Energy Absorption and Dynamic Deformation of Backing Material for Ballistic Evaluation of Body Armour

The measurement of back face signature (BFS) or behind armour blunt trauma (BABT) is a critical aspect of ballistic evaluation of body armour. BFS is the impact experienced by the armour wearing body, when subjected to a non-penetrating projectile. Mineral or polymeric clay is used to measure the BFS. In addition to stopping the projectile, the body armour can be used only when the BFS also falls within permissible limits. The extent of the BFS depends upon the behavior of the backing material in different loading conditions and prior history. This paper explains some of the studies carried out on the backing material used for ballistic evaluation in Terminal Ballistics Research Laboratory, Chandigarh. It has been observed that the backing material is highly non-linear viscoelastic in nature. The depth of deformation is also linearly proportional to the impact energy and temperature. The effect of time on the depth of deformation is gradual and does not influence the BFS values during a standard ballistic evaluation comprising of 6-8 shots.Defence Science Journal, 2013, 63(5), pp.462-466, DOI:http://dx.doi.org/10.14429/dsj.63.382

Study of the b→dℓℓb \to d \ell\ell transitions in the Standard Model and test of New Physics sensitivities

After incorporating all the available experimental data and the most up-to-date Lattice and light cone sum rule (LCSR) inputs on the form factors, we analyze the exclusive $b\to u\ell\nu_{\ell}$ and $b\to d\ell \ell$ decays simultaneously. We have extracted the shape of all the associated form factors using which we provide predictions in the standard model for the branching ratios, direct CP asymmetries and isospin asymmetry for $B\to\pi\ell \ell$ and various angular observables for $B\to\rho\ell \ell$ transitions. Also, we have tested the sensitivities of these observables towards physics beyond the standard model (BSM).For the $B\to\rho\ell \ell$ decays, we have defined tagged and untagged observables and predicted them in the SM and BSM. In the context of BSM, we have found some compelling information. The respective predictions in a few benchmark scenarios are given, which can be tested in the experiments at the LHCb and the Belle.Comment: Further comments and a few more references have been adde

Rheology of Fumed Silica and Polyethylene Glycol Shear Thickening Suspension with Nanoclay as an Additive

Shear thickening properties of fumed silica-polyethylene glycol (PEG) with shear thickening fluid (STF) of different concentrations and with an organically modified clay, Nanomer I.28 E as nano-additive have been investigated by both steady-state and dynamic state rheology. Difference in rheology if instead of nanoclay, an equal wt% of additional fumed silica is added to 20 per cent fumed silica-PEG200 STF, has been studied. At 25 °C, in case of addition of nanoclay the increase in critical viscosity is less than that observed for same additional amount of fumed silica. Interestingly, an opposite result is seen at higher temperatures i.e. 45 °C and 55 °C. Moreover, the difference in steady-state and dynamic state viscosity values decreases on addition of nanoclay. It is noted that an increase in concentration of clay increases the value of dynamic parameters whereas for STF of only fumed silica particles the values are constant irrespective of the change in concentration. More importantly, ease of processing, elasticity, stability and consistency of rheological results of STF increases to a significant extent on addition of relatively inexpensive nano-additive

Rheology Based Design of Shear Thickening Fluid for Soft Body Armor Applications

The ballistic resistance of high-strength fabrics improves upon impregnation with Shear Thickening Fluids (STFs). The performance of such STF treated fabrics depends on the rheological properties of the STF which in turn are governed by the physicochemical properties of the STF. The present study utilizes rheological characterization of shear thickening silica-polyethylene glycol dispersions (of different material configurations in terms of packing fraction, particle size and continuous phase viscosity) to assess their performance and obtain the best STF material configuration for ballistic body armor applications based on the design criteria proposed herein. The ballistic performance assessment results showed that the STFs with high packing fractions which thicken discontinuously, are highly effective compared to the continuously shear thickening fluids. Furthermore, the use of smaller particle size dispersed phase in the STF formulation was determined to be economical. Also, the use of lower molecular weight dispersion medium was suggested as it allows for a broader working temperature range of the STF. Additionally, the technological issues associated with the development and the practical application of STF-Armor were addressed

Prevalence of extended-spectrum beta-lactamases producing isolates obtained from patients of pediatric critical care unit in a tertiary care hospital

