Controlled Atmosphere Conditions Research Articles

The effects of high CO2pre-storage treatments and rate of establishment of controlled atmosphere conditions on bitter pit and bruise susceptibility of ‘Bramley’s Seedling’ apples

SummaryBitter pit incidence in Bramley apples that were cooled prior to either slow (three weeks) or rapid (one day) establishment of controlled atmosphere (CA) conditions (9% CO2, 12% O2) was 14.7 and 3.2% respectively. Bruise susceptibility was also reduced by rapid CA establishment although the rate of fruit softening was unaffected. The control of bitter pit by pre-storage treatment with 15–25% CO2 for one to three weeks was no better than by rapid establishment of CA, although bruise susceptibility was further reduced by some treatments. Some pre-storage treatments caused injury to the apple skin and flesh (brownheart). The extent to which fruits were injured was dependent on CO2 concentration and the duration of CO2 treatment. There was some evidence that early picked fruit not cooled prior to CO2 treatment was more severely injured both internally and externally by CO2 than that harvested later and cooled prior to treatment.

Modeling the Effect of O2 and CO2 on Respiration and Quality of Stored Tomatoes

ABSTRACT TOMATOES were stored under 20 gas environments involving O2 and CO2 concentration of 5 to 20%, respectively. Two models were developed to predict the respiration rate of tomatoes stored under controlled atmosphere conditions. Although Model-II was found to be slightly better than Model-1, Model-1 was simpler to use. O2 concentration was observed to have more pronounced effect than the CO2 concentration on the firmness of tomatoes. Tomatoes stored at 21 C and under 5% O2 and 5 to 15% CO2 gas environments for up to 45 days had no significantly different off-flavor than tomatoes stored at 12 C under ambient conditions.

Monochromatic X-ray irradiation system (0.08-0.4 nm) for radiation biology studies using synchrotron radiation at the photon factory.

A monochromatic X-ray irradiation system in the 0.08-0.4 nm wavelength range is described. This uses for the first time, synchrotron radiation at the Photon Factory as an X-ray source (2.5 GeV electron storage ring). It consists of a beam shutter, a Si crystal monochromator, ionization chambers for monitoring exposures, a sample stage, and a control system. The beam is 2.7 × 30 mm at the sample position with a fairly uniform intensity of several kR/min (one C · kg-1 · min-1). The wavelength is an extremely pure Δλ/λ ?? 10-3. A 35 mm culture dish is moved across the vertical height (2.7 mm) of the X-ray beam using a sample scanning stage. This improves the uniformity of the radiation intensity on the sample. The sample can be irradiated under normal or controlled atmospheric conditions. Since 1984, a variety of biological materials have been irradiated, including cultured mammalian cells. Results of yeast cells are presented to illustrate the performance of this irradiation system.

A Multipurpose Controlled Atmosphere Facility for Production of Rapidly Solidified Particulate

AbstractThe design and operation of equipment to generate rapidly solidified samples in batches as large as 5 kg, under closely controlled atmosphere conditions, is described. Two modes of operation are possible at present: gas atomization-substrate solidification (GASS) and crucible melt extraction (CME). Both produce particulate, the former with a flake type morphology, the latter as a discontinuous fibre. Several aluminium alloys have been processed via GASS and one of them (Al–9 wt-%Mn) has been compared to the same composition processed in air access equipment. Tin and a lead-antimony alloy have been used to demonstrate the operational characteristics of the crucible melt extraction mode. PM/0319

