Chemical composition of leaf and root essential oils of Boenninghausenia albiflora Reichb. from northern India
The leaf and root essential oil composition of Boenninghausenia albiflora Reichb and Meissner (family: Rutaceae), collected from Uttarakhand, India, was analysed by capillary gas chromatography and gas chromatography–mass spectrometry. The major constituents identified in the leaf essential oil were β-myrcene, (Z)-β-guaiene, (Z)-β-ocimene and β-caryophyllene, whereas bicyclogermacrene, α-terpinyl acetate, geijerene and β-copaene-4α-ol were identified as the major constituents of the root essential oil. This is the first time that the chemical compositions of leaf and root essential oils of B. albiflora have been investigated in detail. The results show significant qualitative and quantitative variations in leaf and root oil composition.
Compositional Variations in Volatile Constituents of Boenninghausenia albiflora Reichb. from Western Himalaya
The essential-oil yield and composition of the aerial parts of Boenninghausenia albiflora were analyzed and compared by capillary GC-FID and GC–MS at different stages of growth and on drying prior to distillation. The essential-oil content of the aerial parts was found to vary from 0.15–0.20 % at different phenophases. Essential-oils were mainly composed of sesquiterpenoids (44.62–52.11 %) and monoterpenoids (25.73–45.95 %). Sesquiterpenoids (44.62–52.11 %) portion of essential-oils was represented by germacrene D (4.18–18.21 %), epi-α-cadinol (0.14–16.25 %), β-caryophyllene (4.62–13.14 %), globulol (0.26–9.22 %), and β-copaene-4α-ol (0.14–7.52 %); while β-myrcene (2.09–26.11 %) and β-pinene (8.36–13.77 %) were the major monoterpenoids. Variations in essential-oil yield (0.15–0.20 %), and contents of monoterpene hydrocarbons (19.38–42.59 %), sesquiterpene hydrocarbons (15.38–36.92 %) and oxygenated sesquiterpenes (9.97–36.73 %) due to different growth stages (vegetative, flowering and seed setting stages) of B. albiflora were noticed. On drying viz. sun and shade drying of the aerial parts of B. albiflora have no drastic influence on essential-ol quality; but significant quantitative variations were noticed. Further, variations in essential-oil composition of leaf and root essential-oils of B. albiflora collected from four different climatic locations were also compared.
Slotted Waveguide Antenna With Two Radiation Nulls
A design of a linear array antenna having two radiation nulls and otherwise omnidirectional radiation pattern is reported. A new configuration of a waveguide broad wall longitudinal slot doublet with positive and negative offsets with respect to the waveguide center line is used to design the array. This type of doublet produces two radiation nulls. Each of the null directions can be shifted at least up to plusmn25deg by proper choice of slot offset. Resonance and radiation characteristics of the proposed doublet are also presented. Finally, one linear array antenna consisting of seven doublets has been fabricated. Measurements show that the 15 dB null widths are 14.2deg and the null depths are at least 24.8 dB. Maximum gain ripple in the omnidirectional region is 1.75 dB.