scholarly journals Evaluation of Horizontal Recirculatory Air Curtain Efficiencies: Cooler to Conditioned Space

2014 ◽  
Author(s):  
Daniel J. Rhyner
Keyword(s):  
Energy Transfer ◽  
Energy Loss ◽  
Cold Storage ◽  
Theoretical Calculations ◽  
Energy Losses ◽  
Tracer Gas ◽  
Environmental Chamber ◽  
Air Curtain ◽  
Cold Room ◽  
Chamber Size

Air curtains have long been used to reduce losses from high traffic doorways in cold storage facilities. Different varieties of air curtains have been used including vertical (down blast) non-recirculatory, horizontal non-recirculatory and horizontal recirculatory. The effectiveness of air curtains to provide thermal separation between rooms of differing temperatures has long been a matter of debate. Previous experiments have been done to determine the effectiveness using tracer gas decay methods. This paper will evaluate the thermal effectiveness of the horizontal recirculatory air curtain when applied in a typical cooler application using an environmental chamber. This allowed testing of the air curtain’s ability to reduce infiltration on the actual thermal envelope. A vertical non-recirculatory air curtain was also evaluated for comparison purposes. The air curtains were tested in an environmental chamber that was divided into two rooms of differing temperature. The chamber was instrumented to measure all energy transfer into and out of each room. The cold room was maintained at a temperature of 4°C (39°F) and the warm room was maintained at a temperature of 24°C (75°F) and 60% RH throughout all tests. Three phases of testing were conducted for each air curtain to completely evaluate all energy losses — a completely closed doorway test for calibration, a completely open doorway test with no air curtains and an open doorway test with the air curtains adjusted and running. Completion of the testing revealed the horizontal recirculatory air curtain had a thermal efficiency of 71% while the vertical non-recirculatory air curtain had an efficiency of 38%. The results were slightly lower than theoretical calculations which may be attributable to chamber size. Additional tests were conducted using a smaller doorway for comparison. Applying the results from the smaller doorway yields an effectiveness of 76.2%. Using the theoretical open doorway energy loss yields an effectiveness of 80%. Paper published with permission.

Thymine Dimerization Induced by Oxidative DNA Lesions and Epigenetic Intermediates via Triplet-Triplet Energy Transfer

2020 ◽  
Author(s):  
Mauricio Lineros-Rosa ◽  
Antonio Francés-Monerris ◽  
Antonio Monari ◽  
Miguel Angél Miranda ◽  
Virginie Lhiaubet-Vallet
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Transient Absorption ◽  
Theoretical Calculations ◽  
Dna Lesions ◽  
Transient Absorption Spectroscopy ◽  
Triplet Energy ◽  
Pyrimidine Dimers ◽  
Triplet Energy Transfer ◽  
Dna Nucleobases

Interaction of nucleic acids with light is a scientific question of paramount relevance not only in the understanding of life functioning and evolution, but also in the insurgence of diseases such as malignant skin cancer and in the development of biomarkers and novel light-assisted therapeutic tools. This work shows that the UVA portion of sunlight, not absorbed by canonical DNA nucleobases, can be absorbed by 5-formyluracil (ForU) and 5-formylcytosine (ForC), two ubiquitous oxidative lesions and epigenetic intermediates present in living beings in natural conditions. We measure the strong propensity of these molecules to populate triplet excited states able to transfer the excitation energy to thymine-thymine dyads, inducing the formation of the highly toxic and mutagenic cyclobutane pyrimidine dimers (CPDs). By using steady-state and transient absorption spectroscopy, NMR, HPLC, and theoretical calculations, we quantify the differences in the triplet-triplet energy transfer mediated by ForU and ForC, revealing that the former is much more efficient in delivering the excitation energy and producing the CPD photoproduct. Although significantly slower than ForU, ForC is also able to harm DNA nucleobases and therefore this process has to be taken into account as a viable photosensitization mechanism. The present findings evidence a rich photochemistry crucial to understand DNA photodamage and of potential use in the development of biomarkers and non-conventional photodynamic therapy agents.

Collisional activation of large ions. Energy losses and an impulsive collision theory of energy transfer

1994 ◽  
Vol 90 (2) ◽  
pp. 239 ◽  
Author(s):  
Caroline D. Bradley ◽  
Jonathan M. Curtis ◽  
Peter J. Derrick ◽  
Margaret M. Sheil
Keyword(s):  
Energy Transfer ◽  
Collisional Activation ◽  
Energy Losses ◽  
Collision Theory

Odour and VOC confining in large enclosures using air curtains

2001 ◽  
Vol 44 (9) ◽  
pp. 165-171 ◽  
Author(s):  
M. Pavageau ◽  
E.M. Nieto ◽  
C. Rey
Keyword(s):  
Particle Image ◽  
Flow Dynamics ◽  
Leakage Flow ◽  
Experimental Facility ◽  
Tracer Gas ◽  
Air Curtain ◽  
Air Supply ◽  
Leakage Flow Rate ◽  
Image Velocimetry ◽  
Air Tightness

Experiments were conducted on a two stream air-curtain prototype designed for VOC and odour confinement in a truck unloading area. The emphasis was placed on the air supply device. Measurements using tracer gas techniques were performed to assess the effectiveness of the system in terms of air tightness. Leakage flow rate was estimated for various feeding arrangements. Flow visualisations and particle image velocimetry measurements were carried out for a better understanding of the flow dynamics. Evidence was given of the improvements brought by the herein referred to, “double flux” configuration in comparison to traditional designs. After a brief description of the experimental facility and the basic principle underlying the approach developed, the main results are reported and discussed and recommendations are drawn. Considerations about where the effort will be directed in future works are provided.

