An improved DMAP capability

A set of improvements designed and implemented into a test version of the NASTRAN DMAP (Direct Matrix Abstraction Program) compiler is presented. These modifications simplify the use of the DMAP control language while enhancing its power and versatility. The implemented changes are described and examples are presented to illustrate their use

Implementation on a nonlinear concrete cracking algorithm in NASTRAN

A computer code for the analysis of reinforced concrete structures was developed using NASTRAN as a basis. Nonlinear iteration procedures were developed for obtaining solutions with a wide variety of loading sequences. A direct access file system was used to save results at each load step to restart within the solution module for further analysis. A multi-nested looping capability was implemented to control the iterations and change the loads. The basis for the analysis is a set of mutli-layer plate elements which allow local definition of materials and cracking properties

Carbon accretion in unthinned and thinned young-growth forest stands of the Alaskan perhumid coastal temperate rainforest.

BACKGROUND: Accounting for carbon gains and losses in young-growth forests is a key part of carbon assessments. A common silvicultural practice in young forests is thinning to increase the growth rate of residual trees. However, the effect of thinning on total stand carbon stock in these stands is uncertain. In this study we used data from 284 long-term growth and yield plots to quantify the carbon stock in unthinned and thinned young growth conifer stands in the Alaskan coastal temperate rainforest. We estimated carbon stocks and carbon accretion rates for three thinning treatments (basal area removal of 47, 60, and 73 %) and a no-thin treatment across a range of productivity classes and ages. We also accounted for the carbon content in dead trees to quantify the influence of both thinning and natural mortality in unthinned stands. RESULTS: The total tree carbon stock in naturally-regenerating unthinned young-growth forests estimated as the asymptote of the accretion curve was 484 (±26) Mg C ha-1 for live and dead trees and 398 (±20) Mg C ha-1 for live trees only. The total tree carbon stock was reduced by 16, 26, and 39 % at stand age 40 y across the increasing range of basal area removal. Modeled linear carbon accretion rates of stands 40 years after treatment were not markedly different with increasing intensity of basal area removal from reference stand values of 4.45 Mg C ha-1 year-1to treatment stand values of 5.01, 4.83, and 4.68 Mg C ha-1 year-1 respectively. However, the carbon stock reduction in thinned stands compared to the stock of carbon in the unthinned plots was maintained over the entire 100 year period of observation. CONCLUSIONS: Thinning treatments in regenerating forest stands reduce forest carbon stocks, while carbon accretion rates recovered and were similar to unthinned stands. However, that the reduction of carbon stocks in thinned stands persisted for a century indicate that the unthinned treatment option is the optimal choice for short-term carbon sequestration. Other ecologically beneficial results of thinning may override the loss of carbon due to treatment. Our model estimates can be used to calculate regional carbon losses, alleviating uncertainty in calculating the carbon cost of the treatments

The automated multi-stage substructuring system for NASTRAN

The substructuring capability developed for eventual installation in Level 16 is now operational in a test version of NASTRAN. Its features are summarized. These include the user-oriented, Case Control type control language, the automated multi-stage matrix processing, the independent direct access data storage facilities, and the static and normal modes solution capabilities. A complete problem analysis sequence is presented with card-by-card description of the user input

How Iowa Farmers Respond to Hog Cycles

This look at the yearly farrowing patterns among areas of Iowa and on 105 eastern Iowa farms may help in dealing with hog cycles. It also suggests some strategy you may want to consider in planning your yearly farrowings

States Share in Creating Hog Cycle

Do particular states or regions add more than their share to the ups and downs in hog production? Generally not. Hog-producing states contribute to the cycle roughly in proportion to the total number of hogs they raise

COMPARING THE REACTIONS OF ZOO VISITORS TO IMMERSIVE AND NON-IMMERSIVE EXHIBIT EXPERIENCS

There are many people who visit zoos every year - over 183 million according to the Association of Zoos and Aquariums (2017). These visitors may have different motivations and goals for their visits. However, any zoo they visit will find that the zoo facility and staff have the same main goals: recreation, conservation, and education. Understanding how to effectively promote these areas to visitors is important for a zoo's continued success. One of the biggest attraction of zoos includes their animal exhibits. These exhibits may evoke emotional reactions (affective reactions), inspire learning and education to occur (cognitive reactions), and a sense of connection to the environment from the visitors. These reactions can be used by zoo staff to achieve their goals. However, with the diverse visitor population that zoos often encounter, understanding effective methods to communicate with as many people as possible is essential. Many zoos provide a variety of different exhibit experiences. Some of the exhibits include opportunities for visitors to participate in unique experiences that can enhance their different experiences. The purpose of this study was to examine how different exhibit settings encourage different reactions within adult visitors

Overrepresentation of Special Education in the Juvenile Justice System

The following study is based on the representation of special education students in our nation\u27s juvenile justice system. Data was gathered collected through a literature review that analyzes two national studies and other studies from various states. A research study was also conducted in which detention centers in New York State were surveyed regarding the numbers of special education students in their facilities and the implications that special education has on the youth in the juvenile justice system. The findings of the literature review and the New York State study show that youth with disabilities and special education classification are overrepresented in our juvenile justice system when compared to the public school system