Search results

1 – 10 of over 5000
To view the access options for this content please click here
Article

Belinda T. Orzada, Mary Ann Moore and Billie J. Collier

Undesirable garment drape often occurs because of the manufacturer’s desire to save fabric by rotating patterns to position them more closely in the marker, and thus…

Abstract

Undesirable garment drape often occurs because of the manufacturer’s desire to save fabric by rotating patterns to position them more closely in the marker, and thus cutting the garment off‐grain. This study was designed to subjectively and objectively measure the effect of grain alignment on fabric and garment drape. Data from an apparel industry survey were utilized to establish tilt values for quantitative analysis of drape and shear. Twelve tilt combinations were examined. No significant differences were found between drape values of control samples and those with tilt variations. Generally, shear stiffness and hysteresis values increased as tilt angles increased across all fabrics. Asymmetry of shear curves also increased. Twenty‐one apparel design students subjectively evaluated fabrics draped on a pedestal and skirts constructed in each tilt variation. Fabric drape amount evaluations were more highly correlated with drape values than were drape preference evaluations. Advanced design students were more sensitive to small differences in garment drape than were beginning students.

Details

International Journal of Clothing Science and Technology, vol. 9 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

To view the access options for this content please click here
Article

Navya Thirumaleshwar Hegde, V.I. George, C. Gurudas Nayak and Kamlesh Kumar

The purpose of this paper is to give reviews on the platform modeling and design of a controller for autonomous vertical take-off and landing (VTOL) tilt rotor hybrid…

Abstract

Purpose

The purpose of this paper is to give reviews on the platform modeling and design of a controller for autonomous vertical take-off and landing (VTOL) tilt rotor hybrid unmanned aerial vehicles (UAVs). Nowadays, UAVs have experienced remarkable progress and can be classified into two main types, i.e. fixed-wing UAVs and VTOL UAVs. The mathematical model of tilt rotor UAV is time variant, multivariable and non-linear in nature. Solving and understanding these plant models is very complex. Developing a control algorithm to improve the performance and stability of a UAV is a challenging task.

Design/methodology/approach

This paper gives a thorough description on modeling of VTOL tilt rotor UAV from first principle theory. The review of the design of both linear and non-linear control algorithms are explained in detail. The robust flight controller for the six degrees of freedom UAV has been designed using H-infinity optimization with loop shaping under external wind and aerodynamic disturbances.

Findings

This review will act as a basis for the future work on modeling and control of VTOL tilt rotor UAV by the researchers. The development of self-guided and fully autonomous UAVs would result in reducing the risk to human life. Civil applications include inspection of rescue teams, terrain, coasts, border patrol buildings, police and pipelines. The simulation results show that the controller achieves robust stability, good adaptability and robust performance.

Originality/value

The review articles on quadrotors/quadcopters, hybrid UAVs can be found in many literature, but there are comparatively a lesser amount of review articles on the detailed description of VTOL Tilt rotor UAV. In this paper modeling, platform design and control algorithms for the tilt rotor are presented. A robust H-infinity loop shaping controller in the presence of disturbances is designed for VTOL UAV.

Details

International Journal of Intelligent Unmanned Systems, vol. 8 no. 3
Type: Research Article
ISSN: 2049-6427

Keywords

To view the access options for this content please click here
Article

Robert Mellin

This paper presents the remarkably edible landscape of Tilting, Fogo Island, Newfoundland. Tilting is a Cultural Landscape District (Historic Sites and Monuments Board…

Abstract

This paper presents the remarkably edible landscape of Tilting, Fogo Island, Newfoundland. Tilting is a Cultural Landscape District (Historic Sites and Monuments Board) and a Registered Heritage District (Heritage Foundation of Newfoundland and Labrador). Tilting has outstanding extant examples of vernacular architecture relating to Newfoundland's inshore fishery, but Tilting was also a farming community despite its challenging sub-arctic climate and exposed North Atlantic coastal location. There was a delicate sustainable balance in all aspects of life and work in Tilting, as demonstrated through a resource-conserving inshore fishery and through finely tuned agricultural and animal husbandry practices. Tilting's landscape was “literally” edible in a way that is unusual for most rural North American communities today. Animals like cows, horses, sheep, goats, and chickens were free to roam and forage for food and fences were used to keep animals out of gardens and hay meadows. This paper documents this dynamic arrangement and situates local agricultural and animal husbandry practices in the context of other communities and regions in outport Newfoundland. It also describes the recent rural Newfoundland transition from a working landscape to a pleasure landscape.

