1,781 research outputs found
Laptop Searches at the United States Borders and the Border Search Exception to the Fourth Amendment
The border search exception to the Fourth Amendment allows broad discretion for United States customs officers to search the belongings of incoming and outgoing international passengers and their luggage. Although courts typically weigh the national security interest in the search against the privacy invasion caused by a potentially intrusive search,, most border searches are constitutional if they are either routine or preceded by reasonable suspicion. Border searches of passengers\u27 laptop computers, including hardware, software, and any external storage devices, pose a constitutional issue. This Note argues that laptop searches not preceded by reasonable suspicion are intrusive because the search may invade upon personal, proprietary, or confidential information that a passenger expects to be kept private, even at the border. Furthermore, this Note argues that even those laptop searches that are preceded by reasonable suspicion may not be constitutional, because border searches must be limited in scope to that which may either confirm or disprove the preceding suspicion
Friction pull plug welding: top hat plug design
Friction Pull Plug Welding is a solid state repair process for defects up to one inch in length, only requiring single sided tooling, or outside skin line (OSL), for preferred usage on flight hardware. The most prevalent defect associated with Friction Pull Plug Welding (FPPW) was a top side or inside skin line (ISL) lack of bonding. Bonding was not achieved at this location due to the reduction in both frictional heat and welding pressure between the plug and plate at the end of the weld. Thus, in order to eliminate the weld defects and increase the plug strength at the plug `top` a small `hat` section is added to the pull plug for added frictional heating and pressure
Friction pull plug welding: chamfered heat sink pull plug design
The average strength of a pull plug weld is increased and weak bonding eliminated by providing a dual included angle at the top one third of the pull plug. Plugs using the included angle of the present invention had consistent high strength, no weak bonds and were substantially defect free. The dual angle of the pull plug body increases the heat and pressure of the weld in the region of the top one third of the plug. This allows the plug to form a tight high quality solid state bond. The dual angle was found to be successful in elimination of defects on both small and large plugs
Friction pull plug welding: chamfered heat sink pull plug design
Friction Pull Plug Welding (FPPW) is a solid state repair process for defects up to one inch in length, only requiring single sided tooling (OSL) for usage on flight hardware. Experimental data has shown that the mass of plug heat sink remaining above the top of the plate surface after a weld is completed (the plug heat sink) affects the bonding at the plug top. A minimized heat sink ensures complete bonding of the plug to the plate at the plug top. However, with a minimal heat sink three major problems can arise, the entire plug could be pulled through the plate hole, the central portion of the plug could be separated along grain boundaries, or the plug top hat can be separated from the body. The Chamfered Heat Sink Pull Plug Design allows for complete bonding along the ISL interface through an outside diameter minimal mass heat sink, while maintaining enough central mass in the plug to prevent plug pull through, central separation, and plug top hat separation
A point mutation in the splice donor site of intron 7 in the as2-casein encoding gene of the Mediterranean River buffalo results in an allele-specific exon skipping
The CSN1S2 cDNA of 10 unrelated Mediterranean
River Buffaloes reared in Southern Italy was amplified
by RT-PCR, while the region from the 6th to the 8th exon
of the CSN1S2 gene was amplified from genomic template.
cDNA sequence comparisons showed
that five individuals had a normal transcript only (named CSN1S2A), one had a
deleted transcript only (named CSN1S2B), because of the splicing out of the 27-bp of
exon 7, and the remaining four had a heterozygous pattern.
Analysis of the genomic sequences revealed a FM865620:
g.773G>C transversion that caused inactivation of the intron 7
splice donor site and, consequently, the allele-specific exon skipping
characteristic of the CSN1S2B allele. The g.773G>C
mutation creates a new AluI restriction site enabling a PCR–
RFLP rapid genotyping assay. The cDNA sequences showed three additional
exonic mutations forming an extended haplotype with
the g.773G>C polymorphism: FM865618: c.459C>T,
c.484A>T and c.568A>G homozygous and heterozygous
respectively in the CSN1S2BB and CSN1S2AB buffaloes. The
first is silent, while the remaining two are non-conservative
(p.Ile162Phe and p.Thp200Ala respectively). The genotype frequencies (37 CSN1S2A/A,
15 CSN1S2A/B and one CSN1S2B/B) are in agreement with
Hardy–Weinberg equilibrium, with the
frequency of the deleted B allele being 0.16.
