Development of a modular dynamometer for triaxial cutting force measurement in turning

Accurate and reliable measurement of cutting forces in turning is essential for tool geometry, tool trajectory and cutting parameters optimization, as well as for tool condition monitoring and machinabilty testing. In this work, an innovative dynamometer for triaxial cutting force measurement in turning, specifically designed to be applied at a milling-turning CNC machine tool endowed with an indexable head, is presented. The device is based on a piezoelectric force ring integrated into a commercial toolshank, and its modular design allows the easy change of the cutting insert without altering sensor preload. The prototype device was assembled and experimentally tested by means of static calibration and dynamic identification, which evidenced good static and dynamic characteristics. Eventually, the sensor was tested in operating conditions by machining a benchmark workpiece.     

Development of an intelligent multisensor chatter detection system in milling

The development of a chatter detection system based on multiple sensors and suitable for application in industrial conditions was investigated in this paper. The signals obtained from a monitoring system composed of accelerometers mounted on the machine head and an axial force sensor were processed by using advanced signal analysis techniques such as wavelet decomposition. The statistical parameters obtained from wavelet decomposition were used to detect chatter by using an artificial intelligence classification system based on neural networks. The outputs of the neural networks for each sensor signal were further combined by using different strategies in order to obtain a multisensor chatter indicator. The performances of different strategies were evaluated by using experimental data, evidencing that it is possible to obtain an efficient chatter detection system both in terms of accuracy and of robustness against malfunctions and compatible with modern machine tool operation and automation.     

Influence of the valve lubricant on the aerodynamic particle size of a metered dose inhaler

Presented in this work are the results of a study designed to investigate the impact of valve lubricant (i.e., silicone oil) on the aerodynamic particle size distribution (PSD) of a steroid suspension metered dose inhaler (MDI) containing propellant HFA-227. The objective of this study was to explore whether the valve lubricant, which is often used in MDI products to prevent valve sticking, can enter an MDI product and potentially impact the aerosol spray dynamics. The results of this work have shown that samples containing valves with high silicone levels produced a larger aerodynamic particle size (by cascade impaction) than samples with low-silicone or silicone-free valves. It is postulated that the presence of silicone in the product may increase the propensity for drug aggregation, thereby leading to an increase in the aerodynamic particle size of the emitted aerosol. These findings stress the importance of evaluating the effects of valve lubricant on the aerodynamic PSD in the early formulation development stage of an MDI.     

Entry port selection for detecting particle size differences in metered dose inhaler formulations using cascade impaction

Different sized glass entry ports were evaluated for their drug collection efficiency during aerodynamic particle sizing of metered dose inhalers (MDIs) using cascade impaction. A comparison was made between collection efficiency in the entry port, impactor plates, and filter using the 1 L, 2 L, and 20 L glass entry ports and the USP and twin impinger entry ports. Entry port losses were dependent on the size of entry port selected, with 1-2 L ports showing optimal recovery on impactor plates, compared to the USP entry port. The 1 L entry port was further compared with the USP entry port in its ability to discriminate between subtle changes in particle size distribution (PSD) in an investigational hydrofluoroalkane (HFA)-based MDI formulation. Deliberately induced differences during product manufacture were easily detected using the 1 L entry port with the Andersen cascade impactor. The USP port was unable to distinguish among products with small particle size differences. An alternative entry port such as the 1 L glass entry port used in this study may provide better means of characterizing the PSD during formulation development and stability testing of MDIs.     

Influence of the size of micronized active pharmaceutical ingredient on the aerodynamic particle size and stability of a metered dose inhaler

Pharmaceutical inhalers are often used to treat pulmonary diseases. Only active pharmaceutical ingredient (API) particles from these inhalers that are less than approximately 5 microm are likely to reach the lung and be efficacious. This study was designed to investigate the impact of micronized API particle size on the aerodynamic particle size distribution (PSD) profile and the particle size stability of a suspension metered dose inhaler (MDI) containing propellant HFA-227 (1,1,1,2,3,3,3 heptafluoropropane) and a corticosteroid. The median API particle size ranged from 1.1 microm to 1.8 microm (97% to 70% of particles <3 microm, respectively). This study showed that increasing the particle size of the API used to manufacture a suspension MDI product increased the aerodynamic PSD of the MDI product. Furthermore, upon storage of the MDI product under temperature cycling conditions, samples containing larger-size API particles were less stable with respect to their aerodynamic PSD than those with smaller-size API particles. It was found that size-dependent particle growth and/or aggregation of the suspended API may be occurring as a result of temperature cycling. In conclusion, this study has shown that the particle size of the raw API impacts the properties and stability of the emitted aerosol spray. Based on the findings from this study, it is recommended that the API particle size be carefully controlled in order to meet specifications set for the finished MDI product.     

