Phone Case Research Articles

Soil Biodegradation of Unidirectional Polyhydroxybutyrate-Co-Valerate (PHBV) Biocomposites Toughened With Polybutylene-Adipate-Co-Terephthalate (PBAT) and Epoxidized Natural Rubber (ENR)

The detrimental impact of discarded plastics on the environment has become of increasing concern and this has led to the development of environmentally friendly ‘green’ polymers. PHBV is one such green polymer that offers biodegradability and renewability, however its mechanical performance is quite limited. This can be improved by reinforcement with natural fibres to form green composites, which offer better mechanical properties while retaining biodegradability. There are, however, few studies examining the biodegradation of toughened PHBV composites. In this work, the biodegradation properties of PHBV/30 vol.% unidirectional flax composites both untoughened and toughened with PBAT and ENR, were studied. Composites were prepared by compression moulding PHBV powder interleaved with unidirectional flax fabric. The toughening agents were cryoground and mixed with the PHBV powder prior to moulding. Biodegradation was conducted in a natural outdoor soil environment and biodegradability was evaluated through weight loss analysis, optical microscopy and electron microscopy. The biodegradability of neat PHBV was minimal but was increased markedly by addition of flax fibres. The toughened composites showed a faster degradation rate than untoughened PHBV/flax, with PHBV/ENR/flax composites having the highest rate likely due to a specific strain of bacteria found worldwide in soil that attacks natural rubber. The biodegradation properties of the composites were superior to those of conventional plastics used in applications such as computer and mobile phone casings, which indicates potential suitability of this class of materials for these applications.

Warpage analysis and optimization of thin-walled injection molding parts based on numerical simulation and orthogonal experiment

With the warpage of a mobile phone case as the index, a numerical model for injection molding was established by CAE software. The process parameters of 5 factors including injection time, mold temperature, melt temperature, packing time and packing pressure were analyzed by orthogonal experiment, the effect of injection process parameters on warpage was studied and the minimum combination of process parameters was obtained. The simulation results show that the warpage was reduced by 6.98% after optimization, and higher quality plastic parts were obtained, which has important guiding significance for the production practice of thin-wall parts.

Wideband Beam-Switchable 28 GHz Quasi-Yagi Array for Mobile Devices

The goal of this paper is to propose a new antenna array architecture that aims to solve the most known limitations of phased antenna arrays, resulting a good candidate for next 5G mobile handsets. The architecture consists of five quasi-Yagi antennas printed on the short edge of a Roger RO3003 substrate, pointing in different directions, and a switch to feed each antenna and steer the beam. Simulations prove that the antenna array can cover the angle of over 180° with high gain over the frequency range from 26 to 40 GHz. Alternative designs to make the structure more compact further demonstrate the validity of the concept. The optimized corner array of four elements is fabricated and passive and active measurements are performed with the Microwave Vision Group (MVG) Starlab 50 GHz. The results of the passive measurements are in accordance with the simulations and show that the proposed quasi-Yagi antenna array has large coverage over the whole bandwidth and peak gain of 8 dBi at 28 and 38 GHz. The active measurements of the array connected to the front end module (FEM) and integrated in the phone case further confirm the radiation properties of the switchable antenna array at 28 GHz in a quasi-real scenario.

Facile and cost-effective strategy for fabrication of polyamide 6 wrapped multi-walled carbon nanotube via anionic melt polymerization of ε-caprolactam

There is a growing demand for the development of a melt process-based nanocomposite manufacturing process capable of minimizing the incorporation of expensive carbon nanotubes (CNTs) by inducing a uniform dispersion of multi-walled CNTs (MWNTs). In this study, we proposed a nanocomposite manufacturing process that includes both physical particle mixing using high-speed rotation and anionic polymerization of ε-caprolactam (CL) to induce a uniform dispersion of MWNTs. MWNTs were uniformly dispersed by powder mixing and then wrapped with polyamide 6 polymers by in-situ polymerization of CL. The synergistic effect of the two sub-processes resulted in an enhanced dispersion of MWNTs and prevented aggregation of the MWNTs. The composites fabricated by the proposed process exhibited electrical conductivities of 4.49 × 10−5 S/m and 1.45 × 10 S/m at 1 wt% and 3 wt% MWNTs, respectively, indicating that by applying the proposed process it is possible to incorporate a smaller amount of MWNT to achieve electrical conductivities applicable for electrostatic discharge (ESD) (>1 X 10−5 S/m) and electromagnetic interference shielding effectiveness (EMI SE) (>10 S/m) applications. An ESD chip tray and EMI SE mobile phone case were fabricated using the prepared composite, and it was verified that the ESD and EMI SE performances can be realized.

