Application of Factorial Design in Selective Laser Sintering

Selective Laser Sintering (SLS) is a complex process involving many process parameters. These parameters are not all independent. A factorial design technique is utilized to study the effects of three main process parameters, laser power, laser beam scanning speed, and powder packing density as well as their interactions on the sintering depth and fractional density. The results of this investigation provide useful information for the further experimental analysis of the process parameters and for selecting suitable parameters for SLS process.Mechanical Engineerin

Social capital, agricultural technical assistance, access to productive resources, and food security in post-conflict Lira, northern Uganda

This study investigated the link between social capital and access to productive resources particularly land, labor, information, and credit, as well as the impact of agricultural technical assistance on resource access among formerly-displaced farm households in Lira, northern Uganda. The study also explored whether established associations between social capital and food security are also observed in post-conflict situations. Food security was measured using the validated Household Food Insecurity Access Scale (HFIAS). Data were collected from March-July 2011 through interviews with 221 heads of household. The study identified socio-demographic and socio-economic factors that influence and differentiate households in terms of access to resources necessary for achieving food security in Lira district. Combining quantitative and qualitative approaches, this study found a strong link between social capital, resource access, and food security outcomes among households in Lira. Social capital in terms of social networks emerged as the main predictor for accessing land, labor, information, and credit. Multivariate logistic regression analysis found a strong positive association between food security and social capital. Socio-demographic factors, particularly gender and educational level of household head, as well as ownership of livestock, and home possessions (which are regarded as indicators of wealth in the area), were also positively associated with access to resources necessary for achieving food security. The study has important policy implications for development intervention programs in post-conflict settings that transition from emergency-based to long-term agricultural development assistance. Results can aid the design of effective food security programs that recognize and support peoples\u27 initiatives and strengthen their social networks while targeting the most vulnerable groups to promote sustainable livelihoods in post-conflict communities

Real Estate Collateral Value and Investment: The Case of China

Previous research on the United States and Japan finds economically large impacts of changing real estate collateral value on firm investment that amplified the business cycles of those countries. Working with unique data on land values in 35 major Chinese markets and a panel of firms outside the real estate industry, we estimate investment equations that yield no evidence of a collateral channel effect. Further analysis indicates that China’s debt is not characterized by the frictions that give rise to collateral channel effects elsewhere. Essentially, financially constrained borrowers appear able credibly to commit to repay debt in China. While there is no impact on investment via the collateral channel, our results should not be interpreted as implying there will be no negative fallout from a potential real estate bust on the Chinese economy. There likely would be, but through different channels

Evaluating Conditions in Major Chinese Housing Markets

High and rising prices in Chinese housing markets have attracted global attention. Price-to-rent ratios in Beijing and seven other large markets across the country have increased by 30% to 70% since the beginning of 2007. Current price-to-rent ratios imply very low user costs of no more than 2%–3% of house value. Very high expected capital gains appear necessary to justify such low user costs of owning. Our calculations suggest that even modest declines in expected appreciation would lead to large price declines of over 40% in markets such as Beijing, absent offsetting rent increases or other countervailing factors. Price-to-income ratios also are at their highest levels ever in Beijing and select other markets, but urban income growth has outpaced price appreciation in major markets off the coast. Much of the increase in prices is occurring in land values. Using data from the local land auction market in Beijing, we are able to produce a constant quality land price index for that city. Real, constant quality land values have increased by nearly 800% since the first quarter of 2003, with half that rise occurring over the past two years. State-owned enterprises controlled by the central government have played an important role in this increase, as our analysis shows they paid 27% more than other bidders for an otherwise equivalent land parcel

The Wharton/NUS/Tsinghua Chinese Residential Land Price Indexes (CRLPI) White Paper

We appreciate the advice and insight of our colleagues Professor Hongyu Liu and Dr. Siqi Zheng on various parts of this project, although we obviously are responsible for any remaining errors. Excellent research assistance was provided by Bo Zhang, Pu Wang, Wei Guo, Mingyue Li, Baoyi Hu, Jingting Huang, and Chenxi Zhao from Tsinghua University, Ying Chen, Hui Liu and Chen Zheng from Wharton, and Jia He and Mingying Xu from the National University of Singapore. Gyourko thanks the Global Research Initiatives Project of the Wharton School at the University of Pennsylvania for financial support. Deng thanks the Institute for Real Estate Studies at the National University of Singapore for financial support. Wu thanks Hang Lung Center for Real Estate at Tsinghua University and the National Natural Science Foundation of China for financial support (No. 712003060 & No. 71373006)