Hyderabad, Mar 17 (PTI) The Nuclear Fuel Complex (NFC) at Kushaiguda here today received an anonymous letter threatening presence of a bomb on its premises, prompting police to conduct a thorough check of the site where nothing suspicious was found.”The letter written in Telugu and dated March 11 was received by the NFC today. It threatened that a bomb has been placed in the Civil Engineering division,” Assistant Commissioner of Police (Alwal Division) Syed Rafeeq told PTI.”A team of Bomb Disposal Unit carried out a thorough security check on the NFC premises, but nothing suspicious was found,” the ACP said.A case has been registered in this connection and further investigation is on.NFC is a production unit of Department of Atomic Energy operative in round-the-clock basis and consists of scientific, technical, administrative and auxiliary employees. It caters to the fuel and Zirconium requirements of the Nuclear Power Program in India.Notably, members in Rajya Sabha earlier this month expressed concern over the lack of wherewithal to check cases of fake letters on bomb scare, with the Union Home Ministry saying it has issued an advisory to all states and UTs to get such cases professionally investigated and prosecuted.There is punishment up to three years under section 505 of IPC (public mischief) and two years under section 507 (criminal intimidation by an anonymous communication). PTI VVK NP KIS
Rohit Sharma led his side from the front with his fourth fifty this season as Mumbai Indians chased down Kolkata Knight Riders’ 174 for five with six wickets in hand and 12 balls to spare. However, it was Kieron Pollard’s innings that changed the complex of the game as he slammed a fiery 17-ball 51 not out to guide Mumbai to their fourth victory this season. (Match Report | Highlights | Points Table)Pollard joined Man of the Match Rohit Sharma (68*) after Mumbai were reduced to 106 for four in 13 overs. With Mumbai middle-order looking vulnerable and all hopes pinned on their skipper once again, Pollard wasted no time in easing the pressure off Rohit with some lusty blows. The West Indian peaked at the right moment timing everything that he hit with the bat to perfection and sending the Wankhede crowd into a frenzy with as many as six maximums in his blazing knock.”We batted brilliantly. Pollard’s form was crucial and he is peaking at the right time. This is going to be our last game here. The support has been superb here. I want to thank the crowd. Mumbai always enjoy perfect cricket. They have been wanting to see Pollard fire,” Rohit said at the post-match presentation ceremony.Wakhede or any other venue in Maharashtra will not host any IPL matches in May due to a severe drought situation in the state. Mumbai have picked Jaipur as the venue to host their remaining three home matches. A final call will be taken by the IPL governing council on Friday.advertisement”It was a good game and we wanted this win badly We stuck to our plans though we dropped a lot of catches. I don’t know what’s our home venue. We will have to understand the conditions and adapt as soon as possible,” he said.Mumbai deserved to winKKR captain Gautam Gambhir denied to give any excuses for their loss, but praised the Mumbai Indians unit.”We are not going to give excuses. We did bowl well. We are also 15 runs short. I thought we needed an innings like Pollard did. At one stage, I thought we would get 190. They deserved to win. I am not going to take about the dew. The dew, toss is not in my hand,” Gambhir said.
Shahjahan KhanA cabinet member on Saturday said ruling Awami League must wrest election victory from the BNP-Jamaat alliance next time.”We’ve to swear allegiance anew to snatch victory in the next elections, defeating the BNP-Jamaat alliance,” shipping minister Shahjahan Khan said at a programme in observance of Victory Day in his hometown of Madaripur.Shahjahan Khan, executive president of the Bangladesh Road Transport Workers Federation. said prime minister Sheikh Hasina-led government would return to power once again.”We’ve to be united and work towards that end. The Awami League will not lose to those who support war criminals and militancy,” he insisted.”Rather, the Awami League will break into gleeful celebration winning the next general elections.”The minister made the observations at the AL office in Madaripur after placing werath at the portrait of Bangabandhu Sheikh Mujibur Rahman.Member of parliament from Madaripur-3 AFM Bahauddin Nasim, district council chairman Miazuddin Khan, district AL president Shahabuddin Mollah and mayor of local pourasava Khalid Hossain were present.
