We analyze the sensitivity to inertial rotations Ω of a micron scale integrated gyroscope consisting of a coupled resonator optical waveguide (CROW). We show here that by periodic modulation of the ...evanescent coupling between resonators, the sensitivity to rotations can be enhanced by a factor up to 10(9) in comparison to a conventional CROW with uniform coupling between resonators. Moreover, the overall shape of the transmission through this CROW superlattice is qualitatively changed resulting in a single sharp transmission resonance located at Ω = 0s-1 instead of a broad transmission band. The modulated coupling therefore allows the CROW gyroscope to operate without phase biasing and with sensitivities suitable for inertial navigation even with the inclusion of resonator losses.
Interception loss (I) can remove substantial portions of water from forested watersheds. Thus, I prediction models are crucial if we are to balance human and ecosystem water needs under a shifting ...climate. This is particularly true for arid/semiarid regions that rely on afforestation efforts for economic or agricultural needs, yet very few of these regions have selected, applied and validated an I prediction model. This study applied/evaluated the reformulated Gash I model to a data set of 54 storms using 50 manual throughfall (TF) observations per site, for two stands of common afforestation tree species in semiarid Northern Iran: Pinus eldarica (Eldar pine) and Cupressus arizonica (Arizona cypress). The reformulated Gash model has rarely been evaluated in semiarid forest stands of these common species. Each species intercepted substantial rainfall during commonly experienced storm conditions-up to 56% (C. arizonica) and 65% (P. eldarica). Mean TF was modestly higher under C. arizonica (76%) than P. eldarica (73%). However, water storage (S) was nearly double for P. eldarica compared to C. arizonica (1.2-0.7mm, respectively). Canopy structural differences also altered the gap fraction (p) for P. eldarica (0.38) in relation to C. arizonica (0.49). Modeling error was low (-1.3% vs. -2.6% for P. eldarica and C. arizonica, respectively), generally underestimating I. On the whole, the validated model performed better for C. arizonica than P. eldarica stands, likely as a result of influence from canopy structural functions not parameterized by the model (e.g., P. eldarica's higher LAI, horizontal leaves/branches, high crown length, and rougher bark) which directly alter S, p, and TF parameters, or indirectly influence the ratio of mean evaporation rate from the wet canopy (mmh-1) to the mean rainfall intensity (mmh-1) () by sheltering intercepted rain water from boundary layer meteorological conditions. It is, therefore, suggested that future work seek to parameterize these canopy parameters. Since I reduces the quantity of water for infiltration and recharge, I estimates and prediction tools are of great value to semiarid and arid regions undergoing afforestation because the model allows land managers to predict impacts of afforestation on water inputs for current and future rainfall scenarios.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Measuring geometric phase shifts has various applications in both quantum and classical interferometry such as measuring acceleration, distances, rotation and magnetic flux. Theoretical analysis of ...coupled ring arrays has been shown to be a promising design for creating small inertial rotation sensors on atom chips. In this paper we build on the theoretical models of transmission of matter waves through an area chirped array of ring interferometers to determine phase regions of the transmission that exhibit high sensitivity to geometric phase shifts,these regions are indicated by sharp transmission resonances. We calculate the slopes of transmission resonances for a range of values for two parameters, the chirp factor γ and the product of the wave number and ring circumference
kL
, we look at the behavior of the slopes of these transmission resonances for defined ranges of
kL
and γ to see in search of transmission resonances with extreme slopes. We find transmission resonances with sensitivities to geometric phase shifts that exceed those found in previous models of area chirped arrays by several orders of magnitude. The area chirp is applied such that the geometric phase shifts (
θ
GP
) in each ring of the array can be expressed in terms of the geometric phase shift in the reference ring of the array, this enables the transmission function
T
(
θ
GP
) to be calculated in terms of the phase shift of a single ring. We investigate
T
(
θ
GP
) for various ring sizes, wave numbers, and chirp factor and look for values of these parameters that lead to sharp transmission resonances in
T
(
θ
GP
). We calculate the sensitivities of rotation via the Sagnac effect and magnetic flux via Aharonov Bohm effect based on the sensitivity of the transmission resonances found in our transmission functions.
Graphical abstract
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
For smooth mappings of the unit disc into the oriented Grassmannian manifold
G
n
,
2
, Hélein (Harmonic Maps Conservation Laws and Moving Frames, Cambridge University Press, Cambridge, 2002) ...conjectured the global existence of Coulomb frames with bounded conformal factor provided the integral of
|
A
|
2
, the squared-length of the second fundamental form, is less than
γ
n
=
8
π
. It has since been shown that the optimal bounds that guarantee this result are:
γ
3
=
8
π
and
γ
n
=
4
π
for
n
≥
4
. For isothermal immersions in
R
3
, this hypothesis is equivalent to saying the integral of the sum of the squares of the principal curvatures is less than
γ
3
. The goal here is to prove that when
n
=
3
the same conclusion holds under weaker hypotheses. In particular, it holds for isothermal immersions when
|
A
|
2
is integrable and the integral of
|
K
|
, where
K
is the Gauss curvature, is less than
4
π
. Since
2
|
K
|
≤
|
A
|
2
this implies the known result for isothermal immersions, but
|
K
|
may be small when
|
A
|
2
is large. The method, which is purely analytic, is then developed to examine the case
n
=
3
when
|
A
|
is only square-integrable. The possibility of extending that result in the language of Grassmannian manifolds to the case
n
>
3
is outlined in an Appendix.
