CMOS compatible metamaterial absorbers for hyperspectral medium wave infrared imaging and sensing applications

We experimentally demonstrate a CMOS compatible medium wave infrared metal-insulator-metal (MIM) metamaterial absorber structure where for a single dielectric spacer thickness at least 93% absorption is attained for 10 separate bands centred at 3.08, 3.30, 3.53, 3.78, 4.14, 4.40, 4.72, 4.94, 5.33, 5.60 μm. Previous hyperspectral MIM metamaterial absorber designs required that the thickness of the dielectric spacer layer be adjusted in order to attain selective unity absorption across the band of interest thereby increasing complexity and cost. We show that the absorption characteristics of the hyperspectral metamaterial structures are polarization insensitive and invariant for oblique incident angles up to 25° making them suitable for practical implementation in an imaging system. Finally, we also reveal that under TM illumination and at certain oblique incident angles there is an extremely narrowband Fano resonance (Q < 50) between the MIM absorber mode and the surface plasmon polariton mode that could have applications in hazardous/toxic gas identification and biosensing

Octave-spanning broadband absorption of terahertz light using metasurface fractal-cross absorbers

Synthetic fractals inherently carry spatially encoded frequency information that renders them as an ideal candidate for broadband optical structures. Nowhere is this more true than in the terahertz (THz) band where there is a lack of naturally occurring materials with valuable optical properties. One example are perfect absorbers that are a direct step toward the development of highly sought after detectors and sensing devices. Metasurface absorbers that can be used to substitute for natural materials suffer from poor broadband performance, while those with high absorption and broadband capability typically involve complex fabrication and design and are multilayered. Here, we demonstrate a polarization-insensitive ultrathin (∼λ/6) planar metasurface THz absorber composed of supercells of fractal crosses capable of spanning one optical octave in bandwidth, while still being highly efficient. A sufficiently thick polyimide interlayer produces a unique absorption mechanism based on Salisbury screen and antireflection responses, which lends to the broadband operation. Experimental peak absorption exceeds 93%, while the average absorption is 83% from 2.82 THz to 5.15 THz. This new ultrathin device architecture, achieving an absorption-bandwidth of one optical octave, demonstrates a major advance toward a synthetic metasurface blackbody absorber in the THz ban

Linking organizational trust and performance through ambidexterity

Purpose – The literature provides mixed empirical evidence on the trust–performance relationship. The purpose of this paper is to shed additional light on this relationship, using organizational ambidexterity as an explanatory variable. Design/methodology/approach – A structural equation technique was used to examine survey data obtained from 377 Spanish organic agro-food industries. Findings – The results obtained provide support to show that organizational ambidexterity has a mediating role in the relationship between organizational trust and firm performance, in the organic agro-food industry. Research limitations/implications – This study used a sample taken from only one industry and country. Future research could expand the model to other countries and industries. Practical implications – This study suggests that managers could use tools to enhance organizational trust that would help to improve firm performance, given that trust can cause employees to adopt behaviors related to ambidexterity. Therefore, managers can use trust as a mechanism to encourage more stable relationships, increase the transfer of existing knowledge, facilitate experimentation and express ideas to promote organizational ambidexterity, thus benefiting firm performance. Originality/value – This research paper offers a new insight into how ambidexterity affects the organizational trust-firm performance relationship. Even though there is growing theoretical importance given to the concepts of trust and ambidexterity, the empirical evidence that demonstrates how both variables are related to firm performance, especially in emerging sectors, is scarce

Single Shot Temporal Action Detection

Temporal action detection is a very important yet challenging problem, since videos in real applications are usually long, untrimmed and contain multiple action instances. This problem requires not only recognizing action categories but also detecting start time and end time of each action instance. Many state-of-the-art methods adopt the "detection by classification" framework: first do proposal, and then classify proposals. The main drawback of this framework is that the boundaries of action instance proposals have been fixed during the classification step. To address this issue, we propose a novel Single Shot Action Detector (SSAD) network based on 1D temporal convolutional layers to skip the proposal generation step via directly detecting action instances in untrimmed video. On pursuit of designing a particular SSAD network that can work effectively for temporal action detection, we empirically search for the best network architecture of SSAD due to lacking existing models that can be directly adopted. Moreover, we investigate into input feature types and fusion strategies to further improve detection accuracy. We conduct extensive experiments on two challenging datasets: THUMOS 2014 and MEXaction2. When setting Intersection-over-Union threshold to 0.5 during evaluation, SSAD significantly outperforms other state-of-the-art systems by increasing mAP from 19.0% to 24.6% on THUMOS 2014 and from 7.4% to 11.0% on MEXaction2.Comment: ACM Multimedia 201