People gather to attend a vigil outside Finsbury Park Mosque, close to the scene of a van attack in Finsbury Park, north London on June 19, 2017. Ten people were injured when a van drove into a crowd of Muslim worshippers near a mosque in London. Photo: AFPLondoners bearing flowers and messages of solidarity gathered Monday at the spot where a man ploughed a van into Muslims leaving prayers at a mosque, the fourth terror strike in Britain in four months.Eleven people were injured in the attack, which took place early Monday near Finsbury Park mosque, north London, raising fears of retaliation against Muslims after recent assaults by Islamic extremists.One elderly man, who had collapsed just before the incident, was pronounced dead at the scene, but it is not yet known whether his death was directly linked to the van assault.Among the roughly 100 people at the vigil, some carried signs reading “United Against All Terror”.“One of the things that all these terrorists share is a perverse ideology that wants to fuel division and divide our communities. We’re not going to let them,” said Mayor Sadiq Khan, speaking after prayers at the Muslim Welfare House on Monday evening.Flowers were left at the scene where hours earlier the 47-year-old van driver was pinned down by locals and shielded from violence by an imam, before being detained by police.The driver was later arrested on suspicion of “the commission, preparation or instigation of terrorism including murder and attempted murder”, the police said.The suspect was identified by British media as Darren Osborne, a father of four who lived in the Welsh capital Cardiff.As police searched a property, five residents speaking to journalists from the Press Association news agency identified images of the arrested man as their neighbour, Osborne.Security Minister Ben Wallace told BBC radio that the suspect was “not known to us”.Stepped-up police presenceLondon police chief Cressida Dick said the incident was “quite clearly an attack on Muslims” and promised a stepped-up police presence near mosques as the holy month of Ramadan draws to a close.Witness Abdiqadir Warra told AFP the van “drove at people” and that some of the victims were carried for several metres along the road.“He was shouting: ‘I want to kill all Muslims’,” another witness, Khalid Amin, told BBC television.The Finsbury Park Mosque said the van “deliberately mowed down Muslim men and women leaving late evening prayers” at the mosque and the nearby Muslim Welfare House shortly after midnight.Eleven people were hurt, all Muslims, with nine requiring hospital treatment. Two were in a very serious condition, police said.One Algerian man was among those injured, the north African country said.Locals pinned down the driver and the imam of the Muslim Welfare House stepped in to stop him receiving a mob beating.France and Germany quickly condemned the attack and Egypt’s Al-Azhar institution, the leading authority in Sunni Islam, condemned it as “sinful”.“Al-Azhar affirms its total rejection of this terrorist, racist, sinful act, calling on Western countries to take all precautionary measures to limit the phenomenon of Islamophobia,” it said in a statement.US President Donald Trump’s daughter Ivanka expressed solidarity with the worshippers in a tweet but her father has so far not commented.Community in shockPrime Minister Theresa May, who was heavily criticised for failing to meet survivors of a devastating fire in a London tower block last week, visited Finsbury Park Mosque where she met local faith leaders.May condemned the assault as “sickening”, saying Britain’s determination to fight “terrorism, extremism and hatred… must be the same, whoever is responsible”.The use of a vehicle to mow down pedestrians drew horrifying parallels with this month’s London Bridge attack.In that incident, three men slammed a van into pedestrians before embarking on a stabbing spree—an attack claimed by the Islamic State group.In March London was hit with another car and knife rampage, that one near parliament. It was also claimed by IS.This time the attacker deliberately targeted Muslims, according to the police.“Over the past weeks and months, Muslims have endured many incidents of Islamophobia and this is the most violent manifestation to date,” said Harun Khan, head of the Muslim Council of Britain, an umbrella body.After the London Bridge attack, the mayor’s office reported a 40-percent increase in racist incidents in the capital and a five-fold increase in anti-Muslim incidents.Mohammed Kozbar, chairman of the Finsbury Park Mosque, described the attack as “cowardly”.“Our community is in shock,” he said, urging people attending prayers to remain vigilant.‘Extraordinary city’It was the third major incident in the capital this month, after the London Bridge attack and last week’s devastating fire in the Grenfell Tower block, in which 79 people are thought to have died.“This is an extraordinary city of extraordinary people,” May said outside Downing Street after chairing an emergency government meeting.“Diverse, welcoming, vibrant, compassionate, confident and determined never to give in to hate.”Last month, a suicide bomber blew himself up outside a pop concert in Britain’s third city of Manchester, killing 22 people, many of them children.The Finsbury Park Mosque was once a notorious hub for radical Islamists but has changed markedly in recent years under new management.Its former imam, Abu Hamza, was jailed for life in New York on terrorism charges in 2015.Despite the change in leadership and the focus on bolstering inter-faith relations, the mosque reported it had received a string of threatening emails and letters in the wake of the Paris attacks.