Neuroticism, marital violence, and the moderating role of stress and behavioral skills.

Do high levels of neuroticism predict intimate partner violence (IPV)? Although neuroticism may predispose partners to increased risks of IPV perpetration, the extent to which it predicts such perpetration is likely to depend on the broader context of the relationship. Consistent with this prediction, the current longitudinal study of 169 community couples revealed that the effects of neuroticism on IPV perpetration over the first 4 years of marriage were moderated by observations of problem-solving behavior and objective ratings of chronic stress. Specifically, although husbands and wives who scored higher on a measure of neuroticism at the outset of marriage engaged in more IPV throughout the marriage on average, those who possessed more effective problem-solving skills or experienced lower levels of stress were significantly less likely to engage in IPV. Results highlight the importance of considering the broader relationship context when examining predictors of specific interpersonal processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimating the Depth of Deposition (Erosion) at Slope Transitions on Alluvial Fans

A typical flood mitigation structure on an alluvial fan consists of a dike∕channel system that deflects the flow away from the area requiring protection. Such a structure results in a change in channel slope from steep to mild when the flow first encounters the structure and from mild to steep when the flow is released at the downstream end of the structure. These slope changes result in sediment deposition at the point where the flow encounters the structure and erosion at the point of release. In designing the structure, the length and maximum depth of deposition (erosion) are critical variables that must be estimated. A simple model to estimate these variables is proposed and developed. The hypothesized model has been used to estimate the length and depth of deposition (erosion) on several projects in southern Nevada.     

Stability of Plant Defensive Traits Among Populations in Two Eucalyptus Species Under Elevated Carbon Dioxide

Plant secondary metabolites (PSMs) mediate a wide range of ecological interactions. Investigating the effect of environment on PSM production is important for our understanding of how plants will adapt to large scale environmental change, and the extended effects on communities and ecosystems. We explored the production of PSMs under elevated atmospheric carbon dioxide ([CO₂]) in the species rich, ecologically and commercially important genus Eucalyptus. Seedlings from multiple Eucalyptus globulus and E. pauciflora populations were grown in common glasshouse gardens under elevated or ambient [CO₂]. Variation in primary and secondary chemistry was determined as a function of genotype and treatment. There were clear population differences in PSM expression in each species. Elevated [CO₂] did not affect concentrations of individual PSMs, total phenolics, condensed tannins or the total oil yield, and there was no population by [CO₂] treatment interaction for any traits. Multivariate analysis revealed similar results with significant variation in concentrations of E. pauciflora oil components between populations. A [CO₂] treatment effect was detected within populations but no interactions were found between elevated [CO₂] and population. These eucalypt seedlings appear to be largely unresponsive to elevated [CO₂], indicating stronger genetic than environmental (elevated [CO₂]) control of expression of PSMs.     

Transient organic jams in Puerto Rican mountain streams after hurricanes

Extreme storms in forested environments commonly increase inputs of coarse particulate organic matter (CPOM) and large wood (LW) to streams. Protruding boulders and bedforms, mid‐channel bars, and standing trees can trap CPOM and LW. These organic accumulations can become large enough to span the bankfull channel width, or the accumulations can be predominantly along the channel margins. We refer to both types of accumulations as transient organic jams (TOJs). TOJs can create diverse geomorphic and ecological effects in channel and floodplain environments. We use data collected from mountain streams of the Luquillo Mountains of north‐eastern Puerto Rico following September 2017 Hurricanes Irma and Maria. We examine the location, characteristics, and geomorphic effects of TOJs in channel segments representing diverse drainage areas and channel gradients. We ask three questions: (a) Does the downstream spacing of TOJs correlate with variables such as drainage area or channel gradient? (b) What variables best predict the volume of organic matter within individual TOJs or within a channel segment? And (c) is there a threshold within a river network that separates channel segments with channel‐spanning versus marginal TOJs? Datasets include multiple TOJs along each of 12 stream segments and presence/absence of channel‐spanning TOJs along an additional six streams. Data analysis with multiple linear regressions indicates that downstream spacing, average volume, and total volume per channel length of TOJs correlate significantly with bankfull channel width. Using the akaike information criterion with correction (AICc) model selection method, Strahler stream order has the most influence on the probability of TOJs being marginal or spanning.