277 research outputs found
Design and characterization simulation of Ti: sapphire-based femtosecond laser system using Lab2 tools in the NI LabView
We report on the 825-nm center wavelength, 9.17 mJ pulse energy
Ti:sapphire-based femtosecond laser system simulation carried out by Lab2 tools
in LabVIEW (National Instruments, Inc.). The design investigation and
characterization of stretched, amplified and compressed pulses made by
intensity module and second harmonic generation (SHG) frequency-resolved
optical gating (FROG) module in Lab2. The minimum pulse duration of ~37.80 fs
at the output of the compressor end obtained by simulations. The variation of
pulse energy, FWHM and central wavelength versus number of passes in the
amplifier are computed. The lab2 tools help to design and characterize laser
system before to set up on the optical table. The simulation results save time
to calculate parameters which are essential in femtosecond laser system
designing. The Lab2 simulation tools, along with financial constraints, it is
easier, simple and efficient to obtain results in short time
Plant Responses to Biotic and Abiotic Stresses: Crosstalk between Biochemistry and Ecophysiology
Physio-Chemical Characterization of Biochar, Compost and Co-Composted Biochar Derived from Green Waste
Organic wastes are naturally biodegradable, but they contribute to environmental pollution and management issues. Composting and pyrolysis are widely used technologies for recycling these wastes into valuable organic products for soil health and crop production. In the current study, fruits vegetables waste (FVW) was converted to biochar, compost, and co-composted biochar. The microcrystal structure, functional groups, surface morphology, and nutrient contents of organic materials were investigated by XRD, FTIR, SEM-EDS, AAS, multi C-N analyzer, and ICP-OES techniques. Heavy metals contamination was not detected in the biomass used for pyrolysis and compost preparation. FVW had an acidic pH (5.92), while biochar, compost, and co-composted biochar had an alkaline pH. Total macronutrient (K, Na, S) and micronutrient (Cu, Fe) concentrations were higher in compost and co-composted biochar, with the exception of K, which was higher in biochar. Biochar had the highest surface area (4.99 m(2)g), followed by FVW, compost, and co-composted biochar. Co-composted biochar had a porous structure. Si, Ca, and Al contents were common in all organic materials, while P, K, Mg, and S were found with lower concentrations in both biochar and compost. Iron was only found in compost and co-composted biochar. Quartz, sylvite, and calcite were common minerals found in all organic treatments. Biochar contained more aromatic carbon ring structure C=C/C=O and aromatic C-H bending as compared to FVW and compost, thus, making biochar a stable carbon rich material suitable for soil carbon sequestration
Synthesis of 5-aryl-2-[spiro-(1,3-dithiolane)-2,4'-(3'-chloro-2'-azetidinon)-1'-yl]-1,3,4-oxa (thia)-diazoles and 5-aryl-2-[spiro-(1,3-dithiolane)-2,2'-(4'- thiazolidinon )-3'-yl]-1,3,4-oxa(thia)diazoles as antimicrobial agents
625-62
Non-linear propagation effects of intense femtosecond pulses on low order harmonics in solids
The non-linear propagation of the intense near-infrared (NIR) driving field
in wide bandgap materials pose a challenge and an opportunity to control the
spectral properties of high harmonic generation (HHG) in solids. Here, we have
investigated the non-linear propagation effects of the ultrafast intense
near-infrared (NIR) driving field at 800 nm of 40 fs pulse duration operating
at a repetition rate of 1 kHz focused on the wide bandgap dielectrics such as
MgO, Chromium (Cr) doped MgO (Cr: MgO), Sapphire (Sa) crystals and fused silica
(FS). Furthermore, we have generated second and third harmonic (TH) in these
materials to explore the non-linear response at a strong field. To quantify the
non-linear propagation effects, low-order harmonics have been generated in
reflection and compared with the harmonics generated in transmission. We
observe spectral shifts and broadening of the driving field spectrum which is
imprinted on the harmonics. We attribute these effects to strong
photoionization, generation of free-carrier density and self-phase modulation
effects. We have also studied the polarization dependence of second harmonic
generation (SHG) and TH in FS. The linear polarization dependence of below
bandgap harmonics in FS and Sa generated in reflection demonstrated the sharp
anisotropy than in transmission. This work shows the sensitivity to control the
spectral profile of harmonics by manipulating the driving field, showing the
possibility of new tailored solid-state XUV sources for optical diagnostics
Rising atmospheric temperature impact on wheat and thermotolerance strategies
Temperature across the globe is increasing continuously at the rate of 0.15–0.17 °C per decade since the industrial revolution. It is influencing agricultural crop productivity. Therefore, thermotolerance strategies are needed to have sustainability in crop yield under higher temperature. However, improving thermotolerance in the crop is a challenging task for crop scientists. Therefore, this review work was conducted with the aim of providing information on the wheat response in three research areas, i.e., physiology, breeding, and advances in genetics, which could assist the researchers in improving thermotolerance. The optimum temperature for wheat growth at the heading, anthesis, and grain filling duration is 16 ± 2.3 °C, 23 ± 1.75 °C, and 26 ± 1.53 °C, respectively. The high temperature adversely influences the crop phenology, growth, and development. The pre-anthesis high temperature retards the pollen viability, seed formation, and embryo development. The post-anthesis high temperature declines the starch granules accumulation, stem reserve carbohydrates, and translocation of photosynthates into grains. A high temperature above 40 °C inhibits the photosynthesis by damaging the photosystem-II, electron transport chain, and photosystem-I. Our review work highlighted that genotypes which can maintain a higher accumulation of proline, glycine betaine, expression of heat shock proteins, stay green and antioxidant enzymes activity viz., catalase, peroxidase, super oxide dismutase, and glutathione reductase can tolerate high temperature efficiently through sustaining cellular physiology. Similarly, the pre-anthesis acclimation with heat treatment, inorganic fertilizer such as nitrogen, potassium nitrate and potassium chloride, mulches with rice husk, early sowing, presoaking of a 6.6 mM solution of thiourea, foliar application of 50 ppm dithiothreitol, 10 mg per kg of silicon at heading and zinc ameliorate the crop against the high temperature. Finally, it has been suggested that modern genomics and omics techniques should be used to develop thermotolerance in wheat.Higher Education Commission (HEC) Pakistan | Ref. 1a55b19f0b99ca1
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