Distributed Temperature Sensing through Network Analysis Frequency-Domain Reflectometry.

In this paper, we propose and demonstrate a network analysis optical frequency domain reflectometer (NA-OFDR) for distributed temperature measurements at high spatial (down to ≈3 cm) and temperature resolution. The system makes use of a frequency-stepped, continuous-wave (cw) laser whose output light is modulated using a vector network analyzer. The latter is also used to demodulate the amplitude of the beat signal formed by coherently mixing the Rayleigh backscattered light with a local oscillator.

Automated Damage Detection Using Lamb Wave-Based Phase-Sensitive OTDR and Support Vector Machines.

In this paper, we propose and demonstrate a damage detection technique based on the automatic classification of the Lamb wave signals acquired on a metallic plate. In the reported experiments, Lamb waves are excited in an aluminum plate through a piezoelectric transducer glued onto the monitored structure. The response of the monitored structure is detected through a high-resolution phase-sensitive optical time-domain reflectometer (ϕ-OTDR).

An experimental study of liquid micro-jets produced with a gas dynamic virtual nozzle under the influence of an electric field.

The results of an experimental study of micro-jets produced with a gas dynamic virtual nozzle (GDVN) under the influence of an electric field are provided and discussed for the first time. The experimental study is performed with a 50% volume mixture of water and ethanol, and nitrogen focusing gas. The liquid sample and gas Reynolds numbers range from 0.

Lamb Wave Detection for Structural Health Monitoring Using a ϕ-OTDR System.

In this paper, the use of a phase-sensitive optical time-domain reflectometry (ϕ-OTDR) sensor for the detection of the Lamb waves excited by a piezoelectric transducer in an aluminum plate, is investigated. The system is shown to detect and resolve the Lamb wave in distinct regions of the plate, opening the possibility of realizing structural health monitoring (SHM) and damage detection using a single optical fiber attached to the structure. The system also reveals the variations in the Lamb wave resulting from a change in the load conditions of the plate.

Alternative Geometric Arrangements of the Nozzle Outlet Orifice for Liquid Micro-Jet Focusing in Gas Dynamic Virtual Nozzles.

Liquid micro-jets are crucial for sample delivery of protein crystals and other macromolecular samples in serial femtosecond crystallography. When combined with MHz repetition rate sources, such as the European X-ray free-electron laser (EuXFEL) facility, it is important that the diffraction patterns are collected before the samples are damaged. This requires extremely thin and very fast jets.

Drought limits pollen tube growth rate by altering carbohydrate metabolism in cotton (Gossypium hirsutum) pistils.

It has been reported that drought stress (DS) reduces cotton yield by negatively affecting reproductive activities. Some studies have investigated the effects of DS on pollen physiology and biochemistry, but studies exploring the impact of drought on pistil biochemistry and its relationship with pollen tube growth rates in vivo are scarce. In order to investigate these objectives, a greenhouse study was conducted with a drought sensitive cotton cultivar, Yuzaomian 9110.

Coping with drought: stress and adaptive mechanisms, and management through cultural and molecular alternatives in cotton as vital constituents for plant stress resilience and fitness.

Increased levels of greenhouse gases in the atmosphere and associated climatic variability is primarily responsible for inducing heat waves, flooding and drought stress. Among these, water scarcity is a major limitation to crop productivity. Water stress can severely reduce crop yield and both the severity and duration of the stress are critical.

A Comparative Study of Integrated Crop Management System vs. Conventional Crop Management System for Cotton Yield and Fiber Quality With Respect to Fruiting Position Under Different Soil Fertility Levels.

In order to increase cotton productivity and optimize fiber quality on limited arable land, an integrated crop management system (ICMS), which combined with some optimal management practices, is projected to replace the conventional crop management system (CCMS) for cotton production in the Yangtze River valley. The seedcotton yield and fiber quality with respect to fruiting position under ICMS and CCMS were investigated in 2012 and 2013 in two fields differing in soil fertility. Reduced bolls on fruiting branches 1-10 (FB) and at fruiting position 1-2 (FP) on FB could not be fully compensated by increased bolls on FB under CCMS, resulting in more seedcotton yield under ICMS relative to that under CCMS.

Physiological and biochemical changes during drought and recovery periods at tillering and jointing stages in wheat (Triticum aestivum L.).

