Motivated by existing nuclear astrophysics problems, the B-decay of the proton rich nucleus 23Al was studied for the first time with pure samples which were obtained by using the 1H(24Mg,23Al)2n reaction and the MARS recoil separator at Texas A&M University. B and B-y coincidence measurements were made with a fast tape-transport system, scintillator, BGO and HPGe y detectors. The experiment allowed us to measure absolute B branching ratios and to determine logft values for transitions to final states in 23Mg, including the isobaric analog state (IAS), and, therefore, to determine unambiguously the spin and parity of the 23Al ground state to be J^Pi = 5/2+. This work excludes the large increases in the radiative proton capture cross section for the reaction 22Mg(p, )23Al at astrophysical energies, which were implied by claims that the spin and parity of the 23Al ground state were J^Pi = 1/2+. More precise half life and mass determinations of 23Al were obtained from the experimental data. The logft for the Fermi transition to its isobaric analog state in 23Mg was also determined for the first time. This IAS and a state 16 keV below it were observed, well separated in the same experiment for the first time. The B-decay scheme of the proton rich nucleus 23Al was established. We can now solve a number of inconsistencies in the literature, exclude strong isospin mixing claimed before, and obtain a new determination of the resonance strength. The IAS and the state 16 keV below it are resonances in the 22Na(p, )23 Mg reaction at energies that are important in novae. This second state turns out to be the resonance that gives the most important contribution in the depletion of 22Na from novae. Both of the reactions of 22Mg(p, )23Al and 22Na(p, )23Mg have been suggested as possible candidates for diverting some of the flux in oxygen-neon novae explosions from the A=22 into the A=23 mass chain.

We introduce a new method of mass measurement for particles in decay chains. The method relies upon performing a likelihood analysis on the phase space of the decay in its full dimensionality in a Lorentz-invariant formulation. This method is applicable for any decay chain, but we demonstrate it specifically in the case of a four-body final state decay in which one of the final particles is invisible. We directly compare our method to the edge and endpoint method and show that our new method can achieve higher precision with limited statistics. / text

Using the NEMO-3 detector, 410.4 g of ¹¹⁶Cd with a total exposure of 1.65 kg• y and 932 g of ⁸²Se with a total exposure of 3.75 kg• y were used to measure the half-life of two-neutrino double beta decay (2[nu][beta][beta]) to the ground states of ¹¹⁶Sn and ⁸²Kr and to place a lower limit on the neutrinoless double becay decay (0[nu][beta][beta]) to the same ground states. Under the single-states dominance hypothesis, the 2[nu][beta][beta] half-lives are found to be T 1/2(¹¹⁶Cd) = (2.90 ± 0.03(stat) ± 0.15(syst)×10¹⁹ yr and T 1/2(⁸²Se) = [10.62±0.11(stat)±0.56(syst)]×10¹⁹ yr. 0[nu][beta][beta] is excluded to 90% confidence level at T 1/2 ≥ 1.12 × 10²³ yr for ¹¹⁶Cd and T 1/2 ≥ 3.90 × 10²³ yr for ⁸²Se. These half-lives correspond to effective Majorana neutrino masses of m ≤ (4.33 - 5.54) eV and m ≤ (2.28 - 2.82) eV, respectively, in the light Majorana exchange mechanism. / text

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We have performed a sequential decay analysis of the reaction / (pi)('-)p (--->) (omega)(pi)('0)n / at 8.45 GeV/c in a counter - spark chamber experiment conducted at the Argonne National Laboratory Zero Gradient Synchrotron. The production and decay properties of the B('0) meson are presented, along with the differential cross section for the reaction (pi)('-)p (--->) B('0)n. We present evidence for the existence of the (rho)'(1250) meson (IJ('PC) = 11('--)). Our study of the B('0) production indicates dominance of A(,2) exchange (nucleon spin flip). We have found significant amounts of D-wave in the B('0) (--->) (omega)(pi)('0) decay. The production mechanisms for (rho)'(1250) are similar to those for (rho)(770) production and are dominated by (pi) exchange.

The decays of Br^75 and Br^74 to Se^75 and Se^74 respectively.

The use of wood-based composites has increased dramatically over the last two decades due to a number of factors. One reason is that Oriented Strand Board (OSB) is being increasingly utilized in residential applications in place of plywood. However, the use of OSB in residential construction is often limited because of its susceptibility to attack by biological pathogens such as mold and decay fungi. The environmental conditions that exist in certain use categories can be so adverse that the performance of these composites is negatively affected. This study was divided into two parts. The first phase examined the effectiveness of fungicides or combinations of fungicides (including some metal-containing preservatives) for enhancing the mold resistance of strandboard. During the second part of the study, preliminaryexperiments investigated the effectiveness of fungicides or combinations of fungicides using anagar-block test to estimate the preservative toxic threshold retention. The compatibility of the fungicide on the resin curing was studied by measuring change in the resin gelation and viscosity. After these screening experiments were completed, large size boards were prepared and mechanical and decay resistance properties were examined. It was found that mold and decay resistance properties of strandboard directly were related with the biocide type and its concentration. Greater protection of the strandboard was achieved with an increase in preservative retention levels. However, due to the relatively high cost of non-metallic (organic) preservatives, it is important to find the minimum amount of preservative that can protect the OSB against mold and decay fungi. One method of reducing the cost and increasing efficacy is to combine different fungicides to determine whether synergism exists. Even if synergism does not occur, it may reduce the overall cost by combining a less expensive biocide with a smaller amount of a more expensive biocide wheretheir biocidal efficacy complements each other. In addition, it is important to understand that high retention of preservative may also cause negative effects on the mechanical properties of strandboard. This maybe noticeable of the high retention level of the biocide when a greater negative effect on the internal bonding (IB) strength may be recorded. Lower IB strength for treated strandboard may be attributed to the formulation of chemical residue in the wood surface, which may interfere with the reaction between wood and phenol formaldehyde (PF) resin. Surface-active agents in the preservative may also cause the PF resin to over-penetrate into wood decreasing bond strength. Increasing moisture content of strands by the introduction of an emulsified aqueous biocide solution, may cause dilution of the resin, and reduced bonding. It should also be noted that high retention of preservative which cause a change in the viscosity and gelation time of PF resins would be problematic for the operation of an OSB plant. For viscosity change, it could significantly affect the flow properties of the resin on the wood furnish and its atomization as it is spraying onto the wood furnish. In addition, it may require further modification to the equipment that supplies the resin to the spray nozzle. For changes in the gelation time, this may require changes to the press time at the OSB plant.