Reversible polymer could lead to repeat recycling

When recycling plastics, contamination and chemistry conspire to degrade the quality of each recycled generation. In a perfect world, a polymer could be converted to its monomer building blocks, then made into new plastic over and over. Researchers have been working to develop such chemistry, and Brett Helms and colleagues from Lawrence Berkeley National Laboratory now demonstrate a new approach (Nat. Chem. 2019, DOI: 10.1038/s41557-019-0249-2). Their polymer is based on a network of reversible diketoenamine bonds formed in a ball mill using click chemistry reactions between triketones and polyamines like tris(2-aminoethyl)amine. Helms says that the resulting plastics, which the group refers to as poly(diketoenamine)s (PDKs), have mechanical properties on par with thermoplastic polyurethanes, which are used in products such as mobile phone cases and shoe soles. PDKs are in a class of plastics called vitrimers that are characterized by a cross-linked polymer network. The materials, which behave like glass,...

Conversion of Hand Phone Case Waste into Liquid Fuels in a Microwave Reactor

Hand phone case waste as one of the highest e-waste contributors can cause severe problems to human and environment. It should be processed or converted to obtain more useful products. The purpose of this study is to investigate liquid fuels production from hand phone case waste through pyrolysis and distillation processes under microwave irradiation. In each experiment, about 150 g of hand phone case with a size of 1-2 cm2 were pyrolyzed at 450°C for 1.5 hours. In order to improve pyrolysis process, the sample was mixed with carbon materials as absorber at a weight ratio of 2:1. The produced liquid fuel was then distilled to obtain gasoline, kerosene, and diesel fractions. The result showed that the average yield of liquid fuel from pyrolysis of hand phone case waste was 57 % by mass. After liquid fuel distillation process, the average yields of each fuels fraction were 21.2 vol.% gasoline, 25.2 vol.% kerosene, 26.1 vol.% diesel, and 27.5 vol.% heavy fuel and residue.

A Feasibility Study of Mobile Phone Casings Remanufacturing

Remanufacturing is a process when used product or core is brought to ‘like-new’ condition, might be with an upgrade in performance. This process complies with technical specifications, including engineering, quality, and testing standards. It yields a fully warranted product. The purpose of this study was to conduct initial research on the feasibility of remanufacturing primarily on the mobile phone casings to provide information and consideration for a firm that would do remanufacturing of mobile phones. A series of material characterization on several mobile phone casings manufactured by major international brands revealed that remanufacturing is not a viable route to attempt. The evaluation shows that remanufacturing used casing mobile phone require several stages of repair, which cause an increase in the cost that can, in turn, affect the prices.

Designing and Measuring the Hot-Embossing Machine with Hybrid Positioning Functions

The demands of the ability of industrial automotive production are rising. The precision positioning is the most important among the manufacturing and measuring. Molds might result in making equipment deviations via poor accuracies on mass production because of the poor design and front processing. It influences the qualities of products, or damages the mold themselves. Based on the Hot-Embossing process, the study designed a set including the Hot-Embossing machine with platform for positioning system holding the mold. The positioning and adjusting function, with X, Y, C axis, separates the Hot-Embossing machine from the traditional one. Taken smart phone case as the experimental designed concept and verified the pressing molds with the final thickness with the before and after correction for lengths, wide, and the error values of horizontal symmetry to investigate the accuracies of positioning capability. Then, verifying the Hot-Embossing machine from reconstruction of the product.

