Immobilization of photocatalyst on supporting materials for pollutant control

This study demonstrated facile and practical approaches of immobilizing photocatalyst powder on supporting substrates and investigated the pollutant removal performance of the obtained materials. These findings opens the opportunities for applying the photocatalytic materials for practical water and air pollutant management

Depression and Internet use in a Sample of Malaysian Undergraduate Students

This study used a set of questionnaire to investigate the Internet use and depression level in a sample of Malaysian undergraduate students, which identified 12 cases as pathological Internet use (PIU) in a total sample of 90 students using Beard and Wolf’s (2001) criterion. Students with PIU spent significantly longer time on Internet and experienced extremely higher level of depression (M=42.83, SD=11.86) than their non-PIU counterparts (M=26.26, SD=14.79), which is in the severe level. The gender difference on depression was also detected in this study but not for time spent online. Lastly, this study found that students with PIU would like to spent more time on SNS, browsing with no specific purpose, and online media viewing, while students with increasing level of depression would accelerate the time spent online, especially on SNS, browsing with no specific purpose, and instant messaging. The same Internet application (SNS and browsing with no specific purpose) chose by students with PIU and high level of depression implied that there may be close association on developing depression and PIU related to usage of SNS and browsing with no specific purpose

Impacts of Environmental Mass Incidents: A Comparative Analysis of Three Cases in China

Public participation in the environmental issues is gradually becoming a part in institutional and policy design in China. In practice, however, its implementation and enforcement cannot be guaranteed for various reasons. Under an unsound participatory mechanism, environmental mass incidents represent an extreme form of environmental public participation. The study evaluates the impacts of environmental mass incidents by comparing three representative cases. Four dimensions are emphasized in this study, including: (1) the nature and benefits of the infrastructure projects, (2) the causes of the environmental mass incidents, (3) the primary players leading the environmental mass incidents and their performance, and (4) the media's role. Overall, the decision makers are supposed to adaptively empower people through public participation in environmental decision-making, and to achieve a balance between concessions and control

A Micromechanics-based Multiscale Approach toward Continental Deformation, with Application to Ductile High-Strain Zones and Quartz Flow Laws

Earth’s lithosphere may be regarded as a composite material made of rheologically heterogeneous elements. The presence of these heterogeneous elements causes flow partitioning, making the deformation of Earth’s lithosphere heterogeneous on all observation scales. Understanding the multiscale heterogeneous deformation and the overall rheology of the lithosphere is very important in structural geology and tectonics. The overall rheology of Earth’s lithosphere on a given observation scale must be obtained from the properties of all constituents and may evolve during the deformation due to the fabric development. Both the problem of flow partitioning and characterization of the overall rheology are closely related and require a fully mechanical multiscale approach. This thesis refines a micromechanics-based multiscale modeling approach called the self-consistent MultiOrder Power Law Approach (MOPLA). MOPLA treats the heterogeneous rock mass as a continuum of rheologically distinct elements. The rheological properties and the mechanical fields of the constituent elements and those of the composite material are computed by solving partitioning and homogenization equations self-consistently. The algorithm of MOPLA has been refined and implemented in MATLAB for high-performance computing. The micromechanical approach is used to investigate the deformation of ductile high-strain zones, advancing previous work on this subject to a full mechanical level. This thesis considers a ductile high-strain zone as a flat heterogeneous inclusion embedded in the ductile lithosphere subjected to a tectonic deformation due to remote plate motion. The kinematic and the mechanical fields inside and outside the high-strain zone, including the finite strain accumulation in there, are solved by partitioning equations. The overall rheology of the high-strain zone is obtained by means of a self-consistent homogenization scheme. Understanding the continental rheology requires an accurate quartz dislocation creep flow law. Despite decades of experimental studies, there are considerable discrepancies in quartz flow law parameters. This thesis proposes that the discrepancies could be explained by considering both the pressure effect on the activation enthalpy and the slip system dependence of the stress exponent. Two distinct dislocation creep flow laws corresponding to two dominant slip systems are determined based on the current dataset of the creep experiments on quartz samples

Evaluation and Comparison of Dynamic Treatment Regimes: Methods and Challenges.

Dynamic treatment regimes (DTRs) are sequences of decision rules that link the patient history with treatment recommendations. Clinical scientists have become increasingly interested in the development of DTRs in various fields including substance abuse, mental health and cancer. The Sequential Multiple Assignment Randomized Trial (SMART) is a multi-stage trial design that explicitly targets the development of high-quality DTRs. In this dissertation, we develop statistical methodologies, which can be applied to SMART data, that either address novel research questions regarding the construction of a high-quality DTR, or exhibit better performance than existing statistical methods. In Chapter 2, we develop an assisted estimator that can be used to compare the mean outcomes of a pair of competing DTRs. The term “assisted” refers to the fact that estimators from the structural nested mean model, a parametric model for the intermediate causal effect at each time point, are used in the process of estimating the mean outcome. In Chapter 3, we compare a pre-determined set of DTRs in terms of a repeated-measures outcome that spans across multiple treatment stages in a SMART. We illustrate the repeated-measures modeling considerations, that are particular to SMART studies, by discussing three case studies in autism, child ADHD and adult alcoholism. In Chapter 4, we focus on the well developed and widely used weighted-and-replicated (WR) estimator that is used to compare a pre-determined set of DTRs in terms of an end-of-study outcome. The typically used sandwich estimator for the variance of the WR estimator can be biased for the true variance when the sample size is small; therefore, we derive a small-sample adjusted estimator for the variance of WR estimator. In Chapter 5, we introduce the ongoing work regarding the search for the optimal treatment decision rule within a pre-specified parametrized class, with the additional aim to make inference about the usefulness of including one particular variable as a tailoring variable. We consider a regularized estimator for the optimal policy, with two components of regularization motivated by two issues of the original unregularized estimator.PhDStatisticsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113451/1/luxi_1.pd