Droplet Morphology-Based Wettability Tuning and Design of Fog Harvesting Mesh to Minimize Mesh-Clogging.

Fog harvesting relies on intercepting atmospheric or industrial fog by placing a porous obstacle, for example, a mesh and collecting the deposited water. In the face of global water scarcity, such fog harvesting has emerged as a viable alternative source of potable water. Typical fog harvesting meshes suffer from poor collection efficiency due to aerodynamic bypassing of the oncoming fog stream and poor collection of the deposited water from the mesh. One pestering challenge in this context is the frequent clogging up of mesh pores by the deposited fog water, which not only yields low drainage efficiency but also generates high aerodynamic resistance to the oncoming fog stream, thereby negatively impacting the fog collection efficiency. Minimizing the clogging is possible by rendering the mesh fibers superhydrophobic, but that entails other detrimental effects like premature dripping and flow-induced re-entrainment of water droplets into the fog stream from the mesh fiber. Herein, we improvise on traditional interweaved metal mesh designs by defining critical parameters, viz., mesh pitch, shade coefficient, and fiber wettability, and deducing their optimal values from numerically and experimentally observed morphology of collected fog water droplets under various operating scenarios. We extend our investigations over a varying range of mesh-wettability, including superhydrophilic and hydrophobic fibers, and go on to find optimal shade coefficients which would theoretically render clog-proof fog harvesting meshes. The aerodynamic, deposition, and overall collection efficiencies are characterized. Hydrophobic meshes with square pores, having fiber diameters smaller than the capillary length scale of water, and an optimal shade coefficient are found to be the most effective design of such clog-proof meshes.

Hashimoto's encephalopathy.

Hashimoto's encephalopathy (HE) is a completely treatable but relapsing neuroendocrine disorder associated with Hashimoto's thyroiditis (HT). Though numerous neurological manifestations are often associated with thyroid disorder, this entity is less documented. We are reporting a case of HE in a 65 year old female presenting with sudden onset deep coma following an attack of mild fever and vomiting for two days. Patient was a known diabetic. Hypoglycemic coma, diabetic ketacidosis and hyperosmolar coma were excluded by laboratory investigations. High blood sugar was corrected with insulin. She had hyponatremia and hypokalemia which were corrected with electrolyte replacement. Liver function tests were normal, but serum ammonia was mildly raised. CSF study was normal. Despite correction of her metabolic derangements patient failed to regain her consciousness. CT scan of brain was normal. MRI of brain revealed diffuse brain atrophy. Patient's thyroid function tests were normal but anti-thyroid peroxidase (anti-TPO) antibody was highly raised. EEG showed diffuse slow wave pattern. Intravenous dexamethasone (24 mg/d) was started. Patient regained consciousness slowly over a period of one month. To reduce the toxicity of steroid, oral azathiprine 50 mg/day was added later with tapering of steroid dose. HE must be kept in mind in comatose patients when other metabolic, infective and structural neurological causes have been excluded. Proper and timely treatment can salvage the patient.