scholarly journals Energy Transfer during the Tidal Encounter of Disc Galaxies

1983 ◽  
Vol 100 ◽  
pp. 355-356
Author(s):  
Philip L. Palmer
Keyword(s):  
Energy Transfer ◽  
Energy Loss ◽  
Numerical Simulations ◽  
Merging Galaxies ◽  
Analytic Work ◽  
Instability Modes ◽  
Impulsive Approximation ◽  
Disc Galaxies

Numerical simulations of merging galaxies do not include a disc component due to bar instability modes. Analytic work is based upon the impulsive approximation which leads to energy loss by the perturber. However, for the perturber to become bound we need consider parabolic encounters. Here we present an analytic technique suitable for all types of encounters.

scholarly journals A Method of Predicting the Energy Losses in Vaneless Diffusers of Centrifugal Compressors

1989 ◽  
Author(s):  
Huashu Dou
Keyword(s):  
Experimental Data ◽  
Energy Loss ◽  
Total Energy ◽  
Wall Friction ◽  
Energy Losses ◽  
Flow Conditions ◽  
Centrifugal Compressors ◽  
Flow Losses ◽  
Vaneless Diffusers ◽  
Good Agreement

The flow losses in the veneless diffusers of centrifugal compressors is investigated. It is found that the total energy loss in vaneless diffusers is a function of Bsin2 α0 when inlet flow conditions and radius ratio between inlet and outlet are given. A wall friction coefficient equation is derived and a method of predicting the total energy loss excepting mixing loss is presented. A comparison is made between results obtained from this method and experimental data generated by the author as well as data from the literature. Good agreement is obtained.

scholarly journals Chemical identification through two-dimensional electron energy-loss spectroscopy

2020 ◽  
Vol 6 (28) ◽  
pp. eabb4713
Author(s):  
Renwen Yu ◽  
F. Javier García de Abajo
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Electronic Device ◽  
Theoretical Calculations ◽  
Chemical Species ◽  
High Sensitivity ◽  
Two Dimensional ◽  
Excitation Spectra ◽  
Electron Energy Loss

We explore a disruptive approach to nanoscale sensing by performing electron energy loss spectroscopy through the use of low-energy ballistic electrons that propagate on a two-dimensional semiconductor. In analogy to free-space electron microscopy, we show that the presence of analyte molecules in the vicinity of the semiconductor produces substantial energy losses in the electrons, which can be resolved by energy-selective electron injection and detection through actively controlled potential gates. The infrared excitation spectra of the molecules are thereby gathered in this electronic device, enabling the identification of chemical species with high sensitivity. Our realistic theoretical calculations demonstrate the superiority of this technique for molecular sensing, capable of performing spectral identification at the zeptomol level within a microscopic all-electrical device.

scholarly journals Plasmonic Metalattices: A Correlated Monochromated Electron Energy Loss Study and Theoretical Calculations

2019 ◽  
Vol 25 (S2) ◽  
pp. 678-679
Author(s):  
Parivash Moradifar ◽  
Lei Kang ◽  
Pratibha Mahale ◽  
Yunzhi Liu ◽  
Nabila N. Nova ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Theoretical Calculations ◽  
Electron Energy Loss

THE ENERGY LOSS, THE DETERIORATION DEPTH, AND THE LIGHT OUTPUT FOR HEAVY IONS IN ZnO:Zn

1967 ◽  
Vol 45 (12) ◽  
pp. 4039-4051 ◽  
Author(s):  
L. Hastings ◽  
A. van Wijngaarden
Keyword(s):  
Energy Loss ◽  
Heavy Ions ◽  
Light Output ◽  
Average Energy ◽  
Ion Beams ◽  
Low Energy ◽  
Energy Losses ◽  
Sufficient Energy ◽  
Low Energy Ions ◽  
Total Average

Local regions on the surface of ZnO:Zn phosphor samples were deteriorated by a large number of low-energy ions. In this manner thin films which did not luminesce under ion bombardment were prepared. The phosphor samples were then scanned across energetic ion beams with sufficient energy to traverse the thin phosphor films. By comparing the luminescent response to this ion excitation in the damaged and undamaged portions of the phosphor surface, the total average energy losses of 1H, 4He, 14N, 40Ar, and 84Kr in passing through the films were determined. It was found that the energy losses for the heavier projectiles, when compared with the energy loss of hydrogen, are appreciably smaller than the energy losses predicted by the Lindhard and Scharff theory.The deterioration depth of the phosphor under prolonged bombardment is proportional to the speed of the damaging projectiles.

Energy losses of ions implanted in matter

1996 ◽  
Vol 11 (11) ◽  
pp. 2876-2883 ◽  
Author(s):  
J. H. Liang ◽  
K. Y. Liao
Keyword(s):  
Energy Loss ◽  
Nuclear Energy ◽  
Critical Energy ◽  
Carbon Films ◽  
Electronic Energy ◽  
Energy Losses ◽  
Nuclear Energy Loss ◽  
Light Ions ◽  
First Moment ◽  
First Four Moments

A set of simple and accurate formulae for the first four moments of nuclear and electronic energy losses is proposed. A new variable is introduced to include the finite maximum-impact-parameter effect in the nuclear stopping process, which is assumed to be infinite in most studies. A critical energy at which the electronic energy loss is equal to the nuclear energy loss is also defined. It determines whether the nuclear or the electronic stopping process is the dominant mechanism in terms of incident-ion energy. The critical energy increases for heavy ions implanted in heavy target materials during the first moment of energy loss. The second moment of electronic energy loss is important only for light ions implanted at high ion energies. The third and fourth moments of nuclear energy loss are much larger than those of the electronic energy loss for all ion-target combinations. Theoretical predications of the projected ranges and range stragglings for gold ions implanted in carbon films are close to the experimental data when these proposed four moments of nuclear and electronic energy losses are considered.

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