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Composite materials invigorated by various reinforcements have changed the complexion of material processing in the automotive and aerospace industries. In partnership with different fillers, the glass fiber has taken the proper steps towards enhancing the properties of epoxy resins cogently. In this experimentation, the enhancement of mechanical characteristics of E-glass fiber-strengthened epoxy resin affiliated with the inclusion of various filler materials was determined. For this, epoxy resin was reinforced by altering the E-glass fiber concentration and micron-sized Al2O3, TiO2,and graphite particulate fillers via the traditional method of hand lay-up. Experimentation on the characteristics of the fabricated composites was well implemented through six essential tests: tensile, flexural, impact, compressive, hardness and a scanning electron microscope (SEM) test. The results averred that epoxy composite reinforced with 15% graphite particulate filler and 22.5 % E-glass fiber displayed the best tensile and hardness characteristics. On the contrary, 15% TiO2and 22.5% E-glass fiber composites exhibited the highest flexural strength. Al2O3filler indicated some potential in upgrading mechanical properties but was not commendable compared to the other two fillers. The introduction of selected fillers did not proliferate the impact and compressive characteristics, unfortunately. According to the SEM test, graphite particles were observed to be best dispersed with the matrix compared to other fillers.

ABSTRACTDue to their increased hardness, hardened steels are referred to as difficult-to-cut metals. Machining such hardened steels (hard machining) is preferred since it minimizes process stages and processing time. However, severe machining in dry conditions needs larger specific energy for metal removal, reducing tool life dramatically at higher velocities which affect the product quality as well. Cutting fluids influence machinability through cooling, lubricating, and washing away chips. Excessive usage of cutting fluids harms the environment, economy, and operators’ health. Researchers are so focusing on MQL as a sustainable green cooling alternative to potentially damaging conventional cooling approaches.In this current work, MQL was initially introduced with its core ideas and functions. As a follow-up, the application of MQL in various machining techniques especially for hardened steel was discussed. A complete evaluation of the various modes of MQL was presented, along with its advantages and disadvantages. According to studies, using NFs as a coolant and lubricant has grown more popular than any other way due to its superior performance in temperature control, improved surface quality, and low environmental threat. Finally, this article provides easy-to-follow instructions on how to use MQL in various ways to improve the machinability of hardened steel.

ABSTRACTThis study focussed on the multi-response optimisation of turning process using an easier and accurate hybrid approach namely Taguchi-PCA-Utility approach. Turning of alloy steel under dry and LN2-assisted cryogenic cooling with two different geometry-shaped uncoated carbide inserts was carried out based on suitable design of experiments (Taguchi L16 orthogonal array). Five vital responses in turning such as temperature, roughness, feed force, cutting force and MRR were measured by varying the input factors (speed, feed, cutting condition and cutting inserts type). Principal component analysis (PCA) for relative weight calculation of responses and utility concept for deriving out the unified process index were followed. The optimum parameter settings for maximum utility value were found at 134 m/min speed with 0.12 mm/rev feed rate under cryogenic cooling using SNMG 120408-type cutting insert. Finally, in order to verifying the significance of proposed approach validation tests were conducted.

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The performance of any unmanned aerial vehicle largely depends upon its weight as this characteristic dictates its payload capacity and flight duration. This paper presents a multiphysics simulation method for designing a unibody quadcopter airframe with optimum weight in SolidWorks. By adopting the computer-aided topology optimization concept, the mass of the frame is decreased by 91% (from 1558.44 to 134.738 grams) after getting rid of the unwanted elements, while not compromising its structural rigidity. The efficacy of the model is assessed by finite element analysis and it is found that the stress would remain within the acceptable limit. The optimized structure shows an operating life of 1.6×105cycles in the fatigue analysis and experiences significantly less drag force in the computational fluid dynamics test than the original airframe for several angles of attack, thus proving the superiority of the optimized frame over the initial model. Finally, additive manufacturing is performed to fabricate the optimized structure using PLA material. 3D printing through the fused deposition modeling technique is chosen since it is ideal for fabricating intricate engineering prototypes compared to orthodox manufacturing processes. While creating the frame, a 45° overhang angle is maintained to ensure the usage of less support material.

A diagnosis of superior vena cava obstruction (SVCO) generally is made on clinical grounds and can be confirmed by SVCO-specific diagnostic tests. When the obstruction is long-standing, clinical recognition may [...]

Samir Sarkar, MD(*); K Tarafdar, MD; S R Dhar, MD, FCCP and K Gupta, MD, FCCP. Division of Pulmonary Medicine, Coney Island Hospital, Brooklyn, NY. PURPOSE: To identify the risk [...]

