Window Life Research Articles

Advances and challenges in value chain development in ‘Kinnow’ mandarin and mango industries of Pakistan

'Kinnow' mandarin and mango are the leading fruit industries of Pakistan. Although, these industries differ in geographic and socio-economic aspects they do, however, share some inherent issues in production (finance, nurseries, management, quality, etc.) and diverse challenges in postharvest (skilled labour, infrastructure, etc.) and marketing (domestic and export). The 'Kinnow' industry is concentrated in central to upper Punjab Province, with smaller production units, but more developed in terms of infrastructure and export marketing; the mango industry is spread over a 600-km belt in the south across two provinces (Punjab and Sindh), with larger production units but lesser developed area. The value chain development in 'Kinnow' industry has been mainly led by the private sector and has become a unique example for other prospective horticultural industries. Developments in the mango industry are more recent and mainly institutionally driven through various international and national projects. The majority of the orchards in both commodities are contracted and marketing is done through commission agents. However, the trend is changing now with direct buying by exporters. In mangoes, more recent on-farm infrastructural developments and capacity building have provided impetus for farm-direct export by growers but they are still constrained by issues such as finance, skilled labour and market linkages. A common feature of the two industries is migrant skilled labour for harvesting, grading and packing, which mostly comes from southern Punjab and moves from lower Sindh, starting with the mango harvest in May, and continues through summer working in Punjab for mangoes, then after a pause (October) moves to the 'Kinnow' industry, where it continues until March. While 'Kinnow' has better shipping life and a comparatively stable market, export marketing remains challenging due to increasing competition and changing requirements and market access issues. Mango, with limited harvest window and shelf life has many postharvest management and marketing issues, although gaining momentum due to its exotic taste and various value-added products, and developments in its prospects for sea-freighting to distant markets like Europe. This analysis of two industries provides useful lessons for future developments and policy formulation for other industries in Pakistan and in other less industrialized countries.

Lisson Grove: Part One

Lisson Grove: Part One Stanley Plumly (bio) On December 28, 1817, the painter Benjamin Robert Haydon hosts what he refers to in both his diaries and Autobiography as “the immortal dinner.” What follows is the first half of the first chapter of a book about that dinner, its guests, and the implied world surrounding it—a moment in cultural and literary history framed by the Regency and Romanticism. The stated reasons for the dinner are, one, that Haydon wants to introduce his young friend John Keats to the great William Wordsworth and, two, that Haydon wishes to celebrate his progress on his most important and largest historical painting so far, “Christ’s Entry into Jerusalem.” Haydon has invested three years in this work, with three more to go. Keats, Wordsworth, and Charles Lamb (also a dinner guest) appear as spectators in the most vivid quadrant of the painting, along with anachronistic versions of Newton and Voltaire. Later arriving guests include John Landseer, Joseph Ritchie, and John Kingston. After thoughtful and entertaining discussions of poetry and art and their relation to Enlightenment science, the dinner party evolves into a lively, even raucous evening. Haydon also refers to this memorable event as “an immortal evening.” The title of the book is The Immortal Evening. I Keats has the most ground to cover. From Well Walk, in the village of Hampstead, to Lisson Grove, west and a little south of what will soon be London’s Regent’s Park, is a distance of about three, maybe a bit more, miles. In 1817, it will be a walk through countryside and emerging outlying city, a combination first of open fields, small woods, and close-in lanes yielding to streets of shops and market gardens, row [End Page 340] housing and classic Georgian brick and stucco houses, some of them mansion-sized. There is also, along the way, the occasional modest furniture or china factory. It is three days after Christmas, and he will have likely started out in the early afternoon since Sunday dinner will be served at a regular 3:30. By report it is already one of those severely cold winter seasons—just three years ago the Thames had frozen over during “the Great Frost of 1813-1814,” and this year seems to be suffering the lingering effects. Keats is wearing, of course, his great coat, the same coat or one much like it that he will forget to take with him on another, later winter day in February, 1820, on a visit into London proper, when the temperature suddenly drops and the consequence is the hemorrhage that will prove to be his “death warrant.” This far from central London there is yet no gas street lighting, so he is probably carrying a lantern for the night walk back. Of the two other major guests invited to dinner, Charles Lamb is next in the distance he must travel—more than a mile and a half, maybe two miles, depending on the route from Russell Street, Covent Garden, just above the Thames. He has recently moved from Inner Temple Lane, from west along the route of the river. “Here we are transplanted,” he writes to Dorothy Wordsworth the month before. “We are in the individual spot I like best, in all this great city. The theatres, with all their noises, Covent Garden, dearer to me than any gardens of Alcinous, where we are sure of the earliest peas and ’sparagus. Bow Street, where the thieves are examined, within a few yards of us. Mary had not been here four-and-twenty hours before she saw a thief. She sits at the window working; and casually throwing out her eyes, she sees a concourse of people coming this way, with constable to conduct the solemnity. These little incidents agreeably diversify a female life.” Perhaps what Lamb is also saying, without meaning to sound condescending, is that Mary’s window life is distracting as well. Mary is Lamb’s devoted but emotionally fragile sister. To get to Lisson Grove, Lamb must pass through his beloved but compromised “commercial” area of the Garden, with businesses [End Page 341] ranging from brothels, taverns, even Turkish baths, to...

Transparent Armor Ceramics as Spacecraft Windows

The slow crack growth parameters of several transparent armor ceramics were measured as part of a program to lighten next generation spacecraft windows. Transparent magnesium aluminate (spinel, MgAl2O4) and AlON exhibit superior slow crack resistance relative to fused silica, which is the historical material of choice. For spinel, slow crack growth, strength, and fracture toughness are significantly influenced by the grain size, and alumina‐rich phases and porosity at the grain boundaries lead to intergranular fracture in coarse grain spinel. Functions describing the required mass for a desired window life imply that transparent ceramics can lighten window panes from a slow crack growth perspective.

