Clarifier Scum Removal Can Be Both Simple and Efficient

The presence of floating scum and trash has troubled many wastewater treatment facilities. These accumulations on circular primary clarifiers, secondary clarifiers, and sludge thickeners are an unsightly nuisance, reduce performance, and cause odors. The added Operation and Maintenance effort—sometimes unsuccessful—can cause a deterioration of the staff morale and adversely impact other plant operations. Skimmers have become more complex and costly, full radial and ducking types, in an attempt to solve these problems. However, a review of conventional scum skimmers revealed that they were not optimized to ensure that flotables could be rapidly moved to the scum ramp/trough. The common problems were low angles of attack of the skimmer, undersized ramps for scum removal, and adverse effects of wind. The recommended skimmer has a bend at a radial point which results in a 25–30° angle of attack and 200–300% higher transport capacity than the tangential skimmer. The paper provides a methodology to establish the quantity of flotables to be removed, design of the bent skimmer and sizing of the scum ramp/trough in a series of tables and graphs.     

Visual monitoring performance in three subgroups of male delinquents.

Administered a questionnaire measuring psychopathic, neurotic, and subcultural delinquency to 268 male delinquents. 3 groups of 15 Ss each were formed from Ss who scored above the mean on 1 scale and below the mean on the other 2. It was predicted that the more psychopathic Ss would show a greater performance decrement on a vigilance task. A significant effect was found between groups and a significant decrement over trials for signals detected and RTs; psychopathic Ss performed consistently poorer than the other 2 groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quench protection studies of LHC interaction region quadrupoles atFermilab

High gradient quadrupoles are being developed by the US-LHC Accelerator Project for the LHC interaction region inner triplets. Protection strip heaters are the primary means of protecting these magnets against excessively high coil temperatures and coil voltage to ground as a result of a spontaneous quench. The main objective of the quench protection R&D program is to optimize the heater performance within the constraints of the LHC heater power supply and quench detection system. The results of these studies on several two meter long model magnets are presented     

Quench performance and mechanical behavior of the first Fermilab-built prototype high gradient quadrupole for the LHC interaction regions

As part of the US LHC program to provide high gradient superconducting quadrupoles for the LHC interaction regions, a 5.5 meter long prototype magnet has been built and tested horizontally in a production type cryostat at Fermilab. This prototype magnet was used to validate the mechanical and magnetic design, production fabrication and assembly tooling. The first prototype magnet has met the LHC requirements of operating at 215 T/m with excellent magnetic field harmonics. This paper summarizes the test results of this magnet, including quench tests and mechanical behavior over several thermal cycles.     

Test results from the LQXB quadrupole production program at Fermilab for the LHC interaction regions

As part of the US-LHC Accelerator Project, Fermilab is producing fully cryostated assemblies that will be installed as the Q1, Q2 and Q3 optical elements for the LHC Inner Triplets. The main quadrupole magnets in the Q1 (LQXA) and Q3 (LQXC) assemblies are MQXA elements designed and fabricated by KEK and Toshiba, while those in the Q2 (LQXB) assemblies are MQXB quadrupoles designed and fabricated by Fermilab. The cryostat assemblies for all magnets are designed by Fermilab, and final assembly of the optical elements occurs at Fermilab. This paper describes the production test results for the second LQXB cryostat assembly.     

Contingency model of leadership effectiveness: Some experimental results.

Conducted 2 parallel experiments with 78 and 96 undergraduates to replicate and further study the contingency model of leadership effectiveness proposed by F. Fiedler. Ss were assigned to 3-man groups and completed a high and a low structured task after selecting a leader. Ss completed a measure of leadership style, the Least Preferred Co-worker (LPC) scale, a group atmosphere scale, and a leader behavior scale. None of the observed correlations for either study reached significance, and in Exp. II, only 2 of the 7 correlations were in the hypothesized direction. Results along with those of other studies are discussed as casting doubt on the plausibility of the contingency model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)