scholarly journals Design of a Purely Mechanical Sensor-Controller Integrated System for Walking Assistance on an Ankle-Foot Exoskeleton

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3196 ◽  
Author(s):  
Xiangyang Wang ◽  
Sheng Guo ◽  
Haibo Qu ◽  
Majun Song
Keyword(s):  
Human Body ◽  
Proper Time ◽  
Metabolic Cost ◽  
Human Locomotion ◽  
Essential Elements ◽  
Integrated System ◽  
External Power Source ◽  
Key Factor ◽  
External Power ◽  
The One

Propulsion during push-off (PO) is a key factor to realize human locomotion. Through the detection of real-time gait stage, assistance could be provided to the human body at the proper time. In most cases, ankle-foot exoskeletons consist of electronic sensors, microprocessors, and actuators. Although these three essential elements contribute to fulfilling the function of the detection, control, and energy injection, they result in a huge system that reduces the wearing comfort. To simplify the sensor-controller system and reduce the mass of the exoskeleton, we designed a smart clutch in this paper, which is a sensor-controller integrated system that comprises a sensing part and an executing part. With a spring functioning as an actuator, the whole exoskeleton system is completely made up of mechanical parts and has no external power source. By controlling the engagement of the actuator based on the signal acquired from the sensing part, the proposed clutch enables the ankle-foot exoskeleton (AFE) to provide additional ankle torque during PO, and allows free rotation of the ankle joint during swing phase, thus reducing the metabolic cost of the human body. There are two striking advantages of the designed clutch. On the one hand, the clutch is lightweight and reliable—it resists the possible shock during walking since there is no circuit connection or power in the system. On the other hand, the detection of gait relies on the contact states between human feet and the ground, so the clutch is universal and does not need to be customized for individuals.

scholarly journals Automatic Solar Panel Tracking System

2019 ◽  
Vol 9 (1) ◽  
pp. 264-269
Keyword(s):  
Solar Energy ◽  
Alternative Energy ◽  
Tracking System ◽  
Solar Panel ◽  
Controlled System ◽  
Solar Tracking ◽  
External Power Source ◽  
External Power ◽  
R 134A ◽  
The One

Solar Energy is the one of best renewable source of alternative energy. The efficiency of the solar panel can be improved more by tracking it in such way that it always faces perpendicular to the sun-rays throughout the day rather than it is kept fixed at an angle. At present, there are three methods for solar tracking, out of which refrigerant method is found to be more efficient as it is of a passive type and requires no external power source for its operation. In this project we have used R-134a [Tetrafluoroethene (CF3CH2F)] as the refrigerant medium for tracking the panel. To store the refrigerant, we have made use of two canisters and a copper conduit for connecting the canisters. The tracking system works on the principle of Differential Pressure Controlled system where high-pressure refrigerant from one canister to other flows and due to imbalance in the weight of canisters, the panel will tilt in the direction of the side where the weight is high due to gravity. Thus, our main objective is to harvest more solar energy at a much lower cost than the available trackers.

scholarly journals Rapid and Localized Soldering Using Reactive Films for Electronic Applications

2019 ◽  
Vol 16 (4) ◽  
pp. 182-187
Author(s):  
Rabih Khazaka ◽  
Donatien Martineau ◽  
Toni Youssef ◽  
Thanh Long Le ◽  
Stéphane Azzopardi
Keyword(s):  
Phase Distribution ◽  
Coefficient Of Thermal Expansion ◽  
Applied Pressure ◽  
Temperature Sensitive ◽  
Soldering Process ◽  
External Power Source ◽  
Solder Reflow ◽  
External Power ◽  
The One ◽  
Joint Quality