A life cycle approach to Green Public Procurement of building materials and elements: A case study on windows

Green Public Procurement (GPP) is a significant policy tool for reducing the environmental impacts of services and products throughout their whole life cycle. Scientific and easily verifiable environmental criteria, based on a life cycle approach, should be developed and used within procurement procedures. In this paper, Life Cycle Assessment (LCA) is applied to wood windows showing how it can support the criteria definition. After a foreword on GPP development in Italy, the evaluation features of the environmental performances of building materials and components are outlined. The LCA case study is then presented, describing the use of the analysis results to define the environmental criteria. LCA allowed to identify the main impacts and the critical processes of the window life cycle, giving a scientific framework to discuss GPP criteria with manufacturers associations and stakeholders. Nevertheless, it couldn’t help neither in identifying detailed criteria for GPP nor to define numerical thresholds to be used as reference in procurement procedures. The appropriate strategies should be selected taking into account the technical status of the market, the standard development and the voluntary industry commitments, involving manufacturers associations. Finally, some elements to develop a structured approach for GPP of construction materials are presented.

Laboratory-unit investigations of palladium-treated titanium foil for dry scrubber application

Titanium foil is employed for electron transparent windows in the electron beam dry scrubber process. The foil suffers corrosion, which limits the window life. Here, the examination of a palladium-coated window, prepared by ion beam assisted deposition and plasma source ion assisted deposition (PSIAD), after service in a pilot-scale plant is reported. Most significantly, the adhesion of the coating was reduced by the flue gas. Where the coating remained adherent, corrosion was negligible. Elsewhere, general, intergranular and pitting corrosion occurred. A PSIAD coating provided the best performance.

Klystrons for the Stanford linear accelerator center

A 2-mile-long linear accelerator has been built at Stanford University that uses 245 klystrons to produce an electron beam with an energy up to 20 GeV. Although most of the tubes used are being procured from industry, a major portion of the development work has been and is still being done at Stanford. We will review the important results of this work. In general, the klystrons are designed to produce a minimum of 21 MW peak power with extremely stringent phase and amplitude stability performance requirements. They are focused by permanent magnets and operate up to 250 kV beam voltage with a microperveance of 2. During the past few years, gradual improvements in performance have been achieved by optimizing the bunching parameter and the output cavity coupling, and we have measured efficiencies approaching 45 percent in a permanent magnet. Permanent magnet structure limitations, field shaping, and changes in the klystron design to reduce the magnetic field requirements will be discussed. The output window life has been improved by coating techniques developed to decrease single surface multipactor and reduce window operating temperature. Questions of coating stability will also be discussed. Finally, the paper will touch on the initial results of statistical analysis of tube life as a function of operating experience.

Fiber Reinforced Ceramics for Electromagnetic Window Applications

This paper presents the results of a program for the development of aircraft and missile electromagnetic windows to operate at temperatures above 800°F. Included is a review of the experimental work involved in developing a radome composite, high temperature design data and electromagnetic window model fabrication. Experimental work performed in developing the basic composite and much of the design data was sponsored under Air Force Contract No. AF 33(657)-11469. Investigation has shown that the material offers an electromagnetic window life of several hundred hours at 1000°F and several minutes life at 2500°F. This is accomplished from a reinforced aluminum phosphate ceramic material that is processed by conventional fiberglass reinforced plastic fabrication methods.

Problems related to very high power windows at microwave frequencies

A discussion is given of the types of windows used on the 20 MW klystrons which serve as sources of radio-frequency power for the high-energy linear electron accelerator at Stanford University. Both ceramic disk windows and ceramic cone windows have been used for this purpose, and several methods of mounting the window in the output waveguide of the tube have been tried. The choice of both physical and electrical characteristics of the windows are dictated by considerations of size, power level, irradiation by electrons and X-rays, vacuum requirements and the like. The single most important requirement of these windows is that they should have long life, since window life is now the major factor in life of the tubes. Results are presented on average life of the windows over the period of the last few years. The causes of failure are not completely understood at the present time, but a discussion is given of the typical kinds of failure and the factors which influence window life. The goal of window research at Stanford is to increase the reliable operation life of windows from the present value of approximately 1900 h to perhaps 5000 h.

High-power windows at microwave frequencies

During the past ten years the Microwave Laboratory at Stanford University has been engaged in development work on high-power klystrons. One of these is used in the linear accelerator and is operated at 20 MW (peak) and a few kilowatts average. The others, now produced commercially, operate between 1 and 3 MW (peak) in the X-, S- and L-bands. The characteristics of the output windows of these tubes are briefly reviewed, and the information obtained on life and the mechanism of failure of the windows used for the linear-accelerator klystron is considered in detail. From the operation of approximately 120 windows used with the accelerator tubes, an average window life of nearly 2000 hours has been observed. Most of the windows used with the accelerator consist of a ceramic disc in a circular waveguide. Most failures appear to start as a series of small holes in the ceramic, one of which eventually punctures the disc. The general direction of the puncture is normal to the direction of the E-field in the guide. The reasons for these failures are not yet clearly understood. Experimental and theoretical investigations are continuing on the effects of the impurities of the material, particle bombardment, X-ray bombardment, and geometry of the window. We expect, when a better understanding of the mechanism of failure has been achieved, that the average window life can be increased to a minimum of 5 000 hours.