Influence of intergranular phases on edge integrity of Si3N4/SiC wood cutting tools

Si₃N₄/SiC composites used for industrial wood cutting were processed by a near net shape route involving gas pressure sintering with sintering additives such as Al₂O₃, La₂O₃, Y₂O₃ and MgO. The cutting edge integrity of these knives was tested in a cutting trial and compared to knives made by a hot pressing route. It was found that the intergranular phase has a crucial influence on the cutting edge integrity. The boundary phase was analysed by EFTEM and EDX mapping on TEM samples: in gas pressure sintered composites the crystallisation of the apatite Y₅Si₃O₁₂N phase was identified. In the hot pressed composite the boundary phase consisted only of silicates. These composites showed better edge stability than cutting tools with a Y-N-apatite phase. The formation of the type of intergranular phase was found to be determined by the amount of MgO sintering aid and the temperature of the post sintering heat treatment.     

Nevermore Shall the Stranger Ride.

A favorite theme which runs through stories of the Old West goes something like this: "When the tall saddle-weary stranger rode into town the local inhabitants carefully avoided asking about his past; everyone had a past but was free to reveal or conceal it as he saw fit." There is evidence that this philosophy did, in fact, prevail in the Old West. What a man had done in the past was irrelevant. In this column the author points out that this is no longer possible. The recent development of accuracy and efficiency of machines has begun to change this situation. Large amounts of personal data are increasingly used by governmental officials at all levels in granting, modifying, and denying the small everyday privileges and responsibilities which ultimately have major significance in our social, economic, personal, and vocational lives. With little effort, intelligence concerning all individuals could be collected, keyed to the magic number, and retained in a central repository for immediate reference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of sintering and sintering additives on the mechanical and microstructural characteristics of Si3N4/SiC wood cutting tools

Si₃N₄/SiC cutting tools were fabricated by industrial near net shape fabrication processes. The samples were consolidated by gas-pressure sintering and pressure less sintering using three different additive systems. The mechanical and microstructural properties were compared to composites made by hot pressing. The composites fabricated by gas-pressure sintering showed 99% density, the Vickers hardness was 17.2 GPa and the fracture toughness reached 4.5 MPa√m. Machining trials on wood showed that a post-sintering treatment by hot isostatic pressing increases the integrity of the cutting tip due to a devitrification of the intergranular phase.     

Psychologists and cartoonists.

"To assess one component of the public image of the psychologist… the present writers have theorized that a content or thematic analysis of cartoons might be relevant." An analysis of 4760 cartoons contained in 6 popular magazines for the years 1949 and 1959 led to the conclusions that: (a) considerable overlap in public image does occur between psychologists, psychiatrists, and other psychologically oriented personnel; (b) psychology as a science and as a profession does not appear to excite the public imagination and generate public interest; (c) psychology has kept pace with members of various other professions and occupations; (d) the psychologist does not seem to have any distinctive identifying symbol which he can easily claim as his own. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The ABC maltose transporter

OBJECTIVE: To define the electrophysiologic mechanism(s) by which MCI-154, a putative Ca2+ sensitizer, produces a positive inotropic response without a positive chronotropic response, we examined effects of MCI-154 on the action potential of atrial preparations and the membrane currents of atrial myocytes. METHODS: The action potentias were recorded from left atrial and sinoatrial node preparations of guinea pigs by the use of standard microelectrode techniques. The whole-cell membrane currents were recorded from enzymatically-dissociated guinea pig atrial myocytes using conventional patch clamp techniques. RESULTS: In isolated left atria, MCI-154 increased the developed tension in a concentration-dependent manner. MCI-154 at concentrations of 10 and 100 microM increased the action potential duration (APD) in left atria stimulated at 0.5 Hz. In sinoatrial node preparations MCI-154 at a concentration of 100 microM produced a negative chronotropic response and prolonged APD. In single right atrial myocytes, MCI-154 at concentrations of 10 and 100 microM failed to increase the inward L-type Ca2+ current, but decreased the delayed rectifier K+ current (IK) in a concentration-dependent manner. MCI-154 decreased IK elicited by short depolarizing pulses more markedly than that induced by long depolarizing pulses. In addition, MCI-154 produced only a little inhibition of IK in the presence of E-4031, a specific blocker of rapidly activating component of IK (IKr). CONCLUSIONS: MCI-154 preferentially blocks IKr and the inhibitory action on IKr may be partly involved in the negative chronotropic and positive inotropic responses in atrial preparations.     

Quantification of biographical data for predicting vocational rehabilitation success.

To devise an instrument based on biographical data to classify applicants for State vocational rehabilitation services in terms of success and to construct expectancy charts to indicate probability of success of future applicants. The Ss were 200 clients closed in fiscal year 1960 as being employed and 200 closed in fiscal year 1960 as being unemployed, as well as 40 in each category closed during fiscal year 1961. 86 items of personal data were obtained for key K1 and 20 selected items were obtained for key K2. Results were: variance between criterion subgroups could be maximized for classification, scores could be derived to classify clients, scores could be combined to establish expectancy charts, and K2 predicted expectancies better than K1. (PsycINFO Database Record (c) 2010 APA, all rights reserved)