Compression Drying of Sapwood

A compression drying experiment carried out on small blocks of sapwood from Pinus radiata, Araucaria cunninghamii. Eucalyptus regnans, and E. obliqua is described. Effects of initial moisture content, speed of compression, specimen thickness and orientation on moisture loss and energy input were studied. All specimens were compressed perpendicular to the grain to the same stress in either a radial or tangential direction in a jig that prevented lateral expansion. Force and deformation changes of the specimens were recorded during compression, and water loss at the end of the process was measured. From these data, volumetric compressions, moisture losses, energy inputs, and energy efficiencies of water removal were calculated.The analyses of variance confirmed that initial moisture content, species and wood specific gravity, amount of volumetric strain, rate of compression, and specimen orientation all affected unit water removal; specimen thickness did not. The lower density softwoods deformed to a greater extent than the hardwoods and lost more water. More water was removed from wetter specimens than drier ones at the same stress, and a slow compression rate caused a greater water loss than a more rapid rate. Specimens compressed tangentially lost more water than those compressed radially. Energy efficiency of water removal was greatest in the relatively low specific gravity Pinus radiata specimens with high moisture contents which were compressed tangentially at a slow rate

Fermion Masses and Mixing in Extended Technicolor Models

We study fermion masses and mixing angles, including the generation of a seesaw mechanism for the neutrinos, in extended technicolor (ETC) theories. We formulate an approach to these problems that relies on assigning right-handed $Q=-1/3$ quarks and charged leptons to ETC representations that are conjugates of those of the corresponding left-handed fermions. This leads to a natural suppression of these masses relative to the $Q=2/3$ quarks, as well as the generation of quark mixing angles, both long-standing challenges for ETC theories. Standard-model-singlet neutrinos are assigned to ETC representations that provide a similar suppression of neutrino Dirac masses, as well as the possibility of a realistic seesaw mechanism with no mass scale above the highest ETC scale of roughly $10^3$ TeV. A simple model based on the ETC group SU(5) is constructed and analyzed. This model leads to non-trivial, but not realistic mixing angles in the quark and lepton sectors. It can also produce sufficiently light neutrinos, although not simultaneously with a realistic quark spectrum. We discuss several aspects of the phenomenology of this class of models.Comment: 74 pages, revtex with embedded figure

Empirical extension of the interpersonal theory of suicide: Investigating the role of interpersonal hopelessness

The Interpersonal Theory of Suicide posits that hopelessness about thwarted belongingness and perceived burdensomeness is an important risk factor for the desire for suicide and suicide risk. Past research has indicated that general feelings of hopelessness interact with the constructs of thwarted belongingness and perceived burdensomeness to predict suicide ideation. However, no research has explicitly tested whether hopelessness specific to the interpersonal constructs of thwarted belongingness and perceived burdensomeness predicts suicide ideation and suicide risk. Participants in the current study (N = 173) were undergraduate students oversampled for history of suicide ideation, planning for suicide, and suicide attempt(s). Participants completed study measures online, including a new measure of hopelessness about thwarted belongingness and perceived burdensomeness. Results indicated that a three-way interaction of thwarted belongingness, perceived burdensomeness, and hopelessness about these interpersonal constructs, but not general hopelessness, predicted unique variance of suicide ideation and suicide risk. Results suggest that hopelessness about thwarted belongingness and perceived burdensomeness may be an important target for reducing suicidal desire