Disperse-and-Mix: Oil as an ‘Entrance Door’ of Carbon-Based Fillers to Rubber Composites

Oil was employed as an ‘entrance door’ for loading rubber with carbon-based fillers of different size and dimensionalities: 1D carbon nanotubes (CNTs), 2D graphene nanoplatelets (GNPs), and 3D graphite. This approach was explored, as a proof of concept, in the preparation of tire tread, where oil is commonly used to reduce the viscosity of the composite mixture. Rubber was loaded with carbon black (CB, always used) and one or more of the above fillers to enhance the thermal and mechanical properties of the composite. The CNT-loaded system showed the best enhancement in mechanical properties, followed by the CNT-GNP one. Rubber loaded with both graphite and GNP showed the best enhancement in thermal conductivity (58%). The overall enhancements in both mechanical and thermal properties of the various systems were analyzed through an overall relative efficiency index in which the total filler concentration in the system is also included. According to this index, the CNT-loaded system is the most efficient one. The oil as an ‘entrance door’ is an easy and effective novel approach for loading fillers that are in the nanoscale and provide high enhancement of properties at low filler concentrations.

Numerical Study of the Transmission of Exhaled Droplets between the Instructor and Students in a Typical Classroom

Conducting physical attendance exams during pandemics is a challenge facing many educational institutes and universities. Our study’s main objective is to numerically simulate the expected transmission of the harmful exhaled droplets of aerosols from an infected instructor to students in an exam room ventilated by a number of spiral diffusers. Several critical parameters, including the droplet size, the ventilation rate, and status of the entrance door were considered in the analysis. Two dimensionless indices, i.e., the specific normalized average concentration (SNAC) and the exceedance in exposure ratio (EER), were introduced to examine the effect of the said parameters on student exposure to the harmful droplets. The study revealed that the 5 mm droplets were less hazardous as they resulted in an 87% reduction in exposure when compared with the small 1 mm size droplets. We also found that when the ventilation rate ratio (VRR) increased above unity, an upward entrainment process, due to the swirl diffuser, of the aerosol droplets took place, and consequently the risk of student exposure was reduced. The results also demonstrated that increasing VRR from zero to 1 and then to 2 decreased the exceedance in the student exposure from 3.5 to 2.15 and then to less than zero, respectively. The study also showed that keeping the lecture room’s main door open is recommended as this reduced the risk of exposure by 26% in the case of a VRR equal to 2.

Cloud Based Face Recognition using Machine Learning

The main motive of this paper is to implement a system where the employees and the visitors are granted access to enter the office by recognizing their face images. And henceforth, the access is granted only when the employee or the visitor enters the correct pin into the keypad which is concerned for authentication purpose.Without any usage of the tag keys or identity card an employee can easily unlock the entrance door once his face is recognized. A Raspberry pi, a camera, a memory card and a keypad is the hardware components that is required in this system. The face recognition and the authentication carried out by the keypad is controlled by the cloud based platforms and the local based Web Services. The authentication mechanism and the face recognition provides a safe and and increased level of security which gives a protection against spoofing attacks where there is no need of carrying any tag keys or access cards.

Numerical Analysis of Smoke Spreading in a Medium-High Building under Different Ventilation Conditions

Smoke from fires in residential buildings represents the greatest threat to the life and health of inhabitants and firefighters at the scene of an accident. Therefore, the aim of this study was to reconstruct a numerical model for the estimation of smoke spread in a medium-high building under different ventilation conditions. Here, the three-dimensional geometry of a designated medium-high building was reconstructed and an exit door in the basement was specified as a smoke inlet; a window in the upper part was marked as outlet; and an entrance door, which allowed the outside air to enter the building after opening, was designated as an inlet door. The initial simulation, in which no air could enter the building, predicted the time taken for the staircase to become filled with smoke. In a second simulation, the entrance door was a fresh air inlet. The results showed that, for the analyzed building, rapid use of the mechanical ventilation can shorten the time of operations and improve their safety.

Efficacy of Intelligent Mosquito System (I.M.O.S) with Xmos Mini Aerosol Against Aedes in 17th College, Universiti Putra Malaysia

This study reports the efficacy of I.M.O.S (Intelligent Mosquito System) by using Xmos mini aerosol in reducing Aedes mosquito population in 17th College, Universiti Putra Malaysia (UPM). Prior to the experiment, the Aedes mosquito population was determined in all blocks of the 17th College, UPM. The I.M.O.S. was installed above the entrance door of the hall and two rooms and was set to automatically spray at 6.30 am and 4.00 pm every day. No intervention was used in the control house. Adult efficacy study was conducted by placing 20 Aedes mosquitoes in each cage and was hung at a distance of 10 feet from the I.M.O.S. The mortality caused by I.M.O.S throughout the exposed two hours and after 24 hours of exposure was recorded. The number mosquito eggs population were calculated throughout the installation of I.M.O.S. Data were analysed using two-way ANOVA and paired T-test, respectively. The mean number of Aedes mosquito eggs and ovitraps index showed no significant difference (p>0.05) between control and treatment blocks. There were significant differences (p<0.05) in the percentage of knockdown of adult Aedes mosquitoes (10, 20, 30, 60 and 120 minutes after exposure) and the mortality of adult Aedes mosquitoes after 24 hours exposure. Nano and slow-release technology of the I.M.O.S with Xmos mini aerosol proved that this type of intervention can kill adult Aedes mosquitoes. Thus, it is a potential intervention for vector control and management.

Brain Abscess of Otorhinolaryngologic Origin: Study of 80 Cases in the Neurosurgery Department of Conakry University Hospital Center

Introduction: Brain abscesses are serious conditions that can be life-threatening if left untreated. The objective of our study was to determine the epidemiological, clinical, paraclinical, therapeutic and evolutionary characteristics of cerebral abscesses of otorhinolaryngological origin in our department. Methods and Materials: This was a retrospective study of 80 cerebral abscess files of otorhinolaryngological origin collected over a period of 5 years (January 2014-December 2018) at the neurosurgery department of Conakry University Hospital Center. Results: Abscesses of otorhinolaryngological origin represented 72% of all abscesses. The mean age was 14.7 years with a sex ratio of 4. The clinical picture was dominated by fever (92%), focal signs (55%) and intracranial hypertension (46%). The entrance door was 84% sinus. The frontal site was predominant, 44 cases. Eighty-two percent of patients underwent surgery and 18% were treated with antibiotic therapy alone. The evolution was favorable in 75% of the cases with a mortality rate of 15%. Conclusion: Brain abscesses are a medical-surgical emergency. The forms of otorhinolaryngologic origin are dominated by sinusitis. Despite the therapeutic difficulties, the prognosis remains acceptable in our study, 15% of deaths.

Proposal of Air Supply Smoke Control System about Stair-case Considering Stack Effect & Opening of the Outside Door

Most of the special escape staircase smoke control systems for high-rise buildings in accordance with the national fire safety code NFSC 501A are constructed with smoke control only vestibule, making it difficult to expect a proper role in an emergency. This standard, which was created by introducing the concept of air supply pressurized smoke control 25 years ago, created Korea´s smoke control only vestibule, which was not found in developed countries, and has been mainly applied to it to fit into the poor architectural environment of the time. However, there is a fundamental flaw there, so the performance test for completion without occupants is passed, but in the presence of occupants, the performance does not come out properly and it is being blamed for being useless. In this regard, the author proposes a method of air supply pressurized smoke control for stair-case that avoid the smoke control method only vestibule, reduces the stack effect with good cost-effectiveness, and considers opening the outside entrance door of the stair-case.