George Robert, MD(*); N Subramanian, MD and S R Dhar, MD. Coney Island Hospital, Brooklyn, NY. PURPOSE: To determine whether the presence of cardiac arrhythmias during acute COPD exacerbations has [...]

Rajeeve Thachil, MD(*); A Balasubramanian, MD; K Padmanabhan, MD; S Sridhar, MD and S R Dhar, MD. Coney Island Hospital, Brooklyn, NY. PURPOSE: Lung biopsy (LB) is usually done in [...]

Rajeeve T Thachil, K. Padmanabhan, S. R. Dhar--Department of Pulmonary Medicine, Coney Island Hospital, Brooklyn, NY, U.S.A. Introduction: Diffuse panbronchiolitis (DPB) is a chronic inflammatory disorder of unknown etiology that [...]

Purpose: A wide range of changes occur in the partial pressure of oxygen ([O.sub.2]) while doing Arterial Blood Gas (ABG). The most likely reason would be inadvertent admixture with ambient [...]

Aim: To evaluate the importance of CT scanning in the staging of a solitary pulmonary nodule. Methods: A retrospective review of 50 charts of patients with carcinoma of lung, over [...]

Aim: To determine the clinical significance of a low diffusion capacity (DCO) as the only abnormality on pulmonary function testing. Methods: Pulmonary Function Tests (PFT) done in the last 2 [...]

Aim: When the pulmonary function study reveals restrictive function and a low diffusion capacity (DLCO); volume corrected diffusion capacity (DL/VA) is used to differentiate restriction resulting from chest wall conditions [...]

Introduction: It is a general perception that elderly patients requiring mechanical ventilation do poorly due to age and comorbid factors. We selected 369 consecutive patients above the ages of 65 [...]

(Chest 1994; 106:1867-68) A 35-year-old asian male cab driver presented with a 1-week history of increasing swelling of the left lower limb. Findings on examination of the left leg was [...]

A 59-year-old Chinese man was admitted to the hospital with massive hemoptysis. He had a history of cavitary pulmonary tuberculosis, with episodes of mild hemoptysis over the past two years. [...]

This paper presents the results of a longitudinal survey of 100 owner-managed new and small ventures. The survey was designed to explore the strategic orientations of new ventures and their performance implications. Results of the analytical study based on the application of factor analysis and cluster analysis indicate the existence of multiple strategies adopted by new ventures in order to remain competitive. The multiple regression models and cluster-wise performance analysis further indicate that a venture's competitive strategy significantly influences its performance. On the other hand, a complete lack of strategic orientation in a new venture may lead to negative performance and subsequently may even threaten its very survival.

An attempt has been made to quantify the effects of composition, and aging time and temperature, on the mechanical properties of AI-Zn-Mg-Cu alloys, with the help of statistically designed experiments; for this, the method of design of 2nfactorial experiments is used to obtain response surface equations. The coefficients in the regression equations obtained are corrected with the help of the t test. The equations obtained are checked by Fischer's F test and are found to be quite adequate in predicting the mechanical properties with 95% accuracy. The equations developed agree with the results obtained by the usual methods. The equations show that the main effects of Mg, Zn, and Cu are to contribute positively to the strength and hardness above the base level. The interaction between Zn and Mg representing the η′-phase shows an increase in strength, whereas cit does not appear to contribute to the strength by any kind of binary or ternary interaction. Mg contributes most among the three elements to the strength for the range of compositions studied. The equations indicate that the highest levels of time and temperature lead to a decrease in the strength properties of the alloys. All three elements reduce the elongation, with Mg having the most effect; Cu does not, however, measurably reduce the percentage elongation; although it is found to help in retaining the peak strength values at the temperatures of aging studied in this investigation.

This paper considers the problem of optimally locating new facilities on a sphere among existing facilities so that the sum of all weighted geodesic distance pairs is minimized. A method involving an iterative solution is presented. The procedure involves the approximation of the domain of objective function, which in the limit approaches to that of the original objective function. Computational experience with the procedure is described.