Defining the metabolic strategies used by wheat to tolerate and recover from drought events will be important for ensuring yield stability in the future, but studies addressing this critical research topic are limited. To this end, the current study quantified the physiological, biochemical, and agronomic responses of a drought tolerant and drought sensitive cultivar to periods of water deficit and recovery. Drought stress caused a reversible decline in leaf water relations, membrane stability, and photosynthetic activity, leading to increased reactive oxygen species (ROS) generation, lipid peroxidation and membrane injury.

Potassium improves photosynthetic tolerance to and recovery from episodic drought stress in functional leaves of cotton (Gossypium hirsutum L.).

To investigate whether potassium (K) application enhances the potential of cotton (Gossypium hirsutum L.) plants to maintain physiological functions during drought and recovery, low K-sensitive (Siza 3) and -tolerant (Simian 3) cotton cultivars were exposed to three K rates (0, 150, and 300 KO kg ha) and either well-watered conditions or severe drought stress followed by a recovery period. Under drought stress, cotton plants showed a substantial decline in leaf water potential, stomatal conductance, photosynthetic rate, and the maximum and actual quantum yield of PSII, resulting in greater non-photochemical quenching and lipid peroxidation as compared to well-watered plants.

Simulative Global Warming Negatively Affects Cotton Fiber Length through Shortening Fiber Rapid Elongation Duration.

Global warming could possibly increase the air temperature by 1.8-4.0 °C in the coming decade.

Title: Potassium application regulates nitrogen metabolism and osmotic adjustment in cotton (Gossypium hirsutum L.) functional leaf under drought stress.

To evaluate the role of potassium (K) in maintaining nitrogen metabolism and osmotic adjustment development of cotton functional leaves to sustain growth under soil drought and rewatering conditions, the plants of two cotton cultivars Siza 3 (low-K sensitive) and Simian 3 (low-K tolerant), were grown under three different K rates (K0, K1, and K2; 0, 150, and 300kgKOha, respectively) and exposed to drought stress with 40±5% soil relative water content (SRWC). The drought stress was applied at flowering stage by withholding water for eight days followed by rewatering to a well-watered level (75±5% SRWC). The results showed that drought-stressed plants of both cultivars showed a decrease in leaf relative water content (RWC) and osmotic potential in the functional leaves and developed osmotic adjustment with an increase in the contents of free amino acids, soluble sugars, inorganic K, and nitrate as compared to well-watered plants.

Adaptation to and recovery from drought stress at vegetative stages in wheat (Triticum aestivum) cultivars.

Studying plants' capability to adapt and recover from drought stress is essential because of the ever-changing nature of drought events. To evaluate the genotypically variable morpho-physiological adaptations to drought stress and recovery after re-watering, two wheat cultivars (Luhan-7 and Yangmai-16) were pot-cultured under three levels of water stress: severe (35-40% field capacity, FC) and moderate water deficits (55-60% FC) and well-watered conditions. Drought stress was applied at tillering (Feekes 2 stage) and jointing (Feekes 6 stage), respectively, followed by re-watering, and we observed changes in leaf characteristics, growth and physiological activities during water stress and rewatering periods as well as final grain yield traits at maturity.

Nitrogen Nutrition Improves the Potential of Wheat (Triticum aestivum L.) to Alleviate the Effects of Drought Stress during Vegetative Growth Periods.

Efficient nitrogen (N) nutrition has the potential to alleviate drought stress in crops by maintaining metabolic activities even at low tissue water potential. This study was aimed to understand the potential of N to minimize the effects of drought stress applied/occur during tillering (Feekes stage 2) and jointing (Feekes stage 6) growth stages of wheat by observing the regulations and limitations of physiological activities, crop growth rate during drought periods as well as final grain yields at maturity. In present study, pot cultured plants of a wheat cultivar Yangmai-16 were exposed to three water levels [severe stress at 35-40% field capacity (FC), moderate stress at 55-60% FC and well-watered at 75-80% FC] under two N rates (0.

Improved tolerance to post-anthesis drought stress by pre-drought priming at vegetative stages in drought-tolerant and -sensitive wheat cultivars.

Wheat crop endures a considerable penalty of yield reduction to escape the drought events during post-anthesis period. Drought priming under a pre-drought stress can enhance the crop potential to tolerate the subsequent drought stress by triggering a faster and stronger defense mechanism. Towards these understandings, a set of controlled moderate drought stress at 55-60% field capacity (FC) was developed to prime the plants of two wheat cultivars namely Luhan-7 (drought tolerant) and Yangmai-16 (drought sensitive) during tillering (Feekes 2 stage) and jointing (Feekes 6 stage), respectively.