Donald TrumpA US federal judge on Saturday lifted Trump administration restrictions that barred some refugees from the country, the latest in a series of immigration-related legal setbacks for the president.The United States said in October that it would resume accepting refugees after a 120-day ban ordered by President Donald Trump expired, but some-including those from 11 “high-risk” countries, most of which are Muslim majority-were still barred from entering.In his ruling on Saturday, Judge James Robart ordered American authorities to resume processing and admitting so-called “follow-to-join” refugees, which would once again allow the spouse and unmarried children of a refugee already in the country to be admitted.And he also ordered that “follow-to-join” refugees and “other refugees with a bona fide relationship to a person or entity within the United States” from the 11 “high-risk” countries be processed and admitted as well.The ruling is in response to motions for preliminary injunctions filed in two separate cases.“Plaintiffs in both cases are refugees, who find themselves in dire circumstances, their family members who yearn to be reunited with them, and humanitarian organizations whose fundamental mission is to help these vulnerable refugees resettle in the United States,” Robart wrote in his ruling.“Plaintiffs in both cases present compelling circumstances of irreparable harm inflicted by the federal agencies’ action at issue here.”Trump’s attempts at banning travelers from several mainly Muslim nations have been met with successive legal challenges this year.Critics say the president’s measures target Muslims, while the Trump administration has sought to cast the restrictions as being aimed at shoring up security.
Laura Isensee/Houston Public MediaParent and activist Travis McGee addressed a crowd of people at the HISD meeting while the board was in closed session and before a scuffle erupted with police officers.Months ago in May, Houston Mayor Sylvester Turner announced that he wanted the city to get directly involved in local schools.Now that desire has evolved into a new nonprofit, created by Turner’s education office.It’s the latest effort to address problems with Houston’s chronically under-performing schools and the threat of a state take-over, but already it’s drawing protests and push-back from parents and education advocates.“I recognize there needs to be a collaborative effort and shouldn’t be something I should do by myself, but collaboratively, there should be no low-performing schools in my city,” Turner said earlier this year.The city-related nonprofit is called the Coalition for Educational Excellence and Equity in Houston. News 88.7 obtained state records that show Turner’s education chief Juliet Stipeche and three civic leaders are heading up the coalition. Listen About half a dozen people protested the idea at City Hall. Bobbie Cohen called it an effort to privatize public education.“I don’t know why the city has decided to involve itself in a nonprofit coalition with three board members none of whom seem to have any real expertise in education, unless, of course, you count lobbying for ALEC which is an organization that has never met a government entity it did not want to privatize,” Cohen said. Still, Turner defended the effort: “It is an offer, it is up to HISD. No one here is trying to force HISD to do anything. No one.”HISD Board President Rhonda Skillern-Jones told News 88.7 that the board will vote on issuing an RFP (meaning a Request for Proposal) on Thursday. “After then we will know how to move forward,” said Skillern-Jones.Earlier this year, when the HISD board considered approving an outside partnership for struggling schools, the controversial measure sparked protests and arrests at the public meeting.EDITOR’S NOTE: This story has been updated to include the comment by HISD Board President Rhonda Skillern-Jones. Share X Under the state law known as SB 1882, the Houston Independent School District could give the nonprofit temporary control of some Houston schools. That in turn would give the district a two-year pause on steep sanctions, including a potential state takeover.The board has to decide by early February if it wants to pursue this effort or any other partnership for struggling schools. This week, the HISD board added a new agenda item for its meeting Thursday to decide if they want to request any outside partnerships.On Tuesday, Turner issued new details on the objectives of the coalition and defended it at City Hall.He outlined in a statement that the nonprofit aims to administer 15 HISD schools. They would include struggling schools that could trigger state sanctions and their related schools in their neighborhoods, or feeder patterns. Turner also said that he plans to appoint six more board members to the nonprofit. So far, three business executives are the only voting members: Corbin J. Robertson Jr.; Trinidad “Trini” Vasquez-Mendenhall; and Stephanie Nellons-Paige. X To embed this piece of audio in your site, please use this code: 00:00 /00:57 00:00 /00:54 Listen To embed this piece of audio in your site, please use this code:
