Impacts of Groundwater Pumping for Hydraulic Fracturing on Aquifers Overlying the Eagle Ford Shale.

Hydraulic fracturing (HF) events consume high volumes of water over a short time. When groundwater is the source, the additional pumping by rig/frack supply wells (RFSWs) may impose costs on owners of other sector wells (OSWs) by lowering the hydraulic head. The Carrizo-Wilcox aquifer in south Texas is the main source of water for HF of the Eagle Ford Shale (EFS) Play. The objectives are to assess the impacts of groundwater pumping for HF supply on: (1) hydraulic heads in OSWs located nearby an RFSW and (2) volumetric fluxes between layers of the regional aquifer system compared to a baseline model without the effect of RFSW pumping. The study area spans the footprint of the EFS Play in Texas and extends from 2011 to 2020. The pumping schedules of 2500 RFSWs were estimated from reported pumped water volumes to supply 22,500 HF events. Median annual drawdowns in OSWs ranged from 0.2 to 6.6 m, whereas 95th percentile annual drawdowns exceeded 20 m. The magnitudes of drawdown increased from 2011 to 2020. Of the four layers that comprise the Carrizo-Wilcox aquifer, the upper Wilcox was the most intensively pumped for HF supply. During the peak HF year of 2014, the net flux to the upper Wilcox was 292 Mm3 compared to the baseline net flux for the same year of 278 Mm3 -a relative gain of 14 Mm3 . Pumping for HF supply has the potential to negatively impact nearby OSWs by capturing water from adjacent aquifer layers.

Tunnel-Structured ζ-V2O5 as a Redox-Active Insertion Host for Hybrid Capacitive Deionization.

Much of the earth's water has a salt content that is too high for human consumption or agricultural use. Enhanced oil recovery operations generate massive volumes of produced water waste with a high mineral content that can substantially exacerbate water distress. Current deionization techniques such as reverse osmosis function by removing the water (majority phase) from the salt (minority phase) and are thus exceedingly energy-intensive. Furthermore, these methods are limited in their ability to selectively extract high-value ions from produced water waste and brine streams. Hybrid capacitive deionization holds promise for enabling both desalination and resource recovery. In this work, we demonstrate the construction of a hybrid capacitive deionization cell that makes use of tunnel-structured ζ-V2O5 as a redox-active positive electrode material. By augmenting surface adsorption with Faradaic insertion processes, a 50% improvement in the ion removal capacity for K and Li ions is obtained as compared to a capacitive high-surface-area carbon electrode. The extracted ions are accommodated in surface sites and interstitial sites within the one-dimensional tunnel framework of ζ-V2O5. The kinetics of ion removal depend on the free energy of hydration, which governs the ease of desolvation at the electrode/electrolyte interface. The overall ion removal capacity additionally depends on the solid-state diffusion coefficient. ζ-V2O5 positive electrodes show substantial selectivity for Li+ removal from mixed flow streams and enrichment of the Li-ion concentration from produced water waste derived from the Permian Basin.

Textured ceramic membranes for desilting and deoiling of produced water in the Permian Basin.

Oil production in the Permian Basin gives rise to large volumes of produced water contaminated by silt, emulsified oil, and additives used for enhanced oil recovery. There is intense interest in the design of membrane modules as sustainable alternatives for produced water treatment to enable the reuse of produced water for agricultural applications, injection into aquifers, and redeployment in oil recovery. Here, we report a hierarchically textured cement-based membrane exhibiting orthogonal wettability, specifically, superhydrophilic and underwater superoleophobic characteristics. The in situ formation of ettringite needles accompanied by embedding of glass spheres imbues multiscale texturation to stainless-steel mesh membranes, enabling the separation of silt and oil from produced water at high flux rates (1600 L h-1Û°m-2, at ca. 2.7 bar). Oil concentration is reduced as low as 1 ppb with an overall separation efficiency of 99.7% in single-pass filtration. The membranes show outstanding mechanical resilience and retention of performance across multiple cycles.

Trigeminal neuralgia: When does neurovascular contact turn into a conflict?

BACKGROUND: The most common cause for trigeminal neuralgia is contact of the trigeminal nerve with an offending vessel which is also observed routinely in many asymptomatic patients. Therefore, the aim of this study was to determine when an asymptomatic Neuro Vascular Contact (NVC) turned into a neurovascular conflict and made the patient symptomatic. METHODS: All patients who underwent Magnetic Resonance Imaging (MRI) brain with clinical diagnosis of trigeminal neuralgia formed the study group and all cases of sensorineural hearing loss formed the control group. RESULTS: Out of 51 cases of trigeminal neuralgia 27 were males and 24 were females. The neurovascular contact was seen in 41 (80.4%) cases and 17 (28.3%) controls. Change in caliber of trigeminal nerve was seen in 27 (52.9%) cases and only in 01 (1.66%) control. Arterial imprint on nerve was seen in 26 (50.9%) cases and 01 (1.66%) control. Distortion of the course of nerve was seen in 12 (23.5%) cases and 01 (1.66%) control. Superior cerebellar artery was commonest vessel seen in contact with nerve on affected side in 25 (61%) cases. CONCLUSION: Demonstrating neurovascular contact alone is not enough for diagnosis of conflict as it is also present in some asymptomatic individuals, therefore it is important to identify thinning of nerve, arterial imprint or grooving and distortion in course of nerve, as these are more reliable signs of a conflict between the vessel and the nerve, and these cases are best treated surgically by Micro Vascular Decompression (MVD).