Feasibility of Real-Time Mobile Phone Case Notification by Village Malaria Workers in Rural Myanmar: A Mixed Methods Study

Malaria burden has markedly decreased in Myanmar and is on course for elimination by 2030. Interrupting of local transmission is essential, and timely notification within 24 hours of disease occurrence by frontline village malaria workers (VMWs) is a crucial initial component of timely follow-up by response teams. Here we studied the feasibility of real-time case notification using mobile phones among VMWs in the remote Banmauk Township, Sagaing Region, Myanmar. A structured quantitative and qualitative questionnaire was used for data collection after implementing the intervention for six months between May and October 2018. Ten VMWs from the National Malaria Control Programme (NMCP) in ten scattered villages from the township were randomly recruited and given one day of on-site training on reporting methods and how to use their own mobile phone. VMWs received 5,000MMK (approximately 3USD) per month remuneration. The baseline demographics of VMWs were not significantly different. Twenty-four out of 25 (96%) malaria patients were notified within 24 hours by the ten VMWs during the study period. All submitted information were said to be complete and correct. VMWs suggested the system as simple and acceptable despite some challenges. In the qualitative study, almost all VMWs were satisfied with the system and willing to use it in the future. This mobile phone reporting system is more efficient and easier to use than other more complicated online mobile applications. However, only a few indicators can be submitted using this approach and the system cannot be used in areas without network coverage.

Customizations, collections and corporations: Mass production and self-expression

Collecting and customizing highlight the interrelation of fan works and fan practices with corporate counterparts. Neither can be neatly isolated from the other. Corporations appropriate multiple aspects of material fan practices to encourage consumption, framing choice as customization and mass-produced merchandise as rare collectibles. Meanwhile, fans practice mini-mass-production, making multiple versions of fan works for sale or trade. Moving beyond an artificial value-laden binary opposition between fan customizations and collections or corporate versions, it would be more productive to focus on how both satisfy human urges for control and self-expression via one’s own creations and possessions. The personal investment of time and effort offers an expression and extension of self. Fans use toys, shoes, phone cases and other merchandise as raw materials for their creations. What varies is the amount of time, energy, skill or material resources individuals are able or willing to invest. Thus multiple supposedly distinct fan practices interconnect: customizers modifying or creating beloved fan objects; customers selecting from predetermined options to make their own variations on shoes, phone cases and other merchandise; shoppers seeking slight variations in seemingly identical items or collectors assembling work created by corporations or other customizers to display their own creations. Even if corporations monetize some forms of self-expression, collecting or customizing such items should be recognized as a form of fan activity instead of dismissed as mere consumerism.

Application of a Compact Electromagnetic Bandgap Array in a Phone Case for Suppression of Mobile Phone Radiation Exposure

In this paper, a mobile phone case incorporating electromagnetic bandgap (EBG) material is studied to intercept electromagnetic (EM) waves from the phone and reduce the specific absorption rate (SAR). A loop antenna for the personal communications service 1900-MHz band is considered. In addition, three different mobile phone cases associating EBG structures with optimized positions are used to improve SAR reduction. Furthermore, antenna performance with an EBG structure is investigated with a full-body EM simulation program, SEMCAD X, and an individual performance analysis of each EBG structure was carried out by using Ansoft HFSS. A human head phantom to replicate the specific anthropomorphic mannequin model was used for measurements. From simulation and measurement, it is found that placing an EBG structure in a phone case can improve antenna gain and reduce SAR. Moreover, a maximum gain increment of 19% and an SAR reduction of 24% were found. This paper reveals the future applications of EBG structures for SAR reduction in mobile phones.

Multicomponent Intervention for Patients Admitted to an Emergency Unit for Suicide Attempt: An Exploratory Study.

Suicide is a major cause of premature deaths worldwide and belongs to the top priority public health issues. While suicide attempt is the most important risk factor for completed suicide, intervention for suicide attempters (SA) have produced mixed results. Since an important proportion of SA request medical care, emergency units (EU) are an opportune setting to implement such interventions. This exploratory study evaluated the feasibility and acceptability of a multicomponent intervention for SA admitted to an EU. The intervention consisted of coordination by a case manager of a joint crisis plan (JCP), an early meeting with relatives and the existing care network, as well as phone contacts during 3 months after suicide attempt. Among 107 SA admitted to the emergency unit during the study period, 51 could not be included for logistical reason, 22 were excluded, and intervention was offered to 34. Of these, 15 refused the intervention, which was thus piloted with 19 SA. First-time attempters most frequently declined the intervention. Feasibility and acceptability of phone contacts and case manager were good, while JCPs and meetings were difficult to implement and perceived as less acceptable. Refusal pattern questions the global acceptability and is discussed: JCPs and meetings will have to be modified in order to improve their feasibility and acceptability, especially among first-time attempters.