Zusammenfassung 1.Silberchlorid, Silberchromat, Kalziumsilikat, Kuprifluorid und Bariumsulfat werden, wenn sie in Gegenwart von Glyzerin oder in konzentrierten Zuckerlösungen gefällt werden, nicht peptisiert.2.Die Hydroxyde von Eisen, Nickel, Kobalt, Thorium und Quecksilber können durch Zusatz von Aetzalkali zu den Lösungen der entsprechenden Metallsalze in Gegenwart von Glyzerin oder konzentrierter Zuckerlösung peptisiert werden. Bei Gold- und Uransalzen muß an Stelle von Aetzalkali Ammoniumhydroxyd verwendet werden. Die Peptisation erfolgt nur dann, wenn das Alkali zur Mischung von Salz. und Glyzerin zugesetzt wird; setzt man aber die Salzlösung zur Mischung von Alkali und Glyzerin zu, so erfolgt Ausfällung. Leitfähigkeitsversuche stützen diese Ergebnisse.3.Wie Leitfähigkeitsmessungen zeigen, sind die Hydroxyde von Al, Cr, Pb, Hg und Cu zum größten Teil im Alkalihydroxyd als Kolloide, das Zinkhydroxyd hingegen hauptsächlich als Zinkat gelöst. In ähnlicher Weise bilden die Hydroxyde von Al, Fe und Cr in Essigsäure kolloide Lösungen, das Zinkhydroxyd hingegen bildet Zinkazetat.4.Die Umwandlungen der blauen Hydroxyde von Kupfer bzw. Kobalt in eine schwarze bzw. rote Modifikation sind vom gleichen Typus und werden durch verschiedene Katalysatoren in nahezu gleicher Weise beeinflußt.5.Die Hydroxyde von Al, Cr und Zn werden von Ferrihydroxyd adsorbiert, wenn letzteres in Lösungen dieser Hydroxyde in Alkali gefällt wird.

We describe a patient in whom extensive thromboembolic occlusion of the pulmonary arteries led to hypercapnia, in spite of a large increase in minute ventilation.

THERE is considerable difference of opinion regarding the possibility of the oxidation of nitrites by oxygen to nitrates. Berzelius reported that when aqueous solutions of alkali nitrites are boiled in air, they absorb oxygen with the formation of nitrates. G. Lunge and E. Frémy, J. Lang1and others showed that aqueous solutions of nitrites pass into nitrates. According to R. Abegg and H. Pick2, oxygen of the air oxidises a solution of silver nitrite to silver nitrate. On the other hand, E. Divers3, Sir P. C. Rây4, C. Russworm5, M. Oswald6, and others observed no oxidation of solutions of nitrites in air. C. Matignon and G. Marchal7reported that an aqueous solution of sodium nitrite is not oxidised by prolonged contact with oxygen, under a pressure of 50–55 atmospheres, even in the presence of a catalyst. But when the pressure is raised to 175 atmospheres and temperature to 395°–530°, solid sodium nitrite is almost completely oxidised to nitrate.

IN a recent communication1Götz, Dobson and Meetham have reported that the average height of ozone in the atmosphere at Arosa, Switzerland, is about 20 km. This height is much less than the former estimates. Götz and Ladenburg2and Buisson3are in agreement with this view. Even at a height of 2–3 km. a perceptible amount of ozone may be present, but the highest concentration seems to be at a height of 15–50 km.

SINCE 1916, when one of us1reported that this reaction is very sensitive to light and that the dark reaction has a high temperature coefficient, a large amount of work has been carried out on this chemical change by several chemists2.

IN previous communications1 it was reported that the value of farmyard manure (cow dung) is due not only to its nitrogen content but also to its power to fix nitrogen of the air. Our field experiments show that when wet, fresh collected cow dung is added to soil at the rate of 25 tons per acre, 33 lb. of nitrogen present in the cow dung is added and 135 lb. of nitrogen per acre is actually fixed from air, while in the dark the fixation is 65 lb. per acre.

IN recent publications1, it has been shown that the absorption of light by a mixture of two reacting substances is greater than the absorptions of the reacting substances considered separately. Thus the absorption in the visible and ultra-violet regions by a mixture of N/400 aqueous iodine and 2N potassium oxalate is much greater than the light absorption by N/800 aqueous iodine and N potassium oxalate taken separately. This relation has been observed with numerous chemical reactions taking place in aqueous solutions.

THE ordinary denitrification taking place in the absence of oxygen and in presence of an easily oxidisable organic substance and a nitrate effected by many micro-organisms, is well known. There is another variety of nitrogen loss, which takes place in presence of oxygen, but has not yet been satisfactorily explained. It will be evident that this loss of nitrogen from the soil, which may amount to double the quantity of nitrogen taken up by plants, is due to an oxidation process followed by a photochemical and catalytic decomposition.

WHEN freshly collected cow-dung (containing 0.368 per cent nitrogen and 7.5 per cent carbon) is mixed with soil and exposed to sunlight daily for six hours in dishes, nitrogen fixation is observed. Thus the nitrogen content of a mixture containing 500 gm. soil and 100 gm. cow-dung rose from 0.0905 per cent on July 27 to 0.14 per cent on November 4, 1936.