The birefringent dielectric metasurfaces were designed using silicon nanofins on top of a glass substrate. To achieve the desired phase shifts, 2-D parameter optimization was conducted using a rigorous coupled wave analysis (RCWA) method. The RCWA semi-analytical method is typically applied in computational electromagnetics to solve scattering from periodic dielectric structures. The length L and width W of the nanofin were in the range of 80 to 280 nm, height at 600 nm and period size P at 400 nm. The values were carefully selected to ensure the phase of the output light eliminated any undesired orders of diffraction. For the simulation, the nanofin was placed on a glass substrate and subjected to a fixed wavelength of incident light at 800 nm. Simulation results indicated the amplitude of transmission for most nanofins with diverse cross-sections were beyond 90 percent efficiency. The scientists determined orientation angles of the nanofins using equations derived in the study to experimentally demonstrate multichannel polarization multiplexing. Holography is a powerful tool that can reconstruct wavefronts of light and combine the fundamental wave properties of amplitude, phase, polarization, wave vector and frequency. Smart multiplexing techniques (multiple signal integration) together with metasurface designs are currently in high demand to explore the capacity to engineer information storage systems and enhance optical encryption security using such metasurface holograms. The scientists first derived a multiplexing algorithm to support the dynamic vectorial holographic display and encryption process. By using the correct polarization keys, the receiver could obtain the exact information delivered. By increasing the complexity of such images, even higher flexibility was obtained alongside detailed analysis of the reconstructed vectorial image properties. Since the device containing metasurfaces is compact in size, in practice, it can be easily transported with encoded information. , Nature Communications To pattern the design of interest, Zhao et al. engineered several dielectric silicon metasurfaces on top of a glass substrate using plasma etching, followed by electron beam lithography. The metasurfaces were composed of 1000 x 1000 nanofins, i.e. nanostructures with the ability to augment heat transfer via surface area enhancement and liquid-solid-interactions. The researchers studied two schemes of multiple polarization channels; with or without rotation using the birefringent dielectric metasurfaces—to realize the holograms. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. a) Schematic illustration of an amorphous silicon nanofin positioned on a glass substrate. The metasurface will be composed of a periodic arrangement of such unit-cells. b–e) Simulation results for the amplitude and phase of the transmission coefficients txx and tyy shown for a 2D parameter optimization by using a rigorous coupled wave analysis method. The length and width of the nanofin are both swept in the range of 80–280 nm at an incident wavelength of 800 nm. Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. Experimental setup and scanning electron microscopy images of the fabricated metasurface samples. a) The experimental setup for the observation of the holographic images. The two linear polarizers (LP1, LP2) and two quarter-wave plates (QWP1, QWP2) are used to set the precise polarization combination for the incident/transmitted light. The lens images the back focal plane of the microscope objective lens (×40/0.6) to a CCD camera. b–e) Scanning electron microscopy images of two typical fabricated silicon metasurface samples shown with a top and side view. The metasurface holograms are composed of 1000 × 1000 nanofins with different cross-sections and orientation angles. Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. The two-channel polarization and angle-multiplexed hologram represents a cartoon tiger, cartoon snowman, teapot and teacup. Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. , Nature Nanotechnology Multichannel polarization-multiplexed holograms (“Dice”). Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. More information: Ruizhe Zhao et al. Multichannel vectorial holographic display and encryption, Light: Science & Applications (2018). DOI: 10.1038/s41377-018-0091-0 Guoxing Zheng et al. Metasurface holograms reaching 80% efficiency, Nature Nanotechnology (2015). DOI: 10.1038/nnano.2015.2 Lingling Huang et al. Three-dimensional optical holography using a plasmonic metasurface, Nature Communications (2013). DOI: 10.1038/ncomms3808 Journal information: Light: Science & Applications Holography based on metasurfaces is a promising candidate for applications in optical displays/storage with enormous information bearing capacity alongside a large field of view compared to traditional methods. To practically realize metasurface holograms, holographic profiles should be encoded on ultrathin nanostructures that possess strong light-matter interactions (plasmonic interactions) in an ultrashort distance. Metasurfaces can control light and acoustic waves in a manner not seen in nature to provide a flexible and compact platform and realize a variety of vectorial holograms, with high dimensional information that surpass the limits of liquid crystals or optical photoresists. Among the existing techniques employed to achieve highly desired optical properties, polarization multiplexing (multiple signal integration) is an attractive method. The strong cross-talk associated with such platforms can, however, be prevented with birefringent metasurfaces (two-dimensional surfaces with two different refractive indices) composed of a single meta-atom per unit-cell for optimized polarization multiplexing.Nevertheless, the full capacity of all polarization channels remains to be explored for improved information storage capacity within metasurface holograms and in holographic optical devices. In a recent study, Ruizhe Zhao and co-workers