Background: Over the past decades, antibiotic-resistant Gram-negative bacteria commonly Enterobacteriaceae such as Escherichia coli and Klebsiella pneumoniae have increased significantly. These microorganisms have great clinical importance because they increase hospital stay of the patients in the intensive care unit (ICU) leading to high morbidity and mortality. Because of their role in increasing morbidity and mortality, this study was performed to isolate extended-spectrum beta-lactamase (ESBL) producing Gram-negative bacilli screened by phenotypical method and further projected into molecular characterization by polymerase chain reaction. Aims and Objectives: The aims and objectives are to isolate the Gram-negative multidrug-resistant strains from clinically suspected bacterial infections in patients of neonatal, sick newborn, and pediatric ICU and to study antibiotic sensitivity pattern of isolated Gram-negative multidrug-resistant strains with special reference to molecular characterization. Materials and Methods: A total of 100 Gram-negative bacilli were isolated. Screening of ESBL positivity was done by double-disk synergy test (combined disc test method). Their antibiogram profile was interpreted. With the use of designed primers, 26 ESBL isolates each of E. coli and Klebsiella spp. were processed for molecular analysis of beta-lactamase family genes TEM and CTX-M. Results: Within the 100 samples, majority of the isolates (45%) were Klebsiella spp. and 40% was E. coli isolates. Highest ESBL-producing organisms were observed within E. coli (65%). Prevalence bla-TEM gene was highest followed by bla-CTX-M. These ESBL-producing organisms were found to be resistant to multiple classes of antibiotics. With extensive ESBL surveillance and proper usage of antibiotics, this threatening rise of antibiotic resistance can be mitigated. Conclusion: Gram-negative isolates showed high resistance to commonly used antibiotics. Significant proportions of them were MDR strains. Such high antibiotic resistance is associated with significant morbidity and mortality among pediatric population. MDR along with possession of ESBL associated resistance genes among Gram-negative bacilli pose a serious problem in therapeutic management of patients. Our study signifies that there is a high probability of Gram- negative bacilli to be multi-drug resistant and ESBL positive and earliest detection of such cases should be made

Measurement of Angular Coefficients of Bˉ→D∗ℓνˉℓ\bar{B} \to D^* \ell \bar{\nu}_\ell: Implications for ∣Vcb∣|V_{cb}| and Tests of Lepton Flavor Universality

We measure the complete set of angular coefficients $J_i$ for exclusive $\bar{B} \to D^* \ell \bar{\nu}_\ell$ decays ($\ell = e, \mu$). Our analysis uses the full $711\,\mathrm{fb}^{-1}$ Belle data set with hadronic tag-side reconstruction. The results allow us to extract the form factors describing the $B \to D^*$ transition and the Cabibbo-Kobayashi-Maskawa matrix element $|V_{\rm cb}|$. Using recent lattice QCD calculations for the hadronic form factors, we find $|V_{\rm cb}| = (41.0 \pm 0.7) \times 10^3$ using the BGL parameterization, compatible with determinations from inclusive semileptonic decays. We search for lepton flavor universality violation as a function of the hadronic recoil parameter $w$, and investigate the differences of the electron and muon angular distributions. We find no deviation from Standard Model expectations

Observation of charmed strange meson pair production in Υ(2S)\Upsilon(2S) decays and in e+e−e^{+}e^{-} annihilation at s=10.52 GeV\sqrt{s} = 10.52~ \rm{GeV}