Details

Open House International, vol. 34 no. 2
Type: Research Article
ISSN: 0168-2601

Keywords

To view the access options for this content please click here
Article

Tommy H. Thomason

Tilt rotor aircraft will add new dimensions to corporate and charter air transportation beginning in the 1980s or 1990s. The tilt rotor combines the VTOL capability of the…

Abstract

Tilt rotor aircraft will add new dimensions to corporate and charter air transportation beginning in the 1980s or 1990s. The tilt rotor combines the VTOL capability of the helicopter with the speed, range, and fuel economy of the turboprop aircraft. The civil use of he helicopter has expanded enormously in the last 25 years because of its effectiveness in point‐to‐point transportation and its capability to operate from confined or limited areas. The tilt rotor dramatically increases that effectiveness because it hovers like a helicopter but cruises at twice the speed for twice the range on the same amount of fuel.

Details

Aircraft Engineering and Aerospace Technology, vol. 50 no. 7
Type: Research Article
ISSN: 0002-2667

To view the access options for this content please click here
Article

Shouhong Miao and Qixin Cao

The purpose of this paper is to present a two‐wheeled inverted pendulum with self‐tilt‐up motion ability. With this ability, the two‐wheeled inverted pendulum can erect…

Abstract

Purpose

The purpose of this paper is to present a two‐wheeled inverted pendulum with self‐tilt‐up motion ability. With this ability, the two‐wheeled inverted pendulum can erect without assistance, and then the vehicle can be autonomously deployed. The paper proposes an approach to achieve this self‐tilt‐up motion, which involves precessional motion.

Design/methodology/approach

A flywheel is mounted inside the vehicle to perform high‐speed spinning. The flywheel and body of the vehicle are forced to move around a fixed point and precessional motion occurs. As a result of the precessional motion, a moment is synchronously generated to tilt the body up to the upright position. Since no external force is applied on this two‐wheeled inverted pendulum, it is called self‐tilt‐up motion. A 3D model and a prototype are built to validate this approach.

Findings

The simulation and experimental results show that the self‐tilting‐up motion is successful.

Research limitations/implications

This paper presents a self‐tilt‐up motion for a two‐wheeled inverted pendulum. With the analysis of the dynamics, simulation demonstrations and prototype development, the results show that the vehicle could perform self‐tilt‐up motion without any assistance. The principle of this self‐tilt‐up motion involves processional motion of rigid body. We also pointed out the factors that play important roles in influencing the performance of self‐tilt‐up motion and then define the switching time for the motion to switch to dynamic balance movement.

Originality/value

Traditional multi‐wheel robots cannot work when they overturn. However, the two‐wheeled inverted pendulums with self‐tilt‐up ability do not have this shortcoming. They can stand up to keep working even if they fall down. A two‐wheeled inverted pendulum with self‐tilt‐up ability can be applied to many places. Equipped with solar battery, it can be used as an independent explorer. This type of vehicle can be deployed in swarms for planetary detection. For example, many small two‐wheeled inverted pendulums assist a lunar rover for exploration, samples gathering, etc.

Details

Industrial Robot: An International Journal, vol. 38 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

To view the access options for this content please click here
Article

Yikang Du, Kuanmin Mao, Hongqi Liu, Xiaobo Mao and Zhihang Li

This paper aims to present a simplified method to predict the pressure of the recess, no matter whether the tilt center coincides with the geometric center of the…

Abstract

Purpose

This paper aims to present a simplified method to predict the pressure of the recess, no matter whether the tilt center coincides with the geometric center of the hydrostatic journal bearings.

Design/methodology/approach

To validate the effectiveness of the presented model, computational fluid dynamics (CFD) method and experimental method are performed in this study.

Findings

By comparing the CFD results and the experimental results, the pressure of the recess is related to the tilt direction, the tilt center, the width of the land and the circumferential angle of the land.

Originality/value

The mathematic model requires equivalent resistance of land edge – tilt position, tilt direction, tilt angle and the thickness of oil film instead of any digital iteration. Furthermore, a novel experimental apparatus including a circular hydrostatic bearing called ball bearing is designed to study the tilt effect produced by manufacturing error and offset load force on the pressure of the recess.

