Design and data analysis for a belt-for-blind for visual impaired people

This research designs a new walking support system for the blind people in order to navigate without any assistance from others or using any guide cane. With the help of this device, a user can move independently and able to walk freely almost like a normal person. In this research, a belt for blind wearable around the waist is equipped with four ultrasonic sensors and one sharp infrared sensor. A mathematical model has been developed based on the specifications of the ultrasonic sensors to identify optimum orientation of the sensors for detecting stairs and holes. These sensors are connected to a microcontroller along with a laptop so that we can get sufficient data for analysing terrain on the walkway of the blind. Based on the analyses of the acquired data, we have developed an algorithm capable of classifying various types of obstacles. The developed belt for blind device is superior in terms of less weight less, able to detect stair and hole, low cost, less power consumption, adjustable, less training and availability of actuation systems. It was tested and implemented successfully to address all those issues

State of the art review on walking support system for visually impaired people

The technology for terrain detection and walking support system for blind people has rapidly been improved the last couple of decades but to assist visually impaired people may have started long ago. Currently, a variety of portable or wearable navigation system is available in the market to help the blind for navigating their way in his local or remote area. The focused category in this work can be subgroups as electronic travel aids (ETAs), electronic orientation aids (EOAs) and position locator devices (PLDs). However, we will focus mainly on electronic travel aids (ETAs). This paper presents a comparative survey among the various portable or wearable walking support systems as well as informative description (a subcategory of ETAs or early stages of ETAs) with its working principal advantages and disadvantages so that the researchers can easily get the current stage of assisting blind technology along with the requirement for optimising the design of walking support system for its users

Colloidal synthesis of laterally confined blue-emitting 3.5 monolayer CdSe nanoplatelets

The typical synthesis protocol for blue-emitting CdSe nanoplatelets (NPLs) yields particles with extended lateral dimensions and large surface areas, resulting in NPLs with poor photoluminescence quantum efficiency. We have developed a synthesis protocol that achieves an improved control over the lateral size, by exploiting a series of long-chained carboxylate precursors that vary from cadmium octanoate (C-8) to cadmium stearate (C-18). The length of this metallic precursor is key to tune the width and aspect ratio of the final NPLs, and for the shorter chain lengths, the synthesis yield is improved. NPLs prepared with our procedure possess significantly enhanced photoluminescence quantum efficiencies, up to 30%. This is likely due to their reduced lateral dimensions, which also grant them good colloidal stability. As the NPL width can be tuned below the bulk exciton Bohr radius, the band edge blue-shifts, and we constructed a sizing curve relating the NPL absorption position and width. Further adjusting the synthesis protocol, we were able to obtain even thinner NPLs, emitting in the near-UV region, with a band-edge quantum efficiency of up to 11%. Results pave the way to stable and efficient light sources for applications such as blue and UV light-emitting devices and lasers

Thoracoscopic Drainage of Para-Vertebral Abscess - Report of Two Cases

Tuberculosis of the spine is common in tropical countries like Bangladesh and it is the most common site of skeletaltuberculosis as a whole. In addition to the anti-tubercular chemotherapy, paravertebral abscess often require surgicaldecompression. Surgical intervention for the thoracic region needs formal thoracotomy which involves a very longincision over the chest. In this regards, thoracoscopic drainage would have been a good option. Two patients (one 53years old female and other 20 years old male) with para- vertebral abscess with compression and collapse of vertebralbodies resulting cord compression presented with neurological symptoms underwent video assisted thoracoscopicdrainage with biopsy from the abscess wall using a standard laparoscope (as thoracoscope) at the BangabandhuSheikh Mujib Medical University (BSMMU), and a private hospital in Dhaka. The patients were fed on 1st post operativeday and antituberculer chemotheraphy was continued. Post-operative period was uneventful and the patients weredischarged on 8th post operative day with antituberculer chemotheraphy. There was a gradual improvement of neurologicalsymptoms of lower limbs. Till date the 1st and 2nd patient were followed-up for a period of 18 and 12 months respectively.The condition of both patients improved gradually with no neurological deficit. To the best of our knowledge, there wasno previous report of thoracoscopic drainage of para-vertebral abscess from Bangladesh. So this is the 1st report in ourcountry. Thoracoscopic drainage of para-vertebral abscess appears to be a technically feasible, patient friendly modalityof treatment for the spinal tuberculosis in experienced hand with excellent cosmetic out come.Key words: Thoracoscopic drainage; paravertebral abscessDOI: 10.3329/bsmmuj.v3i1.5513BSMMU J 2010; 3(1): 35-3