Micron-scale-integrated optical gyroscopes based on the Sagnac effect have a broad array of potential applications in navigation and inertial motion sensing due to the benefit of on-chip integration ...and potential sensitivities exceeding micro-electromechanical gyroscopes. Here, we analyze the Sagnac effect in a two-dimensional array of evanescently coupled optical microring resonators. We show that the sensitivity to inertial rotations greatly exceeds that of a single resonator with equal enclosed area. Moreover, a comparison between two-dimensional arrays and Sagnac gyroscopes consisting of one-dimensional distributed microresonators arrays of equal footprint shows that the sensitivity to rotations of the two-dimensional array exceeds that of the one-dimensional structures by as much as several orders of magnitude for smaller arrays.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Substantial global pomegranate fruit production occurs in Iranian rainfed orchards.•Canopy rain partitioning currently not considered in orchard management practices.•Orchard management practices ...altered the quantity/pathway of net rainfall to soils.•Thinning/pruning can tailor rainfed orchard stand structure to improve water supply.•Minimal management of rainfed orchards yielded the largest rain interception losses.
Arid pomegranate (Punica granatum) orchards are frequently rainfed. In these systems, orchard managers might be able to manipulate a stand’s canopy structure (e.g., thinning, pruning) to improve rainfall water input to the soil. The aim of this research was to determine how changes in management activities in rainfed pomegranate orchards in arid regions of Central Iran affects rainfall partitioning into throughfall, stemflow, and rainfall interception loss. We monitored gross rainfall, throughfall, stemflow and rainfall interception loss in three stands with varying levels of thinning and pruning. Management practices sufficiently altered the stand and canopy structure of pomegranate orchards to impact the quantity and pathway (throughfall v. stemflow) of rainfall reaching the ground. Decreases in tree height, canopy cover, crown length and LAI were correlated to a significant increase in rainfall reaching the forest floor. Results indicate that orchard managers may be able to prune 40% of the live crown and thin 70% of the stand if the objective it to significantly increase water inputs into the soil. Future research should focus on the impact of canopy management on soil moisture content and soil evaporation and transpiration.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The temporal dynamics of forest canopy rainfall partitioning are important to forest ecology and management as it influences all subsequent hydrological processes along the rainfall-to-discharge flow ...path. Despite a growing body of literature on the importance of coupled hydrological–ecological interactions during periodic forest life cycle events, little work has examined how canopy rainfall partitioning varies across transitional leaf states (between the leafed vs. leafless states). This study analyzed a 3 year field monitoring campaign for two tree species in semiarid Iran (
Robinia pseudoacacia
and
Platanus orientalis
) to describe rainfall partitioning dynamics across the full-leaf, senescence, leafless, and leafing states. Crown saturation point, canopy storage capacity, free throughfall coefficient and the ratio of wet canopy evaporation rate to mean rainfall intensity were related to decreases/increases in plant area index and canopy closure. The high variability of rainfall partitioning observed in this study highlights the importance of transitional leaf states in the temporal characterization of water inputs to forest surfaces and boundary layer.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Understanding canopy water partitioning is vital to agricultural operations.•The first quantitative study of rainfall partitioning for maize fields in Iran.•Rainwater partitioning remained steady ...when LAI of the maize canopy was < 2.5.•Partitioning of rainwater correlated strongly with LAI when LAI was > 3.1.
Maize farmland in Varamin, located southwest of Tehran (Iran).
The aims of this study were to: (1) monitor throughfall and stemflow during rainstorms beneath maize canopies over two growing seasons (2015, 2016); (2) evaluate the effect of maize canopy structure (leaf area index, plant height) on throughfall, stemflow, and interception; and (3) develop an analytical model of rainfall partitioning by maize from controlled rainfall simulations.
Rainfall or irrigation interception by crops and residues has often been overlooked in hydrologic modelling in Iran. However, our results confirm that interception by maize canopy can significantly reduce total water input to the surface (19.9 % and 11.2 % of natural and simulated rainfalls, respectively). Although rainfall amounts and rates were similar between simulations and natural rainfall, differences in interception value may still exist between simulated and natural conditions due to the formation, size distribution, and movement of water droplets emitted from simulation systems vs. natural rainfall water droplets. Throughfall and interception significantly correlated with LAI and height of the maize canopy above thresholds of 2.5 (LAI) and 180 cm (height). The analytical model performed well under natural rain conditions. These results may help farmers’ irrigation scheduling achieve higher irrigation water use efficiency for maize fields, particularly in arid agricultural lands.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
For precipitation to reach the surface of vegetated ecosystems, it must first pass through the canopy. A portion of precipitation, stemflow, drains down branches to the stem. This stemflow may wash ...canopy‐dwelling animals (metazoans) into the litter and soils below; however, stemflow metazoans transport has typically been ignored in past research. In fact, the visual presence of metazoans in stemflow collection bins was reported as “contamination” in past research. Thus, we know little about these organisms' transfer from plant canopies to the surface. To investigate this topic, we monitored metazoan concentrations and composition within stemflow that drained from eight urban tree species (n = 3 per species) over 12 months. Annual (±SE) stemflow recorded from all 24 sampled trees was 19.6 (±3.3) mm (2.3% rainfall). Analysis of 288 samples found 1,307 individuals distributed into seven classes (16 orders) and one organism at phylum level. Considering all trees (n = 24), the annual mean metazoan density in stemflow was 8.6 individuals L−1. Among tree species, there were considerable variations, ranging from 1.0 to 17 individuals L−1. Annual metazoan transport per tree ranged from 20 to 376 individuals m−2 y−1. The most common taxa observed in stemflow from this site included Arachnida (10%), Collembola (33%) and Insecta (56%). Variability in metazoan density within and across species was high, but individual trees with the highest metazoan stemflow density and flux were those with large diameter and exfoliating bark structure. This study demonstrates that stemflow can transport a substantial and diverse meso‐ and macro‐fauna to the surface of urban forests. Future work may be merited on the fate and/or role of these metazoans in litter and soil systems.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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