Details

Industrial Lubrication and Tribology, vol. 70 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

To view the access options for this content please click here
Article

Runlin Chen, Jianlei Wang, XiaoYang Yuan, Longlong Li and Yahui Cui

To meet the high stiffness requirement of bearings used in high-precision spindles, this paper aims to propose a novel kind of bearing composited by hydrostatic cavities…

Abstract

Purpose

To meet the high stiffness requirement of bearings used in high-precision spindles, this paper aims to propose a novel kind of bearing composited by hydrostatic cavities and tilting pads with preload.

Design/methodology/approach

Cavities are cut on the oil seal surface of a hybrid bearing, in which the tilting pads are set up. The load of the bearing is carried by the hydrostatic cavities and tilting pads. The structural features of this compound bearing and the controlling variables of the main stiffness coefficient are presented. Two basic design principles are proposed on the basis of equal machining clearance (EMC) and equal installation clearance (EIC).

Findings

The theoretical analysis indicates that the stiffness of compound bearings under the EMC condition increases to infinity monotonously when the preload coefficient of the tilting pad tends to 1, while the stiffness under the EIC condition has a peak value. Therefore, a synthetic design principle is proposed by synthetically using the above-mentioned two principles. The applicable range of the three principles is discussed through an example.

Originality/value

The study about technological combination of hydrostatic cavity and tilting pad in this paper can provide suggestions for the design of a high-stiffness bearing in a precision spindle.

Details

Industrial Lubrication and Tribology, vol. 70 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

To view the access options for this content please click here
Article

Clara S. Fowler and Elizabeth A. Dupuis

In response to the large number of students needing library instruction, the Digital Information Literacy Office at the University of Texas at Austin created TILT (Texas…

Abstract

In response to the large number of students needing library instruction, the Digital Information Literacy Office at the University of Texas at Austin created TILT (Texas Information Literacy Tutorial). Designed to teach a progression of skills, students learn and practice basic information literacy concepts through problem‐based interactions. Integrating TILT into the existing freshman library instruction programs required adjustments by both faculty and library staff. Composition students take the tutorial before attending an assignment‐driven library session; as a result they are more prepared for advanced research. TILT is promoted by the administration as a library initiative to support both undergraduate and distance education. While there have been some drawbacks, overall benefits and positive impacts are discussed. Suggestions for future development of the tutorial in collaboration with other individuals and institutions are included.

Details

Reference Services Review, vol. 28 no. 4
Type: Research Article
ISSN: 0090-7324

Keywords

To view the access options for this content please click here
Article

Pengju Li, Yongsheng Zhu, Youyun Zhang and Pengfei Yue

– This paper aims to present the theoretical and experimental investigation of the temperature of high speed and heavy haul tilting pad journal bearing.

Abstract

Purpose

This paper aims to present the theoretical and experimental investigation of the temperature of high speed and heavy haul tilting pad journal bearing.

Design/methodology/approach

The bearing is 152.15 mm in diameter with three slenderness ratios (L/D) and three clearance ratios. The equations that govern the flow and energy transport are solved by the finite difference method, and the experimental tests are conducted in a test rig of high speed and heavy haul tilting pad journal bearing. The shaft speed ranges from 3,000 to 16,500 r/min (the highest linear-velocity equals 131.4 m/s), and the three static loads are 10, 20 and 30 KN.

Findings

The comparisons between numerical results and experimental results show better correlations. It is shown in the theoretical and experimental results that the temperature increases with static load and shaft speed and decreases with clearance ratio and L/D.

Originality/value

The theoretical models presented in this paper can be used to predict the temperature of tilting pad journal bearing when the shaft’s linear velocity is up to 130 m/s.

Details

Industrial Lubrication and Tribology, vol. 67 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

To view the access options for this content please click here
Article

M. Asif, Mohammad A. Hassanain, Kh Md Nahiduzzaman and Haitham Sawalha

The Kingdom of Saudi Arabia (KSA) is facing a rapid growth in energy demand mainly because of factors like burgeoning population, economic growth, modernization and…