The Relationship between Art Preference and Attitudes toward Art-Infused Product: With a Focus on the Moderating Role of the Market Exposure of Artwork

Background : As the quality of life improves, people’s interest in art increases and their emotional satisfaction becomes important. Companies often apply artwork to their product packages with the aim of satisfying people’s emotions and enhancing their brand value. However, they tend to apply well-known artwork without considering the characteristics of their target consumers. Therefore, this study aims to understand whether people’s preferences for artwork influence their attitudes toward art-infused products. Methods : We examined whether people’s attitudes toward art-infused products are influenced by their preferences for and the market exposure of artwork. We conducted a study by recruiting 380 undergraduate students in Korea. In the study, we used 6 artworks carefully selected from textbooks and 6 art-infused hypothetical mobile phone cases accordingly. Results : Our study revealed two findings. First, people’s attitudes toward art-infused products increased as their preferences for the artwork increased (hypothesis 1). Second, the effect of people’s art preferences on their attitudes toward art-infused products was greater when the artwork was less exposed to the market than when it was highly exposed (hypothesis 2). Conclusions : The results of this study show that when an artwork is selected for product packaging, people’s preferences for the artwork and its market exposure should be considered, suggesting that selecting a well-known artwork is not always the best option. In sum, this study contributes to the academic discussion on mere exposure effect and art marketing, and it provides insights for designers who aim to apply artwork to differentiate their products.

Compact 3D‐loop antenna with bandwidth enhancement for WWAN/LTE mobile‐phones applications

This study presents a 3D-loop antenna for wireless-wide-area network/long-term evolution (WWAN/LTE) operation. The size is compact and low profile and so the antenna is suitable for mobile-phone applications. The loop itself generates four resonant modes. Three parasitic elements are placed closely to the 3D-meandered loop radiator to generate three more resonant modes. These resonant modes form a dual-band, a lower band and a wide upper band, to cover many current mobile standards. The antenna performance, in terms of impedance bandwidth, efficiency, peak gain and radiation pattern, is studied using simulation. The antenna is also fabricated and the prototyped antenna is measured using the Satimo StarLab system. The measured results of the antenna inside a phone case on a phantom hand and phantom head in the data mode and talk mode, respectively, (defined by the Cellular Telephone Industries Association) are also presented. The measured efficiencies are subsequently used to estimate the total-radiated powers (TRPs). Results show that the TRPs in all covered standards meet the strictest over-the-air testing requirement of Vodafone.

Analysis of Material Based GHG Emissions and Costs for Assembly Products Using Asian Lifecycle Inventory Databases: Cell Phone Case Study

Global warming requires to reduce greenhouse gas (GHG) emissions in global supply chains. In order to reduce the GHG emissions in the supply chains economically, it needs to estimate the GHG emissions and costs for procuring parts for materials by life cycle assessment (LCA). This study applies the material-based estimation method for the GHG emissions and costs by Yoshizaki et al. (2016) to a cell phone, constructs a bill of materials (BOM) when the materials for parts are produced in Asian countries, and compares the material-based GHG emissions and costs in the cases of cell phone and cleaner.

A Study on the Characteristics of Consumer Usage and Analysis of Applicable Fashion Fields of Mobile Messenger’s Emoticon - Focused on Kakao Friends -

The purpose of this study is offering the development of fashion goods and base data of marketing strategies by analyzing ‘Kakao Friends’, the national mobile character. "Kakao Friends" was selected and took it as the subject of analysis in this study. The questionnaires of this study were developed by referring to proceeding research and reference literature. For collecting data, 120 questionnaires were circulated to students, workers and house wives separately. And among the questionnaires, 300 questionnaires were used in the study. For the statistical analysis, SPSS 21 was used and descriptive analysis, multiple component analysis, factor analysis, frequency analysis, paired samples T-test and F-test (ANOVA) were performed. The result was deduced that the mainly used emoticon was different by genders. The most used emoticons of men were ‘Apeach’and ‘Jay-G’ and women’s result were ‘Tube’and ‘Apeach". ‘Frodo’was less used emoticon of men and ‘Jay-G’was less selected by women. When examining the differences of using ratio depending on the gender and status, it was revealed that the difference between genders was existed. In sum, the result was found that usually men use emoticon were less than women. The result of the difference between status, it was found that the most using ratio was not existed in all status. When investigating the most suitable item that application of emoticon, cell phone cases and accessories were selected. Also fashion item’s visibility of emoticon was influenced on the consumer"s preference. The result of consumer preference was that they preferred fashion items which had small visibility of emoticon rather than had huge visibility. So, when grafting emoticon on to the fashion goods, it is better to use in the small part of items. According to the expanded emoticon market, it need to develop continuous story telling to further up as Korea cultural industry so as to beside off the promotion.

