Advances In Structural Design Research Articles

Multiporphyrinic architectures: Advances in structural design for photodynamic therapy

AbstractRationally designed multiporphyrinic architectures for boosting photodynamic therapy (PDT) have attracted significant attentions recently years due to their great potential for light‐mediated generation of reactive oxygen species. However, there is still a gap between the structure design and their PDT performance for biomedical applications. This tutorial review provides a historical overview on (i) the basic concept of PDT for deeply understanding the porphyrin‐mediated PDT reactions, (ii) developing strategies for constructing porphyrinic architectures, like nanorings, boxes, metal‐organic frameworks (MOFs), covalent‐organic frameworks (COFs), vesicles, etc., where we classified into the following three categories: multiporphyrin arrays, porphyrinic frameworks, and others porphyrin assemblies, (iii) the various application scenarios for clinical cancer therapy and antibacterial infection. Also, the existing challenges and future perspectives on the innovation of porphyrinic architectures for clinical PDT applications are mentioned in the end section. Moreover, the porphyrinic nanomaterials with atomically precise architectures provide an ideal platform for investigating the relationship between structures and PDT outputs, design of personalized “all‐in‐one” theranostic agents, and the popularization and application in wider biomedical fields.

Effect of outrigger-belt truss system on the storey drift and maximum displacement of high-rise building

High-rise structures are becoming more common around the world, posing new challenges that necessitate ongoing technological foresight. When a structure’s height rises, it’s anticipated to have a lateral load-resisting system other than shear walls in place to negate the effect of lateral loads. However, advances in structural design and engineering have enabled building systems to withstand lateral forces such as wind and seismic stresses. There are numerous structural solutions tailored to resist lateral forces in the structure without adding to the plan area of the building to stabilize it against lateral load. The Outrigger-belt truss system is a common structural solution for successfully managing excessive drift caused by the lateral load. Hence, in this project, an attempt is made to investigate the characteristics of an Outrigger-Belt truss system. The seismic analysis is limited to the linear static method. A comparative analysis is done using STAAD Pro V8i SS6. Finally, the storey drift and maximum displacements obtained are calculated and the results are compared with the moment-resisting frame and the values are tabulated.

Concrete seawalls: A review of load considerations, ecological performance, durability, and recent innovations

Increasing frequency of extreme weather events, driven by climate change, coupled with growing population densities, have contributed to an increasing demand for coastal structures to protect and stabilize shorelines. Concrete seawalls are a common category of coastal protection structures, designed with the primary objectives of absorbing wave action, preventing coastline erosion, and alleviating flooding. Much research has been carried out on improving concrete seawall performance. This work is a review of the current state-of-the-art in concrete seawalls focusing on design aspects including wave loading and innovative seawall designs, ecological considerations, and durability performance. Different conventional seawalls and their advantages and disadvantages are reviewed. Wave loads on seawalls have received significant attention; and multiple approaches for the quantification for the different types of loads are presented. However, wave load quantification remains a challenging task, especially for novel designs, and performance under load for such designs must be quantified through testing in wave tanks. Drawing inspiration from natural shorelines, modification of surface complexity at a multitude of scales can improve the otherwise poor ecological performance of seawalls. Ecological performance can also be improved by the incorporation of natural materials or structures in seawalls although the exact influence of concrete and other material chemistry on benthic diversity is unclear. The corrosion of the steel is a major durability concern, and the use of non-corrosive reinforcement can increase seawall durability toward corrosion. Other durability concerns include alkali silica reaction and sulfate attack, which can be mitigated through proper mixture design, including through the use of supplementary cementitious materials. Examples of innovative seawall designs and systems which have the capability to outperform conventional seawalls are discussed. Advances in structural design, ecological engineering, and infrastructure materials science will drive the development of multi-functional seawalls which are sustainable, durable, and resilient.