Abstract

Purpose

The Kingdom of Saudi Arabia (KSA) is facing a rapid growth in energy demand mainly because of factors like burgeoning population, economic growth, modernization and infrastructure development. It is estimated that between 2000 and 2017 the power consumption has increased from 120 to 315 TWh. The building sector has an important role in this respect as it accounts for around 80 percent of the total electricity consumption. The situation is imposing significant energy, environmental and economic challenges for the country. To tackle these problems and curtail its dependence on oil-based energy infrastructure, KSA is aiming to develop 9.5 GW of renewable energy projects by 2030. The campus of the King Fahd University of Petroleum and Minerals (KFUPM) has been considered as a case study. In the wake of recently announced net-metering policy, the purpose of this paper is to investigate the prospects of rooftop application of PV in buildings. ArcGIS and PVsyst software have been used to determine the rooftop area and undertake PV system modeling respectively. Performance of PV system has been investigated for both horizontal and tilted installations. The study also investigates the economic feasibility of the PV application with the help of various economic parameters such as benefit cost ratio, simple payback period (SPP) and equity payback periods. An environmental analysis has also been carried out with the help of RETScreen software to determine the savings in greenhouse gas emissions as a result of PV system.

Design/methodology/approach

This study examines the buildings of the university campus for utilizable rooftop areas for PV application. Various types of structural, architectural and utilities-related features affecting the use of building roofs for PV have been investigated to determine the corrected area. To optimize the performance of the PV system as well as space utilization, modeling has been carried out for both horizontal and tilted applications of panels. Detailed economic and environmental assessments of the rooftop PV systems have also been investigated in detail. Modern software tools such as PVsyst, ArcGIS and RETScreen have also been used for system design calculations.

Findings

Saudi Arabia is embarking on a massive solar energy program as it plans to have over 200 GW of installed capacity by 2030. With solar energy being the most abundant of the available renewable resource for the country, PV is going to be one of the main technologies in achieving the set targets. The country has, however, unlike global trends, traditionally overlooked the small-scale and building-related application of solar PV, focusing mainly on larger projects. This study explores the prospects of utilization of solar PV on building roofs. Building rooftops are constrained in terms of PV application owing to wide ranging obstacles that can be classified into five types – structural, services, accessibility, maintenance and others. The total building rooftop area in the study zone, calculated through ArcGIS has been found to be 857,408 m2 of which 352,244 m2 is being used as car parking and hence is not available for PV application. The available roof area, 505,165 m2 is further hampered by construction and utilities related features including staircases, HVAC systems, skylights, water tanks and satellite dish antennas. Taking into account the relevant obstructive features, the net rooftop area covered by PV panels has been found to be in the range 25–41 percent depending upon the building typology, with residential buildings offering the least. To optimize both the system efficiency and space utilization, PV modeling has been carried out with the help of PVsyst software for both the tilted and horizontal installations. In terms of output, PV panels with tilt angle of 24° have been found to be 9 percent more efficient compared to the horizontally installed ones. Modeling results provide a net annual output 37,750 and 46,050 MWh from 21.44 and 28.51 MW of tilted and horizontal application of PV panels, sufficient to respectively meet 16 and 20 percent of the total campus electricity requirements. Findings of the economic analysis reveal the average SPP for horizontal and tilted applications of the PV to be 9.2 and 8.4 years, respectively. The benefit cost ratio for different types of buildings for horizontal and tilted application has been found to be ranging between 0.89 and 2.08 and 0.83 and 2.15, respectively. As electricity tariff in Saudi Arabia has been increased this year by as much as 45 percent and there are plans to remove $54bn of subsidy by 2020, the cost effectiveness of PV systems will be greatly helped. Application of PV in buildings can significantly improve their environmental performance as the findings of this study reveal that the annual greenhouse gas emission in the KFUPM campus can be reduced by as much as 40,199 tons carbon dioxide equivalent.

Originality/value

The PV application on building roof especially from economic perspective is an area which has not been addressed thus far. Khan et al. (2017) studied the power generation potential for PV application on residential buildings in KSA. Asif (2016) also investigated power output potential of PV system in different types of buildings. Dehwas et al. (2018) adopted a detailed approach to determine utilizability of PV on residential building roofs. None of these studies have covered the economics of PV systems. This study attempts to address the gap and contribute to the scholarship on the subject. It targets to determine the power output from different types of building in an urban environment by taking into account building roof conditions. It also provides detailed economic assessment of PV systems. Subsequent environmental savings are also calculated.

Details

Smart and Sustainable Built Environment, vol. 8 no. 1
Type: Research Article
ISSN: 2046-6099

Keywords

1 – 10 of over 5000