The predicted bubaline as2B protein
is 198 aa long instead of 207 aa and would also be characterized
by the presence of Phe at position 147 and Ala at 185
Interpreting Force Concept Inventory Scores: NormalizedGain and SAT Scores
Preinstruction SAT scores and normalized gains (G) on the force concept inventory (FCI) were examined for individual students in interactive engagement (IE) courses in introductory mechanics at one high school (N=335) and one university (N=292), and strong, positive correlations were found for both populations (r=0.57 and r=0.46, respectively). These correlations are likely due to the importance of cognitive skills and abstract reasoning in learning physics. The larger correlation coefficient for the high school population may be a result of the much shorter time interval between taking the SAT and studying mechanics, because the SAT may provide a more current measure of abilities when high school students begin the study of mechanics than it does for college students, who begin mechanics years after the test is taken. In prior research a strong correlation between FCI G and scores on Lawson\u27s Classroom Test of Scientific Reasoning for students from the same two schools was observed. Our results suggest that, when interpreting class average normalized FCI gains and comparing different classes, it is important to take into account the variation of students\u27 cognitive skills, as measured either by the SAT or by Lawson\u27s test. While Lawson\u27s test is not commonly given to students in most introductory mechanics courses, SAT scores provide a readily available alternative means of taking account of students\u27 reasoning abilities. Knowing the students\u27 cognitive level before instruction also allows one to alter instruction or to use an intervention designed to improve students\u27 cognitive level
Friction pull plug welding: dual chamfered plate hole
Friction Pull Plug Welding (FPPW) is a solid state repair process for defects up to one inch in length, only requiring single sided tooling (OSL) for usage on flight hardware. Early attempts with FPPW followed the matching plug/plate geometry precedence of the successful Friction Push Plug Welding program, however no defect free welds were achieved due to substantial plug necking and plug rotational stalling. The dual chamfered hole has eliminated plug rotational stalling, both upon initial plug/plate contact and during welding. Also, the necking of the heated plug metal under a tensile heating/forging load has been eliminated through the usage of the dual chamfered plate hole
The impact of stapling technique and surgeon specialism on anastomotic failure after right-sided colorectal resection. An international multi-centre, prospective audit
There is little evidence to support choice of technique and configuration for stapled anastomoses after right hemicolectomy and ileocaecal resection. This study aimed to determine the relationship between stapling technique and anastomotic failure
The influence of commercially-available carbohydrate and carbohydrate-protein supplements on endurance running performance in recreational athletes during a field trial
Background
It is recommended that endurance athletes consume carbohydrate (CHO) supplements, providing 6-8% CHO concentration, during exercise \u3e 60 minutes to improve athletic performance. Recently research has compared carbohydrate-protein (CHO-P) supplementation to the traditionally used CHO supplementation during endurance exercise, following these supplementation recommendations, in controlled settings, but not under simulated applied conditions such as a field trial. Therefore, the purpose of the present investigation was to test CHO and CHO-P supplementation under applied conditions such that commercially-available isocaloric (CHO-P & double-carbohydrate [CHO-CHO]) and isocarbohydrate (CHO-P & CHO) supplements were compared to a placebo (PLA), within an outdoor running field trial \u3e 60 minutes in order to asses their influence on endurance performance. Methods
Twelve male recreational runners completed four, 19.2 km runs, where they were instructed to run at a pace similar to race pace including a final sprint to the finish, which in this case was the final two laps of the course (1.92 km). Supplementation was provided before the start and in 4 km increments. Performance was measured by time to complete the 19.2 km run and last 1.92 km sprint. Results
Analyses found no difference between supplements in time to complete the 19.2 km run (PLA = 88.6 ± 11.6 min, CHO = 89.1 ± 11.3 min, CHO-P = 89.1 ± 11.8 min, CHO-CHO = 89.6 ± 11.9 min) or last 1.92 km sprint to the finish (PLA = 8.3 ± 1.2 min, CHO = 8.2 ± 1.2 min, CHO-P = 8.2 ± 1.2 min, CHO-CHO = 8.4 ± 1.5 min). Conclusions
When following recommendation for supplementation within a field trial, commercially available CHO and CHO-P supplements do not appear to enhance performance in male recreational runners
Crack of a helicopter main rotor actuator attachment: failure analysis and lessons learned
