a destruction of the iron cyanide complexes under fermentative conditions could be observed for the first time.

scholarly journals Seed Germination of the Herbaceous Vine Tropaeolum pentaphyllum Lam. (Tropaeolaceae): A Neglected Geophyte with High Agricultural Potential

2021 ◽  
pp. 94-105
Author(s):  
Juliana Marcia Rogalski ◽  
Daniela da Silva ◽  
Júlio Tagliari Balestrin ◽  
Kaliandra Severina Mattei ◽  
Angela Julia Dorn ◽  
...  
Keyword(s):  
Seed Germination ◽  
First Year ◽  
Natural Light ◽  
Natural Conditions ◽  
Dark Treatment ◽  
Controlled Conditions ◽  
Agricultural Potential ◽  
Agricultural Use ◽  
Second Year

The objective of this study was to evaluate the seed germination of Tropaeolum pentaphyllum Lam., an endangered geophyte native of southern Brazil with agriculture potential due its edible tubers. Two experiments were carried out in 2017: germination of T. pentaphyllum under natural conditions and under controlled conditions. In the experiments under natural and controlled conditions, the germination of 1,100 and 100 seeds was evaluated, respectively. In the experiment under controlled conditions, two treatments (natural light and dark) were evaluated and each treatment contained 50 seeds. In the natural conditions experiment, in 2018 (first year), of the 1,100 seeds, 5.6% germinated and 76.5% persisted in the soil; and in 2019 (second year), 5.3% of the seeds germinated and no seeds remained in the soil. In natural conditions experiment, 10.9% of seeds germinated over two years. In controlled conditions experiment, in 2018 the germination in dark was higher (48%) compared to natural light (18%); and in 2019, despite the absence of statistical differences, the dark showed a higher value of germination (12%) in relation to natural light (6%). Over two years, dark treatment showed higher germination (60%) compared to natural light (24%) and no seeds remained in the substrate. The production of tubers in plants obtained by seed germination was 98.4% and 100%, in natural and controlled conditions, respectively. The highest germination rates occurred under dark conditions indicating that the species is preferential negative photoblastic. In addition, this species forms a seed bank in the soil, in which the seeds remained for a maximum of two years. The seed germination can contribute to the genetic diversity of crops and the production of seed-tubers, decreasing the collection of tubers in situ, contributing to the conservation and agricultural use of T. pentaphyllum.

A Method of Estimating the In-Situ Density of Dry Uniformly Graded Sand Under Controlled Conditions of Placement

1983 ◽  
Vol 6 (4) ◽  
pp. 196
Author(s):  
ET Selig ◽  
SN Wersching ◽  
R Delpak ◽  
GO Rowlands
Keyword(s):  
Controlled Conditions

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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