Abstract The rapid and localized heating techniques allow the joining of temperature-sensitive materials and components without thermal induced damage commonly encountered when high-temperature solder reflow processes are used. This is also advantageous for making assemblies with materials having a large difference in the coefficient of thermal expansion without induced bowing or cracking. The use of exothermic reactive foil sandwiched between solder preforms is a promising local and rapid soldering process because it does not require any external heat source. The reactive foil is formed from alternatively stacked nanolayers of Ni and Al until it reaches the total film thickness. Once the film is activated by using an external power source, a reaction takes place and releases such an amount of energy that is transferred to the solder preforms. If this amount of energy is high enough, solder preforms melt and insure the adhesion between the materials of the assembly. The influences of the applied pressure, the reactive film (RF) thickness as well as the solder, and the attached materials chemical composition and thickness were investigated. It was shown that the applied pressure during the process has a strong effect on the joint initial quality with voids ratio decreases from 64% to 26% for pressure values between .5 and 100 kPa, respectively. This can be explained by the improvement of the solder flow under higher pressure leading to a better surface wettability and voids elimination. Otherwise, the joint quality was found to be improved once the solder melting duration is increased. This relationship was observed when the thickness of the reactive foil is increased (additional induced energy) or the thickness of solders, Cu, and/or Si is decreased (less energy consumption). The microstructure of the AuSn joint achieved using the RFs shows very fine phase distribution compared with the one obtained using conventional solder reflow process in the oven because of high cooling rate. The mechanical properties of the joint were evaluated using shear tests performed on 350-μm-thick silicon diodes assembled on active metal brazed substrates under a pressure of 100 kPa. The RFs were 60 μm thick and sandwiched between two 25-μm-thick 96.5Sn3Ag.5Cu (SAC) preforms. The voids ratio was about 37% for the tested samples and shear strength values above 9.5 MPa were achieved which remains largely higher than MIL-STD-883H requirements. Finally, the process impact on the electrical properties of the assembled diodes was compared with a commonly used solder reflow assembly and the results show a negligible variation.

Biochemical studies on the production of neuraminidase by environmental isolates of Vibrio cholerae non-O1 from Bulgaria

2011 ◽  
Vol 57 (7) ◽  
pp. 606-610 ◽  
Author(s):  
Rumyana Eneva ◽  
Stephan Engibarov ◽  
Tanya Strateva ◽  
Radoslav Abrashev ◽  
Ignat Abrashev
Keyword(s):  
Vibrio Cholerae ◽  
Pathogenic Bacteria ◽  
Environmental Isolates ◽  
Anaerobic Conditions ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Cholera Vibrio ◽  
Key Factor ◽  
Aeration Conditions ◽  
The One

Neuraminidase is a key factor in the infectious process of many viruses and pathogenic bacteria. The neuraminidase enzyme secreted by the etiological agent of cholera — Vibrio cholerae О1 — is well studied in contrast with the one produced by non-O1/non-O139 V. cholerae. Environmental non-O1/non-O139 V. cholerae isolates from Bulgaria were screened for production of neuraminidase. The presence of the neuraminidase gene nanH was detected in 18.5% of the strains. Тhe strain showing highest activity (30 U/mL), V. cholerae non-O1/13, was used to investigate the enzyme production in several media and at different aeration conditions. The highest production of extracellular neuraminidase was observed under microaerophilic conditions, which is possibly related to its role in the infection of intestine epithelium, where the oxygen content is low. On the other hand, this is another advantage of the microbe in such microaerophilic environments as sediments and lake mud. The highest production of intracellular neuraminidase was observed at anaerobic conditions. The ratio of extracellular to intracellular neuraminidase production in V. cholerae was investigated. The temperature optimum of the enzyme was determined to be 50 °C and the pH optimum to be 5.6–5.8.

scholarly journals Heritage Artefacts in the COVID-19 Era: The Aura and Authenticity of 3D Models

2021 ◽  
Vol 7 (1) ◽  
pp. 519-539
Author(s):  
Thiago Minete Cardozo ◽  
Costas Papadopoulos
Keyword(s):  
User Experience ◽  
Three Dimensional ◽  
3D Models ◽  
Essential Elements ◽  
The Other ◽  
Social Distancing ◽  
The Public ◽  
Affective Experiences ◽  
The One ◽  
Digital Engagement

Abstract Museums have been increasingly investing in their digital presence. This became more pressing during the COVID-19 pandemic since heritage institutions had, on the one hand, to temporarily close their doors to visitors while, on the other, find ways to communicate their collections to the public. Virtual tours, revamped websites, and 3D models of cultural artefacts were only a few of the means that museums devised to create alternative ways of digital engagement and counteract the physical and social distancing measures. Although 3D models and collections provide novel ways to interact, visualise, and comprehend the materiality and sensoriality of physical objects, their mediation in digital forms misses essential elements that contribute to (virtual) visitor/user experience. This article explores three-dimensional digitisations of museum artefacts, particularly problematising their aura and authenticity in comparison to their physical counterparts. Building on several studies that have problematised these two concepts, this article establishes an exploratory framework aimed at evaluating the experience of aura and authenticity in 3D digitisations. This exploration allowed us to conclude that even though some aspects of aura and authenticity are intrinsically related to the physicality and materiality of the original, 3D models can still manifest aura and authenticity, as long as a series of parameters, including multimodal contextualisation, interactivity, and affective experiences are facilitated.

