Development of high slip-resistant footwear outsole using rubber surface filled with activated carbon/sodium chloride

High slip-resistant footwear outsoles can reduce the risk of slip and fall on wet and icy surfaces. Falls on wet and icy surfaces can cause serious life-threatening injuries, especially for older adults. Here we show that footwear outsoles using the rubbers filled with activated carbon or sodium chloride produce higher friction force and reduce the slip rate in walking. We have identified that small depressions were formed on outsole materials filled with activated carbon or sodium chloride during friction between the rubber and surface leading to some air ingress into the interface. While there are air bubbles between the rubber and surface, real contacts are surrounded by water with negative pressure (Laplace pressure). It is considered that the negative pressure promotes real contact formation, which causes high friction. We consider that the outsole materials filled with activated carbon or sodium chloride can reduce the risk of slip-and-fall accidents.

Mixing Process of Two Component Gases by Natural Convection and Molecular Diffusion

A depressurization accident involving the rupture of the primary cooling pipe of the Gas Turbine High Temperature Reactor 300 cogeneration (GTHTR300C), which is a very-high-temperature reactor, is a design-based accident. When the primary pipe connected horizontally to the side of the reactor pressure vessel of GTHTR300C ruptures, molecular diffusion and local natural convection facilitate gas mixing, in addition to air ingress by counter flow. Furthermore, it is expected that a natural circulation flow around the furnace will suddenly occur. To improve the safety of GTHTR300C, an experiment was conducted using an experimental apparatus simulating the flow path configuration of GTHTR300C to investigate the mixing process of a two-component gas of helium and air. The experimental apparatus consisted of a coaxial double cylinder and a coaxial horizontal double pipe. Ball valves were connected to a horizontal inner pipe and outer pipe, and the valves were opened to simulate damage to the main pipe. As a result, it was confirmed that a stable air and helium density stratification formed in the experimental apparatus, and then a natural circulation flow was generated around the inside of the reactor.

Fatal Acute Pneumocephalus after Bilateral Drainage for Chronic Subdural Hematomas: Case Report

Background Pneumocephalus is a well-known complication in the surgical treatment of chronic subdural hematomas; however, its influence remains controversial. The amount of subdural air may vary, and it may cause worsening of symptoms, increase reoccurrence rates, and worsen the outcomes. Lethal outcome following acute onset of massive pneumocephalus was not previously reported. Case Report An 81-year-old man with bilateral hematomas underwent surgery under local anesthesia. Both hematomas were approached in the same surgery, and the drains were placed subdurally. After initial improvement, severe hypertension developed, followed by vital function and neurologic deterioration. Massive pneumocephalus with subarachnoid and contralateral intracerebral hemorrhage was revealed, causing a severe midsagittal shift. Emergency irrigation to evacuate subdural air was performed. However, there was no improvement. Further computed tomography confirmed subdural air collection, but it also revealed hemorrhage progression and intraventricular propagation. No further surgery was indicated. Conclusion Pneumocephalus is an underestimated but potentially devastating complication. Both intraoperative avoidance and postoperative prevention should be utilized to avoid subdural air ingress, and thus evade potentially fatal complications.

Penyerapan Karbondioksida Oleh Kolom Molecular Sieve Pada Sistem Pemurnian Helium Dalam Peluit