A Light Utility Helicopter (LUH), in the course of a training flight, leaving the ground during thetaxi to take off, went into an uncontrolled rolling to the right; consequently the helicopter gradually laid downon the right side. The impact with the runway destroyed the rotating blades up to the hubs rotor. The accidentinvestigation focused on main rotor oscillatory plate servo actuators . These components, directly linked to thecloche movements, regulate main rotor blades plane tilt and pitch. Following the preliminary examination, onlyfront servo actuator attachment was found to be broken in two parts. In detail, the present paper deals with thefracture analysis results. The servo actuator attachment material is a 2014 Aluminum alloy extrudate, undergoneto T651 heat treatment. Fracture surfaces were examined by optical and electronic microscopy in order todetermine the main morphological features and consequently to trace the origin of failure mechanism andcauses. The accordance with the specification requirements about alloy composition was verified by quantitativeelementary analysis through inductive coupled plasma spectroscopy (ICP); furthermore, semi-quantitativeelementary analysis was locally verified by Energy dispersion spectroscopy X ray (EDS_RX). Finally, thehydrogen content of the material was evaluated by the total hydrogen analysis. Microstructural andtechnological alloy characteristics were verified as well by using metallographic microscopy and hardness testingof the material.Macroscopic fracture surfaces evidences were characterized by the lack of any significant plastic deformationsand by the presence of symmetry compared to the servo actuator axis. Microscopic fracture features of both theinvestigated surfaces were not coherent to the hypothesis of an impact of the main rotor to the soil. Furtherachieved evidences, such as grain boundary fracture propagation, the presence of corrosion products, were all inaccordance with a Stress Corrosion Cracking (SCC) progressive fracture mechanism.Finite Element Analysis (FEA) located the highest tensile stress value, when the servo actuator is in its nominalworking condition, at the same points where the corrosion products were more concentrated (i.e. in the part ofthe fracture exposed to oxidative air effect for the longest time). The good agreement between FEA andmorphological evidences allowed to determine the progressive fracture origin area, though it was not possible toindividuate the crack initiation point. In fact, in correspondence to the initiation area of both the fracturesurfaces, shining and flat morphology was found;. then there were evidence of plastic deformations, due to thedetachment of a servo actuator part.The ICP analysis and hardness testing results were in accordance with the material specification requirements.However, the hydrogen content was one order of magnitude greater than the required value and many andunexpected globular formations were observed on the fracture surface. Part of these were dendritic formations,while the others looked smooth and shining. Further, FESEM boundary grain observation gave evidences of ahigh presence of precipitates on the investigated surfaces. Hence, observed microstructural characteristics,boundary grain precipitates and globular formations allowed to hypothesize possible overheating/eutecticmelting phenomena, occurred during manufacturing processes.As widely reported in literature, the AA 2014 alloy is one of the aluminum-copper-magnesium-silicon type,employing copper aluminide (CuAl2 ) as the primary precipitation-hardening agent. The need for a maximumCu phase dispersion in solid solution requires a heat treatment range with an upper limit (507°C) that is near tothe melting of the eutectics (510°C). Moreover, since the 1960s, AA2014 has been defined as sensitive to SCC.This condition is mainly related to the presence of coarse-grained and aligned CuAl2 precipitates. Thisarrangement is due to an overheating (more than 507°C) or to a cooling process carried out too slowly.Microstructural analysis was carried out on three items: 1) a large portion of the broken actuator attachment; 2)on a servoactuator coming from the same production batch; 3) on a servo actuator coming from a differentproduction batch.The microstructure from the broken actuator attachment showed a great amount of precipitates (secondphases) lengthwise aligned to the boundary grain, pores, and also cavities and dendritic globular formations.Analysis results, morphology evidences and reference images available on scientific literature were found to bein excellent agreement and validated the embrittlement and subsequent SCC mechanism hypotesis(intergranular failure propagation).In conclusion, flight accident causes are attributable to main rotor actuator attachment failure.Failure mechanism is classifiable as SCC supported by microstructural anomalies of the material. Theinvestigation of the manufacturing process highlighted how one of the servo actuator batches was not properlyproduced due to poor control and accuracy of heat treatment temperature and/or cooling time. This led tohydrogen embrittlement and to a microstructural problem (globular formations and boundary grainprecipitates). The combination of those phenomena caused an increase of the SCC sensitivity and were thebasic progressive failure driving forces.Nevertheless, as above mentioned, alloy composition was found compliant with the material specificationrequirements and this just because none of the scheduled quality control tests is able to determine the peculiarmicrostructural anomalies reported
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