demonstrated a new method to realize multichannel vectorial holography for dynamic display and high-security applications. In the study, birefringent metasurfaces were explored to control polarization channels and process very different information through rotation. The reconstructed vectorial images could be switched from one form to another with negligible cross-talk by selecting a combination of input/output polarization states. The results are now published in Light: Science & Applications. The scientists were able to design and construct more complex multiplexing functionalities with 12 channels using the same principles of design thereafter. The vectorial images were viewed as holographic reconstructions with the input/output polarization combinations developed as proposed. The technique could also be used to encrypt different images at the same spatial location. In encryption, such superposition can convey a different meaning on reconstruction. As an example, the scientists chose the image of a die with six representative surfaces, and by using different combinations of input/output polarization states, encoded up to six images for viewing.The multiplexing algorithm derived in the study aided the dynamic vectorial holographic display and the encryption of images encoded on birefringent dielectric metasurfaces. By using the correct polarization keys, a receiver could obtain the exact information delivered. Higher flexibility could be obtained by increasing the complexity of the image and changing the medium of encryption to titanium dioxide (TiO2) or silicon nitride (SiN). The correct polarization combination secured the information for enhanced complexity during decryption.The multichannel hologram maintained a relatively large working bandwidth since the reconstructed images could be observed away from the designed wavelength of 800 nm. The study established a design and engineering technique that combined birefringent properties of simple nanofins used as the building blocks, with extra-design freedom of rotation matrix and smart multiplexing algorithms. The results enabled high-dimensional multichannel polarization multiplexed holograms, with up to 12 polarization channels. In this way, efficient light-based encryption and integrated multichannel holographic display techniques can pave the way for advanced communication in high security applications. Principle of the metasurface holography design and statistical results of the number of each nanofin (different cross-sections and orientation angles) contained in the designed metasurface holograms. Schematic illustrations of polarization multiplexed holograms based on dielectric metasurfaces. The red and blue arrows indicate the polarization of the incident light and the transmission axis of the polarizer placed behind the metasurface sample. The red, blue, and green color of the reconstructed images (the words “holography”, “meta”, and “surface”) represent components of the output light, respectively. a) Two channel polarization and an angle multiplexed hologram based on metasurfaces composed of nanofins with different cross-sections but fixed orientation angles, which can be used to reconstruct two sets of off-axis images. b) Multichannel polarization multiplexed hologram based on metasurfaces composed of nanofins with different cross-sections and orientation angles, which can be used to reconstruct three independent images and all combinations of these images (12 channels in total). c) Two-channel polarization- and angle-multiplexed hologram (enables appearance of “cartoon tiger”, “cartoon snowman”, “teapot”, “cup”), b) Multichannel polarization-multiplexed hologram (appearance of the word “holography”, “meta”, “surface”) c) Multichannel polarization-multiplexed hologram (appearance of “dice”) d Multichannel polarization-multiplexed hologram (appearance of a “cartoon person”). Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. © 2018 Science X Network For optical characterization of the metasurface holograms, Zhao et al. used an experimental setup. The magnifying ratio and numerical aperture of the objective lens were carefully chosen to collect all the diffraction light from the sample and reconstruct holographic images in the Fourier plane. The scientists used a second objective/lens to capture the Fourier plane on a CCD camera. They also separately observed two scanning electron microscopy images of the samples with or without rotation to characterize the engineered surface.As a proof-of-principle, using the metasurfaces, Zhao et al. constructed holographic images of a cartoon tiger and a snowman that appeared with high fidelity and high resolution when illuminated by x-polarized light. When the incident light was switched to y-polarization, the reconstructed images changed to a teapot and a teacup. In this experiment, only two polarization channels were available in the setup, with both pairs of the holographic images reconstructed and made to disappear simultaneously by rotating the polarizer behind the sample. The experimental results were in agreement with the simulation to confirm the study’s fundamental design principle. The net diffraction efficiency of the hologram was defined as the ratio of intensity of the single reconstructed image to the power of incident light. Explore further Citation: Multichannel vectorial holographic display and encryption (2018, December 7) retrieved 18 August 2019 from https://phys.org/news/2018-12-multichannel-vectorial-holographic-encryption.html Technique makes more efficient, independent holograms