PENYERAPAN KARBONDIOKSIDA OLEH KOLOM MOLECULAR SIEVE PADA SISTEM PEMURNIAN HELIUM DALAM PELUIT. Peluit adalah desain konseptual reaktor daya yang dirancang berdasar teknologi High Temperature Gas-cooled Reactor (HTGR), dengan siklus konversi daya tidak langsung. Pendingin primer Peluit adalah gas helium dan harus dijaga kemurniannya dari pengotor CO2 dibawah 0,6 parts per million by volume (ppmv) berdasarkan persyaratannya. CO2 terbentuk karena reaksi oksigen atau air dengan karbon di teras pada saat kejadian water/air ingress. Dampak CO2 terhadap sistem, struktur dan komponen (SSK) adalah terjadinya reaksi dekarburisasi pada tabung steam generator. Dalam sistem pemurnian helium Peluit, komponen penyerap CO2 adalah kolom molecular sieve jenis 5A. Penelitian ini bertujuan mendemonstrasikan simulasi proses penyerapan pengotor CO2 pada kolom molecular sieve sepanjang ketinggian kolom yang dirancang sehingga hasil penyerapan menghasilkan konsentrasi batas maksimal pada pendingin primer tidak terlampaui. Metodologi yang digunakan adalah pemodelan perhitungan dengan software Matlab dengan metode penyerapan adalah metode Henry. Tinggi kolom diasumsikan 200 cm, diameter kolom 50 cm, laju aliran gas helium adalah 5% dari aliran utama pendingin primer setara dengan 3,0 kg/s, dan konsentrasi pengotor CO2 adalah 40 ppmv. Berdasarkan simulasi diketahui bahwa setelah 5 detik, gas helium bersih sudah keluar dari ujung kolom dengan konsentrasi pengotor CO2 tersisa 4×10-5 ppmv. Dengan hasil ini menunjukkan bahwa kolom molecular sieve mampu membersihkan pengotor CO2 dengan efisiensi 99,99% dan dapat disimpulkan bahwa molecular sieve tipe 5A cocok digunakan pada sistem pemurnian helium Peluit.

Applications and Perspectives of Ultrasonic Multi-Gas Analysis with Simultaneous Flowmetry

We have developed ultrasonic instrumentation for simultaneous flow and composition measurement in a variety of gas mixtures. Flow and composition are respectively derived from measurements of the difference and average of sound transit times in opposite directions in a flowing process gas. We have developed a sound velocity-based algorithm to compensate for the effects of additional gases, allowing the concentrations of a pair of gases of primary interest to be acoustically measured on top of a varying baseline from ‘third party’ gases whose concentrations in the multi-gas mixture are measured by other means. Several instruments are used in the CERN ATLAS experiment. Three monitor C3F8, (R218), and CO2 coolant leaks into N2-purged environmental envelopes. Precision in molar concentration of better than 2 × 10−5 is routinely seen in mixtures of C3F8 in N2 in the presence of varying known concentrations of CO2. Further instruments monitor air ingress and C3F8 vapor flow (at high mass flows around 1.1 kg s−1) in the 60 kW thermosiphon C3F8 evaporative cooling recirculator. This instrumentation and analysis technique, targeting binary pairs of gases of interest in multi-gas mixtures, is promising for mixtures of anesthetic gases, particularly in the developing area of xenon anesthesia.

Numerical Study of the Air Ingress Accident of the HTR-PM and Possible Mitigation Measures

The double-ended guillotine break (DEGB) of the horizontal coaxial gas duct of a high-temperature gas-cooled reactor is an extremely hypothetical accident, which could cause the air to enter into the primary circuit and react with graphite in the reactor core. The performance of the HTR-PM plant under this extremely hypothetical accident has been studied by the system code TINTE in this work. The results show that the maximum fuel temperature will not reach the temperature design limitation, and the graphite oxidation will not cause unacceptable consequences even under some conservative assumptions. Moreover, nitrogen and helium injected from the fuel charging tube were studied as the possible mitigation measures to further alleviate the consequences of this air ingress accident. The preliminary results show that only the flow rate of nitrogen injected reaches a certain value, which can effectively alleviate the consequences, while for helium injection, both high and small flow rate can prevent or cut off the natural circulation and alleviate the consequences. The reason is that helium is much lighter than nitrogen, and the density difference between the coolant channel and the reactor core is small when helium is injected. Considering the injection velocity, the total usage amount, and the start time of gas injection, helium injected with a small flow rate is suggested.