Maskless lithography for versatile and low cost fabrication of polymer based micro optical structures

For applications in optical communication, sensing or information projection in automotive lighting, polymer based optical devices are of keen interest. Optical structures such as waveguides and gratings are basic blocks for these devices. We report on a simple, versatile, and yet low-cost fabrication method suited for both binary and multilevel diffractive microstructures as well as multimode optical waveguides in polymers. The fabrication of the diffractive structures, i.e. gratings, with two and multiple levels, is achieved by using a maskless optical lithography system employing a spatial light modulator. With the same system, waveguide cladding structures are realized by stitching of multiple single exposure patterns. For replication of these structures on polymer, e.g. polymethyl methacrylate (PMMA), a lab-made hot embossing machine is used. We then employ UV curable material and doctor blading to realize the waveguide cores. The created diffractive and waveguide structures are characterized in terms of diffraction efficiency and optical propagation loss, respectively, showing good optical quality and performance. With our fabrication system we have demonstrated a diffraction efficiency of 71% for multilevel grating structure and a propagation loss for stitched waveguides of 2.07 dB/cm at a wavelength of 638 nm. These basic elements will be employed to realize entire optical measurement systems for applications in sensing and integrated photonics in the next step

Diffractive optics based automotive lighting system : A rear end lamp design for communication between road users

Information projection using laser-based illumination systems in the automotive area is of keen interest to enhance communication between road users. Numerous work on laser-based front end projection employing refractive and reflective optics has been reported so far, while for rear end illumination efforts are more scarce and a different optical design concept due to limited volumetric size and field of view regulations is required. Here, we report on a new and versatile approach for a laser-based rear end lighting system for automotive application which enables projection of information or signals to support other road users. The design is based on thin diffractive optical elements projecting the desired patterns upon illumination. Also, for protection of the road users from the steering laser beam, a diffusive back projection screen is designed to project information while fulfilling both the field of view and safety requirements. The projection system is based on a periodic diffusive structure made of an array of biconic lenses with sizes in the millimeter range. The field of view (FOV) from the simulated lens arrays complies with the angular requirements set by the Economic Commission for Europe (ECE). As a proof of concept, the diffusive screen is fabricated using microfabrication technology and characterized. In future, the screen will be combined with thin diffractive optical elements to realize an entire integrated projection system. © 2020 Muhammad Shaukat Khan et al., published by De Gruyter, Berlin/Boston 2020

A STYLISTIC ANALYSIS OF “THE RIME OF THE ANCIENT MARINERâ€

If a specimen of literary art is seen as a fine tapestry of words made by the skilled seamstress—the poet, then the lexis and structure of a language are the raw materials—the fabric and the thread—by weaving which into specific patterns the finished product is achieved. The choice of materials and their arrangement into unique patterns always bear an image of their creator, or the artist; thus, a close view of them reveals the artist’s identity and brings out the meaningful message that underlies the ornate running threads. Mostly, the students of literary studies cannot appreciate the beauty of the literary classics on their own. Consequently, they simply mimic the ideas, and sometimes even the words, of famous professional critics when asked to give their own critical judgment on the aesthetic merit or the thematic quality of a literary work in the shape of a home assignment, classroom presentation or an annual assessment test. Now, the researcher has got the inspiration for carrying out this study from an idea expounded in Widdowson (1975) that this mimicry can be replaced by genuine individual opinion if the students, or even those people who have non-academic concerns with literature, are brought to a standpoint from where they can have a closer view of the raw materials, the language resources, which are involved in the making of a literary product. And, if the product in its finished form cannot elicit a desired response from them then making them sensitive to the process of its making can be quite effective in this regard. Through the present study, an attempt has been made to show an easy access to the outlandish world of verse by means of the linguistic route which is laid with the familiar flagstones of grammar and vocabulary. Meaning thereby that in this study the elusiveness of poetry will be dealt with the precision of a social scientist, the linguist. The approach which serves as the basis of this study is not an invention of the researcher; rather, it is a well-known twentieth century approach known as stylistics (Jeffries McIntyre, 2010, p. 30). Samuel Taylor Coleridge’s famous ballad, “The Rime of the Ancient Marinerâ€, being a widely read poem and bearing various stylistics features, offered itself as an ideal object for this study. The poet’s aesthetic message is explored by analyzing the finest details of his linguistic expression. And, careful considerations have been made throughout the study to prevent the overlooking of any instance of deviant linguistic units or recurring patterns for interpretation because such elements contribute largely to the meaning of any literary product. The study is descriptive in its nature therefore qualitative data has been integrated with and substantiated by the quantitative one.  Keywords: stylistics, literature, lexical, semantic and graphological deviation