We observe the process $\Upsilon(2S)\to D_s^{(*)+} D_{sJ}^{-}$ and continuum production $e^+e^- \to D_s^{(*)+} D_{sJ}^-$ at $\sqrt{s} = 10.52$ GeV (and their charge conjugates) using the data samples collected by the Belle detector at KEKB, where $D_{sJ}^-$ is $D_{s1}(2536)^-$ or $D^{*}_{s2}(2573)^-$. Both $D_{sJ}^-$ states are identified through their decay into $\bar{K}\bar{D}^{(*)}$. We measure the products of branching fractions ${\cal B}(\Upsilon(2S) \to D_{s}^{(*)+} D_{sJ}^-) {\cal B}(D_{sJ}^-\to \bar{K} \bar{D}^{(*)})$ and the Born cross sections $\sigma^{\rm Born}(e^+e^- \to D_{s}^{(*)+} D_{sJ}^-) {\cal B}(D_{sJ}^-\to \bar{K} \bar{D}^{(*)})$, and then compare the ratios $R_1 \equiv {\cal B}(\Upsilon(2S)\to D_{s}^{(*)+} D_{sJ}^-)/{\cal B}(\Upsilon(2S)\to\mu^{+}\mu^-)$ for $\Upsilon(2S)$ decays and $R_2 \equiv \sigma^{\rm Born}(e^+e^-\to D_{s}^{(*)+}D_{sJ}^-)/\sigma^{\rm Born}(e^+e^-\to \mu^{+}\mu^-)$ for continuum production. We obtain $R_1/R_2 = 9.7\pm 2.3 \pm 1.1$, $6.8 \pm 2.1 \pm 0.8$, $10.2 \pm 3.3 \pm 2.5$, and $3.4 \pm 2.1 \pm 0.5$ for the $D_s^+ D_{s1}(2536)^-$, $D_s^{*+} D_{s1}(2536)^-$, $D_s^+ D_{s2}^{*}(2573)^{-}$, and $D_s^{*+} D_{s2}^{*}(2573)^{-}$ final states in the $D_{sJ}^-\to K^{-} \bar{D}^{(*)0}$ modes, respectively. Therefore, the strong decay is expected to dominate in the $\Upsilon(2S)\to D_{s}^{(*)+}D_{sJ}^-$ processes. We also measure the ratios of branching fractions ${\cal B}(D_{s1}(2536)^-\to K_S^0 D^{*}(2010)^{-})/{\cal B}(D_{s1}(2536)^-\to K^{-} D^{*}(2007)^0) = 0.48 \pm 0.07 \pm 0.02$ and ${\cal B}(D_{s2}^{*}(2573)^- \to K_S^0 D^-)/{\cal B}(D_{s2}^{*}(2573)^- \to K^{-}D^0) = 0.49 \pm 0.10 \pm 0.02$, which are consistent with isospin symmetry. The second ratio is the first measurement of this quantity. Here, the first uncertainties are statistical and the second are systematic

Search for the lepton flavour violating decays B+→K+τ±ℓ∓B^{+} \to K^{+} \tau^\pm \ell^\mp (ℓ=e,μ\ell = e, \mu) at Belle

We present a search for the lepton-flavour-violating decays $B^+ \to K^+ \tau^\pm \ell^\mp$, with $\ell = (e, \mu)$, using the full data sample of $772 \times 10^6$ $B\overline{B}$ pairs recorded by the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We use events in which one $B$ meson is fully reconstructed in a hadronic decay mode. We find no evidence for $B^\pm \to K^\pm \tau \ell$ decays and set upper limits on their branching fractions at the 90% confidence level in the $(1$-$3) \times 10^{-5}$ range. The obtained limits are the world's best results.Comment: 14 pages, 6 figure

Search for charged-lepton flavor violation in Υ(2S)→ℓ∓τ±\Upsilon(2S) \to \ell^\mp\tau^\pm (ℓ=e,μ\ell=e,\mu) decays at Belle

We report a search for the charged-lepton flavor violation in $\Upsilon(2S) \to \ell^\mp\tau^\pm$ ($\ell=e,\mu$) decays using a $25~\mathrm{fb}^{-1}$ $\Upsilon(2S)$ sample collected by the Belle detector at the KEKB $e^{+}e^{-}$ asymmetric-energy collider. We find no evidence for a signal and set upper limits on the branching fractions ($\mathcal{B}$) at 90$\%$ confidence level. We obtain the most stringent upper limits: $\mathcal{B}(\Upsilon(2S) \to \mu^{\mp}\tau^{\pm}) < 0.26 \times 10^{-6}$ and $\mathcal{B}(\Upsilon(2S) \to e^{\mp}\tau^{\pm}) < 1.02 \times 10^{-6}$.Comment: 11 pages, 3 figures, Submitted to JHE

Search for lepton-flavor-violating τ\tau decays into a lepton and a vector meson using the full Belle data sample

Charged-lepton-flavor-violation is predicted in several new physics scenarios. We update the analysis of $\tau$ lepton decays into a light charged lepton ($\ell$ = $e^{\pm}$ or $\mu^{\pm}$) and a vector meson ($V^0$ = $\rho^0$, $\phi$, $\omega$, $K^{\ast0}$, or $\overline{K}{}^{\ast0}$) using 980 fb$^{-1}$ of data collected with the Belle detector at the KEKB collider. No significant excess of such signal events is observed, and thus 90% credibility level upper limits are set on the $\tau \rightarrow \ell V^0$ branching fractions in the range of (1.7--$4.3) \times 10^{-8}$. These limits are improved by 30% on average from the previous results.Comment: 19 pages, 5 figures; added one sentence in Acknowledgments; added a systematic uncertainty about the number of background estimation, and corrected some sentence