Tubercular spondylitis: A review of MRI findings in 80 cases.

BACKGROUND: Tuberculosis of spine is known as tubercular spondylitis or Pott's spine. The vertebral involvement leads to various pathological processes such as abscess formation, cord compression, and gibbus deformity. Magnetic Resonance Imaging (MRI) is the imaging modality of choice which not only helps in diagnosing a case of Pott's spine but also gives valuable information about its impending complications, thereby, aiding in management of these cases. METHODS: In this study, MRI scans of 80 proven cases of tubercular spondylitis were studied retrospectively for the various pathological processes affecting the spine. RESULTS: Of the 80 cases included in this study, 68.8% of cases were male and 31.2% of cases were females. Majority of cases were seen in 21-40 yrs age group. Lumbar vertebrae were more commonly affected than the dorsal vertebrae. Contiguous two vertebral involvement was the most common pattern, and skip lesions were seen in 5% of cases. Pre-, paravertebral and epidural soft tissue component was seen in 96.25% and 62.5% of cases, respectively. Intervertebral disc Involvement was noted in 95% of cases, and cord edema was seen in 15% of cases. CONCLUSION: Tubercular spondylitis or Pott's spine is an extrapulmonary form of tuberculosis which affects the spine. MRI is the imaging modality of choice not only in diagnosing the condition but also in guiding the surgical management. The cases of spinal tuberculosis were systematically analyzed for various pathological lesions which are produced in the spine as the disease progresses.

Intracranial hypotension: An uncommon entity with common presentation.

Headache disorders are among the most common presenting complaints in any neurology outpatient department. International Headache Society classifies headaches as "primary" or "secondary". The causes of secondary headaches are varied and intracranial hypotension is one of them. It typically presents clinically with postural headaches but most of the times, its diagnosis is delayed, as it is an uncommon cause and there is poor awareness among the medical fraternity about this condition. Imaging, especially magnetic resonance imaging (MRI), plays a crucial role in the diagnosis of intracranial hypotension by not only confirming the diagnosis but also detecting the cause in some cases. This case series tries to highlight the MRI findings of intracranial hypotension in three cases with different etiologies.

Coronary CT angiography: A retrospective study of 220 cases.

BACKGROUND: Coronary artery disease (CAD) is a common cause of morbidity and mortality worldwide. Although catheter coronary angiography (CCA) is the gold standard in the diagnosis and management of CAD, coronary CT angiography (CCTA) has shown promising results for the same. METHODS: CCTA was done using 40 slice multi-detector CT (Somatom Sensation, Siemens, Germany) machine in 220 patients of suspected CAD. Patients were classified as (a) normal (no calcific or soft plaque), (b) non-obstructive coronary disease (<50% stenosis), (c) obstructive coronary disease (>50% stenosis), or (d) a non-diagnostic study. RESULTS: 96 (43.6%) cases were found to have normal coronary arteries on CCTA, 41 (18.6%) patients were classified as having non-obstructive disease, 67 (30.5%) patients were defined to have obstructive CAD, and 16 cases (7.3%) were inconclusive. Significantly obstructive triple vessel disease was noted in 4 (6%) cases. Double vessel disease was seen in 25 (37.3%) cases and single vessel disease was seen in 38 (56.7%). Single most common vessel with obstructive CAD was left anterior descending artery and was noted in 30 (44.7%) out of 67 such cases. The least affected vessel was left circumflex in 15 cases (22.3%). Median calcium score for non-obstructive CAD was 60 (range 30-95), and for obstructive CAD 300 (range 120-780). CONCLUSION: Key benefits of CCTA lie in the avoidance of CCA since it has a high negative predictive value. CCTA has a definite role in post-stent and post-coronary artery bypass graft patients.

Clinical mimics of acute appendicitis: Is there any role of imaging?

Acute appendicitis (AA) is a common surgical emergency. Accurate and timely diagnosis of AA is essential for successful outcome. Imaging plays an important role in the diagnosis, exclusion of AA as well as diagnosing alternative clinical conditions which can closely simulate AA. A correct alterative diagnosis may obviate the need of unnecessary appendectomy or may even change the treatment regime altogether. This pictorial essay illustrates various clinical conditions which mimicked AA clinically during our day to day practice.

"Breast within a breast" sign: Mammary hamartoma.

Breast hamartomas are uncommon benign tumors of the breast. Imaging appearance of a breast hamartoma can vary widely. "Breast within a breast" sign on mammography is considered pathognomonic of this unusual entity. We describe mammographic and Magnetic Resonance Imaging (MRI) appearance of a case of hamartoma breast.

Dry imaging cameras.

Dry imaging cameras are important hard copy devices in radiology. Using dry imaging camera, multiformat images of digital modalities in radiology are created from a sealed unit of unexposed films. The functioning of a modern dry camera, involves a blend of concurrent processes, in areas of diverse sciences like computers, mechanics, thermal, optics, electricity and radiography. Broadly, hard copy devices are classified as laser and non laser based technology. When compared with the working knowledge and technical awareness of different modalities in radiology, the understanding of a dry imaging camera is often superficial and neglected. To fill this void, this article outlines the key features of a modern dry camera and its important issues that impact radiology workflow.