Objective-free excitation of quantum emitters with a laser-written micro parabolic mirror

The efficient excitation of quantum sources such as quantum dots or single molecules requires high NA optics which is often a challenge in cryogenics, or in ultrafast optics. Here we propose a 3.2 um wide parabolic mirror, with a 0.8 um focal length, fabricated by direct laser writing on CdSe/CdS colloidal quantum dots, capable of focusing the excitation light to a sub-wavelength spot and to extract the generated emission by collimating it into a narrow beam. This mirror is fabricated via in-situ volumetric optical lithography, which can be aligned to individual emitters, and it can be easily adapted to other geometries beyond the paraboloid. This compact solid-state transducer from far-field to the emitter has important applications in objective-free quantum technologies

Nitrogen-enriched activated carbon derived from plant biomasses: a review on reaction mechanism and applications in wastewater treatment

As a key kind of evolving carbonaceous adsorbent, nitrogen-enriched activated carbon has drawn a lot of focus due to its better physiochemical ability to eliminate an extensive range of wastewaters contaminants under severe conditions. Its environment-friendly character is one more reason behind this focus. Nitrogen also has immense effect on activated carbon structures’ pollutants adsorption capability; therefore, it is an area of interest. Reports concerning the reaction pathway of C-N (carbon-nitrogen) bond creation on AC surface are limited. Determining such mechanisms is challenging but critical to understand bond characteristics after carbonization. Moreover, it is vital to ascertain real-time kinetics concerning adsorption phenomena in liquid phase. Such a latest trend indicates that regulated nitrogen uses for carbonaceous substances having a biomass-based origin can provide the desired morphological characteristics produced through interconnections, production of enclosed holes, enhanced surface area, better adsorption ability, and many other benefits in contrast to conventional carbon-based substances. This review points out the developments in the main processes to introduce nitrogen atoms into the carbon matrix by utilizing different N-comprising chemical compounds. The nitrogen enrichment processes, reaction mechanisms and effects of nitrogen incorporation on the plant biomass-derived activated carbons (NEACs) are presented in brief. On the basis of their established physicochemical attributes, the adsorption performances of different biomass-derived NEACs have also been dealt with. More significantly, the review covers the technical issues in the present phase, topical trends, research gaps, economic viability along with a technical alignment recommendation to address the prevailing disadvantages

Introduction of emergency contraceptive pills in the public health system of Pakistan: A south-to-south collaboration

This report describes a south-to-south collaboration to assist the Ministry of Health of Pakistan to introduce emergency contraception (EC) into its family planning program, supported by the Population Council’s USAID-funded Frontiers in Reproductive Health (FRONTIERS) program. The collaboration consisted of a three-day visit by senior managers from the Pakistani health authorities to Bangladesh to familiarize them with the EC program in that country, followed by a two-day consultative meeting in Islamabad to draw up concrete plans for introduction of the method into the Pakistan system. Participants at the consultation developed plans to introduce EC into both community-based distribution and clinical programs. The plans included staff training; commodity logistics; and development of information, education, and communication materials, many of which will be adapted from materials used in other EC projects in the region supported by FRONTIERS. The activity successfully met its goals. Providing south-to-south technical assistance was demonstrated to be an effective strategy for introducing sensitive services and is recommended for other regions and similar services

shape control of zincblende cdse nanoplatelets

Water matters: the aspect ratio of CdSe nanoplatelets can be precisely tuned by adjusting the fraction of hydrated cadmium acetate in the synthesis