Traumatic carotid-cavernous sinus fistula (TCCF) is a rare but significant vascular abnormality in the skull base found after craniomaxillofacial trauma. Although the direct type is usually caused by trauma, the onset of symptoms in TCCF may present several weeks after injury. We present the case of a patient who sustained a blunt head injury from falling down and was hospitalized with skull base fracture associated with zygomatic complex fractures on the right side. After surgery, the recovery was uneventful and the patient was discharged without any problems. On the eighth week postoperatively, the patient returned to hospital presenting tinnitus, bruit on the right orbital area, diplopia, eye pain, and headache. The patient also had severe limitation of ocular movement on lateral gaze. After having brain angio-CT, which showed a dilated superior ophthalmic vein, the diagnosis of CCF with cranial nerve VI was confirmed. The fistula was occluded successfully by using coils. After the procedure, tinnitus, bruit, and headache were reduced immediately. On following up 4 months after coiling, cranial nerve VI palsy and related symptoms-diplopia and limit of ocular movement-were improved significantly. Although TCCFs usually manifest symptoms early after trauma, in this case, the patient presented clinical signs 8 weeks post-injury, while the longest time that was acknowledged in another previously released article was 6 weeks. According to this case, we recommend a careful follow-up until 2 months for patients with skull base fracture in order to rule out the risk of CCF.
A thermoelectric generator (TEG) is a clean electricity generator from a heat source, usually waste heat. However, it is not as widely utilized as other electricity generators due to low conversion efficiency from heat to electricity. One approach is a system-level net power optimization for a TEG system composed of TEGs, heat sink, and fans. In this paper, we propose airflow reuse after cooling preceding TEGs to maximize system net power. For the accurate system net power, we model the TEG system, air, and heat source with proper dimension and material characteristics, and simulate with a computational fluid dynamics program. Next, the TEG power generation and the fan power consumption are calculated in consideration of the Seebeck coefficient and internal electrical resistance varying with hot and cold side temperatures. Finally, we find the optimal number of TEGs and fan speed generating the most efficient system net power in various TEG systems. The results show that the system with a side fan with a specific number of TEGs provides a system net power up to 58.6% higher than when with a top fan. The most efficient system net power with the side fan increases up to four TEGs generating 1.907 W at 13,000 RPM.
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