Design, Fabrication, and Test of a High-Strength Uniform Pressure Actuator

Electromagnetic forming using a uniform pressure actuator (UPA) has advantages for forming many components, such as car door pockets, cell phone cases, and fuel cell panels. However, how to generate magnetic pressures on sheet metal with enough high uniformity and high strength is a challenging issue. To improve the strength of the coil, current UPAs were machined out of a solid block of high-strength copper alloy, but its strength was still limited. In this paper, the design idea of pulsed high-field magnets has been applied to improve the coil's strength in a better way. A UPA with high strength has been designed, fabricated, and tested. A series of simulation analysis and experiments have been done; it has been found that the uniformity of the magnetic force on sheet would be increased with the decrease of the wire spacing and the wire width. In addition, the experiment results show that sheets with a thickness of 1 mm can be effectively deformed with a maximum of 14.6 mm under 2.88-kJ energy and the deformation of the sheet is in high uniformity along the direction perpendicular to the wire.

Cosmetic obsolescence? User perceptions of new and artificially aged materials

This paper presents the findings of a user study which explored tactile and aesthetic responses to new and artificially aged mobile phone cases made from bamboo, walnut, cork, leather, brushed titanium, plastic and rubber. The paper outlines test methods for accelerated ageing of the external enclosures of consumer electronics based on the types of wear experienced in use, and the use of semantic differential scales (SDS) to probe user attitudes to these materials. The results indicate that preferences for the materials tested were extremely subjective, and even a single participant can have conflicting requirements for the characteristics of the materials (for example, sleek and shiny yet easy to grip). Whilst in general participants preferred the new materials and saw the ageing process as negative, there were examples where the aged samples either scored more highly due to durability (titanium) or received positive comments about the aesthetic changes caused by severe ageing (bamboo and leather). This study captured the participants' immediate, visceral response to the materials, which may be very different to their feelings towards materials and objects that they have owned and interacted with for a period of time.

ECG Authentication for Mobile Devices

Traditional mobile login methods, like numerical or graphical passwords, are vulnerable to passive attacks. It is common for intruders to gain access to personal information of their victims by watching them enter their passwords into their mobile screens from a close proximity. With this in mind, a mobile biometric authentication algorithm based on electrocardiogram (ECG) is proposed. With this algorithm, the user will only need to touch two ECG electrodes (lead I) of the mobile device to gain access. The algorithm was tested with a cell phone case heart monitor in a controlled laboratory experiment at different times and conditions with ten subjects and also with 73 records obtained from the Physionet database. The obtained results reveal that our algorithm has 1.41% false acceptance rate and 81.82% true acceptance rate with 4 s of signal acquisition. To the best of our knowledge, this is the first approach on mobile authentication that uses ECG biometric signals and it shows a promising future for this technology. Nonetheless, further improvements are still needed to optimize accuracy while maintaining a short acquisition time for authentication.

Understanding mobile phone case evaluative criteria of US Millennials

ABSTRACTMillennials are the crucial market segment in mobile marketing and retail industry due to their heavy usage and higher dependency on mobile devices. The purpose of this study was to investigate the influence of personal traits of college students with different majors on mobile phone case evaluative criteria. Five hundred-and-nine college students were recruited as participants in various disciplines/majors using a non-representative, convenience sampling technique. Findings showed that fashion majors exhibited higher levels of personal traits variables that were themed around fashion, such as self-monitoring tendency, fashion involvement, and proclivity to experiment with appearance, compared to non-fashion majors. Fashion majors were found to be significantly more dependent on their mobile devices, compared to non-fashion students. These findings provide valuable information to help the mobile phone industry understand young consumers’ evaluation criteria and develop their product and marketing strategy accordingly.