Policy on SMEs in Pakistan:: Relationship between Entrepreneurial Orientation, Firm Performance and Ownership Structure

To strengthen growth of SMEs in Pakistan, it is important for the policy makers to understand some significant related variables. For instance, Entrepreneurial Orientation (EO) is one such variable which can affect the performance of any business substantially; however, it is debatable if some of its dimensions do not affect the firm performance. This research investigates the relationship among the EO dimensions, firms’ performance and ownership structure. In this study, the collection of data was done by using a self-administered questionnaire survey using a 5-point Likert scale and Statistical Package for social sciences (SPSS) version 24. The findings revealed that EO has a statistically significant effect on firms’ performance and when checked individually for each dimension of the EO, it was clear that results for innovation were statistically insignificant, because innovation needs certain time and specific environmental conditions to yield significant results, whereas results for risk-seeking, proactive approach, autonomy, aggressive attitude, and competitive spirit were statistically significant and positively linked with the firms’ performance. The findings of this research reveal that ownership structure does play a significant moderating role on the relationship between performance of the firm and EO dimensions (Innovativeness, Proactiveness and competitive Energy) while Ownership structure doesn't play any significant moderating role between firm performance and few other EO dimensions (risk-attitude, autonomy and aggressiveness). Keywords:     Public Policy, Entrepreneurial Orientation, Firm Performance, Ownership Structure, Small & Medium Enterprises (SMEs), Pakista

Petrophysics based Reservoir Evaluation of the Cretaceous Lower Goru “C” Sands, Middle Indus Basin, Sindh, Pakistan

This study demonstrates the reservoir investigation of the Cretaceous Lower Goru “C” sand interval using exploratory well data from the middle Indus basin of Sindh. The petrophysical parameters including volume of shale, effective porosity, and water saturation of the investigated reservoir interval were calculated. The shale volume calculation results in 30–35% of non-clean (shale) lithology, which is high as compared to Sawan-01 and Sawan-08 wells. The effective porosity ranges from 12–16%, while the average value of water saturation in the complete interval of “C” sand falls in the range of 50–60%. However, certain zones with relatively lower water saturation values of around 30-50% are also observed. These zones are considered better pay zones in comparison to the other intervals. A “gas effect” phenomenon observed on cross plots represents the area of neutron-density cross-over indicating the presence of lighter hydrocarbons in this reservoir zone interva

Fly Ash an Alternative of Clay in Bricks: A Sustainable Solution for Future Constructions

Clay (CL) bricks have been commonly used in construction industry for centuries. The negative environmental impacts of use of CL bricks include rapidly depleting fertile clayey layer of soil and the high energy consumption of CL bricks, which have led to the development of alternative brick units incorporating waste materials. Fly ash (FA) brick has been identified as a sustainable and environmental friendly alternative of traditional CL brick, which reduces carbon dioxide (CO2) emissions and hence global warming. This study aims to develop eco-friendly geopolymer mortar brick mixes using FA and CL without heat curing and applying molding pressure. This study investigates influences of percentage replacements of CL with FA and curing period on the compressive strength (CS) of geopolymer mortar brick mixes. In the preparation of geopolymer mortar mixes, the percentage replacements of CL with FA varied from 0 to 100% (0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%) using 12 M sodium hydroxide (NaOH) solution. A total of 11 geopolymer mortar mixes were cast and cured at 14, 28, 56 and 90 days. The optimum CS of 49.7 MPa with 80% replacement of CL with FA using 12 M NaOH solution at 90 days was achieved. This study is expected to contribute in reducing the level of CO2 emissions, which will subsequently reduce global warming and smog formation in Pakista

Incidental renal cell carcinoma in pelvic malignancies

Simultaneous diagnosis of renal cell carcinoma with pelvic malignancies is rare but a well-documented phenomenon. It is not uncommon to have incidental renal masses on imaging done for investigating other tumors. There are no established guidelines for the treatment of patients with dual malignancies. The management of such patients is challenging and requires a multidisciplinary approach. We present a series of three cases with a diagnosed pelvic malignancy but further workup revealed a kidney tumor. Both the malignancies were evaluated individually and diagnosed as two different primary neoplastic lesions. This case series examines each distinct patient\u27s presentation, discusses the diagnosis, and compares and contrasts the findings while discussing the literature on this topic