Structural Characteristics of Allomyrina Dichotoma Beetle＇s Hind Wings for Flapping Wing Micro Air Vehicle

In this study, we present a complete structural analysis ofAllomyrina dichotoma beetle＇s hind wings by investigating their static and dynamic characteristics. The wing was subjected to the static loading to determine its overall flexural stiffness. Dy- namic characteristics such as natural frequency, mode shape, and damping ratio of vibration modes in the operating frequency range were determined using a Bruel ＆ Kjaer fast Fourier transform analyzer along with a laser sensor. The static and dynamic characteristics of natural Allomyrina dichotoma beetle＇s hind wings were compared to those of a fabricated artificial wing. The results indicate that natural frequencies of the natural wing were significantly correlated to the wing surface area density that was defined as the wing mass divided by the hind wing surface area. Moreover, the bending behaviors of the natural wing and artificial wing were similar to that of a cantilever beam. Furthermore, the flexural stiffness of the artificial wing was a little higher than that of the natural one whereas the natural frequency of the natural wing was close to that of the artificial wing. These results provide important information for the biomimetic design of insect-scale artificial wings, with which highly ma- neuverable and efficient micro air vehicles can be designed.     

Vehicle manufacturing water use and consumption: an analysis based on data in automotive manufacturers’ sustainability reports

Purpose

The goal of this study is to develop an estimate of water use and consumption in automotive manufacturing to enhance the data quality of vehicle life cycle assessments that include life cycle water impacts. A benchmark is developed to compare water resources across manufacturing and nonproduction-related manufacturing processes, including an indication whether indirect water consumption due to electricity generation is significant.

Methods

Data from 12 original equipment manufacturers’ (OEM’s) sustainability reports are examined for the years 2006 to 2010. Distinctions are made between “water use” and “water consumption.” These factors are divided by total reported production to develop use and consumption values in cubic meter/vehicle for comparison. Additionally, total energy consumption is converted to indirect water consumption based on the water consumed in the generation of electricity for the electricity grid mix.

Results and discussion

Excluding outliers, average direct water use is 5.20 and 5.95 m³/vehicle for manufacturing and company-wide activities, respectively, with corresponding standard deviations of 1.42 and 1.20 m³/vehicle. Average direct water consumption was calculated to be 1.25 and 4.29 m³/vehicle for manufacturing and company-wide activities, respectively, with corresponding standard deviations of 0.52 and 1.56 m³/vehicle. Average indirect water consumption due to electricity consumption is found to be 2.21 m³/vehicle. Variability arises through different understandings on the words “consumption” and “use,” reporting continuity between years and in classification of data as it relates to manufacturing, nonmanufacturing, or company-wide activities.

Conclusions

These water values show that needs vary widely across OEMs. Additionally, the magnitude of the indirect water consumption results indicates that OEMs should focus on both indirect and direct water consumption to reduce their overall water footprint. The results also highlight the potential for significance and variability in indirect water consumption, in particular for “cradle-to-gate” type of impact assessments, dependent on electricity generation water consumption assumptions. It is hoped that with the introduction of water reporting standards like the International Organization of Standardization 14046, manufacturers will provide a more comprehensive summary of their water use and consumption in the future.     

Formulation and Release Behavior of Doxycycline–Alginate Hydrogel Microparticles Embedded into Pluronic F127 Thermogels as a Potential New Vehicle for Doxycycline Intradermal Sustained Delivery

The aim of this work was the formulation and characterization of alginate (ALG)–doxycycline (DOX) hydrogel microparticles (MPs) embedded into Pluronic F127 thermogel for DOX intradermal sustained delivery. ALG–DOX MPs were formed by adding a solution of the drug into a 1.5% polymer solution while stirring. The MPs were cross-linked by dispersion into a 1.2% CaCl₂ solution. Free MPs were characterized in terms of size, drug content, and release behavior by HPLC and UV–vis. DOX and hydrogel MPs were embedded into PF127, PF127-HPMC, and PF127-Methocel thermogels. The thermogels were characterized in terms of gelling time, morphology, and release behavior. A target release period of 4–7 days was considered optimal. The hydrogel MPs were about 20 μm in size with 90% of the population <59 μm. Drug content was about 35% (w/w). DOX released rapidly from the MPs, 90% within 2 days. An expected faster release was observed for free DOX from the thermogels with 80–90% of drug released after 3.5–4 h even in the presence of 1% HPMC or Methocel. The release was sustained after embedding the MPs into PF127 and PF127-HPMC thermogels. In particular, the PF127-HPMC thermogel showed an almost linear release, reaching 80% after 3 days and 90% up to 6 days. Although a further characterization and formulation assessment is required to optimize MP characteristics, ALG/DOX-loaded hydrogel MPs, when embedded into a PF127-HPMC thermogel, show a potential for achieving a 7-day sustained release formulation for DOX intradermal delivery.