Design principles for achieving red emission in Eu2+/Eu3+ doped inorganic solids

Rare earth (RE) ions activated inorganic phosphors with multi-color emissions have received considerable attention because of their emerging applications in solid-state lighting, backlight displays, lasers, biomedical imaging, and so on. This tutorial review concerns the design principles for Eu2+ and Eu3+ activated red-emitting inorganic solids and highlights the influencing factors on the luminescence performance. Based on the recent advances in structural design of inorganic RE phosphors, we proposed several design principles for achieving red emission in Eu2+/Eu3+ ions doped solid-state materials. On the one hand, for the realization of red emission from Eu2+ ion, the used strategies include the following: (1) designed synthesis of new Eu2+-doped nitride or sulfide phosphors, (2) anionic substitution achieves large centroid shift, (3) Eu2+ occupies polyhedrons with small coordination numbers to obtain large ɛcfs, (4) doping concentration controls the distribution of Eu2+ ions, (5) mixed ligands induce large ΔS, and (6) doping Eu2+ in nitrides with UCr4C4-type structure to achieve narrow-band red emission. On the other hand, for the red emission originating from a Eu3+ ion, the design principles are listed as follows: (i) designed synthesis of Eu3+-doped phosphors with small CT energy, (ii) realization of low excitation energy by doping sensitizer ions, (iii) Eu3+ luminescence enhancement by charge compensation, and (iv) occupation of unsymmetrical sites to maintain high color purity of Eu3+. Finally, we discuss and look at the future opportunities for Eu2+/Eu3+ activated red phosphors.

Broadcasting from the “Mediated Center:” Baltimore’s Candelabra Television Tower, circa 1959

ABSTRACTThe rise of post-WWII television markets around the world required new technical solutions for broadcast media. These solutions became novel examples of urban-scale infrastructure, including the “television tower” as a unique structure. Among early American examples is Baltimore’s three-mast “candelabra” television tower, completed in 1959. Although the project’s feasibility depended upon advances in structural design, its most significant innovation was institutional. As an early example of “infrastructure sharing,” Baltimore’s candelabra tower illustrates how innovative built form can engender a new relationship among technology, urban infrastructure, and the production of cultural capital.

Recent advances in structure design for enhancing photocatalysis

Semiconductor photocatalysis has attracted considerable attention because it is a promising way to deal with the global energy scarcity and environmental degradation. Over the past few decades, numerous strategies have been put forward to improve the visible-light absorption and decrease the electron–hole recombination of semiconductor photocatalysts. This review mainly focuses on the recent progress in morphology and the structure design of heterostructure-based semiconductor photocatalysts. In addition, the photocatalytic performance of semiconductor systems discussed mainly involves the environmental and energy application, including the degradation of pollutants, hydrogen generation and reduction of CO2 to form hydrocarbon fuel. Finally, the challenges and perspectives for future development of photocatalysts are also addressed.

Layered Double Hydroxide‐Based Catalysts: Recent Advances in Preparation, Structure, and Applications

AbstractLayered double hydroxides (LDHs) are a class of functional anionic clays, which consist of positively charged host layers (brucite‐like M(OH)6 octahedra) and interlayer anions. By virtue of their unique combination of structural features (including the tunability of both host layers and interlayer guest anion, exfoliation property, structure topological transformation, confinement effect), LDHs have many potential applications in heterogeneous catalysis—as catalysts themselves, catalyst supports, or catalyst precursors. In addition, the properties of LDH‐based catalysts can be tailored for specific purposes by facile modulation of their surface/interface defect structure (e.g., oxygen vacancy defects or metal defects), controlling the concentration/strength of surface acid/base sites, tuning the geometric/electronic structure of active sites, or by taking advantage of the confinement effect intrinsic to 2D materials. In addition, by utilizing the topological structural transformation of LDH precursors, supported metal catalysts can be obtained (as single metals, bimetallic alloys or heterostructures, and intermetallic compounds) with tunable particle size/morphology and intriguing electronic properties. The main focus of this review is on recent advances in structure design, preparation, and catalytic applications of LDH‐based heterogeneous catalysts. In addition, future challenges and development strategies are discussed from the viewpoints of modulation of intrinsic active sites and establishment of scalable fabrication processes.

Diagrid: An innovative, sustainable, and efficient structural system

Summary In recent years, diagrid structures have received increasing attention among both designers and researchers of tall buildings for creating one-of-a-kind signature structures. This paper presents a state-of-the-art review of diagrid structures. First, various diagrid configurations, main factors affecting their behaviors, and related design parameters and approaches are discussed. Then, diagrid applications for free-form steel and concrete structures are introduced showing the diagrid applicability for complex structures followed by recent advances in structural design of diagrid connections, diagrid nonlinear behavior, and structural control of diagrids. Recent studies about a new variation of tubular and diagrid systems, hexagrids, are discussed briefly. Finally, the diagrid potential in design of sustainable buildings is delineated.

Advances in DNA Nanostructure-Based Smart Drug Delivery Systems

Highly specific deoxyribonucleic acid (DNA) base-pairing not only carries genetic information, but also provides the basis for self-assembly of novel nanostructures with programmable shapes and sizes. Unlike single-stranded and double-stranded DNA, DNA nanostructures exhibit good cellular permeability. They also have characteristics of uniform size, easy functionalization, precise addressability, excellent water solubility and high biocompatibility. Due to their unique properties, these tailored molecular devices are ideal nanoscale systems for targeting cells and triggering cellular responses. Recent progress in the field of DNA nanotechnology has demonstrated effectiveness and advantages of DNA nanostructures as smart and targeted drug delivery systems or imaging agents within living organisms. In this review, we summarize the recent advances in structure design, cargo loading and cellular delivery of DNA nanocarriers, and discuss their potential in therapeutic applications.

