This paper reports a generation of short-pulsed thulium-doped fiber laser (TDFL) in Q-switching operation incorporation of homemade graphene oxide (GO) saturable absorber (SA). The GO SA is embedded ...with a polymer to form a GO film. A piece of the GO film is integrated into the TDFL cavity for generating a self-started Q-switching operation at 1943nm wavelength. The 3-dB bandwidth, repetition rate, and pulse width of the laser are obtained as 9nm, 15.76kHz–25.08kHz, and 5.08μs–4.2μs, respectively. The maximum pulse energy of 0.698μJ obtainable at 344mW pump power, with a peak power of 137.4mW. With a shortest pulse width size at a maximum pump power of 491mW, the higher peak power is determined about 162mW. By integrating our stable Q-switched laser with an optical amplifier, numerous applications such as a material cutting with the eye-safe feature can be realized. This shows a small piece of the GO can modulate a light and use for the pulsed laser industry.
Abstract
Sitophilus oryzae
(rice weevil) known as severe pest to many stored products, including rice. Gender density of
S. oryzae
is a critical information in predicting the rate of stored grain ...lost. However, the techniques used in gender identification of
S. oryzae
is a destructive technique which involved dissection to identify its reproductive organ. It was a tidious work and very time consuming. Thus, this study focused on the use of non destructive technique which only based on numerical information of
S. oryzae
morphological features to identify its gender. The numerical information was analysed and tested against two model i.e. Discriminant Analysis Model and Support Vector Machine Model. The result show that rostrum length and width were adequate to be used in the Discriminant Analysis Model for gender identification of
S. oryzae
with 91% correct classification, while Support Vector Machine Model perform poorly in classification with 62% correct classification. Gender identification of
S. oryzae
using numerical information features were more accurate and liable compared to normal identification which based on the internal reproductive organ.
We managed to produce a stable Q-switched pulse laser operating at 1563 nm using Lutetium (III) oxide (Lu2O3) material as a saturable absorber (SA). The Lu2O3 was deposited onto a D-shaped optical ...fiber and inserted into an erbium-doped fiber laser (EDFL) cavity for pulse generation. The D-shaped fiber was prepared by polishing wheel technique using rough and fine sandpapers to obtain a smooth surface and thus ensure an efficient light-matter interaction inside the SA. The proposed Q-switched EDFL generated pulses with duration as short as 11.84 μs at a repetition rate of 19.7 kHz. The Q-switched laser output was stable within the pump power of 68 mW–96 mW with the corresponding pulse energy and output power of 0.16 μJ–0.18 μJ and 2.76 mW–3.49 mW respectively. The signal-to-noise ratio was around 46.26 dB, which indicates the stability of the laser. The results show that the proposed Lu2O3 SA based on D-shaped fiber is suitable for realizing a portable Q-switched light source.
Abstract
The estimation of chlorophyll content in leaves by the chlorophyll meter (SPAD 502) is more favourable than by the extraction method for studies on photosynthesis or senescence where the ...total chlorophyll is estimated on the same leaf over time. However, till date there is lack of information available on leaf chlorophyll content of Fig (Ficus carica L.) cv. Iraqi grown in containers under different root zone spatial limitation and controlled porosity level. Hence, this study aim to determine the effect of both factors on leaf chlorophyll content of the crop. The experiment was design in randomized complete block design (RCBD) with four replications. The Soil-Plant Analyses Development (SPAD) chlorophyll meter (Minolta Camera Co., Ltd., Japan), has been used for instantly measuring the amount of chlorophyll present in plant leaves. Based on the results, the application of Mix 3 (50% sand: 50% clay) with high root zone spatial gave the highest chlorophyll content compared to other treatment. The application of the right root zone and porosity level may gave positive effect on leaf chlorophyll content of F. carica cv. Iraqi grown under greenhouse condition.
Abstract
As a result of its substantial energy density, layered LiNi0.8Co0.15Al0.05O2 cathode materials are thought to be the most promising of the next-generation cathode materials for electric ...vehicles (EVs). In this research, self propagating combustion (SPC) is used to prepare cathode materials made of pristine LiNi
0.8
Co
0.15
Al
0.05
O
2
(NCA) and NCA doped with 1% Fe to produce LiNi
0.8
Co
0.14
Fe
0.01
Al
0.05
O
2
. Based on X-Ray Diffraction (XRD) results, pristine and doped NCA cathode materials were pure and single phase. Reference Intensity Ratio (RIR) values for pristine and doped NCA are 0.87 and 1.12 respectively indicating that the amount of cation mixing was reduced with Fe doping. Through Rietveld refinement, it was discovered that the addition of Fe to NCA resulted in a decrease in cation mixing from 13.56% to 4.07%.It was found that both pristine and doped NCA possessed polyhedral like shape morphology. It can be seen that doping with 1% Fe does not change much in the crystallite size of the materials. By having less cation mixing, Fe doped was found to greatly improve the structural integrity of NCA cathode materials, which in turn improved the materials’ electrochemical performance.
Here we investigate, using relativistic fluid theory and Vlasov-Maxwell simulations, the local heating of a dense plasma by two crossing electron beams. Heating occurs as an instability of the ...electron beams drives Langmuir waves, which couple nonlinearly into damped ion-acoustic waves. Simulations show a factor 2.8 increase in electron kinetic energy with a coupling efficiency of 18%. Our results support applications to the production of warm dense matter and as a driver for inertial fusion plasmas.
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