Bodily Dasein and Chinese Script Components

2017 ◽  
Vol 2017 (2) ◽  
Author(s):  
Kwan Tze-wan
Keyword(s):  
Human Body ◽  
The Body ◽  
Chinese Script ◽  
Chinese Characters ◽  
Body Parts ◽  
Constitutive Principle ◽  
New Perspective ◽  
Social Environmental ◽  
The One ◽  
Definition Of

AbstractIn the Shuowen, one of the earliest comprehensive character dictionaries of ancient China, when discussing where the Chinese characters derive their structural components, Xu Shen proposed the dual constitutive principle of “adopting proximally from the human body, and distally from things around.” This dual emphasis of “body” and “things around” corresponds largely to the phenomenological issues of body or corporeality on the one hand, and lifeworld on the other. If we borrow Heidegger’s definition of Dasein as Being-in-the world, we can easily arrive at a reformulation of Xu Shen’s constitutive principle of the Chinese script as one that concerns “bodily Dasein.” By looking into various examples of script tokens we can further elaborate on how the Chinese make use not only of the body in general but various body parts, and how they differentiate their life world into material nature, living things, and a multifaceted world of equipment in forming a core basis of Chinese characters/components, upon which further symbolic manipulation such as “indication”, “phonetic borrowing”, semantic combination, and “annotative derivation”, etc. can be based. Finally, examples will be cited to show how in the Chinese scripts the human body (and its parts) might interact with other’s bodies (and their parts) or with “things around” (whether nature, living creatures, or artifacts) in various ways to cover the social, environmental, ritual, technical, economical, and even intellectual aspects of human experience. Bodily Dasein, so to speak, provides us with a new perspective of understanding and appreciating the entire scope of the Chinese script.

scholarly journals Molecules and Functions of Cornus officinalis Bark Volatiles

2018 ◽  
pp. 828
Author(s):  
Wanxi Peng
Keyword(s):  
Amino Acids ◽  
Weight Loss ◽  
Human Body ◽  
Essential Elements ◽  
Pharmacological Effects ◽  
Bioactive Components ◽  
Medicinal Material ◽  
Cornus Officinalis ◽  
Analysis Methods ◽  
Made In

Cornus officinalis Sieb. et Zucc is a traditional Chinese valuable medicinal material. Clinically, it is customary to use ripe fruits from which seeds have been removed for medicinal purposes. The pulp contains 16 amino acids and a large number of essential elements for the human body. In recent years, with the expansion of the application of cornus officinalis, its pharmacological and pharmacological effects have been increasingly studied. At present, significant achievements have been made in the study of the bioactive components of cornus officinalis. The research of these achievements has been based on the research of the fruit of cornus officinalis. The study of branches or bark of cornus officinalis is very rare. With the fruit of cornus officinalis getting more and more attention, in order to solve the problem of the shortage of cornus officinalis fruit in the market, in this paper, starting from the study of bark of cornus officinalis, TGA-DTG and PY-GC-MS analysis methods were used to study the weight loss and pyrolysis of cornus officinalis bark, providing a basis for more fully utilizing cornus officinalis resources. With reference.

scholarly journals La electricidad en las relaciones España-Portugal

Finisterra ◽  
2012 ◽  
Vol 39 (78) ◽  
Author(s):  
Cayetano Espejo Marín
Keyword(s):  
Electric Power ◽  
European Community ◽  
Electricity Market ◽  
Essential Elements ◽  
The Other ◽  
Energy Resources ◽  
Electricity Supply ◽  
The One ◽  
New Phase ◽  
National Borders

From the early 1960s onwards, Spain and Portugal have maintained far-reaching programs for the exchange of electric power. These contacts have afforded, on the one hand, an increase in the security of electricity supply for both countries and, on the other, a better exploitation of their particular energy resources. The likely launching of the Iberian Electricity Market in April 2004 will lead to a new phase in the relations between Portugal and Spain. The new Market is based on three essential elements: i) the expansion of electric links along their shared national borders, ii) the setting up of a lone Operator for the single Iberian Market and iii) the coordination of the two Operators that exist nowadays, RED ELÉCTRICA DE ESPAÑA and REDE ELÉCTRICA NACIONAL. The Iberian Electricity Market will be the first to comprise countries of the European Community only and it will generate one-tenth of the electric power consumed in Europe, being the fourth largest producer.