Benefits of ethylene removal during apple storage

SUMMARYThe potential use of an ethylene absorbent in controlled atmosphere storage of two varieties of apple has been investigated. With Golden Delicious, the rise in ethylene concentration during controlled atmosphere storage can be delayed for about 40 days but not prevented by inclusion of potassium permanganate in the storage container. But with Bramley's Seedling, potassium permanganate can delay ethylene accumulation for over 200 days. Ethylene treatment of Bramley's Seedling in a flowing stream of 5% CO2:3% O2:92% N2 caused accelerated softening, accumulation of α‐farnesene and earlier onset of superficial scald. Use of potassium permanganate to remove ethylene during storage in static controlled atmosphere conditions retarded all three processes in Bramley's Seedling kept in 5% CO2:3% O2 and in 9% CO2:12% O2. However, in one experiment, ethylene removal in 5% CO2:3% O2, led to external and internal symptoms of CO2 damage. A subsequent investigation of the combined effects of harvest date, store temperature and ethylene removal in 5% CO2:3% O2 did not show any damage or accumulation of succinic acid which is known to be involved in CO2 injury. This experiment revealed that ethylene removal could be successfully accomplished on Bramley fruit harvested up to a month after the usual date and little α‐farnesene accumulated in this fruit. Nevertheless scald did develop on late picked fruit and this raises doubts about the causal role of farnesene in scald.

2448. An apparatus for constant stress creep testing in ultrahigh vacuum and in controlled atmosphere conditions

2448. An apparatus for constant stress creep testing in ultrahigh vacuum and in controlled atmosphere conditions

An apparatus for constant stress creep testing in ultrahigh vacuum and in controlled atmosphere conditions

An ultrahigh vacuum creep testing apparatus is described which enables controlled gaseous environments to be maintained in the pressure range of 0.01 nTorr at 298K to 1m Torr at 1223K. Studies of the influence of oxidation on the creep ductility of copper and iron have been made possible by varying the reduction or oxidation potential of the test environments with hydrogen or oxygen additions. Some design advantages and typical experimental operating conditions and results are indicated to illustrate the scope of the apparatus.

Characteristics of impulse breakdown of standard rod gaps under controlled-atmosphere conditions

The effect of humidity, polarity and irradiation on the 1/50μs impulse voltage breakdown and time lag of standard rod gaps has been determined for a range of spacings from 5cm to 30cm and a range of humidities from 1g/m3 to 24g/m3. An anomalous condition is reported for a 5cm unirradiated gap under positive impulses in which the slope of the humidity characteristic is opposite to that normally obtained. It is shown that, although the time lag is independent of humidity, the probability of breakdown in the sigmoid region is not independent of humidity.

The Influence of Ethylene, Oxygen, and Carbon Dioxide on the Ripening of Bananas

The combined and separate influence of O2, CO2, and ethylene on the ripening of bananas was studied. A significant difference in behavior was observed between uninitiated and initiated green fruit. High CO2 concentrations and low O2 concentrations inhibited ethylene synthesis and ripening in uninitiated fruit, and low O2 concentrations greatly reduced the total respiration necessary for a given degree of ripening. This suggested that part of the climacteric rise was not absolutely necessary for ripening and may represent wasted energy. The influence of O2 and CO2 on the ethylene production rates suggested that one of the ways in which controlled atmosphere storage conditions retarded fruit ripening was through a reduction in rate of ethylene synthesis. Though both uninitiated and initiated bananas were green only the former could be preserved by controlled atmosphere conditions.

Controlled-Atmosphere dc Arc for the Quantitative Determination of Rare Earths in Calcium Fluoride

This paper discusses the investigation of optimum controlled-atmosphere conditions for the analysis of rare earths in calcium fluoride and describes the specific technique evolved for the determination of terbium and holmium. The limits of detection and precision of the method are given.

Controlled atmosphere levitation system

A levitation system designed to melt and cast small quantities of metals under controlled-atmosphere conditions is described. Temperature control of the levitated sample and certain other practical aspects of the technique are discussed on the basis of experience gained over a two-year development period.

STUDIES WITH MEDICATED AEROSOLS

Excerpt Evidence presented below indicates that the lungs, because of their anatomic structure, can serve as an excellent means for the introduction of certain medications, in aerosol form,§intende...