Recent advances in structure design and functionalization of polymer based damping materials

High performance and multifunctional are the two main emphases in the study of polymer damping materials. This paper reviews the latest research progress in polymer damping materials from the aspect of novel structural design of polymer networks and microstructure, including gradient structures, dynamic supramolecular networks, dangling chains based networks and low density porous structures. Meanwhile, the functionalization of polymer damping materials is also summarized, such as self-healing, shape-memory and recyclability. Furthermore, the development trends and future challenges in this field are discussed.

The End of Earthquake Hazard

Unlike some other natural disasters such as droughts, floods, or hurricanes, earthquakes are selectively destructive to humans. Other life forms are relatively immune to earthquake damage. As we learn to diagnose and prevent earthquake disasters we may begin to reflect on the impending demise of earthquake hazard. What will happen when human societies will be as little affected by this hazard as social insects are today--a modest goal, considering our relative technological superiority over ants or bees? In the next few decades, fundamental advances in structural design and building technology are likely to reverse the current trend toward increased vulnerability of structures to earthquakes, which has been attributed to changes in land use since the 1950's related to urbanization. Recent seismic disasters in Mexico City, the San Francisco Bay area, and Kobe were clearly related to soft ground conditions. Thus one key advance in the control for seismic disasters will...

TECHNOLOGICAL ADVANCES IN AIRCRAFT CARRIER DESIGN

ABSTRACTSince the signing of the Contract Design Plane for the CVN 68 (the U.S. Navy's latest Class of Aircraft Carriers) In 1963, considerable technological advances have been made in Naval Ship Design. This paper provides specific examples of how new technology has affected traditional Carrier design practices and techniques, and also indicates areas where future advanced technology will be needed. It is divided into four sections: 1) Computer Design Application; 2) Total Ship Energy Conservation Analysis; 3) Advances in Structural Design; and 4) Impact of V/STOL Aircraft.The increased use of the computer to define ship characteristics in the initial stage of ship design is discussed, followed by a report on efforts to include energy conservation as an integral part of the design process. The energy conservation approach uses traditional analytical techniques to develop innovative design configurations that will achieve energy savings. Of the many advances in Carrier structural design, two specific examples are given: 1) Elimination of the infamous “knee‐knockers” (high sills in passageway openings) common to Gallery Deck structure, and 2) Successful attempts at reducing the thickness of aircraft elevator platforms. The paper concludes by pointing out some possible challenges facing the ship designer and some of the technology already created by the expected introduction of advanced design Vertical/Short Takeoff and Landing (V/STOL) aircraft.

A review of progress in gas lubrication

The past decade has witnessed a rapid evolution in the technology of gas lubrication which has been accompanied by the application of gas bearings on an increasing scale. Before 1960, existing applications were restricted to two specialized areas: gyroscopes for inertial navigation and gas circulators in nuclear reactors. Now they are widely employed in manufacturing industry, in grinding machines, drilling machines and hand tools and in a wide range of medical and scientific instruments. This progress has been made possible by the solution of two or three major technical problems and the assimilation of myriad minor advances in structural design, materials and manufacturing techniques.

Development of Synthetic Resin Adhesives

THE development of synthetic resin adhesives has proceeded very fast since about 1937 when the first urea formaldehyde wood glues were being produced on a pilot scale. The excellent resistance of these materials to weathering conditions has enabled very considerable advances in structural design both in wooden structures and rather more recently in metal aircraft. These synthetic resin adhesives are basically ‘thermosetting’, that is to say, they harden by the addition of catalysts or by the application of heat, the chemical process which takes place being irreversible and not dependent upon the evaporation of solvents. This concept leads not only to good weather resistance, but also to the practicality of sticking together non‐porous materials such as metal. The first use of bonding of mstal in aircraft structures was in the de Havilland Hornet in 1943,1 and since then bonding has proved its advantages over other methods of joining for both primary and secondary structures. Other new methods of fabrication have appeared since that time and the requirements for structures in terms of loading and environment have changed considerably; but both mctal‐to‐metal bonding and its newer partner honeycomb sandwich show signs of much more extensive use in the future. These two most important applications of synthetic resin adhesives in modern aircraft will now be considered.