Structural geology of the Nemaha Ridge in Kansas

Four maps in pocket.Digitized by Kansas State University Librarie

An investigation on the operation model of an art and cultural organisation in Hong Kong

published_or_final_versionMedia, Culture and Creative CitiesMasterMaster of Social Sciences in Media, Culture and Creative Citie

Osmotic Flow and Volume Change in Clay Soils

The engineering profession has been called upon by the public in recent years to provide ever increasing degrees of containment for low level waste contained in shallow subsurface waste containment facilities. To provide this protection, the use of engineered liners or barriers has become a common design feature. In many cases, these barriers are constructed out of natural clays or artificial mixtures of clay minerals. The use of soil barriers to contain waste products consisting of strong electrolyte solutions, has met with mixed success. Clays of lowest permeability are also those whose behavior is the most influenced by the presence of salt solutions. Failures of clay liners exposed to electrolyte solutions have not been well documented. The mechanism for failure seems to be the result of shrinkage of the clay, which then leads to the development of a secondary structure of cracks and fissures. Field cases of liner failure have often been described as occurring as a result of "osmotic desiccation". The general objective of this study was to define, and quantify, the mechanisms controlling the rate and magnitude of volume change in clay soils exposed to strong electrolyte solutions. A review of the literature presented two possible mechanisms termed osmotically consolidation. Osmotically induced consolidation occurs as a result of for osmotic volume change. induced consolidation and These were osmotic rapid flow of water out of the sample in response to osmotic gradients. Osmotic consolidation occurs as as result of a reduction in the net electrostatic repulsive stresses between clay particles. A general theoretical description of osmotically induced consolidation and osmotic consolidation was developed. A phenomenological approach was adopted to describe fluid flow in response to osmotic gradients. A Darcy type flow law was used to related osmotic flows to osmotic gradients through a conductivity term called the osmotic permeability. To describe osmotic consolidation, the osmotic pressure of the pore fluid was selected as a stress state variable. Volume changes were linked to the osmotic pressure of the pore fluid through a constitutive relationship. The soil property used to define changes in soil volume due to osmotic pressure changes was called the osmotic compressibility. A numerical solution to the theoretical description of osmotic flow and volume change was developed using finite element techniques. This model was used to characterize the processes of osmotic and osmotically induced consolidation. A laboratory program was undertaken to monitor the osmotic flow and volume change in two clays; Regina Clay and an Ottawa SandI Na montmorillonite mixture. From the results of these tests the dominant mechanism of volume change for these clays was found to be osmotic consolldatipn. The test procedures developed allowed the soil properties describing osmotic flow and volume change to be evaluated. A technique was developed by which the electrostatic repulsive stresses within a clay could be measured indirectly through laboratory testing. The results indicated that the onset of fracturing may be predicted by comparing the change in the net repulsive stress that occurs as result of changing pore fluid concentrations, to the confining stress within the soil

Predicting Revision Following In Situ Ulnar Nerve Decompression for Patients With Idiopathic Cubital Tunnel Syndrome.

PURPOSE: To determine the incidence of revision and potential risk factors for needing revision surgery following in situ ulnar nerve decompression for patients with idiopathic cubital tunnel syndrome (CTS). METHODS: We conducted a retrospective chart review of all patients treated at 1 specialty hand center with an open in situ ulnar nerve decompression for idiopathic CTS from January 2006 through December 2010. Revision incidence was determined by identifying patients who underwent additional surgeries for recurrent or persistent ulnar nerve symptoms. Bivariate analysis was performed to determine which variables had a significant influence on the need for revision surgery. RESULTS: Revision surgery was required in 3.2% (7 of 216) of all cases. Age younger than 50 years at the time of index decompression was the lone significant predictor of need for revision surgery. Other patient factors, including gender, diabetes, smoking history, and workers\u27 compensation status were not predictive of the need for revision surgery. Disease-specific variables including nerve conduction velocities, McGowan grading, and predominant symptom type were also not predictive of revision. CONCLUSIONS: For patients with idiopathic CTS, the risk of revision surgery following in situ ulnar nerve decompression is low. However, this risk was increased in patients who were younger than 50 years at the time of the index procedure. The findings of this study suggest that, in the absence of underlying elbow arthritis or prior elbow trauma, in situ ulnar nerve decompression is an effective, minimal-risk option for the initial surgical treatment of CTS. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic III

Evaluation and Management of Sleep Disorders in the Hand Surgery Patient.

Despite posing a significant public health threat, sleep disorders remain poorly understood and often underdiagnosed and mismanaged. Although sleep disorders are seemingly unrelated, hand surgeons should be mindful of these because numerous conditions of the upper extremity have known associations with sleep disturbances that can adversely affect patient function and satisfaction. In addition, patients with sleep disorders are at significantly higher risk for severe, even life-threatening medical comorbidities, further amplifying the role of hand surgeons in the recognition of this condition

Geographic and Age-Based Variations in Medicare Reimbursement Among ASSH Members.

Background: The purpose of this study was to investigate how American Society for Surgery of the Hand (ASSH) members\u27 Medicare reimbursement depends on their geographical location and number of years in practice. Methods: Demographic data for surgeons who were active members of the ASSH in 2012 were obtained using information publicly available through the US Centers for Medicare and Medicaid Services (CMS). Hand-surgeons-per-capita and average reimbursement per surgeon were calculated for each state. Regression analysis was performed to determine a relationship between (1) each state\u27s average reimbursement versus the number of ASSH members in that state, (2) average reimbursement versus number of hand surgeons per capita, and (3) total reimbursement from Medicare versus number of years in practice. Analysis of variance (ANOVA) was used to detect a difference in reimbursement based on categorical range of years as an ASSH member. Results: A total of 1667 ASSH members satisfied inclusion in this study. Although there was significant variation among states\u27 average reimbursement, reimbursement was not significantly correlated with the state\u27s hand surgeons per capita or total number of hand surgeons in that given state. Correlation between years as an ASSH member and average reimbursement was significant but non-linear; the highest reimbursements were seen in surgeons who had been ASSH members from 8 to 20 years. Conclusions: Peak reimbursement from Medicare for ASSH members appears to be related to the time of surgeons\u27 peak operative volume, rather than any age-based bias for or against treating Medicare beneficiaries. In addition, though geographic variation in reimbursement does exist, this does not appear to correlate with density or availability of hand surgeons