scholarly journals CBX7 is Dualistic in Cancer Progression Based on its Function and Molecular Interactions

2021 ◽  
Vol 12 ◽  
Author(s):  
Jun Li ◽  
Taohui Ouyang ◽  
Meihua Li ◽  
Tao Hong ◽  
MHS Alriashy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cancer Progression ◽  
Circular Rnas ◽  
Regulate Gene Expression ◽  
Epigenetic Regulator ◽  
Key Factor ◽  
The One ◽  
Related Proteins ◽  
Polycomb Repressive Complex 1 ◽  
Oncosuppressor Genes

Chromobox protein homolog 7 (CBX7) is a member of the Chromobox protein family and participates in the formation of the polycomb repressive complex 1(PRC1). In cells, CBX7 often acts as an epigenetic regulator to regulate gene expression. However, pathologically, abnormal expression of CBX7 can lead to an imbalance of gene expression, which is closely related to the occurrence and progression of cancers. In cancers, CBX7 plays a dual role; On the one hand, it contributes to cancer progression in some cancers by inhibiting oncosuppressor genes. On the other hand, it suppresses cancer progression by interacting with different molecules to regulate the synthesis of cell cycle-related proteins. In addition, CBX7 protein may interact with different RNAs (microRNAs, long noncoding RNAs, circular RNAs) in different cancer environments to participate in a variety of pathways, affecting the development of cancers. Furthermore, CBX7 is involved in cancer-related immune response and DNA repair. In conclusion, CBX7 expression is a key factor in the occurrence and progression of cancers.

What Italian business disliked about a European common market

2008 ◽  
Vol 49 (2) ◽  
Author(s):  
Francesca Fauri
Keyword(s):  
Great Majority ◽  
Production Costs ◽  
Export Market ◽  
Export Demand ◽  
Italian Economy ◽  
Key Factor ◽  
Treaty Of Rome ◽  
The One ◽  
Medium Firms ◽  
Opening Up

AbstractThe possibility of enlarging Italy’s export market was the key factor that made industrialists repeatedly express their consent for a unified market, even in their earliest statements on the matter. The great majority of Italian business declared itself in favour of a united market dependent upon a given set of conditions: gradual abolition of tariffs, leveling of production costs among members, free circulation of workers (as well as of goods and capital) and inclusion in the Treaty of Art.109 on the resumption of tariff controls or measures of safeguard where a sudden crisis in the balance of payments occurs.The policy of Italian business towards EEC integration in those years was the result of a compromise between protectionist sectors (small-medium firms) on the one hand and, on the other, firms belonging to the so-called automobile cycle (Fiat, Pirelli etc.) and the engineering sector, whose growth had been led by export demand and favoured opening up the Italian economy to international competition.Once the Treaty of Rome was signed, there were issues that Italian industrialists did not like. However, on the whole, participation was never called into question and, despite a few skeptical voices, Italian business valued European integration as a unique opportunity to enlarge the market, increase foreign demand and improve competitiveness. The Italian economic miracle had begun to take shape.

scholarly journals Nonperturbative one-loop effective action for QED with Yukawa couplings

2018 ◽  
Vol 33 (27) ◽  
pp. 1850157 ◽  
Author(s):  
Theodore N. Jacobson ◽  
Tonnis ter Veldhuis
Keyword(s):  
Effective Action ◽  
Proper Time ◽  
Background Field ◽  
Field Approximation ◽  
Chiral Anomaly ◽  
Dirac Fermion ◽  
Yukawa Couplings ◽  
Time Formalism ◽  
The One ◽  
The Relationship

We derive the one-loop effective action for scalar, pseudoscalar, and electromagnetic fields coupled to a Dirac fermion in an extension of QED with Yukawa couplings. Using the Schwinger proper-time formalism and zeta-function regularization, we calculate the full nonperturbative effective action to one loop in the constant background field approximation. Our result is nonperturbative in the external fields, and goes beyond existing results in the literature which treat only the first nontrivial order involving the pseudoscalar. The result has an even and odd part, which are related to the modulus and phase of the fermion functional determinant. The even contribution to the effective action involves the modulus of the effective Yukawa couplings and is invariant under global chiral transformations while the odd contribution is proportional to the angle between the scalar and pseudoscalar couplings. In different limits the effective action reduces either to the Euler–Heisenberg effective action or the Coleman–Weinberg potential. We also comment on the relationship between the odd part of the effective action and the chiral anomaly in QED.

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