Fractal Metasurface Absorbers with Octave-Spanning Bandwidth

Synthetic fractals offer a degree of freedom for varying resonance frequency, and are an ideal candidate for broadband absorbing devices – especially in the terahertz (THz) band where there is a lack of naturally absorbing materials. Metasurface absorbers often suffer from poor broadband performance, whilst strongly-absorbing broadband devices are typically complex multilayer structures [1,2]. Here, we overcome this limitation by developing an ultra-broadband metasurface absorber based on fractal cross resonators [3], capable of experimentally achieving one Optical Octave bandwidth and peak absorption of 93%. We attribute this to a novel absorption mechanism based on both Salisbury screen and anti-reflection responses. Such work is beneficial in realising THz blackbody absorbers, and for bolometric sensing capabilities

Diseño y montaje de una planta piloto para la extracción de quitina y proteínas

El proyecto se basó en el diseño y montaje de una planta piloto para la extracción química de Quitina y proteínas a partir de desechos de crustáceos (camarón y langostino). Se determinó el contenido de humedad del material y las condiciones experimentales óptimas de volumen y concentración de los reactivos involucrados en el proceso. Además, se realizó un análisis técnico y económico del mismo. Los resultados mostraron que la materia prima tiene un alto contenido de humedad entre 68-80% y que las condiciones experimentales para la obtención de Quitina dependen fuertemente de las características del material. Bajo estas condiciones se obtuvo una recuperación mayor del 98% para el caso de caparazón de camarón y de aproximadamente un 58% en el caso del langostino. Por otro lado, para la extracción de proteínas se encontró que la mayor producción ocurre a pH 4.0 y con soluciones provenientes del proceso de desproteinización, sin trituración previa de la materia prima. El estudio técnico proporcionó información básica sobre los costos e inversión del proceso operativo, datos sobre las instalaciones y los equipos asociados al proceso productivo. El análisis económico mostró que se debe tener una inversión inicial de US $10,520.94 para el montaje de la planta piloto y de US$ 4,852.58 para gastos de transporte y operación por seis meses. Palabras claves: caparazón de camarón; langostino; método químico; planta piloto; proteínas, quitina. DOI: http://dx.doi.org/10.5377/nexo.v22i2.42 Nexo: Revista Científica Vol. 22, No. 02, pp.45-55/Diciembre 200

Diseño y montaje de una planta piloto para la extracción de quitina y proteínas

The aim of this project was the design and set up of a pilot plant for chitin and proteins chemical recovery from shrimp shells and squat lobsters. The moisture content of the material and optimal experimental conditions of volume and concentration of the process reagents were determined. Additionally, a technical and economical analysis of production process was performed. The results showed that the raw material has high moisture content, between 68-80% wet basis, and the experimental conditions for chitin extraction depend strongly on the material characteristics. Under these conditions, recuperation of 98% for shrimp shells and approximately of 58% for squad lobster was obtained. On the other hand, the proteins recovery showed that the largest production occurs at pH 4.0 and using solutions from deproteination step without grinding of raw material. The technical study provided basic information about set up costs and operating process investment, and data about facilities and equipments related to productive process. The assessment revealed that an initial investment of US $10,520.94 for pilot plant set up and US$ 4,852.58 for transport and operating costs for six months must be done. Keywords: chemical method; chitin; pilot plant; proteins; shrimp shell; squat lobster.DOI: 10.5377/nexo.v22i2.42Nexo: Revista Científica Vol. 22, No. 02, pp.45-55/Diciembre 2009El proyecto se basó en el diseño y montaje de una planta piloto para la extracción química de Quitina y proteínas a partir de desechos de crustáceos (camarón y langostino). Se determinó el contenido de humedad del material y las condiciones experimentales óptimas de volumen y concentración de los reactivos involucrados en el proceso. Además, se realizó un análisis técnico y económico del mismo. Los resultados mostraron que la materia prima tiene un alto contenido de humedad entre 68-80% y que las condiciones experimentales para la obtención de Quitina dependen fuertemente de las características del material. Bajo estas condiciones se obtuvo una recuperación mayor del 98% para el caso de caparazón de camarón y de aproximadamente un 58% en el caso del langostino. Por otro lado, para la extracción de proteínas se encontró que la mayor producción ocurre a pH 4.0 y con soluciones provenientes del proceso de desproteinización, sin trituración previa de la materia prima. El estudio técnico proporcionó información básica sobre los costos e inversión del proceso operativo, datos sobre las instalaciones y los equipos asociados al proceso productivo. El análisis económico mostró que se debe tener una inversión inicial de US $10,520.94 para el montaje de la planta piloto y de US$ 4,852.58 para gastos de transporte y operación por seis meses. Palabras claves: caparazón de camarón; langostino; método químico; planta piloto; proteínas, quitina.DOI: http://dx.doi.org/10.5377/nexo.v22i2.42Nexo: Revista Científica Vol. 22, No. 02, pp.45-55/Diciembre 200